Enaminouraciles as Precursors for Synthesis of Pyrimido[4,5-a]pyrimidine- 2,4-diones

Abstract

The reaction of 6-aminouracil 1 with formaldehyde and secondary amines in ethanol at room temperature gave the corresponding 5-alkylaminomethyl derivatives (2a-c) and bis(4- pyrimidyl) methane (4). Also, Mannich reaction with primary aliphatic and aromatic amines at room temperature afforded pyrimid[4,5-d]pyrimidine (5 and 6). Treatment of 1 with o-phenylenediamine through transamination gave com pound 7 which cyclized through intramolecular Mannich reaction with formalin to yield pyrimido[4,5-e]-[l,4]diazepine (8).