A. N. Chernega

Anilinomethylidene derivatives of cyclic 1,3-dicarbonyl compounds in the synthesis of new sulfur-containing pyridines and quinolines

Simple methods for the synthesis of previously unknown sulfur-containing pyridin-2-ones and 5,6,7,8-tetrahydroquinolines from cyanothioacetamide and anilinomethylidene derivatives of cyclic 1,3-dicarbonyl compounds were developed. Structures and chemical transformations of compounds obtained were studied.

Luminescence induced by strong cation–anion π–π interactions in crystals of viologen analogues

The crystal structures of bis[2-(1-alkyl-pyridinium-4-yl)vinyl]benzenes and their unusual structure-luminescence dependence are reported and discussed. It has been found that luminescence of viologen analogues can be activated by tuning their molecular and crystal structure (via modification of the N-alkyl substituents, exchange of anion, including or excluding the solvent molecules) in an unusual way. The formation of π-stacked close ionic pairs leads to a significant increase in luminescence intensity, which is attributed to strong π–π interactions.

Reactions of α-Halo Ketones with 5-Benzyl- and 5-Phenoxymethyl-2H,3H-1,3,4-oxadiazole-2-thiones

Alkylation of 5-substituted 2H,3H-1,3,4-oxadiazole-3-thiones with α-bromo ketones in alkaline solutions yields 5-substituted 2-aroylmethylthio-1,3,4-oxadiazoles; in acidic solutions these compounds re- arrange into 4-aryl-3-arylacetamido-2H,3H-1,3-thiazol-2-ones.

Dealkylation of 4-phosphorylated 5-alkoxypyrazoles: Easy synthetic access to P-chloro ylides†

The chlorination of 5-alkoxypyrazoles containing bis-(dialkylamino)- or diphenylphosphino groups at the4-position afforded highly unstable chlorophosphoni-um chlorides that dealkylated giving chlorobis(di-alkylamino)- and chlorodiphenylphosphonium(3-methyl-5-oxo-1-phenyl-5H-pyrazol-4-yl)ides. The P-chloro ylides do not react with aromatic aldehydes, but chlorine atoms are easily substituted with OH, NH2 ArNH, and Et2N residues. They also exhibit basic properties and add hydrogen chloride with protonation at N-2.

1,3,2-Oxazaphosphorinanes in rhodium(I) complexes

Abstract Acetylacetonate complexes of rhodium(I) with 1,3,2-oxazaphosphorinanes were obtained. The structure and features of the stereochemistry of these compounds were studied by X-ray crystallography, and 1H and 31P NMR spectroscopy. The places 1,3,2-oxazaphosphorinanes take in the spectrochemical series of organophosphorus ligands is discussed.

The mannich reaction in the synthesis of N,S-containing heterocycles 4. Aminomethylation of 6-amino-3,5-dicyano-1,4-dihydropyridine-2-thiolates: A convenient regioselective route to 3,5,7,11-tetraazatricyclo[7.3.1.02,7]tridec-2-ene derivatives

Treatment of N-methylmorpholinium 4-R-6-amino-3,5-dicyano-1,4-dihydropyridine-2-thiolates (R = 2-ClC6H4 and 2-MeOC6H4) with primary amines in the presence of an excess of formaldehyde gave 13-R-8-thioxo-3,5,7,11-tetraazatricyclo[7.3.1.02,7]tridec-2-ene-1,9-dicarbonitrile derivatives in high yields (66–95%). In a similar way, aminomethylation of 3-R-10-amino-7,11-dicyano-9-aza-3-azoniaspiro[5.5]undeca-7,10-diene-8-thiolates (R = Me and Et) afforded 1′-alkyl-8-thioxospiro[3,5,7,11-tetraazatricyclo[7.3.1.02,7]tridec-2-ene-13,4′-piperidine]-1,9-dicarbonitriles in 43–91% yields. Alternatively, these compounds were obtained by multicomponent cyclocondensation of N-alkylpiperidin-4-ones, cyanothioacetamide, primary amines, and aqueous formaldehyde. The starting 3-R-10-amino-7,11-dicyano-9-aza-3-azoniaspiro[5.5]undeca-7,10-diene-8-thiolates were prepared by a new method from N-alkylpiperidin-4-ones and cyanothioacetamide. The structure of 5,11-bis(4-ethoxyphenyl)-13-(2-methoxyphenyl)-8-thioxo-3,5,7,11-tetraazatricyclo[7.3.1.02,7]tridec-2-ene-1,9-dicarbonitrile was examined by X-ray diffraction analysis.

Synthesis and Properties of 1,3-Diaryl-5,6-dihydro-8H-imidazo[2,1-c]-1,4-oxazinium Bromides

It has been established that the condensation of 3-(4-methoxyphenylamino)-5,6-dihydro-2H-1,4-oxazine with substituted phenacyl bromides occurs at the exocyclic nitrogen atom with formation of 3-aryl-3-hydroxy-1-(4-methoxyphenyl)-2,5,6,8-tetrahydro-3H-imidazo[2,1-c]-1,4-oxazinium bromides. By treatment of the latter with acetic anhydride 3-aryl-1-(4-methoxyphenyl)-5,6-dihydro-8H-imidazo[2,1-c]-1,4-oxazinium bromides are formed. The structures of the compounds synthesized were determined via1H NMR spectroscopy and X-ray diffraction.

MOLECULAR AND CRYSTAL STRUCTURE AND ELECTRON DENSITY DISTRIBUTION IN P-BIS(TRIMETHYLSILYL)AMINO-C,C-DICHLOROMETHYLENEPHOSPHINE

Abstract Molecular and crystal structure of P-bis(trimethylsilyl)amino-C,C-dichloromethylenephosphine which is a liquid at ambient temperature (m.p. ∼ -9°C) was determined at - 120°C by the low-temperature X-ray diffraction method and deformation electron density maps were calculated. Experimental evidence is obtained for the conclusion that in P-aminosubstituted phosphaalkenes the n N-πP==C conjugation causes not only shortening of the single P-N bond through which this conjugation is transferred but also shortening of the P==C double bond. Comparison of peculiarities of electron density distribution is given for both highly conjugated and double-bond localized phosphaalkenes.

Crystalline and Molecular Design of Functionalized Viologens

The regularities of molecular and crystalline structure of functionalized (including mesoionic) viologens were systematically studied. For this purpose a number of fundamentally new viologenic systems was synthesized containing functional groups in side substituents. As a result of extensive X-ray structural studies it is revealed that unlike “classical” viologens, which in crystal form cation-anion pairs or cation-anion stacks, functionalized viologens are bound into endless chains by means of strong intermolecular hydrogen bonds.

Synthesis, structure, and properties of piperidinium 3-(4-chlorophenyl)-2-cyano-3-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-enyl)thiopropionimidate

Condensation of 4-chlorobenzaldehyde with cyanothioacetamide and dimedone in the presence of piperidine afforded piperidinium 3-(4-chlorophenyl)-2-cyano-3-(2-hydroxy-4,4-dimethyl-6-oxocyclohex-1-enyl)thiopropionimidate. This salt was studied by X-ray diffraction analysis and used in the synthesis of the previously unknown partially hydrogenated 2-alkylthioquinolin-2-ones.