Sergey Belyakov

Synthesis, structure and cytotoxicity of 3-C, N, S, Se substituted benzo[b]selenophene derivatives

Synthesis, molecular structure and cytotoxic activity of a series of 3-C, N, S, Se substituted benzo[b]selenophene derivatives on human fibrosarcoma HT-1080, mouse hepatoma MG-22A, and mouse fibroblasts 3T3 cell lines are described. The correlation between compound LD(50) 3T3 fibroblast cell line and HT-1080 morphology was shown.

Concerning the transannular bond in silatranes and germatranes: a quantum chemical study

Abstract For a series of silatranes and germatranes the structure of isolated molecules was investigated by the quantum chemistry molecular orbital method. The transannular bond N→M lengthens with the strengthening of a substituent +I-effect, however, in the solid state the bond length depends considerably on the crystal field effects. Due to the latter, this transannular bond in crystals is shorter than that in isolated molecules.

SYNTHESIS AND MOLECULAR STRUCTURE OF PHENYL AND TOLYLGERMATRANES

The crystals of arylgermatranes Figure options Download full-size image Download as PowerPoint slide (R=H (I), 4-CH3 (II), 3-CH3 (III), 2-CH3 (IV)), have been obtained to study the influence of a substituent position on coordination of the germanium atom. Compounds I–IV were prepared by the insertion of GeBr2 into the carbonbromine bond of the corresponding arylbromide, conversion of aryltribromogermanes to triethoxy derivatives by alcoholysis and their transalkoxylation with triethanolamine to germatranes; or by the condensation of halobenzene with GeCl4 in the presence of copper powder followed by alcoholysis and cyclization. The crystal structure of compounds I–IV was studied via the X-ray diffraction method. The intramolecular donor–acceptor bond Ge←N in arylgermatranes (2.212–2.230 A) is longer than that in the corresponding furyl- and thienylgermatranes. Introduction of a substituent into o-position of the benzene ring decreases the NGeC angle value from 177.5 to 144.2°. The quantum chemical calculations were performed to investigate structures I–IV in isolated molecules.

Synthesis, physicochemical characterization, cytotoxicity, antimicrobial, anti-inflammatory and psychotropic activity of new N-[1,3-(benzo)thiazol-2-yl]-ω-[3,4-dihydroisoquinolin-2(1H)-yl]alkanamides.

A series of new N-[(benzo)thiazol-2-yl]-2/3-[3,4-dihydroisoquinolin-2(1H)-yl]ethan/propanamide derivatives was synthesized and characterized by (1)H, (13)C NMR and IR spectroscopy and mass-spectrometry. A single crystal X-ray study of N-(1,3-benzothiazol-2-yl)-2-[3,4-dihydroisoquinolin-2(1H)-yl]ethanamide is reported to determine its conformational feature. The investigated compounds were found to be active in psychotropic in vivo, anti-inflammatory in vivo and cytotoxicity in vitro screening. They possess marked sedative action, reveal high anti-inflammatory activity, have selective cytotoxic effects and NO-induction ability concerning tumour cell lines. Some of the compounds synthesized demonstrate antimicrobial action. An attempt was made to correlate the biological results with their structural characteristics and physicochemical parameters. Some specific combinations of types of activities for the synthesized compounds have been revealed.

1-Fluorogermatrane—germatrane with the shortest intramolecular N → Ge bond

Abstract 1-Hydroxygermatrane readily reacts with boron trifluoride etherate in acetonitrile to give 1-fluorogermatrane in good yield. The length of the N → Ge donor-acceptor bond equals 2.011(9) A, which is the shortest among all studied for germatranes.

Fluorescent substituted amidines of benzanthrone: synthesis, spectroscopy and quantum chemical calculations.

Several new substituted amidine derivatives of benzanthrone were synthesized by a condensation reaction from 3-aminobenzo[de]anthracen-7-one and appropriate aromatic and aliphatic amides. The obtained derivatives have a bright yellow or orange fluorescence in organic solvents and in solid state. The novel benzanthrone derivatives were characterized by TLC analysis, (1)H NMR, IR, MS, UV/vis, and fluorescence spectroscopy. The solvent effect on photophysical behaviors of these dyes was investigated, and the results showed that the Stokes shift increased, whereas quantum yield decreased with the growth of the solvent polarity. The structure of some dyes was confirmed by the X-ray single crystal structure analysis. AM1, ZINDO/S and ab initio calculations using Gaussian software were carried out to estimate the electron system of structures. The calculations show planar configurations for the aromatic core of these compounds and two possible orientations of amidine substituents. The calculation results correlate well with red-shifted absorption and emission spectra of compounds.

Molecular Structure of Selenophenes and Tellurophenes. (Review)

The results of X-ray diffraction investigations of compounds containing selenophene and tellurophene fragments are reviewed and analyzed. The structural features of unsubstituted selenophene and tellurophene and their mono-, di-, tri-, and tetrasubstituted derivatives and also the structure of the complexes of selenophenes and tellurophenes with transition metals are discussed.

The Synthesis and Cytotoxic Properties of Selenopheno[3,2-c]- and Selenopheno-[2,3-c]quinolones*

We have developed a method for the synthesis of novel selenophene-containing polycyclic heterocycles, derivatives of selenopheno[3,2-c]- and selenopheno[2,3-c]quinolones. The cytotoxic activity of these compounds was studied in vitro. The molecular structure of 3-bromo-5-methyl-2-(piperidin-2-ylmethyl)selenopheno[3,2-c]quinolin-4(5H)-one was confirmed by X-ray analysis.

Reactions of 4-Chloro-3-formylcoumarin with Arylhydrazines

The interaction of 3-formyl-4-coumarin with arylhydrazine hydrochlorides in the presence of sodium acetate gave the corresponding 3-arylhydrazonomethyl-4-chlorocoumarin, and with phenylhydrazine, 4-bromo- and 4-chlorophenylhydrazine hydrochlorides in the presence of two equivalents of triethylamine gave either 1-aryl- or 2-aryl[1]benzopyrano[4,3-c]pyrazol-4-ones depending on the reaction conditions. In reactions of 4-chloro-3-formylcoumarin with 2,4-dichloro-, 2,4-difluoro-, 2-hydroycarbonyl-, 4-nitro- and 3,5-di(trifluoromethyl)phenylhydrazine, 2-pyridyl- and 2-quinoxalylhydrazine in the presence of excess of triethylamine the 2-aryl[1]benzopyrano[4,3-c]pyrazol-4(2H)-ones were obtained exclusively. The structures of 1-phenyl- and 2-(2-pyridyl)[1]benzopyrano[4,3-c]pyrazolo-4(1H)ones were confirmed by X-ray crystallography. A simple method is proposed to distinguish between 1- and 2-substituted [1]benzopyrano[4,3-c]pyrazolo-4-ones on the basis of the 1H NMR chemical shifts of the C(3)-H proton in two solvents - DMSO-d6 and CDCl3.

Synthesis, molecular structure and biological activity of bromobenzylgermatranes

The new series of benzylgermatranes , R=H ( I ), 2-Br ( II ), 3-Br ( III ), 4-Br ( IV ), has been obtained to study the influence of a substituent position on coordination of the germanium atom, the values of bond angles and neurotropic activity. Compounds I – IV were prepared by insertion of GeBr 2 into carbon–bromine bond of the corresponding benzylbromide or bromobenzylbromide in refluxing toluene, conversion of benzyl- or bromobenzyltribromogermanes into triethoxy derivatives by alcoholysis, and transalkoxylation with triethanolamine. The crystal structure of compounds I – IV was studied via the X-ray diffraction method. The intramolecular donor–acceptor bond N→Ge in benzylgermatranes (2.175–2.219 A) is shorter than that in tolylgermatranes (2.212–2.230 A). Biological investigations have demonstrated that all benzylgermatranes ( I – IV) are low toxic compounds (LD 50 >1000 mg kg −1 ) with high anaesthetic and anti-Corazol activity. Benzylgermatrane ( I ), 3-bromobenzylgermatrane ( III ) and 4-bromobenzylgermatrane ( IV ) improve memory processes and completely prevent animals from retrogradal amnesia (RA) caused by electroshock.