A Short and Convenient Synthesis of 3-Aminomethyl-5-imino-8-nitro-2,3-dihydroimidazo[1,2-a]pyridines

ABSTRACT A two-step synthesis of 3-(N-substituted aminomethyl)-5-(N-substituted imino)-2,3-dihydro-imidazo[1,2-A]pyridines is reported. Starting from 3-bromomethyl-5-chloro-2,3-dihydroimidazo[1,2-A]pyridine, the synthesis comprises two consecutive reactions with primary amines. The products are derived from a three-dimensional molecular scaffold and may therefore be useful in medicinal chemistry in the search for small molecules that can adapt optimally to the three-dimensional binding sites of biological targets. The present synthesis is also particularly suitable for the preparation of combinatorial libraries since primary amines are commercially available in great structural diversity. Moreover, the second step is selective for primary amines, which means that secondary amino groups can be introduced into the products without the need for protection.