New [<i>f</i>]‐fused xanthines: Synthesis of 1,3‐dipropyl‐1<i>H</i>,3<i>H</i>‐pyrazino, pyrido, pyrimido and pyrrolo[2, 1‐<i>f</i>]purine‐2,4‐diones

Abstract

Abstract Synthesis of 1,3‐dipropyl‐1 H ,3 H ‐pyrazino, pyrido, pyrimido and pyrrolo[2,1‐ f ]purine‐2,4‐diones, starting from 5,6‐diamino‐1,3‐dipropylpyrimidine‐2,4‐dione 1 and 6‐chloro‐1,3‐dipropylpyrimidine‐2,4‐dione 14 is described. A new synthetic approach to 1,3‐dipropyl‐1 H ,3 H ‐pyrido(or pyrazino)[1′,2′‐1,2]pyrimido[4,5‐ d ]pyrimidine‐2,4,5‐triones 19 e, f, h has been also developed.