Derivatives of 2-hydroxy-4-mercapto-6-methylpyrimidine-5-carboxylic acid. II. Pirazolo-[3,4-d]-pyrimidine and hydrazinopyrimidine.

Heating of 2-hydroxy-4-mercapto-6-methylpyrimidine-5-carboxylic acid 1 with hydrazine or its derivatives in ethanolic solution gave 4-hydrazino derivatives 10--12. However, at 150--160 degrees in the absence of a solvent after decarboxylation the 4-hydrazino derivatives 13 and 14 were formed. Under similar conditions form 2 (the ethyl ester of 1), 4-methylpyrazole-[3,4-d]-5(H)-pyrimidine-3,6-dione and the corresponding 1--substituted derivatives 3,7,8 of this ring system were obtained. These compounds were easily chlorinated (POCl3/PCl5) in 6 and 3 and 6 position. Compounds 3 and 7 have strong cytostatic activity in vitro and in vivo, compound 13 acts as virostatic and antiinflammatory.