Search

2-Mercapto-1,3,4-triazoles and 2-amino-1,3,4-thiadiazoles were synthesized by successive transformations of 5-arylisoxazole- and 4,5-dichloroisothiazole-3-carboxylic acids and their derivatives. The amino group of 5-(4,5-dichloroisothiazol-3-yl)-1,3,4-thiadiazol-2-amine was acylated with 5-phenylisoxazole-3-carboxylic acid chloride. Simple approaches to the preparation of previously unknown heterocyclic assemblies containing two or three azole rings with a high potential for biological activity are described.

The reaction of 4-substituted anilines with 3,4,4-trichloro-1,1-bis(3,5-dimethyl-1H-pyrazol-1-yl)-2-nitrobuta-1,3-dienes led to 1-arylamino-3,4,4-trichloro-1-(3,5-dimethyl-1H-pyrazol-1-yl)-2-nitrobuta-1,3-dienes, which under the action of 2-aminopyridines underwent heterocyclization to the corresponding 2-arylamino-substituted 4-(dichloromethylidene)-3-nitro-4H-pyrido[1,2-a]pyrimidines. The molecular structure of 4H-pyrido[1,2-a]pyrimidine containing the (4-ethoxyphenyl)amine substituent at position 2 was determined by X-ray structural analysis.

New regioisomeric indazolones containing fluorine atoms in the aromatic ring have been synthesized in high yield by the interaction of 2-acylcyclohexane-1,3-diones, and of their enol methyl ethers, obtained by methylating the initial β,β′-triketones with dimethyl sulfate in the presence of calcined potassium carbonate, with 4-fluorophenylhydrazine hydrochloride and with pentafluorophenylhydrazine. The structures of the synthesized compounds were confirmed by data of IR and 1H, 13C, and 19F NMR spectra.

Treatment of 3,4-dihydroisoquinolines with triacetylmethane in refluxing alcohol for 2-3 h gave 3-acetyl-4-methylpyrido[2,1-a]isoquinolin-2-ones. Their basic physicochemical properties have been studied.

Ionic hydrogenation of 8-aza-16-thiagona-1,3,5(10),13-tetraene-12,17-diones has been carried out by regioselective reduction of the carbonyl part of the aminovinylketothiolactone group to give 8-aza-16-thiagona-1,3,5(10),13-tetraen-17-ones.