Efficient One‐Pot Synthesis of 2,4‐Di(het)aryl and 2,4‐Diamino Pyrido[3,2‐d]pyrimidines Involving Regioselective SNAr and Palladium‐Catalyzed Reactions.

An efficient and original synthesis of various 2,4-disubstituted pyrido[3,2-d]pyrimidines is reported. One-pot di(het)arylation and diamination approaches were used to obtain highly functionalized products in very good yields. The two one-pot processes were compared to their step-by-step related synthesis. Both routes started from 2,4-dichloropyrido[3,2-d]pyrimidine 1 and included a chlorine discrimination during the first reaction.