1
|
Hasegawa K, Muto M, Hamada M, Yamada Y, Tokii T, Koikawa M. Syntheses, Structures, and Electrochemical Properties of Metallacyclic Oxidovanadium(V) Complexes with Asymmetric Multidentate Linking Ligands. Molecules 2024; 29:1700. [PMID: 38675520 PMCID: PMC11052122 DOI: 10.3390/molecules29081700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 03/29/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Trinuclear metallacyclic oxidovanadium(V) complexes, [{VO(L3+2R)}3] (1-3) with asymmetric multidentate linking ligands (H3L3+2R: R = H, Me, Br), were synthesized. The molecular structure of 1 is characterized as a tripod structure, with each V(V) ion coordinated by ONO-atoms from a tridentate Schiff base site and ON-atoms from a bidentate benzoxazole site of two respective H3L3+2H ligands. The intramolecular V⋯V distances range from 8.0683 to 8.1791 Å. Complex 4 is a mononuclear dioxidovanadium(V) complex, (Et3NH)[VO2(HL3+2H)]. Cyclic voltammograms of 1-3 in DMF revealed redox couples attributed to three single-electron transfer processes.
Collapse
Affiliation(s)
| | | | | | | | | | - Masayuki Koikawa
- Department of Chemistry and Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo 1, Saga 840-8502, Japan (Y.Y.); (T.T.)
| |
Collapse
|
2
|
Dumitraș D, Gal E, Silvestru C, Pop A. Metal Complexes Containing Homoleptic Diorganoselenium(II) Ligands: Synthesis, Characterization and Investigation of Optical Properties. Molecules 2024; 29:792. [PMID: 38398544 PMCID: PMC10892405 DOI: 10.3390/molecules29040792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
[(Z)-2'-{2-C6H5-(4H)-oxazol-5-one}CHC6H4]2Se (5, L1) and [(Z)-4'-{2-C6H5-(4H)-oxazol-5-one}CHC6H4]2Se (6, L2) were prepared, structurally characterized and used as ligands to obtain new metal complexes of types [MX(Ln)] [L1: M = Ag, X = OTf (7); M = Au, X = Cl (13); L2: M = Ag, X = OTf (8); M = Au, X = Cl (14)], [(MX)2(Ln)] [M = Ag, X = OTf, L1 (9); L2 (10)], [ZnCl2(Ln)] [L1 (15); L2 (16)] and [Ag(Ln)][PF6] [L1 (11); L2 (12)]. The silver complexes 7 and 8 were ionic species (1:1 electrolytes) in a MeCN solution, while in the solid state, the triflate fragments were bonded to the silver cations. Similarly, the 2:1 complexes 9 and 10 were found to behave as 1:2 electrolytes in a MeCN solution, but single-crystal X-ray diffraction demonstrated that compound 9 showed the formation of a dimer in the solid state: a tetranuclear [Ag(OTf)]4 built through bridging triflate ligands was coordinated by two bridging organoselenium ligands through the nitrogen from the oxazolone ring and the selenium atoms in a 1κN:2κSe fashion. Supramolecular architectures supported by intermolecular C-H∙∙∙π, C-H∙∙∙O, Cl∙∙∙H and F∙∙∙H interactions were observed in compounds 4, 5 and 9. The compounds exhibited similar photophysical properties, with a bathochromic shift in the UV-Vis spectra caused by the position of the oxazolone ring on the phenyl ring attached to the selenium atoms.
Collapse
Affiliation(s)
- Darius Dumitraș
- Supramolecular Organic and Organometallic Chemistry Centre, Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Str. Arany Janos 11, RO-400028 Cluj-Napoca, Romania; (D.D.); (C.S.)
| | - Emese Gal
- Research Center on Fundamental and Applied Heterochemistry, Faculty of Chemistry and Chemical Engineering, Babeș-Bolyai University, Str. Arany Janos 11, RO-400028 Cluj-Napoca, Romania;
| | - Cristian Silvestru
- Supramolecular Organic and Organometallic Chemistry Centre, Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Str. Arany Janos 11, RO-400028 Cluj-Napoca, Romania; (D.D.); (C.S.)
| | - Alexandra Pop
- Supramolecular Organic and Organometallic Chemistry Centre, Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Str. Arany Janos 11, RO-400028 Cluj-Napoca, Romania; (D.D.); (C.S.)
| |
Collapse
|
3
|
Bryndal I, Stolarczyk M, Mikołajczyk A, Krupińska M, Pyra A, Mączyński M, Matera-Witkiewicz A. Pyrimidine Schiff Bases: Synthesis, Structural Characterization and Recent Studies on Biological Activities. Int J Mol Sci 2024; 25:2076. [PMID: 38396753 PMCID: PMC10889512 DOI: 10.3390/ijms25042076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/05/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Recently, 5-[(4-ethoxyphenyl)imino]methyl-N-(4-fluorophenyl)-6-methyl-2-phenylpyrimidin-4-amine has been synthesized, characterized, and evaluated for its antibacterial activity against Enterococcus faecalis in combination with antineoplastic activity against gastric adenocarcinoma. In this study, new 5-iminomethylpyrimidine compounds were synthesized which differ in the substituent(s) of the aromatic ring attached to the imine group. The structures of newly obtained pyrimidine Schiff bases were established by spectroscopy techniques (ESI-MS, FTIR and 1H NMR). To extend the current knowledge about the features responsible for the biological activity of the new 5-iminomethylpyrimidine derivatives, low-temperature single-crystal X-ray analyses were carried out. For all studied crystals, intramolecular N-H∙∙∙N hydrogen bonds and intermolecular C-H∙∙∙F interactions were observed and seemed to play an essential role in the formation of the structures. Simultaneously, their biological properties based on their cytotoxic features were compared with the activities of the Schiff base (III) published previously. Moreover, computational investigations, such as ADME prediction analysis and molecular docking, were also performed on the most active new Schiff base (compound 4b). These results were compared with the highest active compound III.
Collapse
Affiliation(s)
- Iwona Bryndal
- Department of Organic Chemistry and Drug Technology, Faculty of Pharmacy, Wroclaw Medical University, 211A Borowska, 50-556 Wrocław, Poland; (M.S.); (M.M.)
| | - Marcin Stolarczyk
- Department of Organic Chemistry and Drug Technology, Faculty of Pharmacy, Wroclaw Medical University, 211A Borowska, 50-556 Wrocław, Poland; (M.S.); (M.M.)
| | - Aleksandra Mikołajczyk
- Screening Biological Activity Assays and Collection of Biological Material Laboratory, Wroclaw Medical University, 211A Borowska, 50-556 Wrocław, Poland; (A.M.); (M.K.); (A.M.-W.)
| | - Magdalena Krupińska
- Screening Biological Activity Assays and Collection of Biological Material Laboratory, Wroclaw Medical University, 211A Borowska, 50-556 Wrocław, Poland; (A.M.); (M.K.); (A.M.-W.)
| | - Anna Pyra
- Faculty of Chemistry, University of Wroclaw, 14 Joliot-Curie, 50-383 Wrocław, Poland;
| | - Marcin Mączyński
- Department of Organic Chemistry and Drug Technology, Faculty of Pharmacy, Wroclaw Medical University, 211A Borowska, 50-556 Wrocław, Poland; (M.S.); (M.M.)
| | - Agnieszka Matera-Witkiewicz
- Screening Biological Activity Assays and Collection of Biological Material Laboratory, Wroclaw Medical University, 211A Borowska, 50-556 Wrocław, Poland; (A.M.); (M.K.); (A.M.-W.)
| |
Collapse
|
4
|
Al-Salmi IK, Shongwe MS. Ternary Phenolate-Based Thiosemicarbazone Complexes of Copper(II): Magnetostructural Properties, Spectroscopic Features and Marked Selective Antiproliferative Activity against Cancer Cells. Molecules 2024; 29:431. [PMID: 38257344 PMCID: PMC10819714 DOI: 10.3390/molecules29020431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/06/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
The new diprotic ligand 3,5-di-tert-butylsalicylaldehyde 4-ethyl-3-thiosemicarbazone, abbreviated H2(3,5-t-Bu2)-sal4eT, exists as the thio-keto tautomer and adopts the E-configuration with respect to the imine double bond, as evidenced by single-crystal X-ray analysis and corroborated by spectroscopic characterisation. Upon treatment with Cu(OAc)2·H2O in the presence of either 2,9-dimethyl-1,10-phenanthroline (2,9-Me2-phen) or 1,10-phenanthroline (phen) as a co-ligand in MeOH, this thiosemicarbazone undergoes conformational transformation (relative donor-atom orientations: syn,anti → syn,syn) concomitantly with tautomerisation and double deprotonation to afford the ternary copper(II) complexes [Cu{(3,5-t-Bu2)-sal4eT}(2,9-Me2-phen)] (1) and [Cu2{3,5-t-Bu2)-sal4eT}2(phen)] (2). Crystallographic elucidation has revealed that complex 1 is a centrosymmetric dimer of mononuclear copper(II) complex molecules brought about by intermolecular H-bonding. The coordination geometry at the copper(II) centre is best described as distorted square pyramidal in accordance with the trigonality index (τ = 0.14). The co-ligand adopts an axial-equatorial coordination mode; hence, there is a disparity between its two Cu-N coordinate bonds arising from weakening of the apical one as a consequence of the tetragonal distortion. The axial X-band ESR spectrum of complex 1 is consistent with retention of this structure in solution. Complex 2 is a centrosymmetric dimer of dinuclear copper(II) complex molecules exhibiting intermolecular H-bonding and π-π-stacking interactions. The two copper(II) centres, which are 4.8067(18) Å apart and bridged by the thio-enolate nitrogen of the quadridentate thiosemicarbazonate ligand, display two different coordination geometries, one distorted square planar (τ4 = 0.082) and the other distorted square pyramidal (τ5 = 0.33). Such dinuclear copper(II) thiosemicarbazone complexes, which are crystallographically characterised, are extremely rare. In vitro, complexes 1 and 2 outperform cisplatin as antiproliferative agents in terms of potency and selectivity towards HeLa and MCF-7 cancer cell lines.
Collapse
Affiliation(s)
| | - Musa S. Shongwe
- Department of Chemistry, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khod 123, Muscat, Oman
| |
Collapse
|
5
|
Beckett MA, Horton PN, Hursthouse MB, Timmis JL. Synthesis and Thermal Studies of Two Phosphonium Tetrahydroxidohexaoxidopentaborate(1-) Salts: Single-Crystal XRD Characterization of [ iPrPPh 3][B 5O 6(OH) 4]·3.5H 2O and [MePPh 3][B 5O 6(OH) 4]·B(OH) 3·0.5H 2O. Molecules 2023; 28:6867. [PMID: 37836710 PMCID: PMC10574587 DOI: 10.3390/molecules28196867] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/19/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
Two substituted phosphonium tetrahydoxidohexaoxidopentaborate(1-) salts, [iPrPPh3][B5O6(OH)4]·3.5H2O (1) and [MePPh3][B5O6(OH)4]·B(OH)3·0.5H2O (2), were prepared by templated self-assembly processes with good yields by crystallization from basic methanolic aqueous solutions primed with B(OH)3 and the appropriate phosphonium cation. Salts 1 and 2 were characterized by spectroscopic (NMR and IR) and thermal (TGA/DSC) analysis. Salts 1 and 2 were thermally decomposed in air at 800 °C to glassy solids via the anhydrous phosphonium polyborates that are formed at lower temperatures (<300 °C). BET analysis of the anhydrous and pyrolysed materials indicated they were non-porous with surface areas of 0.2-2.75 m2/g. Rhe recrystallization of 1 and 2 from aqueous solution afforded crystals suitable for single-crystal XRD analyses. The structure of 1 comprises alternating cationic/anionic layers with the H2O/pentaborate(1-) planes held together by H-bonds. The cationic planes have offset face-to-face (off) and vertex-to-face (vf) aromatic ring interactions with the iPr groups oriented towards the pentaborate(1-)/H2O layers. The anionic lattice in 2 is expanded by the inclusion of B(OH)3 molecules to accommodate the large cations; this results in the formation of a stacked pentaborate(1-)/B(OH)3 structure with channels occupied by the cations. The cations within the channels have vf, ef (edge-to-face), and off phenyl embraces. Both H-bonding and phenyl embrace interactions are important in stabilizing these two solid-state structures.
Collapse
Affiliation(s)
| | - Peter N. Horton
- Chemistry Department, University of Southampton, Southampton SO17 1BJ, UK
| | | | - James L. Timmis
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
| |
Collapse
|
6
|
Ashaduzzaman M, Lingkon K, De Silva AJ, Bellizzi JJ. Crystallographic and thermodynamic evidence of negative cooperativity of flavin and tryptophan binding in the flavin-dependent halogenases AbeH and BorH. bioRxiv 2023:2023.08.22.554356. [PMID: 37662313 PMCID: PMC10473636 DOI: 10.1101/2023.08.22.554356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The flavin-dependent halogenase AbeH produces 5-chlorotryptophan in the biosynthetic pathway of the chlorinated bisindole alkaloid BE-54017. We report that in vitro, AbeH (assisted by the flavin reductase AbeF) can chlorinate and brominate tryptophan as well as other indole derivatives and substrates with phenyl and quinoline groups. We solved the X-ray crystal structures of AbeH alone and complexed with FAD, as well as crystal structures of the tryptophan-6-halogenase BorH alone, in complex with 6-chlorotryptophan, and in complex with FAD and tryptophan. Partitioning of FAD and tryptophan into different chains of BorH and failure to incorporate tryptophan into AbeH/FAD crystals suggested that flavin and tryptophan binding are negatively coupled in both proteins. ITC and fluorescence quenching experiments confirmed the ability of both AbeH and BorH to form binary complexes with FAD or tryptophan and the inability of tryptophan to bind to AbeH/FAD or BorH/FAD complexes. FAD could not bind to BorH/tryptophan complexes, but FAD appears to displace tryptophan from AbeH/tryptophan complexes in an endothermic entropically-driven process.
Collapse
Affiliation(s)
- Md Ashaduzzaman
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo OH 43606
| | - Kazi Lingkon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo OH 43606
| | - Aravinda J De Silva
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo OH 43606
| | - John J Bellizzi
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo OH 43606
| |
Collapse
|
7
|
Szalai Z, Tóth B, Szabó RO, Bősze S, Karaghiosoff K, Czugler M, Drahos L, Keglevich G. A Study of the Bisphosphonic Derivatives from the Pudovik Reaction of Dialkyl α-Oxophosphonates and >P(O)H Reagents: X-ray Structure and Bioactivity. Molecules 2023; 28:6037. [PMID: 37630289 PMCID: PMC10459769 DOI: 10.3390/molecules28166037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/07/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
New hydroxy-methylenebisphosphonic derivatives were prepared with different P-functions. The outcome of the reaction of α-oxophosphonates (YC(O)P(O)(OR)2) and dialkyl phosphites or diarylphosphine oxides depended on the Y substituent of the oxo-compound, the nature of the P-reagent and the amount of the diethylamine catalyst. Starting from dimethyl α-oxoethylphosphonate, in the presence of 5% of diethylamine, the corresponding Pudovik adduct was the single product. While using 40% of the catalyst, the rearranged species with the >P(O)-O-CH-P(O)< skeleton was the exclusive component. A similar reaction of α-oxobenzylphosphonate followed the rearrangement protocol. X-ray crystallography revealed not only the spatial structures of the three products, but also an intricate pattern evolving from the interplay of slight chemical differences, solvent inclusion and disorder as well as H-bridge patterns, which invite further investigation. In vitro activity of the compounds was assessed on different tumor cell cultures using end-point-type cell tetrazolium-based measurements. These structure-activity studies revealed a cytostatic effect for four rearranged derivatives containing aromatic units. One of them had a pronounced effect on MDA-MB 231 and Ebc-1 cells, showing IC50 = 37.8 and 25.9 µM, respectively.
Collapse
Affiliation(s)
- Zsuzsanna Szalai
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, 1521 Budapest, Hungary; (Z.S.); (B.T.); (M.C.)
| | - Boldizsár Tóth
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, 1521 Budapest, Hungary; (Z.S.); (B.T.); (M.C.)
| | - Rita Oláhné Szabó
- Eötvös Loránd Research Network (ELKH), Research Group of Peptide Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (R.O.S.); (S.B.)
- Department of Genetics, Cell and Immunobiology, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary
| | - Szilvia Bősze
- Eötvös Loránd Research Network (ELKH), Research Group of Peptide Chemistry, Eötvös Loránd University, 1117 Budapest, Hungary; (R.O.S.); (S.B.)
| | - Konstantin Karaghiosoff
- Department Chemie, Ludwig-Maximilians-Universitat München, Butenandtstr. 5-13, D-81377 München, Germany;
| | - Mátyás Czugler
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, 1521 Budapest, Hungary; (Z.S.); (B.T.); (M.C.)
| | - László Drahos
- MS Proteomics Research Group, Research Centre for Natural Sciences, 1117 Budapest, Hungary;
| | - György Keglevich
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, 1521 Budapest, Hungary; (Z.S.); (B.T.); (M.C.)
| |
Collapse
|
8
|
Xerxa E, Laufkötter O, Bajorath J. Systematic Analysis of Covalent and Allosteric Protein Kinase Inhibitors. Molecules 2023; 28:5805. [PMID: 37570774 PMCID: PMC10420927 DOI: 10.3390/molecules28155805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 07/24/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
In drug discovery, protein kinase inhibitors (PKIs) are intensely investigated as drug candidates in different therapeutic areas. While ATP site-directed, non-covalent PKIs have long been a focal point in protein kinase (PK) drug discovery, in recent years, there has been increasing interest in allosteric PKIs (APKIs), which are expected to have high kinase selectivity. In addition, as compounds acting by covalent mechanisms experience a renaissance in drug discovery, there is also increasing interest in covalent PKIs (CPKIs). There are various reasons for this increasing interest such as the anticipated high potency, prolonged residence times compared to non-competitive PKIs, and other favorable pharmacokinetic properties. Due to the popularity of PKIs for therapeutic intervention, large numbers of PKIs and large volumes of activity data have accumulated in the public domain, providing a basis for large-scale computational analysis. We have systematically searched for CPKIs containing different reactive groups (warheads) and investigated their potency and promiscuity (multi-PK activity) on the basis of carefully curated activity data. For seven different warheads, sufficiently large numbers of CPKIs were available for detailed follow-up analysis. For only three warheads, the median potency of corresponding CPKIs was significantly higher than of non-covalent PKIs. However, for CKPIs with five of seven warheads, there was a significant increase in the median potency of at least 100-fold compared to PKI analogues without warheads. However, in the analysis of multi-PK activity, there was no general increase in the promiscuity of CPKIs compared to non-covalent PKIs. In addition, we have identified 29 new APKIs in X-ray structures of PK-PKI complexes. Among structurally characterized APKIs, 13 covalent APKIs in complexes with five PKs are currently available, enabling structure-based investigation of PK inhibition by covalent-allosteric mechanisms.
Collapse
Affiliation(s)
| | | | - Jürgen Bajorath
- LIMES Program Unit Chemical Biology and Medicinal Chemistry, Department of Life Science Informatics, B-IT, Rheinische Friedrich-Wilhelms-Universität, Friedrich-Hirzebruch-Allee 5/6, D-53115 Bonn, Germany
| |
Collapse
|
9
|
Scheidt WR, Oliver AG, Yu D, Li J. Stereochemistry of low-spin cobalt porphyrins. 9. Molecular stereochemistry of two picket fence cobalt(II) derivatives. J Inorg Biochem 2023; 241:112130. [PMID: 36708627 PMCID: PMC9992090 DOI: 10.1016/j.jinorgbio.2023.112130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 01/22/2023]
Abstract
The preparation and molecular structures of two five-coordinate cobalt(II) picket fence porphyrinates with imidazole ligands are described, [Co(TpivPP)(L)] (TpivPP, dianion of picket fence porphyrin). The ligands are the unhindered imidazole, 1-ethylimidazole, and the sterically hindered imidazole, 1,2-dimethylimidazole. Although the equatorial aspects of the geometry are quite equivalent, the axial coordination group geometry strongly reflects the differing steric requirements of the axial ligand. The hindering methyl group in 1,2-dimethylimidazole, adjacent to the coordinated imidazole nitrogen atom, leads to an increased CoNIm bond distance, a tilt of the CoN bond and unequal CoNCIm bond angles, all of which serve to reduce the steric strain when compared with the unhindered derivative.
Collapse
Affiliation(s)
- W Robert Scheidt
- The Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Allen G Oliver
- The Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Dehui Yu
- College of Materials Science and Opto-electronic Technology, University of Chinese Academy of Science, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Jianfeng Li
- The Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA; College of Materials Science and Opto-electronic Technology, University of Chinese Academy of Science, Yanqi Lake, Huairou District, Beijing 101408, China
| |
Collapse
|
10
|
Al-Soud YA, Saber SOW, Shtaiwi A, Alsawakhneh SO, Alhelal KAS, Salman QFA, Abu-Qatouseh L, Khanfar MA, Al-Qawasmeh RA. Nitroimidazoles Part 10. Synthesis, crystal structure, molecular docking, and anticancer evaluation of 4-nitroimidazole derivatives combined with piperazine moiety. Z NATURFORSCH C 2023; 78:93-103. [PMID: 35589618 DOI: 10.1515/znc-2022-0023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 04/30/2022] [Indexed: 11/15/2022]
Abstract
Piperazine-tagged imidazole derivatives 3a (symmetrical di-substituted piperazine) and 5-11 were synthesized through the combination of 4-nitroimidazole derivatives with piperazine moiety. The structural characterization was done by different physical and spectral techniques like NMR (1H and 13C) and mass spectrometry. The constituency of compound 3a was confirmed by X-ray structural analyses. All compounds were assessed for their antiproliferative inhibition potency against five human cancer cell lines namely MCF-7, PC3, MDA-231, A549 and Fibro dental. Compound 5 was found to be the most potent anticancer agents against MCF-7 cell line with IC50 values of (1.0 ± 0 µm) and against PC3 with IC50 value of (9.00 ± 0.028 µm). The molecular docking of compound 5 had been studied, and the results revealed that the newly designed 4-nitroimidazole combined with piperazine moiety derivatives bond to the hydrophobic pocket and polar contacts with high affinity.
Collapse
Affiliation(s)
- Yaseen A Al-Soud
- Department of Chemistry, Faculty of Science, Al al-Bayt University, Al-Mafraq, Jordan
| | | | - Amneh Shtaiwi
- School of Pharmacy, Middle East University, Queen Alia Airport Street, 11118 Amman, Jordan
| | - Sondos O Alsawakhneh
- Department of Chemistry, Faculty of Science, Al al-Bayt University, Al-Mafraq, Jordan
| | - Kafa' A S Alhelal
- Department of Chemistry, Faculty of Science, Al al-Bayt University, Al-Mafraq, Jordan
| | - Qusay F A Salman
- Department of Chemistry, Faculty of Science, Al al-Bayt University, Al-Mafraq, Jordan
| | | | - Monther A Khanfar
- Department of Chemistry, Pure and Applied Chemistry Group, College of Sciences, University of Sharjah, 27272 Sharjah, UAE.,Department of Chemistry, The University of Jordan, 11942 Amman, Jordan
| | - Raed A Al-Qawasmeh
- Department of Chemistry, Pure and Applied Chemistry Group, College of Sciences, University of Sharjah, 27272 Sharjah, UAE.,Department of Chemistry, The University of Jordan, 11942 Amman, Jordan
| |
Collapse
|
11
|
Albuquerque CCV, Teixeira TM, Dos Santos RS, Abreu DC, Silveira-Lacerda EDP, Back DF, da Silva JP, de Araujo MP. Synthesis, characterization, solution chemistry and anticancer activity of [NiCl 2(Ph 2P-N(R)-PPh 2)] (R = 2-CH 2Py, CH 2Ph and p-tol) complexes. J Inorg Biochem 2023; 240:112119. [PMID: 36639323 DOI: 10.1016/j.jinorgbio.2023.112119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/28/2022] [Accepted: 01/01/2023] [Indexed: 01/05/2023]
Abstract
In this work three Ni2+ complexes with general formula [NiCl2(Ph2P-N(R)-PPh2)], R = 2-CH2Py (Py = pyridine) - 1, CH2Ph (Ph = phenyl) - 2 and p-tol (p-tol = p-tolyl) - 3, were synthesized and characterized. These complexes were obtained in high yield by the reaction of NiCl2.6H2O and the corresponding diphenylphosphinoamine ligand (Ph2P-N(R)-PPh2) in CH2Cl2/MeOH (1:1) solution, at room temperature (∼25 °C), and characterized by 1H and 31P {1H} NMR, vibrational spectroscopy in the infrared region, electronic spectroscopy in the UV-Vis regions, elemental analysis (%C, %H, %N) and single-crystal X-ray diffraction. The solution chemistry was studied in CDCl3/dmso-d6 (dimethylsulfoxide) or neat dmso-d6 using complex 2 as a model. The complexes were evaluated as cytotoxic agents against two cancer cells lines, A549 (lung cancer cells), B16F10 (melanoma cells) and the health cells HaCaT (human epithelial keratinocytes).
Collapse
Affiliation(s)
- Carla C V Albuquerque
- Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | - Thallita M Teixeira
- Department of Genetics, Institute of Biological Sciences, Federal University of Goiás, 74001-970 Goiânia, GO, Brazil
| | - Rafael S Dos Santos
- Department of Chemistry, Federal University of Paraná, Polytechnique Center, 81531-980 Curitiba, PR, Brazil
| | - Davi C Abreu
- Department of Genetics, Institute of Biological Sciences, Federal University of Goiás, 74001-970 Goiânia, GO, Brazil
| | | | - Davi F Back
- Department of Chemistry, Federal University of Santa Maria, 97105-900 Santa Maria, RS, Brazil
| | - Juliana P da Silva
- Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, SC, Brazil
| | - Márcio P de Araujo
- Department of Chemistry, Federal University of Santa Catarina, 88040-900 Florianópolis, SC, Brazil; Department of Chemistry, Federal University of Paraná, Polytechnique Center, 81531-980 Curitiba, PR, Brazil.
| |
Collapse
|
12
|
Burguera S, Gomila RM, Bauzá A, Frontera A. Selenoxides as Excellent Chalcogen Bond Donors: Effect of Metal Coordination. Molecules 2022; 27. [PMID: 36557974 DOI: 10.3390/molecules27248837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/09/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022]
Abstract
The chalcogen bond has been recently defined by the IUPAC as the attractive noncovalent interaction between any element of group 16 acting as an electrophile and any atom (or group of atoms) acting as a nucleophile. Commonly used chalcogen bond donor molecules are divalent selenium and tellurium derivatives that exhibit two σ-holes. In fact, the presence of two σ-hole confers to the chalcogen bonding additional possibilities with respect to the halogen bond, the most abundant σ-hole interaction. In this manuscript, we demonstrate that selenoxides are good candidates to be used as σ-hole donor molecules. Such molecules have not been analyzed before as chalcogen bond donors, as far as our knowledge extends. The σ-hole opposite to the Se=O bond is adequate for establishing strong and directional ChBs, as demonstrated herein using the Cambridge structural database (CSD) and density functional theory (DFT) calculations. Moreover, the effect of the metal coordination of the selenoxide to transition metals on the strength of the ChB interaction has been analyzed theoretically. The existence of the ChBs has been further supported by the quantum theory of atoms in molecules (QTAIM) and the noncovalent interaction plot (NCIPlot).
Collapse
|
13
|
Nachon F, Brazzolotto X, Dias J, Courageux C, Drożdż W, Cao XY, Stefankiewicz AR, Lehn JM. Grid-Type Quaternary Metallosupramolecular Compounds Inhibit Human Cholinesterases through Dynamic Multivalent Interactions. Chembiochem 2022; 23:e202200456. [PMID: 36193860 DOI: 10.1002/cbic.202200456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/14/2022] [Indexed: 01/25/2023]
Abstract
We report the implementation of coordination complexes containing two types of cationic moieties, i. e. pyridinium and ammonium quaternary salt, as potential inhibitors of human cholinesterase enzymes. Utilization of ligands containing NNO-coordination site and binding zinc metal ion allowed mono- and tetra-nuclear complexes to be obtained with corner and grid structural type, respectively, thus affecting the overall charge of the compounds (from +1 to +8). We were able to examine for the first time the multivalency effect of metallosupramolecular species on their inhibitory abilities towards acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Importantly, resolution of the crystal structures of the obtained enzyme-substrate complexes provided a better understanding of the inhibition process at the molecular level.
Collapse
Affiliation(s)
- Florian Nachon
- Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, 1 place Gal Valérie André, BP87, 91220, Brétigny-sur-Orge, France
| | - Xavier Brazzolotto
- Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, 1 place Gal Valérie André, BP87, 91220, Brétigny-sur-Orge, France
| | - José Dias
- Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, 1 place Gal Valérie André, BP87, 91220, Brétigny-sur-Orge, France
| | - Charlotte Courageux
- Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, 1 place Gal Valérie André, BP87, 91220, Brétigny-sur-Orge, France
| | - Wojciech Drożdż
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland.,Center for Advanced Technology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, 61-614, Poznań, Poland
| | - Xiao-Yu Cao
- Laboratoire de Chimie Supramoléculaire, Institut de Science et d'Ingénierie Supramoléculaires, Université de Strasbourg, 8 allée Gaspard Monge, 67000, Strasbourg, France
| | - Artur R Stefankiewicz
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland.,Center for Advanced Technology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, 61-614, Poznań, Poland
| | - Jean-Marie Lehn
- Laboratoire de Chimie Supramoléculaire, Institut de Science et d'Ingénierie Supramoléculaires, Université de Strasbourg, 8 allée Gaspard Monge, 67000, Strasbourg, France
| |
Collapse
|
14
|
Pospieszna-Markiewicz I, Fik-Jaskółka MA, Hnatejko Z, Patroniak V, Kubicki M. Synthesis and Characterization of Lanthanide Metal Ion Complexes of New Polydentate Hydrazone Schiff Base Ligand. Molecules 2022; 27:molecules27238390. [PMID: 36500479 PMCID: PMC9736465 DOI: 10.3390/molecules27238390] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/11/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022]
Abstract
The new homodinuclear complexes of the general formula [Ln2L3(NO3)3] (where HL is newly synthesized 2-((2-(benzoxazol-2-yl)-2-methylhydrazono)methyl)phenol and Ln = Sm3+ (1), Eu3+ (2), Tb3+ (3a, 3b), Dy3+ (4), Ho3+ (5), Er3+ (6), Tm3+ (7), Yb3+ (8)), have been synthesized from the lanthanide(III) nitrates with the polydentate hydrazone Schiff base ligand. The flexibility of this unsymmetrical Schiff base ligand containing N2O binding moiety, attractive for lanthanide metal ions, allowed for a self-assembly of these complexes. The compounds were characterized by spectroscopic data (ESI-MS, IR, UV/Vis, luminescence) and by the X-ray structure determination of the single crystals, all of which appeared to be different solvents. The analytical data suggested 2:3 metal:ligand stoichiometry in these complexes, and this was further confirmed by the structural results. The metal cations are nine-coordinated, by nitrogen and oxygen donor atoms. The complexes are two-centered, with three oxygen atoms in bridging positions. There are two types of structures, differing by the sources of terminal (non-bridging) coordination centers (group A: two ligands, one nitro anion/one ligand, two nitro anions, group B: three ligands, three anions).
Collapse
|
15
|
Gomila RM, Frontera A. Matere Bonds vs. Multivalent Halogen and Chalcogen Bonds: Three Case Studies. Molecules 2022; 27:6597. [PMID: 36235133 DOI: 10.3390/molecules27196597] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 09/29/2022] [Accepted: 10/03/2022] [Indexed: 11/07/2022]
Abstract
The term matere bond has been recently used to refer to an attractive noncovalent interaction between any element of group 7 acting as an electrophile and any atom (or group of atoms) acting as a nucleophile. The utilization of metals such as σ-hole donors is starting to attract the attention of the scientific community. In this manuscript, a comparison between matere bonds and well-known σ-hole interactions (halogen and chalcogen bonds) is carried out using three X-ray structures, retrieved from the Cambridge structural database (CSD), and density functional theory calculations (DFT). The novelty of this work resides in the utilization of a neutral Re(VII) system as the matere bond donor and multivalent chalcogen and halogen donors. In fact, as far as our knowledge extends, the description of σ-hole interactions in Se(VI) is unprecedented in the literature. The σ-hole interactions in Re(VII), Se(VI) and Cl(VII) electron acceptors are analyzed and compared using several computational tools.
Collapse
|
16
|
El Salamouni NS, Buckley BJ, Ranson M, Kelso MJ, Yu H. Urokinase plasminogen activator as an anti-metastasis target: inhibitor design principles, recent amiloride derivatives, and issues with human/mouse species selectivity. Biophys Rev 2022; 14:277-301. [PMID: 35340592 DOI: 10.1007/s12551-021-00921-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/18/2021] [Indexed: 01/09/2023] Open
Abstract
The urokinase plasminogen activator (uPA) is a widely studied anticancer drug target with multiple classes of inhibitors reported to date. Many of these inhibitors contain amidine or guanidine groups, while others lacking these groups show improved oral bioavailability. Most of the X-ray co-crystal structures of small molecule uPA inhibitors show a key salt bridge with the side chain carboxylate of Asp189 in the S1 pocket of uPA. This review summarises the different classes of uPA inhibitors, their binding interactions and experimentally measured inhibitory potencies and highlights species selectivity issues with attention to recently described 6-substituted amiloride and 5‑N,N-(hexamethylene)amiloride (HMA) derivatives.
Collapse
|
17
|
Kuchar J, Reinhold K, Rösgen V, Nöthling N, Lehmann CW, Mohr F. Synthesis, Reactivity and Antimicrobial Activity of a Series of 2-Arylamino-1,3-selenazoles. Molecules 2021; 26:7695. [PMID: 34946781 DOI: 10.3390/molecules26247695] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/17/2021] [Accepted: 12/17/2021] [Indexed: 11/16/2022] Open
Abstract
A series of 2-arylamino-1,3-selenazoles was synthesized and their reactivity was studied. The 2-arylamino-1,3-selenazoles and their reaction products were characterized by various spectroscopic methods and X-ray diffraction. In addition, the antimicrobial activity of the 2-arylamino-1,3-selenazoles in a panel of seven bacteria and fungi was examined.
Collapse
|
18
|
Chugunova E, Akylbekov N, Dobrynin A, Burilov A, Boga C, Micheletti G, Frenna V, Mattioli EJ, Calvaresi M, Spinelli D. 4,6-Dichloro-5-Nitrobenzofuroxan: Different Polymorphisms and DFT Investigation of Its Reactivity with Nucleophiles. Int J Mol Sci 2021; 22:13460. [PMID: 34948257 PMCID: PMC8709177 DOI: 10.3390/ijms222413460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/09/2021] [Accepted: 12/12/2021] [Indexed: 11/16/2022] Open
Abstract
This research focuses on the X-ray structure of 4,6-dichloro-5-nitrobenzofuroxan 1 and of some of its amino derivatives (4a, 4e, 4g, and 4l) and on DFT calculations concerning the nucleophilic reactivity of 1. We have found that by changing the solvent used for crystallization, it is possible to obtain 4,6-dichloro-5-nitrobenzofuroxan (1) in different polymorphic structures. Moreover, the different torsional angles observed for the nitro group in 1 and in its amino derivatives (4a, 4e, 4g, and 4l) are strictly dependent on the steric hindrance of the substituent at C-4. DFT calculations on the course of the nucleophilic substitution confirm the role of the condensed furoxan ring in altering the aromaticity of the carbocyclic frame, while chlorine atoms strongly influence the dihedral angle and the rotational barrier of the nitro group. These results corroborate previous observations based on experimental kinetic data and give a deep picture of the reaction with amines, which proceeds via a "non-aromatic" nucleophilic substitution.
Collapse
Affiliation(s)
- Elena Chugunova
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov st. 8, 420088 Kazan, Russia; (A.D.); (A.B.)
- Laboratory of Plant Infectious Diseases, FRC Kazan Scientific Center of Russian Academy of Sciences, Lobachevskogo st. 2/31, 420111 Kazan, Russia
| | - Nurgali Akylbekov
- Laboratory of Engineering Profile “Physical and Chemical Methods of Analysis”, Korkyt Ata Kyzylorda University, Aitekebie str. 29A, Kyzylorda 120014, Kazakhstan;
| | - Alexey Dobrynin
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov st. 8, 420088 Kazan, Russia; (A.D.); (A.B.)
- Institute of Radio Electronics, Photonics and Digital Technologies, Kazan National Research Technical University, 10 Karl Marx Str., 420111 Kazan, Russia
| | - Alexander Burilov
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences, Akad. Arbuzov st. 8, 420088 Kazan, Russia; (A.D.); (A.B.)
- Laboratory of Plant Infectious Diseases, FRC Kazan Scientific Center of Russian Academy of Sciences, Lobachevskogo st. 2/31, 420111 Kazan, Russia
| | - Carla Boga
- Department of Industrial Chemistry ‘Toso Montanari’ ALMA MATER STUDIORUM, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy;
| | - Gabriele Micheletti
- Department of Industrial Chemistry ‘Toso Montanari’ ALMA MATER STUDIORUM, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy;
| | - Vincenzo Frenna
- Department STEBICEF, University of Palermo, Ed.17, Viale delle Scienze, 90128 Palermo, Italy;
| | - Edoardo Jun Mattioli
- Department of Chemistry ‘G. Ciamician’ ALMA MATER STUDIORUM, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy; (E.J.M.); (M.C.)
| | - Matteo Calvaresi
- Department of Chemistry ‘G. Ciamician’ ALMA MATER STUDIORUM, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy; (E.J.M.); (M.C.)
| | - Domenico Spinelli
- Department of Chemistry ‘G. Ciamician’ ALMA MATER STUDIORUM, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy; (E.J.M.); (M.C.)
| |
Collapse
|
19
|
Schulze-Niemand E, Naumann M, Stein M. The Activation and Selectivity of the Legionella RavD Deubiquitinase. Front Mol Biosci 2021; 8:770320. [PMID: 34869597 PMCID: PMC8635228 DOI: 10.3389/fmolb.2021.770320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Eric Schulze-Niemand
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.,Medical Faculty, Institute for Experimental Internal Medicine, Otto-von-Guericke University, Magdeburg, Germany
| | - Michael Naumann
- Medical Faculty, Institute for Experimental Internal Medicine, Otto-von-Guericke University, Magdeburg, Germany
| | - Matthias Stein
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| |
Collapse
|
20
|
Hu H, Bajorath J. Systematic identification of activity cliffs with dual-atom replacements and their rationalization on the basis of single-atom replacement analogs and X-ray structures. Chem Biol Drug Des 2021; 99:308-319. [PMID: 34806310 DOI: 10.1111/cbdd.13985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/31/2021] [Accepted: 11/14/2021] [Indexed: 12/01/2022]
Abstract
Very small chemical changes in active compounds causing large potency effects are of particular interest in medicinal chemistry and drug design. We have systematically searched active compounds with available high-confidence activity data for pairs of structural analogs with dual-atom replacements and additional analogs with corresponding single-atom replacements. From ~287,000 unique qualifying compounds with activity against nearly 1900 unique targets, ~3500 target-based analog pairs with dual-atom replacements were identified. These included 852 pairs with significant differences in compound potency, representing a set of previously unobserved activity cliffs. Comparing these pairs with corresponding single-atom replacement analogs, which were frequently identified, made it possible to systematically analyze how potency changes propagated from single- to dual-atom replacements. The analysis uncovered different potency effects and revealed that individual atom replacements were often decisive for activity cliff formation. For a limited number of activity cliffs, X-ray structures of targets in complex with cliff compounds were available, which aided in rationalizing potency alterations among analogs with single- or dual-atom replacements. The analog pairs identified herein provide a rich resource of structure-activity relationship information and attractive test cases for calibrating computational methods.
Collapse
Affiliation(s)
- Huabin Hu
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Bonn, Germany
| | - Jürgen Bajorath
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Bonn, Germany
| |
Collapse
|
21
|
Hu H, Bajorath J. Systematic assessment of structure-promiscuity relationships between different types of kinase inhibitors. Bioorg Med Chem 2021; 41:116226. [PMID: 34082305 DOI: 10.1016/j.bmc.2021.116226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 12/29/2022]
Abstract
Given the increasing quest for selective kinase inhibitors, we have systematically investigated structural and structure-promiscuity relationships between promiscuous kinase inhibitors and other types with increasing potential for selective kinase inhibition. Therefore, inhibitors with different modes of action were extracted from X-ray structures of kinase complexes. For more than 18,000 promiscuous kinase inhibitors and 1253 type I1/2, II, and allosteric inhibitors with structurally confirmed mechanisms, analogue space was systematically charted. These inhibitors were active against a total of 426 human kinases. While nearly 80% of the promiscuous inhibitors formed related analogues series, only ~30% of other types of inhibitors were involved in such structural relationships and many of these inhibitors also had multi-kinase activity. Thus, most of the investigated type I1/2, II, and allosteric inhibitors with reported single-kinase activity were distinguished from promiscuous inhibitors, thus indicating potential for kinase selectivity. Structural relationships between promiscuous inhibitors and the subset of other inhibitors were organized in a matrix format including kinase activity profiles, revealing structure-promiscuity relationships for follow-up investigations.
Collapse
|
22
|
Mokfi M, Rust J, Lehmann CW, Mohr F. Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for N-Heterocyclic Carbene Complexes. Molecules 2021; 26:3705. [PMID: 34204439 DOI: 10.3390/molecules26123705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/15/2021] [Accepted: 06/15/2021] [Indexed: 11/17/2022] Open
Abstract
The xanthine-derivatives 1,3,7-trimethylxanthine, 1,3-dimethyl-7-benzylxanthine and 1,3-dimethyl-7-(4-chlorobenzyl)xanthine are readily ethylated at N9 using the cheap alkylating agents ethyl tosylate or diethyl sulfate. The resulting xanthinium tosylate or ethyl sulfate salts can be converted into the corresponding PF6- and chloride salts. The reaction of these xanthinium salts with silver(I) oxide results in the formation of different silver(I) carbene-complexes. In the presence of ammonia, ammine complexes [Ag(NHC)(NH3)]PF6 are formed, whilst with Et2NH, the bis(carbene) salts [Ag(NHC)2]PF6 were isolated. Using the xanthinium chloride salts neutral silver(I) carbenes [Ag(NHC)Cl] were prepared. These silver complexes were used in a variety of transmetallation reactions to give the corresponding gold(I), ruthenium(II) as well as rhodium(I) and rhodium(III) complexes. The compounds were characterized by various spectroscopic methods as well as X-ray diffraction.
Collapse
|
23
|
Hofbeck T, Niehaus TA, Fleck M, Monkowius U, Yersin H. P∩N Bridged Cu(I) Dimers Featuring Both TADF and Phosphorescence. From Overview towards Detailed Case Study of the Excited Singlet and Triplet States. Molecules 2021; 26:3415. [PMID: 34200044 DOI: 10.3390/molecules26113415] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
We present an overview over eight brightly luminescent Cu(I) dimers of the type Cu2X2(P∩N)3 with X = Cl, Br, I and P∩N = 2-diphenylphosphino-pyridine (Ph2Ppy), 2-diphenylphosphino-pyrimidine (Ph2Ppym), 1-diphenylphosphino-isoquinoline (Ph2Piqn) including three new crystal structures (Cu2Br2(Ph2Ppy)3 1-Br, Cu2I2(Ph2Ppym)3 2-I and Cu2I2(Ph2Piqn)3 3-I). However, we mainly focus on their photo-luminescence properties. All compounds exhibit combined thermally activated delayed fluorescence (TADF) and phosphorescence at ambient temperature. Emission color, decay time and quantum yield vary over large ranges. For deeper characterization, we select Cu2I2(Ph2Ppy)3, 1-I, showing a quantum yield of 81%. DFT and SOC-TDDFT calculations provide insight into the electronic structures of the singlet S1 and triplet T1 states. Both stem from metal+iodide-to-ligand charge transfer transitions. Evaluation of the emission decay dynamics, measured from 1.2 ≤ T ≤ 300 K, gives ∆E(S1-T1) = 380 cm−1 (47 meV), a transition rate of k(S1→S0) = 2.25 × 106 s−1 (445 ns), T1 zero-field splittings, transition rates from the triplet substates and spin-lattice relaxation times. We also discuss the interplay of S1-TADF and T1-phosphorescence. The combined emission paths shorten the overall decay time. For OLED applications, utilization of both singlet and triplet harvesting can be highly favorable for improvement of the device performance.
Collapse
|
24
|
Taniguchi T, Nishii Y, Mori T, Nakayama KI, Miura M. Synthesis, Structure, and Chiroptical Properties of Indolo- and Pyridopyrrolo-Carbazole-Based C 2 -Symmetric Azahelicenes. Chemistry 2021; 27:7356-7361. [PMID: 33778999 DOI: 10.1002/chem.202100327] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Indexed: 12/14/2022]
Abstract
Treatment of 11,12-bis(1,1'-biphenyl-3-yl or 6-phenylpyridin-2-yl)-substituted 11,12-dihydro-indolo[2,3-a]carbazole with an oxidizing system of Pd(II)/Ag(I) induced effective double dehydrogenative cyclization to afford the corresponding π-extended azahelicenes. The optical resolutions were readily achieved by a preparative chiral HPLC. It was found that the pyridopyrrolo-carbazole-based azahelicene that contains four nitrogen atoms exhibits ca. 6 times larger dissymmetry factors both in circularly dichroism (CD) and circularly polarized luminescence (CPL), |gCD | and |gCPL | values being 1.1×10-2 and 4.4×10-3 , respectively, as compared with the parent indolocarbazole-based azahelicene. Theoretical calculations at the RI-CC2 level were employed to rationalize the observed enhanced chiroptical responses. The (chir)optical properties of the former helicene was further tuned by a protonation leading to remarkable red-shift with a considerable enhancement of the |gCPL | value.
Collapse
Affiliation(s)
- Taisei Taniguchi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Yuji Nishii
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Tadashi Mori
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Ken-Ichi Nakayama
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Masahiro Miura
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| |
Collapse
|
25
|
Hu H, Laufkötter O, Miljković F, Bajorath J. Data set of competitive and allosteric protein kinase inhibitors confirmed by X-ray crystallography. Data Brief 2021; 35:106816. [PMID: 33604432 PMCID: PMC7873384 DOI: 10.1016/j.dib.2021.106816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 01/27/2021] [Indexed: 11/17/2022] Open
Abstract
A data set was generated comprising currently available competitive and allosteric human protein kinase inhibitors confirmed by X-ray crystallography. This data set has been used to systematically explore structural relationships between these types of inhibitors with different mechanisms of action. A major finding of this study has been that these different inhibitor types frequently displayed structural relationships and essentially represented a structural continuum [1]. Use of the data set is not limited to the inhibitor-centric exploration of structural relationships. The collection of kinase inhibitors with structurally confirmed distinct mechanisms of action can also be used, for example, to aid in structure-based drug design or the search for new allosteric kinase inhibitors.
Collapse
Affiliation(s)
- Huabin Hu
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Friedrich-Hirzebruch-Allee 6, D-53115 Bonn, Germany
| | - Oliver Laufkötter
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Friedrich-Hirzebruch-Allee 6, D-53115 Bonn, Germany
| | | | - Jürgen Bajorath
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Friedrich-Hirzebruch-Allee 6, D-53115 Bonn, Germany
| |
Collapse
|
26
|
Affiliation(s)
- Jürgen Bajorath
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Bonn, Germany
| |
Collapse
|
27
|
Kozsup M, Zhou X, Farkas E, Bényei AC, Bonnet S, Patonay T, Kónya K, Buglyó P. Synthesis, characterization and cytotoxicity studies of Co(III)-flavonolato complexes. J Inorg Biochem 2021; 217:111382. [PMID: 33588278 DOI: 10.1016/j.jinorgbio.2021.111382] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/27/2021] [Accepted: 01/27/2021] [Indexed: 11/29/2022]
Abstract
Hypoxia activated Co(III) complexes as prodrugs may provide with a selective delivery of cytotoxic or antibacterial compounds. Whithin this field sixteen novel Co(III) ternary complexes with the general formula [Co(4N)(flav)](ClO4)2, where 4N = tris(2-aminoethyl)amine (tren) or tris(2-pyridylmethyl)amine (tpa) and flav = deprotonated form of differently substituted flavonols have been synthesized, characterized, and their cytotoxicity assayed under both normoxic and hypoxic conditions. Molecular structures of two free flavonols and seven complexes are also reported. In all the complexes the bioligands exhibited the expected (O,O) coordination mode and the complexes showed a slightly distorted octahedral geometry. Cyclic voltammetric studies revealed that both the substituents of the flavonoles and the type of 4N donor ligands had an impact on the reduction potential of the complex. The ones containing tren demonstrated significantly higher stability than the tpa analogues, making these former compounds promising candidates for the development of hypoxia-activated prodrug complexes. Tpa complexes showed higher activity against both selected human cancer cell lines (A549, A431) than their free ligand flavonols, indicating that the anticancer activity of the bioligand can be enhanced upon complexation. However, slight hypoxia-selectivity was found only for a tren complex (11) with moderate cytotoxicity.
Collapse
Affiliation(s)
- Máté Kozsup
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - XueQuan Zhou
- Leiden Institute of Chemistry, Universiteit Leiden, Einsteinweg 55, 2333 CC Leiden, the Netherlands
| | - Etelka Farkas
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Attila Cs Bényei
- Department of Physical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Sylvestre Bonnet
- Leiden Institute of Chemistry, Universiteit Leiden, Einsteinweg 55, 2333 CC Leiden, the Netherlands
| | - Tamás Patonay
- Department of Organic Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Krisztina Kónya
- Department of Organic Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Péter Buglyó
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary.
| |
Collapse
|
28
|
Nagy S, Tóth E, Kacsir I, Makai A, Bényei AC, Buglyó P. Effect of the replacement of tripodal 4N donors by two 2N chelators on the redox and cytotoxic activity of maltolato and deferipronato containing Co(III) complexes. J Inorg Biochem 2021; 220:111372. [PMID: 33962134 DOI: 10.1016/j.jinorgbio.2021.111372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 11/17/2022]
Abstract
Fourteen novel CoIII ternary complexes with the general formula [Co(4N)(2O)]X2 or [Co(2N)2(2O)]X2 where 4N = tris(2-aminoethyl)amine (tren) or tris(2-pyridylmethyl)amine (tpa); 2N = 1,10-phenantroline (phen), 2,2'-bipyridine (bipy), 1,2-diaminoethane (en) or 2-(aminomethyl)pyridine (ampy) and 2O = 1,2-dimethyl-3-hydroxy-4(1H)-pyridinone (dhpH), 3-hydroxy-2-methyl-4-pyrone (maltH) or 2-ethyl-3-hydroxy-4H-pyran-4-one (etmaltH) were synthesized, characterized and their redox features explored. Molecular structure of some selected [Co(2N)2(2O)](ClO4)2 (2N = phen, bipy, en; 2O = dhp, malt) or [Co(4N)(2O)](ClO4)2 (4N = tpa; 2O = etmalt) type complexes were assessed by X-ray diffraction and showed the expected octahedral geometry. Replacement of the 4N donor ligands by two 2N donor ligands resulted in the decrease of the cathodic peak potential of the complexes indicating easier reduction and allowing therefore the tailoring of the redox properties of the complexes. Screening of selected compounds against a human derived cancer cell line, HeLa, showed that, unlike the [Co(4N)(2O)]X2 derivatives, the complexes containing 2N = bipy or phen ligands have better anticancer activity than cisplatin or carboplatin.
Collapse
Affiliation(s)
- Sándor Nagy
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Emese Tóth
- Department of Medical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - István Kacsir
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Attila Makai
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Attila Csaba Bényei
- Department of Physical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary
| | - Péter Buglyó
- Department of Inorganic and Analytical Chemistry, University of Debrecen, H-4032 Debrecen, Egyetem tér 1, Hungary.
| |
Collapse
|
29
|
Hu H, Laufkötter O, Miljković F, Bajorath J. Systematic comparison of competitive and allosteric kinase inhibitors reveals common structural characteristics. Eur J Med Chem 2021; 214:113206. [PMID: 33540355 DOI: 10.1016/j.ejmech.2021.113206] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/14/2021] [Accepted: 01/15/2021] [Indexed: 12/11/2022]
Abstract
Allosteric and ATP-competitive kinase inhibitors act by distinct mechanisms and are expected to have high and low kinase selectivity, respectively. This also raises the question whether or not these different types of inhibitors might be structurally distinct. To address this question, we have assembled data sets of currently available competitive and allosteric kinase inhibitors confirmed by X-ray crystallography and systematically compared these compounds on the basis of different structural criteria. Many competitive and allosteric inhibitors were found to contain the same or similar substructures and a subset of allosteric inhibitors was found to share core structures with ATP site-directed inhibitors. In some instances, small chemical modifications of common cores were found to yield either allosteric or competitive inhibitors. Hence, these different categories of inhibitors with distinct mechanisms of action were often structurally related and represented much more of a structural continuum than discrete states. Additional target annotations were frequently identified for competitive inhibitors, but were rare for allosteric inhibitors. As a part of this study, our collection of kinase inhibitors and the associated information are made freely available to enable further assessment of chemical modifications that distinguish similar kinase inhibitors with distinct mechanisms of action.
Collapse
Affiliation(s)
- Huabin Hu
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Friedrich-Hirzebruch-Allee 6, D-53115, Bonn, Germany
| | - Oliver Laufkötter
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Friedrich-Hirzebruch-Allee 6, D-53115, Bonn, Germany
| | - Filip Miljković
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Friedrich-Hirzebruch-Allee 6, D-53115, Bonn, Germany
| | - Jürgen Bajorath
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Friedrich-Hirzebruch-Allee 6, D-53115, Bonn, Germany.
| |
Collapse
|
30
|
Phintha A, Prakinee K, Jaruwat A, Lawan N, Visitsatthawong S, Kantiwiriyawanitch C, Songsungthong W, Trisrivirat D, Chenprakhon P, Mulholland A, van Pée KH, Chitnumsub P, Chaiyen P. Dissecting the low catalytic capability of flavin-dependent halogenases. J Biol Chem 2021; 296:100068. [PMID: 33465708 PMCID: PMC7948982 DOI: 10.1074/jbc.ra120.016004] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022] Open
Abstract
Although flavin-dependent halogenases (FDHs) are attractive biocatalysts, their practical applications are limited because of their low catalytic efficiency. Here, we investigated the reaction mechanisms and structures of tryptophan 6-halogenase (Thal) from Streptomyces albogriseolus using stopped-flow, rapid-quench flow, quantum/mechanics molecular mechanics calculations, crystallography, and detection of intermediate (hypohalous acid [HOX]) liberation. We found that the key flavin intermediate, C4a-hydroperoxyflavin (C4aOOH-FAD), formed by Thal and other FDHs (tryptophan 7-halogenase [PrnA] and tryptophan 5-halogenase [PyrH]), can react with I-, Br-, and Cl- but not F- to form C4a-hydroxyflavin and HOX. Our experiments revealed that I- reacts with C4aOOH-FAD the fastest with the lowest energy barrier and have shown for the first time that a significant amount of the HOX formed leaks out as free HOX. This leakage is probably a major cause of low product coupling ratios in all FDHs. Site-saturation mutagenesis of Lys79 showed that changing Lys79 to any other amino acid resulted in an inactive enzyme. However, the levels of liberated HOX of these variants are all similar, implying that Lys79 probably does not form a chloramine or bromamine intermediate as previously proposed. Computational calculations revealed that Lys79 has an abnormally lower pKa compared with other Lys residues, implying that the catalytic Lys may act as a proton donor in catalysis. Analysis of new X-ray structures of Thal also explains why premixing of FDHs with reduced flavin adenine dinucleotide generally results in abolishment of C4aOOH-FAD formation. These findings reveal the hidden factors restricting FDHs capability which should be useful for future development of FDHs applications.
Collapse
Affiliation(s)
- Aisaraphon Phintha
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand; School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Kridsadakorn Prakinee
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Aritsara Jaruwat
- Biomolecular Analysis and Application Research Team, National Center for Genetic Engineering and Biotechnology, Klong Luang, Pathumthani, Thailand
| | - Narin Lawan
- Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Surawit Visitsatthawong
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Chadaporn Kantiwiriyawanitch
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Warangkhana Songsungthong
- Biomolecular Analysis and Application Research Team, National Center for Genetic Engineering and Biotechnology, Klong Luang, Pathumthani, Thailand
| | - Duangthip Trisrivirat
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, Thailand
| | - Adrian Mulholland
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol, UK
| | - Karl-Heinz van Pée
- General Biochemistry, Faculty of Chemistry and Food Chemistry, Technical University of Dresden, Dresden, Germany
| | - Penchit Chitnumsub
- Biomolecular Analysis and Application Research Team, National Center for Genetic Engineering and Biotechnology, Klong Luang, Pathumthani, Thailand.
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand; School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
| |
Collapse
|
31
|
Hu H, Bajorath J. Activity cliffs produced by single-atom modification of active compounds: Systematic identification and rationalization based on X-ray structures. Eur J Med Chem 2020; 207:112846. [PMID: 32977219 DOI: 10.1016/j.ejmech.2020.112846] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/10/2020] [Accepted: 09/11/2020] [Indexed: 11/17/2022]
Abstract
In medicinal chemistry, activity cliffs (ACs) are considered as sources of critical structure-activity relationship (SAR) information. ACs are capable of revealing such SAR information because they are formed by pairs or groups of structural analogs that are distinguished by small chemical modifications leading to large variations in compound potency. Such modifications can reveal critically important substitution sites in analog series. Small AC-encoded chemical changes enable the identification of SAR determinants. In this work, we have searched medicinal chemistry data for most "subtle" ACs in which participating compounds are only distinguished by single-atom modifications. These ACs can be directly associated with lead optimization strategies such as positional atom scanning (atom "walks") or heteroatom replacements in ring structures. More than 1500 of these ACs with activity against a variety of targets were identified. To further explore newly identified ACs, we searched for X-ray structures of ligand-target complexes containing participating AC compounds. For a subset of subtle ACs, X-ray structures of complexes made it possible to examine effects of single-atom changes in light of well-defined ligand-target interactions. Since ACs capturing minimal chemical changes are of particular interest for lead optimization and drug design, we make all newly identified ACs and associated structural information freely available as an open access deposition.
Collapse
Affiliation(s)
- Huabin Hu
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Endenicher Allee 19c, D-53115, Bonn, Germany
| | - Jürgen Bajorath
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Endenicher Allee 19c, D-53115, Bonn, Germany.
| |
Collapse
|
32
|
Rigamonti L, Zardi P, Carlino S, Demartin F, Castellano C, Pigani L, Ponti A, Ferretti AM, Pasini A. Selective Formation, Reactivity, Redox and Magnetic Properties of Mn III and Fe III Dinuclear Complexes with Shortened Salen-Type Schiff Base Ligands. Int J Mol Sci 2020; 21:E7882. [PMID: 33114262 DOI: 10.3390/ijms21217882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
The reactivity of the shortened salen-type ligands H3salmp, H2salmen and H2sal(p-X)ben with variable para-substituent on the central aromatic ring (X = tBu, Me, H, F, Cl, CF3, NO2) towards the trivalent metal ions manganese(III) and iron(III) is presented. The selective formation of the dinuclear complexes [M2(μ-salmp)2], M = Mn (1a), Fe (2a), [M2(μ-salmen)2(μ-OR)2)], R = Et, Me, H and M = Mn (3a–c) or Fe (4a–c), and (M2(μ-sal[p-X]ben)2(μ-OMe)2), X = tBu, Me, H, F, Cl, CF3, NO2 and M = Mn (5a–g) or Fe (6a–g), could be identified by reaction of the Schiff bases with metal salts and the base NEt3, and their characterization through elemental analysis, infrared spectroscopy, mass spectrometry and single-crystal X-ray diffraction of 2a·2AcOEt, 2a·2CH3CN and 3c·2DMF was performed. In the case of iron(III) and H3salmp, when using NaOH as a base instead of NEt3, the dinuclear complexes [Fe2(μ-salmp)(μ-OR)(salim)2], R = Me, H (2b,c) could be isolated and spectroscopically characterized, including the crystal structure of 2b·1.5H2O, which showed that rupture of one salmp3− to two coordinated salim− ligands and release of one salH molecule occurred. The same hydrolytic tendency could be identified with sal(p-X)ben ligands in the case of iron(III) also by using NEt3 or upon standing in solution, while manganese(III) did not promote such a C–N bond breakage. Cyclic voltammetry studies were performed for 3b, 4b, 5a and 6a, revealing that the iron(III) complexes can be irreversibly reduced to the mixed-valence FeIIFeIII and FeII2 dinuclear species, while the manganese(III) derivatives can be reversibly oxidized to either the mixed-valence MnIIIMnIV or to the MnIV2 dinuclear species. The super-exchange interaction between the metal centers, mediated by the bridging ligands, resulted in being antiferromagnetic (AFM) for the selected dinuclear compounds 3b, 4b, 5a, 5e,5f, 6a and 6e. The coupling constants J (–2JŜ1·Ŝ2 formalism) had values around −13 cm−1 for manganese(III) compounds, among the largest AFM coupling constants reported so far for dinuclear MnIII2 derivatives, while values between −3 and −10 cm−1 were obtained for iron(III) compounds.
Collapse
|
33
|
Abstract
Herein, we report the synthesis and characterization of a variety of novel poly(hydrogen halide) halogenates (-I). The bifluoride ion, which is known to have the highest hydrogen bond energy of ≈160 kJ mol-1 , is the most famous among many examples of [X(HX)n ]- anions (X=F, Cl) known in the literature. In contrast, little is known about poly(hydrogen halide) halogenates containing two different halogens, ([X(HY)n ]- ). In this work we present the synthesis of anions of the type [X(HY)n ]- (X=Br, I, ClO4 ; Y=Cl, Br, CN) stabilized by the [PPh4 ]+ and [PPN]+ cation. The obtained compounds have been characterized by single-crystal X-ray diffraction, Raman spectroscopy and quantum-chemical calculations. In addition, the behavior of halide ions in hydrogen fluoride was investigated by using experimental and quantum-chemical methods in order to gain knowledge on the acidity of hydrogen halides in HF.
Collapse
Affiliation(s)
- Patrick Voßnacker
- Fachbereich Biologie, Chemie, PharmazieInstitut für Chemie und Biochemie–Anorganische ChemieFreie Universität BerlinFabeckstrasse 34/3614195BerlinGermany
| | - Simon Steinhauer
- Fachbereich Biologie, Chemie, PharmazieInstitut für Chemie und Biochemie–Anorganische ChemieFreie Universität BerlinFabeckstrasse 34/3614195BerlinGermany
| | - Julia Bader
- Fachbereich Biologie, Chemie, PharmazieInstitut für Chemie und Biochemie–Anorganische ChemieFreie Universität BerlinFabeckstrasse 34/3614195BerlinGermany
| | - Sebastian Riedel
- Fachbereich Biologie, Chemie, PharmazieInstitut für Chemie und Biochemie–Anorganische ChemieFreie Universität BerlinFabeckstrasse 34/3614195BerlinGermany
| |
Collapse
|
34
|
Roy P. Bluetongue virus assembly and exit pathways. Adv Virus Res 2020; 108:249-273. [PMID: 33837718 DOI: 10.1016/bs.aivir.2020.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Bluetongue virus (BTV) is an insect-vectored emerging pathogen of wild ruminants and livestock in many parts of the world. The virion particle is a complex structure of consecutive layers of protein surrounding a genome of 10 double-stranded (ds) RNA segments. BTV has been studied extensively as a model system for large, nonenveloped dsRNA viruses. A combination of recombinant proteins and particles together with reverse genetics, high-resolution structural analysis by X-ray crystallography and cryo-electron microscopy techniques have been utilized to provide an order for the assembly of the capsid shell and the protein sequestration required for it. Further, a reconstituted in vitro assembly system and RNA-RNA interaction assay, have defined the individual steps required for the assembly and packaging of the 10-segmented RNA genome. In addition, various microscopic techniques have been utilized to illuminate the stages of virus maturation and its egress via multiple pathways. These findings have not only given an overall understanding of BTV assembly and morphogenesis but also indicated that similar assembly and egress pathways are likely to be used by related viruses and provided an informed starting point for intervention or prevention.
Collapse
Affiliation(s)
- Polly Roy
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
| |
Collapse
|
35
|
de Brevern AG. Analysis of Protein Disorder Predictions in the Light of a Protein Structural Alphabet. Biomolecules 2020; 10:biom10071080. [PMID: 32698546 PMCID: PMC7408373 DOI: 10.3390/biom10071080] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 12/30/2022] Open
Abstract
Intrinsically-disordered protein (IDP) characterization was an amazing change of paradigm in our classical sequence-structure-function theory. Moreover, IDPs are over-represented in major disease pathways and are now often targeted using small molecules for therapeutic purposes. This has had created a complex continuum from order-that encompasses rigid and flexible regions-to disorder regions; the latter being not accessible through classical crystallographic methodologies. In X-ray structures, the notion of order is dictated by access to resolved atom positions, providing rigidity and flexibility information with low and high experimental B-factors, while disorder is associated with the missing (non-resolved) residues. Nonetheless, some rigid regions can be found in disorder regions. Using ensembles of IDPs, their local conformations were analyzed in the light of a structural alphabet. An entropy index derived from this structural alphabet allowed us to propose a continuum of states from rigidity to flexibility and finally disorder. In this study, the analysis was extended to comparing these results to disorder predictions, underlying a limited correlation, and so opening new ideas to characterize and predict disorder.
Collapse
Affiliation(s)
- Alexandre G de Brevern
- INSERM, UMR_S 1134, DSIMB, Univ Paris, INTS, Laboratoire d'Excellence GR-Ex, 75015 Paris, France
| |
Collapse
|
36
|
Rodríguez-Pérez R, Miljković F, Bajorath J. Assessing the information content of structural and protein-ligand interaction representations for the classification of kinase inhibitor binding modes via machine learning and active learning. J Cheminform 2020; 12:36. [PMID: 33431025 PMCID: PMC7245824 DOI: 10.1186/s13321-020-00434-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 04/27/2020] [Indexed: 12/27/2022] Open
Abstract
For kinase inhibitors, X-ray crystallography has revealed different types of binding modes. Currently, more than 2000 kinase inhibitors with known binding modes are available, which makes it possible to derive and test machine learning models for the prediction of inhibitors with different binding modes. We have addressed this prediction task to evaluate and compare the information content of distinct molecular representations including protein–ligand interaction fingerprints (IFPs) and compound structure-based structural fingerprints (i.e., atom environment/fragment fingerprints). IFPs were designed to capture binding mode-specific interaction patterns at different resolution levels. Accurate predictions of kinase inhibitor binding modes were achieved with random forests using both representations. The performance of IFPs was consistently superior to atom environment fingerprints, albeit only by less than 10%. An active learning strategy applying information entropy-based selection of training instances was applied as a diagnostic approach to assess the relative information content of distinct representations. IFPs were found to capture more binding mode-relevant information than atom environment fingerprints, leading to highly predictive models even when training instances were randomly selected. By contrast, for atom environment fingerprints, the derivation of accurate models via active learning depended on entropy-based selection of informative training compounds. Notably, higher information content of IFPs confirmed by active learning only resulted in small improvements in global prediction accuracy compared to models derived using atom environment fingerprints. For practical applications, prediction of binding modes of new kinase inhibitors on the basis of chemical structure is highly attractive.![]()
Collapse
Affiliation(s)
- Raquel Rodríguez-Pérez
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Endenicher Allee 19c, 53115, Bonn, Germany
| | - Filip Miljković
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Endenicher Allee 19c, 53115, Bonn, Germany
| | - Jürgen Bajorath
- Department of Life Science Informatics, B-IT, LIMES Program Unit Chemical Biology and Medicinal Chemistry, Rheinische Friedrich-Wilhelms-Universität, Endenicher Allee 19c, 53115, Bonn, Germany.
| |
Collapse
|
37
|
Jayarajan R, Satheeshkumar R, Kottha T, Subbaramanian S, Sayin K, Vasuki G. Water mediated synthesis of 6-amino-5-cyano-2-oxo-N-(pyridin-2-yl)-4-(p-tolyl)-2H-[1,2'-bipyridine]-3-carboxamide and 6-amino-5-cyano-4-(4-fluorophenyl)-2-oxo-N-(pyridin-2-yl)-2H-[1,2'-bipyridine]-3-carboxamide - An experimental and computational studies with non-linear optical (NLO) and molecular docking analyses. Spectrochim Acta A Mol Biomol Spectrosc 2020; 229:117861. [PMID: 31806479 DOI: 10.1016/j.saa.2019.117861] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/23/2019] [Accepted: 11/24/2019] [Indexed: 06/10/2023]
Abstract
6-Amino-5-cyano-2-oxo-N-(pyridin-2-yl)-4-(p-tolyl)-2H-[1,2'-bipyridine]-3-carboxamide and 6-amino-5-cyano-4-(4-fluorophenyl)-2-oxo-N-(pyridin-2-yl)-2H-[1,2'-bipyridine]-3-carboxamide were synthesized through three-component reaction between N1,N3-di(pyridin-2-yl)-malonamide, aldehyde and malononitrile in water using triethylamine as a base at room temperature. Synthesized compounds were characterized by using different techniques (FT-IR, NMR and X-ray diffraction). Additionally, the mentioned compounds were investigated by computational chemistry methods. Obtained results were supported with calculated results. Additionally, NLO properties and molecular docking analyses of related compounds were examined in detail. The binding modes of the compounds 4a and 4b were explored with the colchicine binding site of tubulin, from molecular docking studies, remarkable interactions have been observed for 4a and 4b near to the colchicines binding site of tubulin that may contribute to the inhibition of tubulin polymerization and anticancer activity.
Collapse
Affiliation(s)
- Ramasamy Jayarajan
- Department of Chemistry, Pondicherry University, Pondicherry 605014, India; Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden
| | - Rajendran Satheeshkumar
- Departamento de Química Orgánica, Facultad de Química, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, 702843 Santiago, Chile
| | | | - Sabarinathan Subbaramanian
- Department of Chemistry, Pondicherry University, Pondicherry 605014, India; Department of Chemistry, SRM Institute of Science and Technology (SRMIST), Vadapalani, Chennai-600026, TamilNadu, India
| | - Koray Sayin
- Department of Chemistry, Faculty of Science, Sivas Cumhuriyet University, 58140 Sivas, Turkey; Sivas Cumhuriyet University Advanced Research and Application Center (CUTAM), 58140 Sivas, Turkey.
| | | |
Collapse
|
38
|
Nachon F, Rosenberry TL, Silman I, Sussman JL. A Second Look at the Crystal Structures of Drosophila melanogaster Acetylcholinesterase in Complex with Tacrine Derivatives Provides Insights Concerning Catalytic Intermediates and the Design of Specific Insecticides. Molecules 2020; 25:molecules25051198. [PMID: 32155891 PMCID: PMC7179448 DOI: 10.3390/molecules25051198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 11/16/2022] Open
Abstract
Over recent decades, crystallographic software for data processing and structure refinement has improved dramatically, resulting in more accurate and detailed crystal structures. It is, therefore, sometimes valuable to have a second look at "old" diffraction data, especially when earlier interpretation of the electron density maps was rather difficult. Here, we present updated crystal structures of Drosophila melanogaster acetylcholinesterase (DmAChE) originally published in [Harel et al., Prot Sci (2000) 9:1063-1072], which reveal features previously unnoticed. Thus, previously unmodeled density in the native active site can be interpreted as stable acetylation of the catalytic serine. Similarly, a strong density in the DmAChE/ZA complex originally attributed to a sulfate ion is better interpreted as a small molecule that is covalently bound. This small molecule can be modeled as either a propionate or a glycinate. The complex is reminiscent of the carboxylate butyrylcholinesterase complexes observed in crystal structures of human butyrylcholinesterases from various sources, and demonstrates the remarkable ability of cholinesterases to stabilize covalent complexes with carboxylates. A very strong peak of density (10 σ) at covalent distance from the Cβ of the catalytic serine is present in the DmAChE/ZAI complex. This can be undoubtedly attributed to an iodine atom, suggesting an unanticipated iodo/hydroxyl exchange between Ser238 and the inhibitor, possibly driven by the intense X-ray irradiation. Finally, the binding of tacrine-derived inhibitors, such as ZA (1DX4) or the iodinated analog, ZAI (1QON) results in the appearance of an open channel that connects the base of the active-site gorge to the solvent. This channel, which arises due to the absence of the conserved tyrosine present in vertebrate cholinesterases, could be exploited to design inhibitors specific to insect cholinesterases. The present study demonstrates that updated processing of older diffraction images, and the re-refinement of older diffraction data, can produce valuable information that could not be detected in the original analysis, and strongly supports the preservation of the diffraction images in public data banks.
Collapse
Affiliation(s)
- Florian Nachon
- Département de Toxicologie et Risques Chimiques, Institut de Recherche Biomédicale des Armées, 91220 Brétigny-sur-Orge, France
- Correspondence: ; Tel.: +33-178-65-1877
| | - Terrone L. Rosenberry
- Departments of Neuroscience and Pharmacology, Mayo Clinic College of Medicine, Jacksonville, FL 32224, USA;
| | - Israel Silman
- Department of Neurobiology, Weizmann Institute of Science, 7610001 Rehovot, Israel;
| | - Joel L. Sussman
- Department of Structural Biology, Weizmann Institute of Science, 7610001 Rehovot, Israel;
| |
Collapse
|
39
|
Giereth R, Mengele AK, Frey W, Kloß M, Steffen A, Karnahl M, Tschierlei S. Copper(I) Phosphinooxazoline Complexes: Impact of the Ligand Substitution and Steric Demand on the Electrochemical and Photophysical Properties. Chemistry 2020; 26:2675-2684. [PMID: 31747089 PMCID: PMC7065177 DOI: 10.1002/chem.201904379] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Indexed: 12/29/2022]
Abstract
A series of seven homoleptic CuI complexes based on hetero-bidentate P^N ligands was synthesized and comprehensively characterized. In order to study structure-property relationships, the type, size, number and configuration of substituents at the phosphinooxazoline (phox) ligands were systematically varied. To this end, a combination of X-ray diffraction, NMR spectroscopy, steady-state absorption and emission spectroscopy, time-resolved emission spectroscopy, quenching experiments and cyclic voltammetry was used to assess the photophysical and electrochemical properties. Furthermore, time-dependent density functional theory calculations were applied to also analyze the excited state structures and characteristics. Surprisingly, a strong dependency on the chirality of the respective P^N ligand was found, whereas the specific kind and size of the different substituents has only a minor impact on the properties in solution. Most importantly, all complexes except C3 are photostable in solution and show fully reversible redox processes. Sacrificial reductants were applied to demonstrate a successful electron transfer upon light irradiation. These properties render this class of photosensitizers as potential candidates for solar energy conversion issues.
Collapse
Affiliation(s)
- Robin Giereth
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Alexander K Mengele
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Wolfgang Frey
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Marvin Kloß
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Andreas Steffen
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Michael Karnahl
- Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Stefanie Tschierlei
- Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| |
Collapse
|
40
|
Feldmann C, Miljković F, Yonchev D, Bajorath J. Identifying Promiscuous Compounds with Activity against Different Target Classes. Molecules 2019; 24:E4185. [PMID: 31752252 DOI: 10.3390/molecules24224185] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/12/2019] [Accepted: 11/15/2019] [Indexed: 11/21/2022] Open
Abstract
Compounds with multitarget activity are of high interest for polypharmacological drug discovery. Such promiscuous compounds might be active against closely related target proteins from the same family or against distantly related or unrelated targets. Compounds with activity against distinct targets are not only of interest for polypharmacology but also to better understand how small molecules might form specific interactions in different binding site environments. We have aimed to identify compounds with activity against drug targets from different classes. To these ends, a systematic analysis of public biological screening data was carried out. Care was taken to exclude compounds from further consideration that were prone to experimental artifacts and false positive activity readouts. Extensively assayed compounds were identified and found to contain molecules that were consistently inactive in all assays, active against a single target, or promiscuous. The latter included more than 1000 compounds that were active against 10 or more targets from different classes. These multiclass ligands were further analyzed and exemplary compounds were found in X-ray structures of complexes with distinct targets. Our collection of multiclass ligands should be of interest for pharmaceutical applications and further exploration of binding characteristics at the molecular level. Therefore, these highly promiscuous compounds are made publicly available.
Collapse
|
41
|
Heynderickx A, Nénon S, Siri O, Lokshin V, Khodorkovsky V. 1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss. Beilstein J Org Chem 2019; 15:2059-2068. [PMID: 31501674 PMCID: PMC6720741 DOI: 10.3762/bjoc.15.203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 08/10/2019] [Indexed: 11/27/2022] Open
Abstract
The synthesis and properties of 1,2,3,4-tetrahydro-1,4,5,8-tetraazaanthracene (THTAA) – a heterocycle involving both >N–H donating and =N– accepting moieties – have been reinvestigated. Unlike previously reported, THTAA is a thermally stable compound that can be re-sublimed at 300–310 °C without decomposition. Controlled introduction of substituents at the nitrogen atoms of THTAA led to variation of its electron donor/acceptor capability that allowed fine-tuning the absorption properties. The propensity of these compounds and a number of its derivatives to form infinite chains involving >N–H···N= and >N–H···Hal−···N+ atoms is demonstrated by X-ray structure analysis. The DFT level optimized and experimental geometry of THTAA and its derivatives show considerable loss of aromaticity within the quinoxaline moiety.
Collapse
Affiliation(s)
- Arnault Heynderickx
- Aix Marseille Université, CNRS CINaM UMR 7325 Campus de Luminy, case 913, 13288, Marseille, France
| | - Sébastien Nénon
- Aix Marseille Université, CNRS CINaM UMR 7325 Campus de Luminy, case 913, 13288, Marseille, France
| | - Olivier Siri
- Aix Marseille Université, CNRS CINaM UMR 7325 Campus de Luminy, case 913, 13288, Marseille, France
| | - Vladimir Lokshin
- Aix Marseille Université, CNRS CINaM UMR 7325 Campus de Luminy, case 913, 13288, Marseille, France
| | - Vladimir Khodorkovsky
- Aix Marseille Université, CNRS CINaM UMR 7325 Campus de Luminy, case 913, 13288, Marseille, France
| |
Collapse
|
42
|
Liu W, Garrett SC, Fedorov EV, Ramagopal UA, Garforth SJ, Bonanno JB, Almo SC. Structural Basis of CD160:HVEM Recognition. Structure 2019; 27:1286-1295.e4. [PMID: 31230945 PMCID: PMC7477951 DOI: 10.1016/j.str.2019.05.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/18/2019] [Accepted: 05/22/2019] [Indexed: 01/07/2023]
Abstract
CD160 is a signaling molecule that interacts with herpes virus entry mediator (HVEM) and contributes to a wide range of immune responses, including T cell inhibition, natural killer cell activation, and mucosal immunity. GPI-anchored and transmembrane isoforms of CD160 share the same ectodomain responsible for HVEM engagement, which leads to bidirectional signaling. Despite the importance of the CD160:HVEM signaling axis and its therapeutic relevance, the structural and mechanistic basis underlying CD160-HVEM engagement has not been described. We report the crystal structures of the human CD160 extracellular domain and its complex with human HVEM. CD160 adopts a unique variation of the immunoglobulin fold and exists as a monomer in solution. The CD160:HVEM assembly exhibits a 1:1 stoichiometry and a binding interface similar to that observed in the BTLA:HVEM complex. Our work reveals the chemical and physical determinants underlying CD160:HVEM recognition and initiation of associated signaling processes.
Collapse
Affiliation(s)
- Weifeng Liu
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA,Present address: Pfizer Inc., 230 East Grand Avenue. South San Francisco, CA 94080, USA
| | - Sarah C. Garrett
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Elena V. Fedorov
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Udupi A. Ramagopal
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA,Present address: Poomaprajna Institute of Scientific Research, #4, 16th Cross, Sadashivanagar, Bangalore 560064, India
| | - Scott J. Garforth
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Jeffrey B. Bonanno
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Steven C. Almo
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA,Department of Physiology and Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA,Lead Contact,Correspondence:
| |
Collapse
|
43
|
Kharel S, Cluff KJ, Bhuvanesh N, Gladysz JA, Blümel J. Structures and Dynamics of Secondary and Tertiary Alkylphosphine Oxides Adsorbed on Silica. Chem Asian J 2019; 14:2704-2711. [PMID: 31168965 DOI: 10.1002/asia.201900632] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Indexed: 11/12/2022]
Abstract
The three secondary phosphine oxides [CH2 =CH(CH2 )4 ]2 HPO (1), [CH2 =CH(CH2 )5 ]2 HPO (2), and [CH2 =CH(CH2 )6 ]2 HPO (3), and two diphosphine dioxides, {[CH2 =CH(CH2 )6 ]2 PO(CH2 )7 }2 (4) and {[CH2 =CH(CH2 )6 ]2 PO(CH2 )4 }2 (5), incorporating long methylene chains, are described. The single crystal X-ray structures of 1, 2, and 5 have been determined. The phosphine oxides 3, 4, and 5 have been adsorbed on silica in submonolayer quantities to give 3 a-5 a. The 1 H, 13 C, and 31 P solid-state NMR spectra of polycrystalline 3-5 have been analyzed and compared with those of 3 a-5 a. The changes of the solid-state NMR characteristics upon adsorption and the surface mobilities of the phosphine oxides are discussed.
Collapse
Affiliation(s)
- Sugam Kharel
- Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas, 77842-3012, USA
| | - Kyle J Cluff
- Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas, 77842-3012, USA
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas, 77842-3012, USA
| | - John A Gladysz
- Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas, 77842-3012, USA
| | - Janet Blümel
- Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas, 77842-3012, USA
| |
Collapse
|
44
|
Kieninger C, Deery E, Lawrence AD, Podewitz M, Wurst K, Nemoto-Smith E, Widner FJ, Baker JA, Jockusch S, Kreutz CR, Liedl KR, Gruber K, Warren MJ, Kräutler B. The Hydrogenobyric Acid Structure Reveals the Corrin Ligand as an Entatic State Module Empowering B 12 Cofactors for Catalysis. Angew Chem Int Ed Engl 2019; 58:10756-10760. [PMID: 31115943 PMCID: PMC6771967 DOI: 10.1002/anie.201904713] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Indexed: 11/09/2022]
Abstract
The B12 cofactors instill a natural curiosity regarding the primordial selection and evolution of their corrin ligand. Surprisingly, this important natural macrocycle has evaded molecular scrutiny, and its specific role in predisposing the incarcerated cobalt ion for organometallic catalysis has remained obscure. Herein, we report the biosynthesis of the cobalt-free B12 corrin moiety, hydrogenobyric acid (Hby), a compound crafted through pathway redesign. Detailed insights from single-crystal X-ray and solution structures of Hby have revealed a distorted helical cavity, redefining the pattern for binding cobalt ions. Consequently, the corrin ligand coordinates cobalt ions in desymmetrized "entatic" states, thereby promoting the activation of B12 -cofactors for their challenging chemical transitions. The availability of Hby also provides a route to the synthesis of transition metal analogues of B12 .
Collapse
Affiliation(s)
- Christoph Kieninger
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria
| | - Evelyne Deery
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | | | - Maren Podewitz
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Klaus Wurst
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Emi Nemoto-Smith
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Florian J Widner
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria
| | - Joseph A Baker
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | | | - Christoph R Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Karl Gruber
- Institute for Molecular Biosciences, University of Graz, Austria
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Bernhard Kräutler
- Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, 6020, Innsbruck, Austria
| |
Collapse
|
45
|
Gabdulkhakov AG, Kostareva OS, Kolyadenko IA, Mikhaylina AO, Trubitsina LI, Tishchenko SV. [Incorporation of Copper Ions into T2/T3 Centers of Two-Domain Laccases]. Mol Biol (Mosk) 2019; 52:29-35. [PMID: 29512633 DOI: 10.7868/s0026898418010056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 06/23/2017] [Indexed: 11/23/2022]
Abstract
Laccase belongs to the family of copper-containing oxidases. A study was made of the mechanism that sustains the incorporation of copper ions into the T2/T3 centers of recombinant two-domain laccase Streptomyces griseoflavus Ac-993. The occupancy of the T3 center by copper ions was found to increase with an increasing copper content in the culture medium and after dialysis of the protein preparation against a copper sulfate-containing buffer. The T2 center was filled only when overproducer strain cells were grown at a higher copper concentration in the medium. Two-domain laccases were assumed to possess a channel that serves to deliver copper ions to the T3 center during the formation of the three-dimensional laccase conformation and dialysis of the protein preparation. A narrower channel leads to the T2 center in two-domain laccases compared with three-domain ones, rendering the center less accessible for copper atoms. The incorporation of copper ions into the T2 center of two-domain laccases is likely to occur in the course of their biosynthesis or the formation of a functional trimer.
Collapse
Affiliation(s)
- A G Gabdulkhakov
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia
| | - O S Kostareva
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia
| | - I A Kolyadenko
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia
| | - A O Mikhaylina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia
| | - L I Trubitsina
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia
| | - S V Tishchenko
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia.,
| |
Collapse
|
46
|
Szabó T, Bényei A, Szilágyi L. Bivalent glycoconjugates based on 1,5-diazabicyclo[3.3.0]octa-3,6-diene-2,8-dione ("bimane") as a central scaffold. Carbohydr Res 2019; 473:88-98. [PMID: 30654289 DOI: 10.1016/j.carres.2019.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/07/2018] [Accepted: 01/05/2019] [Indexed: 11/16/2022]
Abstract
The heteroaromatic fused diazabicyclic "bimane" ring system, discovered four decades ago, is endowed with remarkable chemical and photophysical properties. No carbohydrate derivatives of bimanes have, however, been described thus far. Here we report on the syntheses of a range of bimanes decorated with various glycosyl residues. Mono- and disaccharide residues were attached to syn- or anti-bimane central cores via thio-, disulfido- or selenoglycosidic linkages to obtain novel fluorescent or nonfluorescent glycoconjugates. Cu(I)-catalyzed cycloaddition of glycosyl azides to a bimane diethynyl derivative furnished further bivalent glycoconjugates with sugar residues linked to the central bimane core via 1,2,3-triazole rings. We have determined the crystal and molecular structures of several glycosylated and non-glycosylated bimanes and report fluorescence data for the new compounds.
Collapse
Affiliation(s)
- Tamás Szabó
- Gedeon Richter Plc, H-1103 Budapest, Gyömrői út 19-21, Hungary
| | - Attila Bényei
- Department of Physical Chemistry, University of Debrecen, H-4032, Debrecen, Egyetem tér 1, Hungary
| | - László Szilágyi
- Department of Organic Chemistry, University of Debrecen, H-4032, Debrecen, Egyetem tér 1, Hungary.
| |
Collapse
|
47
|
Housseini B Issa K, Phan G, Broutin I. Functional Mechanism of the Efflux Pumps Transcription Regulators From Pseudomonas aeruginosa Based on 3D Structures. Front Mol Biosci 2018; 5:57. [PMID: 29971236 PMCID: PMC6018408 DOI: 10.3389/fmolb.2018.00057] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/31/2018] [Indexed: 01/19/2023] Open
Abstract
Bacterial antibiotic resistance is a worldwide health problem that deserves important research attention in order to develop new therapeutic strategies. Recently, the World Health Organization (WHO) classified Pseudomonas aeruginosa as one of the priority bacteria for which new antibiotics are urgently needed. In this opportunistic pathogen, antibiotics efflux is one of the most prevalent mechanisms where the drug is efficiently expulsed through the cell-wall. This resistance mechanism is highly correlated to the expression level of efflux pumps of the resistance-nodulation-cell division (RND) family, which is finely tuned by gene regulators. Thus, it is worthwhile considering the efflux pump regulators of P. aeruginosa as promising therapeutical targets alternative. Several families of regulators have been identified, including activators and repressors that control the genetic expression of the pumps in response to an extracellular signal, such as the presence of the antibiotic or other environmental modifications. In this review, based on different crystallographic structures solved from archetypal bacteria, we will first focus on the molecular mechanism of the regulator families involved in the RND efflux pump expression in P. aeruginosa, which are TetR, LysR, MarR, AraC, and the two-components system (TCS). Finally, the regulators of known structure from P. aeruginosa will be presented.
Collapse
Affiliation(s)
- Karim Housseini B Issa
- Laboratoire de Cristallographie et RMN Biologiques (UMR 8015), Centre National de la Recherche Scientifique, Faculté de Pharmacie, Université Paris Descartes, Université Sorbonne Paris Cité, Paris, France
| | - Gilles Phan
- Laboratoire de Cristallographie et RMN Biologiques (UMR 8015), Centre National de la Recherche Scientifique, Faculté de Pharmacie, Université Paris Descartes, Université Sorbonne Paris Cité, Paris, France
| | - Isabelle Broutin
- Laboratoire de Cristallographie et RMN Biologiques (UMR 8015), Centre National de la Recherche Scientifique, Faculté de Pharmacie, Université Paris Descartes, Université Sorbonne Paris Cité, Paris, France
| |
Collapse
|
48
|
Casas JS, Couce MD, Sánchez A, Seoane R, Sordo J, Perez-Estévez A, Vázquez-López E. Triphenyltin derivatives of sulfanylcarboxylic esters. J Inorg Biochem 2018; 180:163-70. [PMID: 29291491 DOI: 10.1016/j.jinorgbio.2017.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 12/11/2017] [Accepted: 12/19/2017] [Indexed: 11/20/2022]
Abstract
The reaction of 3-(aryl)-2-sulfanylpropenoic acids [H2xspa; x: p=3-phenyl-, f=3-(2-furyl)-, t=3-(2-thienyl)-] with methanol or ethanol gave the corresponding methyl (Hxspme) or ethyl (Hxspee) esters. The reaction of these esters (HL) with triphenyltin(IV) hydroxide gave compounds of the type [SnPh3L], which were isolated and characterized as solids by elemental analysis, IR spectroscopy and mass spectrometry and in solution by multinuclear (1H, 13C and 119Sn) NMR spectroscopy. The structures of [SnPh3(pspme)], [SnPh3(fspme)] and [SnPh3(fspee)] were determined by X-ray diffractometry and the antimicrobial activity against E. coli, S. aureus, B. subtilis, P. aeruginosa, Resistant P. aeruginosa (a strain resistant to 'carbapenem'), and C. albicans was tested and the in vitro cytotoxic activity against the HeLa-229, A2780 and A2780cis cell lines was determined for all compounds.
Collapse
|
49
|
Triller G, Scally SW, Costa G, Pissarev M, Kreschel C, Bosch A, Marois E, Sack BK, Murugan R, Salman AM, Janse CJ, Khan SM, Kappe SHI, Adegnika AA, Mordmüller B, Levashina EA, Julien JP, Wardemann H. Natural Parasite Exposure Induces Protective Human Anti-Malarial Antibodies. Immunity 2017; 47:1197-1209.e10. [PMID: 29195810 DOI: 10.1016/j.immuni.2017.11.007] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/22/2017] [Accepted: 11/04/2017] [Indexed: 12/21/2022]
Abstract
Antibodies against the NANP repeat of circumsporozoite protein (CSP), the major surface antigen of Plasmodium falciparum (Pf) sporozoites, can protect from malaria in animal models but protective humoral immunity is difficult to induce in humans. Here we cloned and characterized rare affinity-matured human NANP-reactive memory B cell antibodies elicited by natural Pf exposure that potently inhibited parasite transmission and development in vivo. We unveiled the molecular details of antibody binding to two distinct protective epitopes within the NANP repeat. NANP repeat recognition was largely mediated by germline encoded and immunoglobulin (Ig) heavy-chain complementarity determining region 3 (HCDR3) residues, whereas affinity maturation contributed predominantly to stabilizing the antigen-binding site conformation. Combined, our findings illustrate the power of exploring human anti-CSP antibody responses to develop tools for malaria control in the mammalian and the mosquito vector and provide a molecular basis for the structure-based design of next-generation CSP malaria vaccines.
Collapse
|
50
|
Grajewski J, Mądry T, Kwit M, Warżajtis B, Rychlewska U, Gawroński J. Benzhydryl Ethers of Tartaric Acid Derivatives: Stereochemical Response of a Dynamically Chiral Propeller. Chemphyschem 2017; 18:2197-2207. [PMID: 28544199 DOI: 10.1002/cphc.201700332] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/22/2017] [Indexed: 11/09/2022]
Abstract
The benzhydryl (diphenylmethyl) group is a molecular propeller that can act as a chirality reporter if it is introduced nearby a stereogenic center by making an ether bond. The hydrophobic character of the benzhydryl group allows transformation of insoluble natural tartaric acid derivatives into soluble entities in a nonpolar environment. Electronic circular dichroism spectra, recorded within the short-wavelength region of the phenyl 1 B transitions (190-200 nm) shows strong bisignate Cotton effects. The signs and magnitudes of these Cotton effects are a function of absolute configuration and conformation of the molecule and do not primarily arise from exciton coupling of chiral benzhydryl chromophores. In crystals, the main-chain conformation is stabilized by intramolecular hydrogen bonds and CH-CO dipolar interactions. The number of the donor NH groups has a pronounced effect on the preferred conformations and inclusion properties of benzhydryl-(R,R)-tartaric acid diamides. Evidence is shown for the solvent dependency of the conformations of NH amides of tartaric acid diphenylmethyl ethers.
Collapse
Affiliation(s)
- Jakub Grajewski
- Department of Chemistry, Adam Mickiewicz University, Umultowska 89B, 61-614, Poznań, Poland
| | - Tomasz Mądry
- Department of Chemistry, Adam Mickiewicz University, Umultowska 89B, 61-614, Poznań, Poland
| | - Marcin Kwit
- Department of Chemistry, Adam Mickiewicz University, Umultowska 89B, 61-614, Poznań, Poland
| | - Beata Warżajtis
- Department of Chemistry, Adam Mickiewicz University, Umultowska 89B, 61-614, Poznań, Poland
| | - Urszula Rychlewska
- Department of Chemistry, Adam Mickiewicz University, Umultowska 89B, 61-614, Poznań, Poland
| | - Jacek Gawroński
- Department of Chemistry, Adam Mickiewicz University, Umultowska 89B, 61-614, Poznań, Poland
| |
Collapse
|