“…Compounds like 44 are folic acid antagonists, and they exhibit diverse biological activity [37,38]. Various fused heterocyclic compounds 52-55 were synthesized by condensation of aminoimidazo[1,2-a]-pyridines 51a and 51b with aldehydes 1a and 1f [44] (Scheme 13). Alkyl-substituted imidazonaphthyridines 52 and 53, imidazodipyridines 54, and pyridoimidazodiazepines 55 can exhibit different kinds of pharmacological activity, in particular anticancer, genotoxic, anti-HIV, etc.…”