First Synthesis And Antimicrobial Activity OfN- andS-α-L-Arabinopyranosyl-1,2,4-Triazoles
摘要:
Arabinosylation of some 4-amino- and4-arylideneamino-5-(pyridin- 3- yl)-2,4 dihydro- 1,2,4]triazole- 3- thiones with 2,3,4-tri-O-acetyl-beta-L-arabinopyranosyl bromide led to an efficient synthetic approach to the corresponding N- and S-alpha-L-arabinopyranosides. Structure assignment of these two regiosiomers was based on chemical and spectroscopic evidences. Antimicrobial activities of two selected regioisomeric N- and S-alpha-L-arabinopyranosides were compared. The N-alpha-L-arabinopyranoside showed higher inhibitory effect than its regioisomeric S-alpha-L-arabinopyranoside against Aspergillus fumigatus, Penicillium italicum, Staphylococcus aureus, and Pseudomonas aeruginosa.
The novel triazolothiadiazine analogs 5a–p were obtained via a multistep synthetic sequence beginning with 5-substituted 4-amino-1,2,4-triazole-3-thiols 1. Compound 1, in reaction with various aromatic aldehydes 2 in acetic acid, afforded Schiff bases 3a–p. Cyclization of 3a–p with ethyl chloroacetate 4 in the presence of sodium hydride at room temperature gave triazolothiadiazines 5a–p in good yields