4-Alkyl-6-amino-N 3,N 5-diaryl-2-thioxo-1,2,3,4-tetrahydropyridine-3,5-dicarboxamides: II. Synthesis and selected reactions

Synthesis of substituted thiazol-2-yl-acetamides. Molecular and crystal structure of N-(4-methoxyphenyl)-2-oxo-2-(4-phenylthiazol-2-yl)acetamide

“…Extending our earlier studies on transformation of 3-amino-3-thioxopropanamides [10][11][12][13], herein we report on reactions of amides Ia and Ib with α-bromoketones IIa-IIf at 20°C in DMF.…”

“…3-Amino-3-thioxopropanamides are used in organic synthesis as CH-acids in preparation of functionally substituted pyridines via the Michael reaction [1][2][3][4] as well as C-nucleophiles in nucleophilic vinyl substitution [5,6] and condensation with carbonyl compounds [7,8]. Alkylation of 3-amino-3-thioxopropanamides results in S-methyl derivatives [9].…”

Three-component synthesis of alkyl-substituted functionalized 4H-thiopyrans, 1,2- and 1,4-dihydropyridines, 2-alkylsulfanylpyridines, thieno[2,3-b]pyridines, and cyclohexa-1,3-diene

“…Extending the earlier research on synthesis of alkylsubstituted carbo-and heterocyclic compounds via a multicomponent condensation [5][6][7], we investigated new possibilities of three-component interaction of aliphatic aldehydes Ia-Ij with a number of CH-acids and organic bases under conditions of the Knöevenagel reaction. It was found that condensation of aliphatic aldehydes Ia and Ib with cyanothioacetamide II and ethyl 3-amino-3-thioxopropanoate III in anhydrous ethanol at 20°C in the presence of sodium ethylate resulted in ethyl 2-amino-4-isopropyl-6-mercapto-5-cyano-3-carboxylate IV and diethyl 6,6'-disulfandiylbis(2-amino-4-isobutyl-5-cyanonicotinate V. Apparently, the reaction proceeded through formation of alkene A followed by addition of the CH-acid III to give the adduct B.…”

Three-component synthesis of nicotinamide derivatives based on cross-recyclization of 2,6-diamino-4-aryl-3,5-dicyano-4H-thiopyrans with acetoacetanilide and alkylating reagents

“…Studies on preparation of functionally substituted nicotinamide derivatives [5][6][7][8] showed that cross-recyclization of 2,6-diamino-4-aryl-3,5-dicyano-4H-thiopyrans Ia-Ic with acetoacetanilides IIa and IIb in refluxing ethanol in the presence of an equimolar quantity of triethylamine followed by addition of the alkylating reagent IIIa-IIIe afforded new nicotinamide derivatives such as 6-alkylthio-4,N-diaryl-2-…”

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Three-component reaction of 2,6-diamino-4-aryl-3,5-dicyano-4H-thiopyrans, acetoacetanilides, and alkylating reagents proceeds via cross-recyclization of thiopyrans to form 6-alkylthio-4-aryl-N-aryl-2-methyl-5-cyanonicotinamides, 3-imino-6-methyl-2-(4-methoxybenzoyl)-4-(3,4-dimethoxyphenyl)-N-phenyl-2,3-dihydrothieno[2,3-b]pyridine-5-carboxamide, and 3-amino-6-methyl-4-(3,4-dimethoxyphenyl)-2-(4-oxo-4H-pyrido[1,2-a]-pyrimidin-2-yl)-N-phenylthieno[2,3-b]pyridine-5-carboxamide.Search for biologically active nicotinamide derivatives is a promising to develop herbicides [1, 2] and drugs for Alzheimer's disease treatment [3,4].Studies on preparation of functionally substituted nicotinamide derivatives [5][6][7][8] showed that cross-recyclization of 2,6-diamino-4-aryl-3,5-dicyano-4H-thiopyrans Ia-Ic with acetoacetanilides IIa and IIb in refluxing ethanol in the presence of an equimolar quantity of triethylamine followed by addition of the alkylating reagent IIIa-IIIe afforded new nicotinamide derivatives such as 6-alkylthio-4,N-diaryl-2-Apparently, the reaction pathway included opening of the thiopyran ring to form intermediate VI that was further transformed into arylmethylidenecyanothioacetamide VIII via malononitrile VII elimination [9][10][11]. The Michael addition of acetoacetanilide II to arylmethylidenecyanothioacetamide VIII led to formation of the corresponding labile adduct IX, which underwent intramolecular heterocyclization to give the substituted pyridine X.

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