The p-(dimethylamino)benzaldehyde modification of Hantzsch reaction: Synthesis of 6-(1H-benzimidazol-2-yl)pyrido[2,3-d]pyrimidino-2,4(1H, 3H)-diones

The reaction between p-(dimethylamino)benzaldehyde and 2-acylmethyl-1H-benzimidazoles and 6-amino-1,3-dimethylpyrimidino-2,4(1H,3H)-dione has given previously unknown 5-unsubstituted 6-(1H-benzimidazol-2-yl)pyrido[2,3-d]pyrimidino-2,4(1H,3H)-diones. The reaction occurs on boiling in acetic and acid and includes the formation of 1,4-dihydropyridine-bearing compounds in accordance with the Hantzsch reaction scheme and aromatization as a result of cleavage of N,N-dimethylaniline. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 585–589, April 2007.