Convenient synthesis of novel 4-substituted-amino-5-trifluoromethyl-2,7-disubstituted pyrido[2,3-d]pyrimidines and their antibacterial activity

Novel pyrido[2,3-d]pyrimidines 4 have been synthesised starting from 2-amino-4-trifluoromethyl-6-substituted nicotinonitriles 1 via imine formation, selective amination followed by Dimroth rearrangement. Compound 4 were screened against Gram +ve and -ve bacteria in vitro. Compounds 4h and 4d showed significant activity against all species of Gram positive bacteria and moderate activity against Gram negative bacteria. N-2,4 difluorophenyl compounds 4l and 4m were the least active among all the compounds. All the compounds were inactive against Pseudomonas aeruginosa at the maximum concentration of 200 mu g ml(-1). (c) 2006 Elsevier SAS. All rights reserved.