Acetals of lactams and acid amides

The reaction of dimethylformamide diethylacetal with -cyano--dimethylaminoacrylamide proceeds at the NH₂ amide group to give the corresponding acylformamidine, from which 3-cyano-4-dimethylamino-2-pyridone was obtained by thermal cyclization. Pyrrolo-, pyrido-, and azepino-[3,2-c]pyridine derivatives were similarly synthesized from 1-methyl-2-(2-cyano-2-carbamido)-methylenepyrrolidine and the homologous six- and seven-membered enaminoamides.See [1] for communication XVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1509–1512, November, 1976.     

Lactams of acetals and acid amides, 45. Synthesis of condensed 2-pyridones from activated amides,lactams, and lactones

By reaction of lactim ethers with N-substituted cyanoacetamides, the corresponding enaminoamides were obtained, cyclization of which by dimethylformamide acetal gave derivatives of pyrrolo[3,2-c]pyridine, 1,6-naphthyridine, and pyrido[4,3-b]azepine, having a substituent at the nitrogen atom of the pyridone ring. N-substituted furo[3,2-c]pyridines were synthesized from the diethyl acetals of butyrolactone and 3-(dimethylaminomethylene)butyrolactone and dimethylformamide acetal.For communication 44, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 929–932, July, 1985.     

Synthesis of Pyrazolo[3,4‐b]pyridin‐6‐ones

The procedures for the synthesis of substituted pyrazolo[3,4‐b]pyridine‐6‐ones and some of their properties are reviewed.     

Acetals of lactams and acid amides. 36. Some reactions of enamines of the isoquinoline series and synthesis of pyrimido[4,3-a]isoquinolines

The reactions of 1-methylene-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline derivatives with acyl chlorides were investigated. 2-Oxopyrimido[4,3-a]isoquinoline derivatives were obtained by the reaction of 1-carbamidomethylene-6,7-dimethoxy-1,2, 3,4-tetrahydroisoquinoline with dimethylformamide and dimethylacetamide diethylacetals. The reaction of the latter with phosphorus oxychloride and then with primary amines was used to synthesize a number of hydrochlorides that are derivatives of 2-iminopyrimido[4,3-a]isoquinoline.See [1] for Communication 35.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1095–1099, August, 1982.     

Synthesis and properties of pyrimido[4,5-<Emphasis Type="Italic">a</Emphasis>]- and pyrido[4,3-<Emphasis Type="Italic">a</Emphasis>]carbazole derivatives

Methods for the synthesis of substituted pyrimido [4,5-a]- and pyrido[4,3-a]carbazoles were proposed. Condensation of 2-(dimethylaminomethylene)-6-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-one with guanidine and thiourea afforded 2-amino-8-methyl-6,11-dihydro-5H-pyrimido[4,5-a]carbazole and 8-methyl-3,5,6,11-tetrahydro-2H-pyrimido[4,5-a]carbazole-2-thione, respectively. The reaction of cyano(6-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-ylidene)acetamide with dimethylformamide dimethyl acetal gave N-(dimethylamino-methylene)cyano(6-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-ylidene)acetamide. Cyclization of the latter yielded 1-cyano-8-methyl-3,5,6,11-tetrahydro-2H-pyrido[4,3-a]carbazol-2-one.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2740–2744, December, 2004.     

Lactam acetals

The dependence of pK _a (in nitromethane) and _I of methylene-group-substituted 1-methyl-2-methylenepiperidines is expressed by the equation pK _a =–0.41+11.8 _I. The basicities of tertiary enamines are more than five orders of magnitude greater than the basicities of the corresponding secondary enamines.See [1] for communication VII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 385–388, March, 1974.