1
|
Gerontitis IE, Tsoungas PG, Varvounis G. Naphtho[1,8- de][1,2]Oxazin-4-ol: Precursor to 1,2,8-Trisubstituted Naphthalenes and 1-Unsubstituted Naphtho[1,2- d]isoxazole 2-Oxide: A Novel Isomerization of the N-Oxide to Nitrile Oxide en Route to Isoxazol(in)es. Molecules 2023; 29:48. [PMID: 38202629 PMCID: PMC10779812 DOI: 10.3390/molecules29010048] [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: 11/08/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Naphtho[1,8-de][1,2]oxazin-4-ol and its acyl or benzyl derivatives ring open to various 2,8-dihydroxy-1-naphthonitriles, which, through (de)protection protocols and reduction, afford the target (E)-2-hydroxy-8-methoxy-1-naphthaldehyde. This was converted to its corresponding oxime, which was oxidatively o-cyclized with phenyliodine(III) diacetate (PIDA) to 9-methoxynaphtho[1,2-d]isoxazole 2-oxide. The latter, in deuterated DMSO at room temperature, was rearranged to its isomer 2-hydroxy-8-methoxy(naphthalen-1-yl)nitrile oxide. The isomerization was detected by time-course plot 1H NMR spectroscopy and further identified from its 13C NMR and HRMS spectra. The nitrile oxide was stable in (non)deuterated DMSO for at least 18 h. A 3,4-bis(2-hydroxy-8-methoxynaphthalen-1-yl)-1,2,5-oxadiazole 2-oxide, as a dimerization product or an isocyanate as a rearrangement isomer, was ruled out, the former by its HRMS spectrum and the latter by its 1,3-dipolar cycloaddition reactions to substituted isoxazoles.
Collapse
Affiliation(s)
- Ioannis E. Gerontitis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, 451 10 Ioannina, Greece;
| | - Petros G. Tsoungas
- Department of Biochemistry, Hellenic Pasteur Institute, 127 Vas. Sofias Ave., 115 21 Athens, Greece;
| | - George Varvounis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, 451 10 Ioannina, Greece;
| |
Collapse
|
2
|
Tzeli D, Gerontitis IE, Petsalakis ID, Tsoungas PG, Varvounis G. Self Cycloaddition of o-Naphthoquinone Nitrosomethide to (±) Spiro{naphthalene(naphthopyranofurazan)}-one Oxide: An Insight into its Formation. Chempluschem 2022; 87:e202200313. [PMID: 36479609 DOI: 10.1002/cplu.202200313] [Citation(s) in RCA: 2] [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: 09/12/2022] [Revised: 11/22/2022] [Indexed: 11/25/2022]
Abstract
2-Hydroxy-1-naphthaldehyde oxime was oxidized by AgO (or Ag2 O), in presence of N-methyl morpholine N-oxide (NMMO), to the title spiro adduct-dimer (±)-Spiro{naphthalene-1(2H),4'-(naphtho[2',1':2,3]pyrano[4,5-c]furazan)}-2-one-11'-oxide by a Diels-Alder(D-A) type self-cycloaddition, through the agency of an o-naphthoquinone nitrosomethide (o-NQM). Moreover, 2-hydroxy-8-methoxy-1-naphthaldehyde oxime was prepared and subjected to the same oxidation conditions. Its sterically guided result, 9-methoxynaphtho[1,2-d]isoxazole, was isolated, instead of the expected spiro adduct. The peri intramolecular H bonding in the oxime is considered to have a key contribution to the outcome. Geometry and energy features of the oxidant- and stereo-guided selectivity of both oxidation outcomes have been explored by DFT, perturbation theory and coupled cluster calculations. The reaction free energy of the D-A intermolecular cycloaddition is calculated at -82.0 kcal/mol, indicating its predominance over the intramolecular cyclization of ca. -37.6 kcal/mol. The cycloaddition is facilitated by NMMO through dipolar interactions and hydrogen bonding with both metal complexes and o-NQM. The 8(peri)-OMe substitution of the reactant oxime sterically impedes formation of the spiro adduct, instead it undergoes a more facile cyclodehydration to the isoxazole structure by ca. 4.9 kcal/mol.
Collapse
Affiliation(s)
- Demeter Tzeli
- Laboratory of Physical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou Athens, 157 84, Athens, Greece
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens, 116 35, Greece
| | - Ioannis E Gerontitis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, 451 10, Ioannina, Greece
| | - Ioannis D Petsalakis
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens, 116 35, Greece
| | - Petros G Tsoungas
- Department of Biochemistry, Hellenic Pasteur Institute, 127 Vas. Sofias Ave., 115 21, Athens, Greece
| | - George Varvounis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, 451 10, Ioannina, Greece
| |
Collapse
|
3
|
Tzinavou A, Dolka C, Tsoungas PG, Eycken EVD, Meervelt LV, Varvounis G. Cerium(IV) ammonium nitrate for the tandem nitration and oxidative rearrangement of 2-acetyl-1-naphthol benzoylhydrazones into 1,2-diacylnaphthalenes; synthesis of benzo[f]phthalazines. ARKIVOC 2017. [DOI: 10.24820/ark.5550190.p010.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
4
|
Pairas GN, Perperopoulou F, Tsoungas PG, Varvounis G. The Isoxazole Ring and ItsN-Oxide: A Privileged Core Structure in Neuropsychiatric Therapeutics. ChemMedChem 2017; 12:408-419. [DOI: 10.1002/cmdc.201700023] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 02/13/2017] [Indexed: 01/23/2023]
Affiliation(s)
- George N. Pairas
- Laboratory of Medicinal Chemistry, Department of Pharmacy; University of Patras; 265 04 Patras Greece
| | - Fereniki Perperopoulou
- Laboratory of Enzyme Technology, Department of Biotechnology; Agricultural University of Athens; 75 Iera Odos St. 118 55 Athens Greece
| | - Petros G. Tsoungas
- Laboratory of Biochemistry; Hellenic Pasteur Institute; 127 Vas. Sofias Ave. 115 21 Athens Greece
| | - George Varvounis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry; University of Ioannina; 451 10 Ioannina Greece
| |
Collapse
|
5
|
Abstract
Pyrrolo[1,4]benzodiazepines are tricyclic compounds that are considered “privileged structures” since they possess a wide range of biological activities. The first encounter with these molecules was the isolation of anthramycin from cultures of Streptomyces, followed by determination of the X-ray crystal structure of the molecule and a study of its interaction with DNA. This opened up an intensive synthetic and biological study of the pyrrolo[2,1-c][1,4]benzodiazepines that has culminated in the development of the dimer SJG-136, at present in Phase II clinical trials. The synthetic efforts have brought to light some new synthetic methodology, while the contemporary work is focused on building trimeric pyrrolo[2,1-c][1,4]benzodiazepines linked together by various heterocyclic and aliphatic chains. It is the broad spectrum of biological activities of pyrrolo[1,2-a][1,4]benzodiazepines that has maintained the interest of researchers to date whereas several derivatives of the even less studied pyrrolo[1,2-d][1,4]benzodiazepines were found to be potent non-nucleoside HIV-1 reverse transcriptase inhibitors. The present review is an update on the synthesis of pyrrolo[2,1-c][1,4]benzodiazepines since the last major review of 2011, while the overview of the synthesis of the other two tricyclic isomers is comprehensive.
Collapse
Affiliation(s)
- George Varvounis
- Department of Chemistry, Section of Organic Chemistry and Biochemistry, University of Ioannina, 451 10 Ioannina, Greece.
| |
Collapse
|
6
|
Shaikh AK, Varvounis G. One-pot cascade synthesis of 2,3-disubstituted 2,3-dihydrobenzofurans via ortho-quinone methide intermediates generated in situ. RSC Adv 2015. [DOI: 10.1039/c4ra15024d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A simple and efficient one-pot cascade reaction for the regioselective synthesis of trans or cis/trans-2,3-disubstituted 2,3-dihydrobenzofurans, is described.
Collapse
Affiliation(s)
- Abdul kadar Shaikh
- Section of Organic Chemistry and Biochemistry
- Department of Chemistry
- University of Ioannina
- 45110 Ioannina
- Greece
| | - George Varvounis
- Section of Organic Chemistry and Biochemistry
- Department of Chemistry
- University of Ioannina
- 45110 Ioannina
- Greece
| |
Collapse
|
7
|
Shaikh AK, Varvounis G. Novel synthesis of 3-substituted 2,3-dihydrobenzofurans via ortho-quinone methide intermediates generated in situ. Org Lett 2014; 16:1478-81. [PMID: 24571271 DOI: 10.1021/ol500290e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A new method is presented for the regioselective one-pot synthesis of 3-substituted 2,3-dihydrobenzofurans from 2-bromo-1-{2-[(triisopropylsilyl)oxy]phenyl}ethyl nitrate by fluoride-induced desilylation leading to o-quinone methide generation, Michael addition of different C, N, O, and S nucleophiles, and intramolecular 5-exo-tet elimination of a bromide anion. The method has potential synthetic applications in drug discovery.
Collapse
Affiliation(s)
- Abdul kadar Shaikh
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina , 451 10 Ioannina, Greece
| | | |
Collapse
|
8
|
|
9
|
Abstract
A new mild method has been devised for generating o-(naphtho)quinone methides via fluoride-induced desilylation of silyl derivatives of o-hydroxybenzyl(or 1-naphthylmethyl) nitrate. The reactive o-(naphtho)quinone methide intermediates were trapped by C, O, N, and S nucleophiles and underwent "inverse electron-demand" hetero-Diels-Alder reaction with dienophiles to give stable adducts. The method has useful potential application in natural product synthesis and drug research.
Collapse
Affiliation(s)
- Abdul kadar Shaikh
- Department of Chemistry, University of Ioannina, Section of Organic Chemistry and Biochemistry, 451 10 Ioannina, Greece
| | | | | |
Collapse
|
10
|
|
11
|
Surowiec M, Belekos D, Mąkosza M, Varvounis G. tele Nucleophilic Substitutions of Hydrogen in m-(Trichloromethyl)nitrobenzenes with Cyano and Ester Carbanions. European J Org Chem 2010. [DOI: 10.1002/ejoc.200901303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
12
|
Tsoungas P, Assimomytis N, Sariyannis Y, Stavropoulos G, Varvounis G, Cordopatis P. Anionic ortho-Fries Rearrangement, a Facile Route to Arenol-Based Mannich Bases. Synlett 2009. [DOI: 10.1055/s-0029-1217991] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
13
|
Dolka C, Hecke KV, Meervelt LV, Tsoungas PG, Eycken EVVD, Varvounis G. Novel Thermal and Microwave-Assisted Facile Route to Naphthalen-2(1H)-ones via an Oxidative Alkoxylation-Ring-Opening Protocol. Org Lett 2009; 11:2964-7. [DOI: 10.1021/ol9008574] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chrysanthi Dolka
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece, Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium, Biomolecular Architecture, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, and Ministry of Development, Department of Development and Technology, Messogion 14-16, 115 10 Athens, Greece
| | - Kristof Van Hecke
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece, Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium, Biomolecular Architecture, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, and Ministry of Development, Department of Development and Technology, Messogion 14-16, 115 10 Athens, Greece
| | - Luc Van Meervelt
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece, Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium, Biomolecular Architecture, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, and Ministry of Development, Department of Development and Technology, Messogion 14-16, 115 10 Athens, Greece
| | - Petros G. Tsoungas
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece, Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium, Biomolecular Architecture, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, and Ministry of Development, Department of Development and Technology, Messogion 14-16, 115 10 Athens, Greece
| | - Erik V. Van der Eycken
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece, Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium, Biomolecular Architecture, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, and Ministry of Development, Department of Development and Technology, Messogion 14-16, 115 10 Athens, Greece
| | - George Varvounis
- Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece, Laboratory for Organic & Microwave-Assisted Chemistry (LOMAC), Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium, Biomolecular Architecture, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, and Ministry of Development, Department of Development and Technology, Messogion 14-16, 115 10 Athens, Greece
| |
Collapse
|
14
|
|
15
|
Koriatopoulou K, Karousis N, Varvounis G. Novel synthesis of the pyrrolo[2,1-c][1,4]benzodiazocine ring system via a Dieckmann condensation. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.07.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
16
|
Varvounis G, Liaskopoulos T, Skoulika S, Tsoungas P. Novel Synthesis of Naphthopyranoisoxazoles and Versatile Access to Naphthopyranoisoxazolines. SYNTHESIS-STUTTGART 2008. [DOI: 10.1055/s-2008-1032178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
17
|
Karousis N, Koriatopoulou K, Varvounis G. Synthesis of 1-aroylmethylpyrroles as useful intermediates for further chemical transformation. ARKIVOC 2008. [DOI: 10.3998/ark.5550190.0009.214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
18
|
Varvounis G, Supsana P, Liaskopoulos T, Tsoungas P. DMF-Catalysed Thermal Dehydration of Aldoximes: A Convenient Access to Functionalized Aliphatic and Aromatic Nitriles. Synlett 2007. [DOI: 10.1055/s-2007-991067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
19
|
Liebscher J, Varvounis G, Karousis N. Synthesis of ( E)-3-(1 H-Pyrrol-3-yl)prop-2-ene Derivatives Using Organophosphorous Reagents. SYNTHESIS-STUTTGART 2006. [DOI: 10.1055/s-2006-926426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
20
|
Rotas G, Natchkebia K, Natsvlishvili N, Kekelidze M, Kimbaris A, Varvounis G, Mikeladze D. Action of a novel pyrrolo[1,2-c][1.3]benzodiazepine on the viability of Jurkat and neuronal/glial cells. Bioorg Med Chem Lett 2005; 15:3220-3. [PMID: 15927465 DOI: 10.1016/j.bmcl.2005.05.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Revised: 04/22/2005] [Accepted: 05/02/2005] [Indexed: 11/24/2022]
Abstract
We have designed and synthesized several structural isomers of anthramycin (heterocycles 2, 3, 5, 6, and 8) and found that, in particular, pyrrolobenzodiazepine 8 induces DNA cleavage and formation of small fragments of DNA. The cytotoxic effects of 8 were manifested with both non-transformed primary neuronal/glial cells and transformed Jurkat cells. The other compounds did not change the viability either of transformed or of non-transformed cells, and induced DNA cleavage to a lesser extent.
Collapse
Affiliation(s)
- Georgios Rotas
- Department of Chemistry, University of Ioannina, GR-451 10 Ioannina, Greece
| | | | | | | | | | | | | |
Collapse
|
21
|
Supsana P, Liaskopoulos T, Skoulika S, Kolocouris A, Tsoungas PG, Varvounis G. Thermal rearrangement of spiro[naphthalene(naphthopyranofurazan)]oxides to spiro[naphthalene(phenalenofurazan)oxides. A probable furazan oxide triggered tandem isomerisation process. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.03.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
22
|
Varvounis G, Cordopatis P, Bissyris EE, Belekos D, Magafa V, Tsoungas PG. 2-Amino-4-pyrrolidinothieno[2,3- d]pyrimidine-6-carboxylic Acid as an N-Terminal Surrogate in Amino Acid and Peptide Analogues. SYNTHESIS-STUTTGART 2005. [DOI: 10.1055/s-2005-918426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
23
|
Rotas G, Kimbaris A, Varvounis G. Synthesis of 5-alkyl(or aryl)pyrrolo[1,2-a]quinoxalin-4(5H)-ones by denitrocyclisation of N-alkyl(or aryl)-1-(2-nitrophenyl)-1H-pyrrole-2-carboxamides. Evidence of a Smiles rearrangement. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.09.048] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
24
|
Kimbaris A, Cobb J, Tsakonas G, Varvounis G. Novel pyrrolo[1,2-a][3.1.6]benzothiadiazocine ring synthesis. Unusual Truce–Smiles type rearrangement of 1-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfonyl(or sulfinyl)}acetone. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.07.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
25
|
Mąkosza M, Varvounis G, Surowiec M, Giannopoulo T. Tele vs. Oxidative Substitution of Hydrogen inmeta Monochloromethyl, Dichloromethyl, and Trichloromethyl Nitrobenzenes in the Reaction with Grignard Reagents. European J Org Chem 2003. [DOI: 10.1002/ejoc.200300223] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
26
|
|
27
|
Supsana P, Tsoungas PG, Varvounis G. A novel one-pot synthesis of isomeric naphtho[1,2-d]isoxazole 2-oxide and naphtho[1,8-de][1,2]oxazine ring systems. A case of simultaneous o- and peri-cyclisation in naphthalene. Tetrahedron Lett 2000. [DOI: 10.1016/s0040-4039(00)00029-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
28
|
|
29
|
Gerothanassis IP, Varvounis G. 17O NMR studies of electronic and steric interactions of substituted quinoxaline-2(1H),3(4H)-diones. J Heterocycl Chem 1996. [DOI: 10.1002/jhet.5570330320] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
30
|
Gerothanassis IP, Cobb J, Kimbaris A, Smith JA, Varvounis G. 17O and 14N NMR studies of quinoxaline-2(1H),3(4H)-diones and N,N′-substituted oxamides: The first experimental evidence of torsion angle deformation resulting from an unprecedented through six-bond substituent effect on the diamide group of quinoxaline-2(1H),3(4H)-diones. Tetrahedron Lett 1996. [DOI: 10.1016/0040-4039(96)00492-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
31
|
Cobb J, Demetropoulos IN, Korakas D, Skoulika S, Varvounis G. Synthesis and reactions of 1-aryl-2-nitropyrroles. Structural and conformational study of ethyl N-[2′-[1′-(2-nitropyrrolyl)]phenyl]-N-toluene-4-sulfonamide glycinate. Tetrahedron 1996. [DOI: 10.1016/0040-4020(96)00096-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
32
|
Varvounis G, Giannopoulos T. Synthesis, Chemistry, and Biological Properties of Thienopyrimidines. Advances in Heterocyclic Chemistry 1996. [DOI: 10.1016/s0065-2725(08)60307-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
33
|
Cartwright D, Ferguson JR, Giannopoulos T, Varvounis G, Wakefield BJ. Synthesis of some β-trichloromethyl-azines and -diazines. ACTA ACUST UNITED AC 1995. [DOI: 10.1039/p19950002595] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
34
|
Korakas D, Varvounis G. Synthesis of 5,6-dihydro-4H-pyrrolo[1,2-a][1,4]benzodiazepine and 10,11-dihydro-5H,12H-pyrrolo[2,1-c][1,4]benzodiazocine derivativesviacyclization of 2-aminomethylpyrroles. J Heterocycl Chem 1994. [DOI: 10.1002/jhet.5570310603] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
35
|
|
36
|
Clark J, Shahhet MS, Korakas D, Varvounis G. Synthesis of thieno[2,3-d]pyrimidines from 4,6-dichloropyrimidine-5-carbaldehydes. J Heterocycl Chem 1993. [DOI: 10.1002/jhet.5570300439] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
37
|
Cobb J, Demetropoulos IN, Skoulika S, Varvounis G, Aubry A. Structure determination of some 5,6-dihydropyrrolo-[1,2-a][3,1,6]benzothiadiazocines. J Heterocycl Chem 1992. [DOI: 10.1002/jhet.5570290204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
38
|
Cobb J, Cheeseman GWH, Varvounis G. The use of NMR measurements in the orientation of pyrrolic substitution in 5,6-dihydro-7-methyl-6-oxopyrrolo[1,2 a]-[3,1,6]benzothiadiazocine. J Heterocycl Chem 1989. [DOI: 10.1002/jhet.5570260116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
39
|
|
40
|
|
41
|
|
42
|
Clark J, Varvounis G. Heterocyclic studies. Part 42. Pyrimido[5,4-d][1,2,3]triazines and some related tricyclic compounds. ACTA ACUST UNITED AC 1984. [DOI: 10.1039/p19840001475] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|