Abstract
Reactions of 1, 3-disubstituted 6-chloro-5-formyluracils (1) with phenylhydrazine or methylhydrazine giving 1, 5, 7-and 2, 5, 7-trisubstituted 4, 6-dioxo-4, 5, 6, 7-tetrahydropyrazolo [3, 4-d] pyrimidines (3, 7 and 4) were investigated in detail. It was found out that 5-formyl group in 1 was more reactive than that 6-chloro group. Thus, under cold condition, the reaction of 1 with phenylhydrazine yielded Schiff's bases (2). Upon heating, 1 with equimolar or two equivalent moles of phenylhydrazine gave isomeric compounds, 3 and 4, which were also prepared by other routes. Reactions of methylhydrazine with 1 were also investigated. Furthermore, the Schiff's bases were made to react with other kinds of hydrazines. The reaction products showed that substituent at 1- or 2-position of the products (4, 7) depended on the kind of hydrazine used later.
