Alkylation of allopurinol and inosine with dimethylformamide dimethylacetal or diethylacetal

The alkylation of allopurinol and inosine with dimethylformamide (DMF) dimethylacetal and diethylacetal was studied. Allopurinol is alkylated in both the pyrazole and pyrimidine rings. 1,5- and 2,5-Dimethyl derivatives are formed in the case of methylation. 1,5- and 2,5-Diethyl derivatives, as well as 1-ethyl-4-ethoxypyrazolo3,4-d]pyrimidine, were obtained in the ethylation of allopurinol. The yields of the 1,5-substituted compounds are highest in both cases. The alkylation of inosine with DMF diethylacetal takes place in the 1 and 6 positions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1526–1531, November, 1988.