Ultrasonic-assisted synthesis of 1,4-disubstituted 1,2,3-triazoles via various terminal acetylenes and azide and their quorum sensing inhibition.

An efficient synthesis of 1,4-disubstituted 1,2,3-triazole derivatives was studied. 1,4-Disubstituted 1,2,3-triazoles containing isoxazole and thymidine structures were synthesized in 84-96% yields starting from various terminal isoxazole ether alkynes and β-thymidine azide derivatives via a 1,3-dispolar cycloaddition using copper acetate, sodium ascorbate as the catalyst under ultrasonic assisted condition. All the target compounds were characterized by HRMS, FT-IR, 1H NMR and 13C NMR spectroscopy. Furthermore, the quorum sensing inhibitory activities of synthesized compounds were evaluated with Chromobacterium violaceum (C. Violaceum CV026) based on their inhibition of violacein production, with compound C10-HSL as a positive control. The compounds 8a, 8c and 8f exhibited considerable levels of inhibitory activity against violacein production, and IC50 values were 217±19, 223±20 and 42.8±4.5μM, respectively, which highlighted the potential of these compounds as lead structures for further research towards the development of novel QS inhibitors.