Conventional and Microwave-Assisted Synthesis of Novel 1,2,4-Triazole Derivatives Containing Tryptamine Skeleton and Evaluation of Antimicrobial Activity

Abstract

1,2,4-Triazole-3-one (3) obtained from tryptamine was transformed to the corresponding carbox( thio)amides via several steps (6a-d). Their reaction with sodium hydroxide performed the 1,2,4- triazole derivatives (7a-d). Compounds 7a-d treatment by 2-bromo-1-(4-chlorophenyl)ethanoneain an ambiance with sodium ethoxide afforded the compounds (8a-d). The reduction reaction of 8a-d afforded 1,2,4-triazoles (9a-d). The synthesis of (10a-d), (11a-d) and (12a-d) was afforded treatment of products 9a-d with 4-chlorobenzyl chloride (for 10a-d) or 2,6-dichlorobenzyl chloride (for 11a-d) or 2,4-dichlorobenzyl chloride (for 12a-d). Besides the improved of entirely novel agents having various chemical features than those of the existing ones, another aim is to combined two or more groups into a single hybrid compound. For this reason, a single compound containing more than one group, each with various modes of effect, could be helpful for the cure of bacterial infections. Microwave-assisted and conventional techniques were utilized for the syntheses. The structures of recently obtained molecules were elucidated on the foundation of 1H NMR, ¹³C NMR, FT IR, EI MS methods and elemental analysis. All novel synthesized molecules were investigated for their antimicrobial activity using MIC (minimum inhibitory concentration) method. The aminoalkylation of triazoles (7a-d) formed products 8a-d which have excellent activity against testing bacteria with values between 0.24 and 125 μg/mL. Especially compounds 8a and 8d exhibited much better activity against E. coli than ampicillin used as standard drug. The microwave process ensured a more efficient road to the creation of desired molecules. The antibacterial examination demonstrated that after the carbonyl group is increased the antibacterial activity of the compounds is greatly increased. That's why molecules formed as a result of the alkylation reactions of triazoles has high activity.