Side Chain Bromination of Mono and Dimethyl Heteroaromatic and Aromatic Compounds by Solid Phase N-Bromosuccinimide Reaction without Radical Initiator under Microwave

A series of side chain mono and dibromo derivatives of mono and dimethyl heteroaromatic and aromatic compounds (1–17) were synthesized by one step solid phase N-bromosuccinimide (NBS) reaction without radical initiator by microwave irradiation. The benzylic mono and dibromo products were exclusively preferred except in the case of 6-methylpyridine amides (8 and 9) where nuclear and also side chain bromination resulted. Naphthyridine systems resulted improved yields. By this method, we also report the synthesis of 2-pivaloylaminopterin-6-carbaldehyde.