Pyrido[2,3-d]pyrimidines. 1. Acylation of 2,4,5-trioxo-7-amino-8H-pyrido [2,3-d]pyrimidines

Reaction of 2,4,5-trioxo-7-aminopyrido[2,3-d]pyrimidines with acylating agents takes place both at the amino group and at the cyclic nitrogen atom. Reaction of these compounds with formic acid, chloroacetyl chloride in pyridine, cyanoacetic acid in the presence of acetic anhydride, and oxalyl chloride leads to monoacylation at the amino group but with methyl chloroformate it is the product of acylation at the cyclic nitrogen. Refluxing in acetic anhydride gave mono-, di-, and triacetyl derivatives. The structures of these compounds were proved using spectral data.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 811–814, June, 1990.