1
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Selective transformations of friedelanes isolated from cork smoker wash solids. Steroids 2024; 201:109333. [PMID: 37939981 DOI: 10.1016/j.steroids.2023.109333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 11/05/2023] [Indexed: 11/10/2023]
Abstract
Friedelin (1) and 3-acetoxyfriedel-3-en-2-one (4), commonly known as friedelane triterpenoids, have been isolated from cork smoker wash solids (also known as black wax) on a multi-gram scale. These compounds are valuable starting materials for the synthesis of new friedelane derivatives. Stereoselective reduction of friedelin by treatment with LiAlH4, sodium, or catalytic hydrogenation results in the formation of both isomers of friedelinol (5 and 7) in excellent yields. Similarly, the reduction of 3-acetoxyfriedel-3-en-2-one gave epi-cerin (14) and a series of isomeric 2,3-diols or α-hydroxyketones. These transformations provide the most straightforward and convenient methods for the synthesis of A-ring functionalised friedelane derivatives using easily accessible starting materials.
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2
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Antioxidant activity of novel diosgenin derivatives: Synthesis, biological evaluation, and in silico ADME prediction. Steroids 2022; 188:109115. [PMID: 36154831 DOI: 10.1016/j.steroids.2022.109115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/06/2022] [Accepted: 09/16/2022] [Indexed: 01/11/2023]
Abstract
A series of novel diosgenin (DSG) derivatives has been synthesized and tested in vitro for their antioxidant activity. Initially, four analogues have been evaluated for their cytotoxicity using normal human skin fibroblast (NHDF) as model cells. As a result, 84% of NHDF cells were still alive at 5 µM, so these compounds can be considered as innoxious to fibroblasts at this concentration. Then, hemolytic activity against human erythrocytes was studied in order to evaluate the potential impact of tested compounds against normal host cells. The result < 5% of hemolysis rates suggest no lytic activity for most compounds. After that, the main test - evaluation the antioxidant effect of DSG and its new derivatives against lipid peroxidation in the o/w emulsion model - was performed. The most promising compound (8) exhibited the significant antioxidant activity and the biocompatibility towards normal human dermal fibroblasts and red bloods cells. This p-aminobenzoic derivative revealed 61.6% blocking of induced lipid oxidation. Furthermore, eleven predicted ADME properties were predicted for all tested compounds and revealed that they are in compliance with drug-likeness criteria.
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3
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Effect of modification of betulinic acid at the C3-carbon atom of homolupane triterpenoids on the antiproliferative activity in vitro. J Steroid Biochem Mol Biol 2022; 224:106161. [PMID: 35932956 DOI: 10.1016/j.jsbmb.2022.106161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 07/26/2022] [Accepted: 08/02/2022] [Indexed: 11/15/2022]
Abstract
In search of new cytotoxic derivatives based on the lupane scaffold, methyl betulonate and methyl 20,29-dihydrobetulonate were conjugated with Reformatsky reagents to provide homolupanes extended at the C3-carbon atom. Further transformations of the functional groups afforded a series of derivatives with 2-hydroxyethyl and allyl alcohol moieties. Their varying antiproliferative activity in vitro was then investigated in four cancer cell lines and in normal human BJ fibroblasts. In cervical carcinoma HeLa cells, derivatives 5, 6 and 17 were the most promising with lower micromolar IC50s and no toxicity to fibroblasts, thus showing a high therapeutic index. In addition, induction of apoptosis was found in HeLa cells after 24 h treatment with compounds 5, 6, 13 and 29. This newly synthesized series is more interesting than the published lupane and homolupane triterpenes and saponins, due to their nontoxicity towards healthy human cells and stronger cytotoxicity to various cancer cell lines. This approach increases their potential as anticancer agents.
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4
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Three modes of interactions between anions and phenolic macrocycles: a comparative study. Org Biomol Chem 2022; 20:5095-5103. [PMID: 35699382 DOI: 10.1039/d2ob00880g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Macrocyclic polyphenolic compounds such as resorcin[4]arenes can be considered as multidentate anion receptors. In the current work, we combine new experimental data and reports from the previous literature (solution data and deposited crystal structures from the CCDC) to systematically analyze binding motifs between resorcin[4]arene derivatives and anions, determine the role of supporting interactions from CH donors, ion pairing and estimate their relative strength. We have found that in medium polarity solvents (THF) anion binding is a main driving force for the formation of complexes between resorcinarenes and Alk4NX salts. Three binding modes have been detected using 1H NMR and DOSY, depending on the type of additional interactions. Mode I was observed for upper-rim unsubstituted resorcinarenes, which use OH groups and aromatic CH from the upper rim as hydrogen bond donors to form multidentate and multivalent binding sites at the upper rim. Mode II was observed for upper-rim halogenated resorcinarenes (tetrabromo- and tetraiodo-derivatives), which use OH groups and aliphatic CH atoms from the bridges to support the chelation of anions between aromatic units. This binding mode is also multidentate and multivalent, but weaker and more anion-selective than mode I (works effectively for chlorides but not for bromides). For O-substituted derivatives, mode III is observed, with anions bound in a nest formed by aromatic CH atoms in the lower rim (multidentate but monovalent binding). The relative strength of these three binding modes, their solvent-dependence, and emergence in the crystal structures (CCDC) have been evaluated.
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5
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Abstract
![]()
Spatial sequestration
of molecules is a prerequisite for the complexity
of biological systems, enabling the occurrence of numerous, often
non-compatible chemical reactions and processes in one cell at the
same time. Inspired by this compartmentalization concept, chemists
design and synthesize artificial nanocontainers (capsules and cages)
and use them to mimic the biological complexity and for new applications
in recognition, separation, and catalysis. Here, we report the formation
of large closed-shell species by interactions of well-known polyphenolic
macrocycles with anions. It has been known since many years that C-alkyl
resorcin[4]arenes (R4C) and C-alkyl pyrogallol[4]arenes
(P4C) narcissistically self-assemble in nonpolar solvents
to form hydrogen-bonded capsules. Here, we show a new interaction
model that additionally involves anions as interacting partners and
leads to even larger capsular species. Diffusion-ordered spectroscopy
and titration experiments indicate that the anion-sealed species have
a diameter of >26 Å and suggest stoichiometry (M)6(X–)24 and tight ion pairing
with cations. This self-assembly is effective in a nonpolar environment
(THF and benzene but not in chloroform), however, requires initiation
by mechanochemistry (dry milling) in the case of non-compatible solubility.
Notably, it is common among various polyphenolic macrocycles (M) having diverse geometries and various conformational lability.
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6
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Synthesis and cytotoxic activity of 1,2,3-triazoles derived from 2,3-seco-dihydrobetulin via a click chemistry approach. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.131751] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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7
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Unexpected Reaction Products of Uracil and Its Methyl Derivatives with Acetic Anhydride and Methylene Chloride. J Org Chem 2021; 86:14321-14332. [PMID: 34591486 DOI: 10.1021/acs.joc.1c00748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
New acetyl derivatives of uracil, 6-methyluracil, and thymine were obtained in the course of an unconventional synthesis in methylene chloride. It was shown that products with the acetyloxymethyl fragment are formed according to a mechanism different from that for products with the acetyloxyethyl group. In particular, for uracil it was proven that the reaction with Ac2O, TEA, and CH2Cl2 leads to 1-acetyloxymethyluracil, where the N1 substituent is composed of the -CH2- fragment that originated from CH2Cl2 and the 1-acetyloxy moiety from Ac2O. The reaction of uracil with Ac2O, TEA, CH2Cl2, and DMAP leads to an acetyloxyethyl derivative in which the -CH2-CH2- fragment originates from TEA and the 1-acetyloxy moiety from Ac2O. A possible mechanism for the formation of new compounds was suggested and supported by the density functional theory/B3LYP quantum mechanical calculations. New compounds (39 in total, including seven deuterated) were fully characterized by nuclear magnetic resonance and high-resolution mass spectrometry techniques.
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8
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The reported formation of
5
H
‐dibenzo
[
b,e
][1,4]diazepin‐11(
10
H
)‐ones in the
noncatalyzed
,
base‐promoted
double arylation of anthranilamide revisited. Correction of some product structures. J Heterocycl Chem 2021. [DOI: 10.1002/jhet.4311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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9
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Oxidative Functionalization of Trinor-18α-olean-17(22)-ene Derivatives. Annulation of the E-Ring by an Intramolecular Aldol Reaction. J Org Chem 2021; 86:7636-7647. [PMID: 34033473 DOI: 10.1021/acs.joc.1c00697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
cis-Dihydroxylation of trinor-18α-olean-17(22)-ene 2 with osmium tetroxide led to diol 9. Its cleavage with lead tetraacetate gave tetracyclic ketoaldehyde 10. By comparison, the ozonation of trinor-18α-olean-17(22)-ene 2 in the presence of p-toluenesulfonic acid gave the corresponding ketoacetal 12. Both products were subjected to an intramolecular aldol reaction under the acidic conditions and yielded unusual triterpenes bearing a bicyclo[4.3.1]decane fragment (22). Further manipulation of the protective groups afforded compounds useful in triterpene synthesis, especially in the preparation of potentially biologically active saponins based on a tetracyclic terpene core.
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10
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Fluorescent Molecular Cages with Sucrose and Cyclotriveratrylene Units for the Selective Recognition of Choline and Acetylcholine. J Org Chem 2021; 86:5129-5141. [PMID: 33710904 PMCID: PMC8041319 DOI: 10.1021/acs.joc.1c00019] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The synthesis of
four fluorescent diastereoisomeric molecular cages
containing cyclotriveratrylene and sucrose moieties connected via the naphthalene linkers is reported. These diastereoisomers
were found to be selective and efficient receptors for acetylcholine
and choline. Compound P-5a has a better
affinity for choline over acetylcholine, while cage M-5a exhibits a higher association constant for acetylcholine
over choline. The highest selectivity value was observed for compound M-5a (KACh/KCh = 3.1). Cages P-5a, P-5b, M-5a, and M-5b were fully characterized
by the advanced NMR techniques, and ECD spectroscopy was supported
by DFT calculations. The binding constants Ka of these receptors were determined by fluorescence titration
experiments in acetonitrile.
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11
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Inside Cover: Dodecameric Anion‐Sealed Capsules based on Pyrogallol[5]arenes and Resorcin[5]arenes (Angew. Chem. Int. Ed. 9/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/anie.202100816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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12
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Innentitelbild: Dodecameric Anion‐Sealed Capsules based on Pyrogallol[5]arenes and Resorcin[5]arenes (Angew. Chem. 9/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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13
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Dodecameric Anion-Sealed Capsules based on Pyrogallol[5]arenes and Resorcin[5]arenes. Angew Chem Int Ed Engl 2021; 60:4540-4544. [PMID: 33372317 DOI: 10.1002/anie.202013105] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/07/2020] [Indexed: 11/09/2022]
Abstract
The paper reports formation of exceptionally large capsular species (diameter of c. a. 30 Å) by interactions of polyphenolic macrocycles with 5-fold symmetry with anions. Pyrogallol[5]arenes and resorcin[5]arenes interact with anions via hydrogen bonds involving phenolic OH groups or aromatic CH groups. Based on NMR titration experiments, diffusion coefficients, and geometric requirements, it is postulated that the capsules have (P5H)12 (X- )60 or (R5H)12 (X- )60 stoichiometry and a unique geometry of one of the Platonic solids-a dodecahedron. The capsules exist in THF and in benzene, but not in chloroform, reflecting competitive effects in the solvation of anions. It is also demonstrated that mechanochemical pre-treatment (dry-milling) of solid samples is indispensable to initialize self-assembly in benzene.
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14
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Front Cover: Chiral Molecular Cages Based on Cyclotriveratrylene and Sucrose Units Connected with
p
‐Phenylene Linkers (Eur. J. Org. Chem. 6/2021). European J Org Chem 2021. [DOI: 10.1002/ejoc.202100061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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Chiral Molecular Cages Based on Cyclotriveratrylene and Sucrose Units Connected with
p
‐Phenylene Linkers. European J Org Chem 2021. [DOI: 10.1002/ejoc.202001482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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16
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Dodecameric Anion‐Sealed Capsules based on Pyrogallol[5]arenes and Resorcin[5]arenes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202013105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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17
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Rearrangements of the Betulin Core. Synthesis of Terpenoids Possessing the Bicyclo[3.3.1]nonane Fragment by Rearrangement of Lupane-Type Epoxides. J Org Chem 2020; 86:1084-1095. [PMID: 33353300 DOI: 10.1021/acs.joc.0c02560] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The rearrangements of dihydrobetulin, dihydrobetulinic acid, and abeo-lupane epoxides under acidic conditions (HCl, montmorillonite K10, and BF3·Et2O) were studied. The treatment of dihydrobetulin with HCl or K10 produced abeo-lupane olefins. Their epoxidation afforded epoxides, which, in the presence of protic or Lewis acids, rearranged to dienes or lupanes bearing a bicyclo[3.3.1]nonane fragment. The structure of final products depended on the nature of the catalyst. The HCl promoted 1,4-elimination of water, whereas in the presence of BF3·Et2O bond migration took place preferentially. Montmorillonite K10 favored cyclization to bicyclononane.
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18
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New lupane bidesmosides exhibiting strong cytotoxic activities in vitro. Bioorg Chem 2020; 100:103868. [PMID: 32388425 DOI: 10.1016/j.bioorg.2020.103868] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/16/2020] [Accepted: 04/18/2020] [Indexed: 02/07/2023]
Abstract
Triterpene bidesmosides are considered as highly cytotoxic saponins, usually less toxic against normal cells than monodesmosides, and less haemolytic. Biological activity of the betulin-type bidesmosides, rarely found in Nature, and seldom prepared due to serious synthetic problems, is poorly recognized. We report herein a protocol for the preparation of disubstituted lupane saponins (betulin bidesmosides) by treatment of their benzoates with potassium carbonate in dichloromethane / methanol solution. Cytotoxicity of all compounds was tested in vitro for a series of cancer cell lines, as well as normal human skin BJ fibroblasts. Presence of l-rhamnose moiety is crucial for cytotoxicity of betulin bidesmosides. On the other hand, l-arabinose fragment connected to lupane C-3 carbon atom significantly decreases activity. Presented results clearly show that betulin bidesmosides have significant clinical potential as anticancer agents.
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19
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Synthesis and anti-tumour, immunomodulating activity of diosgenin and tigogenin conjugates. J Steroid Biochem Mol Biol 2020; 198:105573. [PMID: 32017993 DOI: 10.1016/j.jsbmb.2019.105573] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022]
Abstract
A series of novel diosgenin (DSG) and tigogenin (TGG) derivatives with diosgenin or tigogenin steroid aglycons linked to levulinic and 3,4-dihydroxycinnamic acids, dipeptides and various amino acids by an ester bond at the C3-oxygen atom of the steroid skeleton has been synthesized. Diosgenyl esters have been prepared by an esterification reaction (DCC/DMAP) of diosgenin with the corresponding acids. All analogues have been evaluated in vitro for their antiproliferative profile against cancer cell lines (MCF-7, MDA-MB-231, PC-3) and human umbilical vein endothelial cells (HUVEC). Analogue2c (l-serine derivative of TGG), the best representative of the series showed IC50 of 1.5 μM (MCF-7), and induced apoptosis in MCF-7 by activating caspase-3/7. The immunomodulatory properties of six synthesized analogues have been determined by examining their effects on the expression of cytokine genes essential for the functioning of the human immune system (IL-1, IL-4, IL-10, IL-12 and TNF-α). Biological evaluation has revealed that new compounds 4c and 16a do not induce the expression of pro-inflammatory cytokines in THP-1 cells after the lipopolysaccharide (LPS) stimulation. They also stimulate the expression of anti-inflammatory IL-10 that acts stronger than diosgenin itself. An in silico ADME properties(absorption, distribution, metabolism, excretion) study was also performed to predict the pharmacokinetic profile of the synthesized compounds. To shed light on the molecular interactions between the synthesized compounds and the glucocorticoid receptor and the estrogen receptor, 2c, 4c and 16a compounds were docked into the active binding sites of these receptors. The in silico and in vitro data suggested that this new group of compounds might be considered as a promising scaffold for further modification of more potent and selective anticancer and immunomodulatory agents.
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20
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Abstract
Cyclotriveratrylene (CTV) is a C3-symmetrical macrocycle, which can be used as a chiral building block in the construction of supramolecular containers. Coupling of the CTV unit with a sucrose molecule gave enantiopure water-soluble (after deprotection) containers. The absolute configuration of the synthesized capsules was determined by NMR and ECD spectroscopies and DFT calculations.
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21
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Direct Reductive Cyclocondensation of the Nitro Group with the Amido Group: Key Role of the Iminophosphorane Intermediate in the Synthesis of 1,4-Dibenzodiazepine Derivatives. J Org Chem 2019; 84:2277-2286. [PMID: 30707024 DOI: 10.1021/acs.joc.8b02682] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A class of dialkylamino-substituted dibenzodiazepines and their hetero analogues was synthesized by the intramolecular aza-Wittig condensation of the amido group with iminophosphoranes. The one-pot, two-step procedure includes reductive synthesis of the intermediate iminophosphoranes from the corresponding nitroamides and tributylphosphine.
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22
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A diversity of alkylation/acylation products of uracil and its derivatives: synthesis and a structural study. Org Biomol Chem 2019; 17:354-362. [PMID: 30548042 DOI: 10.1039/c8ob02552e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
tert-Butyl dicarbonate (Boc2O) and ethyl iodide (EtI) reactions with uracil (U), thymine (T) and 6-methyluracil (6-MU) were performed following routine procedures in pyridine/DMF solvents and with DMAP as the catalyst. Among 20 synthesized compounds, a derivative of 6-methyluracil substituted by the Boc-pyridine moiety at the C5 position appeared unexpectedly. The NMR spectra confirmed the molecular structure of all uracil derivatives. Parallel quantum mechanical DFT calculations supported the experimental findings.
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23
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Benzo[4,5]thiazolo[3,2- c][1,3,5,2]oxadiazaborinines: Synthesis, Structural, and Photophysical Properties. J Org Chem 2018; 83:12129-12142. [PMID: 30173505 DOI: 10.1021/acs.joc.8b02098] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A family of highly emissive benzo[4,5]thiazolo[3,2- c][1,3,5,2]oxadiazaborinines, conjugated with the donor 4-dimethylaminophenyl group, was designed and synthesized. Their photophysical, both in solution and in the solid state, and structural properties were investigated. The influence of donor and acceptor substituents (R) in the benzothiazole unit on photophysical properties of complexes was found out. The tetrafluorobenzothiazole analogue exhibits nonbonded nuclear spin-spin coupling between fluorines from the BF2 group and α-fluorine atom at the benzene ring. Additionally, this boron complex demonstrates a comparatively high solid-state fluorescence quantum yield (Φ = 0.34).
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24
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Synthesis and Antioxidant Activity of Caffeic Acid Derivatives. Molecules 2018; 23:E2199. [PMID: 30200272 PMCID: PMC6225178 DOI: 10.3390/molecules23092199] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 08/26/2018] [Accepted: 08/28/2018] [Indexed: 11/16/2022] Open
Abstract
A series of caffeic acid derivatives were synthesized via a modified Wittig reaction which is a very important tool in organic chemistry for the construction of unsaturated carbon⁻carbon bonds. All reactions were performed in water medium at 90 °C. The aqueous Wittig reaction worked best when one unprotected hydroxyl group was present in the phenyl ring. The olefinations in the aqueous conditions were also conducted with good yields in the presence of two unprotected hydroxyl groups. When the number of the hydroxyl groups was increased to three, the reaction yields were worse, and the derivatives 12, 13, and 18 were obtained with 74%, 37%, and 70% yields, respectively. Nevertheless, the Wittig reaction using water as the essential medium is an elegant one-pot synthesis and a greener method, which can be a safe alternative for implementation in organic chemistry. The obtained compounds were tested for their antioxidant activity, and 12, 13, and 18 showed the highest activities. Moreover, all synthesized compounds displayed no cytotoxicity, and can therefore be used in the pharmaceutical or cosmetic industry.
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25
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"Choose-a-size" control in the synthesis of sucrose based urea and thiourea macrocycles. Org Biomol Chem 2018; 16:6063-6069. [PMID: 30090916 DOI: 10.1039/c8ob01340c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Highly efficient synthesis of monomeric and dimeric thiourea macrocycles with a per-O-benzylated sucrose scaffold is reported. Application of flow synthesis results in exclusive formation of a monomer in 79% yield. Batch synthesis provides two isomeric dimers in 85% yield. Dimers are capable of anion binding via two thiourea groups acting cooperatively.
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26
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Efficient glycosylation of natural Danshensu and its enantiomer by sugar and 2-deoxy sugar donors. Carbohydr Res 2018; 460:19-28. [PMID: 29501860 DOI: 10.1016/j.carres.2018.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/07/2018] [Accepted: 02/07/2018] [Indexed: 11/15/2022]
Abstract
An efficient methodology of the glycosylation process of a secondary plant metabolite (R-Danshensu) and its enantiomer by sugar and 2-deoxy sugar donors was developed. The overall synthesis of the new sugar derivatives involved two steps, starting from the previously synthesized protected R and S Danshensu (1 and 2). The deoxy sugar derivatives of R and S Danshensu were obtained from available tri-O-acetyl-2-deoxy-D-glucal and di-O-acetyl-2-deoxy-D-ramnal. The direct glycosylation of 1 and 2 using glycal activation by an acid catalyst in all cases led to the α-anomers of deoxy sugar derivatives with good yields. As a result, a novel group of sugar and deoxy sugar conjugates with optically pure polyphenolic acids was successfully synthesized and their cytotoxic profile against two cancer cell lines was tested. An advantageous ADME profile and antiproliferative data classified this new group of compounds as a promising scaffold for further modification of more potent and selective anticancer agents.
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27
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Abstract
A practical synthesis of 28a-homo-28a-selenolupane triterpenes and the corresponding selenosaponins containing d-mannose, l-arabinose, l-rhamnose, and d-idose moieties is described. Selenium containing triterpenes were obtained from the readily available 3-O-allyl-homobetulin mesylate by nucleophilic substitution with the selenocyanate ion which upon reduction of the -SeCN group afforded the free selenol. Glycosylation using classical Schmidt donors gave 1,2-trans selenosaponins as the main product as well as minute amounts of 1,2-cis isomers. This is one of the very few examples of the synthesis of selenoglycosides by direct glycosylation of free selenols. The studied selenol showed high resistance to air oxidation resulting in good stability during the synthesis of selenolupane derivatives. Cytotoxic activities of new homoselenolupane derivatives were also evaluated in vitro and revealed that some triterpenes exhibited an interesting profile against human cancer cell lines.
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28
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A general and convenient method for the synthesis of 2,4-dinitrobenzyl ketones. Almost unlimited access to 2-substituted 6-nitroindoles from 2,4-dinitrotoluene and aldehydes. NEW J CHEM 2018. [DOI: 10.1039/c7nj04919f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Starting from 2,4-dinitrotoluene and aldehydes, 2-substituted 6-nitroindoles with alkyl, cycloalkyl, aryl and heteroaryl (thienyl, furyl, pyridyl) substituents in the 2-position of the indole ring were synthesized. This methodology can be used for synthesis of indoles with non-racemic substituents.
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29
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Chloride-Templated Macrocyclization and Anion-Binding Properties of C2-Symmetric Macrocyclic Ureas from Sucrose. Org Lett 2017; 19:4596-4599. [DOI: 10.1021/acs.orglett.7b02198] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Synthesis and Physicochemical Characterization of the Process-Related Impurities of Eplerenone, an Antihypertensive Drug. Molecules 2017; 22:molecules22081354. [PMID: 28809817 PMCID: PMC6152353 DOI: 10.3390/molecules22081354] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 08/11/2017] [Indexed: 11/16/2022] Open
Abstract
Two unknown impurities were observed during the process development for multigram-scale synthesis of eplerenone (Inspra®). The new process-related impurities were identified and fully characterized as the corresponding (7β,11α,17α)-11-hydroxy- and (7α,11β,17α)-9,11-dichloroeplerenone derivatives 12a and 13. Seven other known but poorly described in the literature eplerenone impurities, including four impurities A, B, C and E listed in the European Pharmacopoeia 8.4 were also detected, identified and fully characterized. All these contaminants result from side reactions taking place on the steroid ring C of the starting 11α-hydroxy-7α-(methoxycarbonyl)-3-oxo-17α-pregn-4-ene-21,17-carbolactone (12) and the key intermediate (7α,17α)-9(11)-enester 7, including epimerization of the C-7 asymmetric center, oxidation, dehydration, chlorination and lactonization. The impurities were isolated and/or synthesized and fully characterized by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry/electrospray ionization (HRMS/ESI). Their 1H- and 13C-NMR signals were fully assigned. The molecular structures of the eight impurities, including the new (7β,11α,17α)-11-hydroxy- and (7α,11β,17α)-9,11-dichloroeplerenone related substances 12a and 13, were solved and refined using single-crystal X-ray diffraction (SCXRD). The full identification and characterization of these impurities should be useful for the quality control and the validation of the analytical methods in the manufacture of eplerenone.
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Transition-metal-free synthesis of 3-(1-pyrrolidinyl)quinolines and 3-(1-pyrrolidinyl)quinoline 1-oxides via a one-pot reaction of 3-(1-pyrrolidinyl)crotonates with nitrobenzenes. Org Biomol Chem 2017; 15:2397-2402. [PMID: 28252152 DOI: 10.1039/c6ob02658c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A carbanion of tert-butyl 3-(1-pyrrolidinyl)crotonate adds to nitrobenzenes to form σH-adducts, which in the presence of pivaloyl chloride and triethylamine are converted into 3-(1-pyrrolidinyl)quinolines or 3-(1-pyrrolidinyl)quinoline 1-oxides depending on the nitrobenzene structure. This is the first methodology in which a quinoline ring is constructed from a substrate bearing a pyrrolidinyl ring. Starting from optically pure enamines, the method allows synthesis of the corresponding chiral products without racemisation.
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Sugar migration induced by the Wagner-Meerwein rearrangement of 28- O -glycosyl-betulin derivatives. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.02.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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A Novel Convergent Synthesis of the Potent Antiglaucoma Agent Tafluprost. Molecules 2017; 22:molecules22020217. [PMID: 28146132 PMCID: PMC6155834 DOI: 10.3390/molecules22020217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 01/25/2017] [Indexed: 11/23/2022] Open
Abstract
Tafluprost (AFP-168, 5) is a unique 15-deoxy-15,15-difluoro-16-phenoxy prostaglandin F2α (PGF2α) analog used as an efficacious ocular hypotensive agent in the treatment of glaucoma and ocular hypertension, as monotherapy, or as adjunctive therapy to β-blockers. A novel convergent synthesis of 5 was developed employing Julia–Lythgoe olefination of the structurally advanced prostaglandin phenylsulfone 16, also successfully applied for manufacturing of pharmaceutical grade latanoprost (2), travoprost (3) and bimatoprost (4), with an aldehyde ω-chain synthon 17. The use of the same prostaglandin phenylsulfone 16, as a starting material in parallel syntheses of all commercially available antiglaucoma PGF2α analogs 2–5, significantly reduces manufacturing costs resulting from its synthesis on an industrial scale and development of technological documentation. Another key aspect of the route developed is deoxydifluorination of a trans-13,14-en-15-one 30 with Deoxo-Fluor. Subsequent hydrolysis of protecting groups and final esterification of acid 6 yielded tafluprost (5). The main advantages are the preparation of high purity tafluprost (5) and the application of comparatively cheap reagents. The preparation and identification of two other tafluprost acid derivatives, tafluprost methyl ester (32) and tafluprost ethyl amide (33), are also described.
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Convergent synthesis of double point modified analogs of 1α,25-dihydroxyvitamin D 2 for biological evaluation. J Steroid Biochem Mol Biol 2016; 164:45-49. [PMID: 26316152 DOI: 10.1016/j.jsbmb.2015.08.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 07/30/2015] [Accepted: 08/20/2015] [Indexed: 01/12/2023]
Abstract
There is a long lasting controversy over the biological activity of vitamin D2 as compared to vitamin D3 in terms of maintaining of calcium homeostasis and raising the level of circulating 25-OH-D. To shed more light on this relationship we synthesized 1α,25-dihydroxyvitamin D2, by a novel convergent strategy, to compare this compound directly with the activity of 1α,25-dihydroxyvitamin D3. The same synthetic strategy also provided a series of (5E,7E) geometric isomers of the natural 1α,25-dihydroxyvitamin D2 as well as a series of double point modified analogs of its (24R)-epimer, including C-22 hydroxy derivatives. The structure of the new analogs was determined by 1H and 13C NMR as well as by mass spectrometry. The influence of (5E,7E) modification, alone or in combination with additional modifications in the side chain, on the activity profile and metabolic deactivation of analogs of 1α,25-dihydroxyvitamin D2 still remains unknown. (5E,7E) modification in the structure of new analogs of 1α,25-dihydroxyvitamin D2 is expected to give analogs with no influence on calcium level, as was previously obtained for the analogs of 1α,25-dihydroxyvitamin D3. Investigation of the affinities for the vitamin D receptor and cell differentiation, transcriptional and calcium activities of the most active form of vitamin D2 and of (5E,7E) analogs, compared to 1α,25-dihydroxyvitamin D3, is underway in the collaborating laboratories.
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Synthesis and evaluation of geometric analogs of 1α,25-dihydroxyvitamin D 2 as potential therapeutics. J Steroid Biochem Mol Biol 2016; 164:50-55. [PMID: 26321387 DOI: 10.1016/j.jsbmb.2015.08.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/18/2015] [Accepted: 08/24/2015] [Indexed: 02/06/2023]
Abstract
An improved convergent strategy was developed for the synthesis of the previously obtained side-chain extended and rigidified analogs of 1α,25-dihydroxyvitamin D2, PRI-1906 and PRI-1907. New (24Z) geometric isomers of the analogs, PRI-1916 and PRI-1917, were also obtained and identified. These side-chain isomers were separable by flash chromatography, as C-25 alcohols, from the synthetic precursors of PRI-1906 and PRI-1907, respectively. The structures of new analogs were determined by advanced techniques of 1H and 13C NMR, including COSY, HSQC and HMBC sequences. Binding affinities of the geometric analogs PRI-1906 and PRI-1916 and their respective C-26, C-27 homologs PRI-1907 and PRI-1917 for the full-length human vitamin D receptor were determined by a fluorescence polarization competition assay. The binding affinity of (24Z) methyl analog PRI-1906 was much higher than that of (24E) analog PRI-1906, while the affinity of (24Z) ethyl analog PRI-1917 was lower than that of the respective PRI-1907. Investigation of the metabolism of these compounds by human CYP24A1 revealed they are much more resistant to CYP24A1 than 1α,25-dihydroxyvitamin D2, indicating they could have longer-term biological effects on target tissues.
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Synthesis of S-(28a-homobetulin-28a-yl) thiophosphate, thiophosphonate, and thiophosphinate. PHOSPHORUS SULFUR 2016. [DOI: 10.1080/10426507.2016.1165679] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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38
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Influence of intramolecular hydrogen bonds on regioselectivity of glycosylation. Synthesis of lupane-type saponins bearing the OSW-1 saponin disaccharide unit and its isomers. Carbohydr Res 2016; 423:49-69. [PMID: 26878488 DOI: 10.1016/j.carres.2016.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/14/2016] [Accepted: 01/21/2016] [Indexed: 10/22/2022]
Abstract
A series of lupane-type saponins bearing OSW-1 disaccharide unit as well as its regio- and stereoisomers were prepared and used for the structure-activity relationships (SAR) study. Unexpected preference for 1→4-linked regioisomers and an unusual inversion of the conformation of the sugar rings were noted. Cytotoxic activity of new lupane compounds was evaluated in vitro and revealed that some saponins exhibited an interesting bioactivity profile against human cancer cell lines. Influence of the protecting groups on the cytotoxicity was investigated. These results open the way to the synthesis of various lupane-type triterpene and saponin derivatives as potential anticancer compounds.
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Mechanochemical Encapsulation of Fullerenes in Peptidic Containers Prepared by Dynamic Chiral Self-Sorting and Self-Assembly. Chemistry 2016; 22:3148-55. [PMID: 26808958 DOI: 10.1002/chem.201504451] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Indexed: 01/24/2023]
Abstract
Molecular capsules composed of amino acid or peptide derivatives connected to resorcin[4]arene scaffolds through acylhydrazone linkers have been synthesized using dynamic covalent chemistry (DCC) and hydrogen-bond-based self-assembly. The dynamic character of the linkers and the preference of the peptides towards self-assembly into β-barrel-type motifs lead to the spontaneous amplification of formation of homochiral capsules from mixtures of different substrates. The capsules have cavities of around 800 Å(3) and exhibit good kinetic stability. Although they retain their dynamic character, which allows processes such as chiral self-sorting and chiral self-assembly to operate with high fidelity, guest complexation is hindered in solution. However, the quantitative complexation of even very large guests, such as fullerene C60 or C70 , is possible through the utilization of reversible covalent bonds or the application of mechanochemical methods. The NMR spectra show the influence of the chiral environment on the symmetry of the fullerene molecules, which results in the differentiation of diastereotopic carbon atoms for C70 , and the X-ray structures provide unique information on the modes of peptide-fullerene interactions.
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Synthesis and Physicochemical Characterization of the Process-Related Impurities of Olmesartan Medoxomil. Do 5-(Biphenyl-2-yl)-1-triphenylmethyltetrazole Intermediates in Sartan Syntheses Exist? Molecules 2015; 20:21346-63. [PMID: 26633332 PMCID: PMC6332230 DOI: 10.3390/molecules201219762] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 11/18/2015] [Accepted: 11/19/2015] [Indexed: 01/19/2023] Open
Abstract
During the process development for multigram-scale synthesis of olmesartan medoxomil (OM), two principal regioisomeric process-related impurities were observed along with the final active pharmaceutical ingredient (API). The impurities were identified as N-1- and N-2-(5-methyl-2-oxo-1,3-dioxolen-4-yl)methyl derivatives of OM. Both compounds, of which N-2 isomer of olmesartan dimedoxomil is a novel impurity of OM, were synthesized and fully characterized by differential scanning calorimetry (DSC), infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry/electrospray ionization (HRMS/ESI). Their ¹H, (13)C and (15)N nuclear magnetic resonance signals were fully assigned. The molecular structures of N-triphenylmethylolmesartan ethyl (N-tritylolmesartan ethyl) and N-tritylolmesartan medoxomil, the key intermediates in OM synthesis, were solved and refined using single-crystal X-ray diffraction (SCXRD). The SCXRD study revealed that N-tritylated intermediates of OM exist exclusively as one of the two possible regioisomers. In molecular structures of these regioisomers, the trityl substituent is attached to the N-2 nitrogen atom of the tetrazole ring, and not to the N-1 nitrogen, as has been widely reported up to the present. This finding indicates that the reported structural formula of N-tritylolmesartan ethyl and N-tritylolmesartan medoxomil, as well as their systematic chemical names, must be revised. The careful analysis of literature spectroscopic data for other sartan intermediates and their analogs with 5-(biphenyl-2-yl)tetrazole moiety showed that they also exist exclusively as N-2-trityl regioisomers.
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Synthesis and Cytotoxicity of 28a-Homothiolupanes and 28a-Homothiolupane Saponins. European J Org Chem 2015. [DOI: 10.1002/ejoc.201501147] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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The synthesis of indolo[2,3-b]quinoline derivatives with a guanidine group: highly selective cytotoxic agents. Eur J Med Chem 2015; 105:208-19. [PMID: 26496013 DOI: 10.1016/j.ejmech.2015.10.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 10/05/2015] [Accepted: 10/10/2015] [Indexed: 12/01/2022]
Abstract
The synthesis of indolo[2,3-b]quinoline derivatives containing guanidine, amino acid or guanylamino acid substituents as well as their in vitro evaluation for the cytotoxic and antifungal activity are reported. The influence of the guanidine group on the selective cytotoxic and hemolytic properties of indolo[2,3-b]quinoline was investigated. Most of the compounds displayed a high cytotoxic activity in vitro and two of the most promising compounds (3 and 12) exhibited a high selectivity between normal and cancer cell-lines. The cytotoxic activity of compound 3 was about 600-fold lower against normal fibroblasts than against A549 and MCF-7 cancer cell lines. Novel entities acted as the DNA-intercalators when tested using a DNA-methyl green assay but demonstrated zero or low hemolytic activity in comparison to their unsubstituted analogs. The mechanism of action was studied for guanidine derivatives 3 and 12 and both compounds were found to be very effective inducers of apoptosis.
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Study on the synthesis of regio- and stereoisomers of the disaccharide unit of the OSW-1 saponin. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.05.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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44
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One-Pot Synthesis of Esters of Cyclopropane Carboxylic Acids via Tandem Vicarious Nucleophilic Substitution-Michael Addition Process. J Org Chem 2015; 80:5436-43. [PMID: 25950949 DOI: 10.1021/acs.joc.5b00204] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
α-Chlorocarbanions generated via base-induced vicarious nucleophilic substitution reaction of alkyl dichloroacetates with nitroarenes react with Michael acceptors to give esters of cyclopropane carboxylic acids substituted with p-nitroaromatic rings.
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N-terminal guanidinylation of the cyclic 1,4-ureido-deltorphin analogues: the synthesis, receptor binding studies, and resistance to proteolytic digestion. J Pept Sci 2015; 21:467-75. [PMID: 25755050 DOI: 10.1002/psc.2762] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/21/2015] [Accepted: 01/23/2015] [Indexed: 12/14/2022]
Abstract
The synthesis of a series of N-guanidinylated cyclic ureidopeptides, analogues of 1,4-ureido-deltorphin/dermorphine tetrapeptide is described. The δ- and μ-opioid receptor affinity of new guanidinylated analogues and their non-guanidinylated precursors was determined by the displacement radioligand binding experiments. Our results indicate that the guanidinylation of cyclic 1,4-ureidodeltorphin peptide analogues does not exhibit a uniform influence on the opioid receptor binding properties, similarly as reported earlier for some linear peptides. All analogues were also tested for their in vitro resistance to proteolysis during incubation with large excess of chymotrypsin, pepsin, and papain by means of mass spectroscopy. Guanidinylated ureidopeptides 1G-4G showed mixed μ agonist/δ agonist properties and high enzymatic stability indicating their potential as therapeutic agents for treatment of pain.
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Dynamic Formation of Hybrid Peptidic Capsules by Chiral Self-Sorting and Self-Assembly. Angew Chem Int Ed Engl 2014; 53:13760-4. [DOI: 10.1002/anie.201407802] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/02/2014] [Indexed: 01/29/2023]
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48
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Dynamic Formation of Hybrid Peptidic Capsules by Chiral Self-Sorting and Self-Assembly. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201407802] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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49
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Synthesis of a sucrose dimer with enone tether; a study on its functionalization. Beilstein J Org Chem 2014; 10:1246-54. [PMID: 24991275 PMCID: PMC4077423 DOI: 10.3762/bjoc.10.124] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/30/2014] [Indexed: 12/22/2022] Open
Abstract
The reaction of appropriately functionalized sucrose phosphonate with sucrose aldehyde afforded a dimer composed of two sucrose units connected via their C6-positions (‘the glucose ends’). The carbonyl group in this product (enone) was stereoselectively reduced with zinc borohydride and the double bond (after protection of the allylic alcohol formed after reduction) was oxidized with osmium tetroxide to a diol. Absolute configurations of the allylic alcohol as well as the diol were determined by circular dichroism (CD) spectroscopy using the in situ dimolybdenum methodology.
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Synthesis of Lupane-Type Saponins Containing an Unusual α-D-Idopyranoside Fragment as Potent Cytotoxic Agents. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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