Synthesis, structure investigations, and antimicrobial activity of selected s-trans-6-aryl-4-isopropyl-2-{2-[(E)-1-phenylalkylidene]-(E)-hydrazino}-1,4-dihydropyrimidine hydrochlorides

A series of 6-aryl-4-isopropyl-2-[2-(1-phenylalkylidene)hydrazino]-1,4-dihydropyrimidine hydrochlorides was prepared and tested for antibacterial and antifungal effects. The title compounds were synthesized by cyclocondensation of N-2-(1-phenylalkylideneamino)guanidines with 1-aryl-4-methyl-2-penten-1-ones. Structure analyses of the prepared compounds were accomplished by means of 1D and 2D NMR spectroscopy. The analyses showed that the ring closure reaction took place regioselectively in all cases and generated exclusively 2-(phenylalkylidenehydrazino)dihydropyrimidines. According to the NOE experiments, the applied N-2-(1- phenylalkylideneamino)guanidines exist in [D-o]DMSO solution as s-trans-(E)- and the title compounds as s-trans-(E,E)-isomers. The antimicrobial activity was evaluated against representative Gram-negative and Gram-positive bacteria, and against the pathogenic yeast Candida albicans, The tested title compounds showed weak antibacterial activity against Gram-positive bacteria, and one compound was active against Candida albicans. (C) 2002 Elsevier Science B.V. All rights reserved.