Synthesis of 6‐benzyl‐ and 6‐phenethyl‐2,4‐diamino‐5,6,7,8‐tetrahydropyrimido[4,5‐ d ]pyrimidines

The preparation of ten aralkyl derivatives of 2,4‐diamino‐5,6,7,8‐tetrahydropyrimido[4,5‐ d ]pyrimidines ( 6 ) has been accomplished. The title compounds were prepared in a simple one step reaction from 2,4,6‐triaminopyrimidine ( 4 ), formaldehyde ( 2 ), and either substituted benzylamines ( 1a‐d ) or substituted phenethylamines ( 1e‐j ). This modified Mannich reaction has been shown to be a general method for such derivatives. Elemental analysis, 1 H nmr and mass spectral data have confirmed the proposed structures. None of the compounds exhibited either antimalarial or antitrypanosomal activity.