Synthesis, antifungal activity, and DFT calculation study of novel 1-acyl-5- amino-1,2,4-triazole-thioether derivatives containing natural gem-dimethylcyclopropane ring structure

Abstract

A series of novel 1-acyl-5-amino-1,2,4-triazole-thioether derivatives containing natural gem-dimethylcyclopropane ring structure were synthesized from natural biomass resource 3-carene. Their structures were confirmed by FT-IR, NMR, ESI-MS, and elemental analysis. The possible mechanism of regioselectivity for the N-acylation reaction of 5-amino-1,2,4-triazole with intermediate 4 was explored by DFT theoretical calculation. All the title compounds were evaluated for antifungal activity in vitro against eight plant pathogens, and some target compounds showed good inhibitory activity against the testedpathogens. For example, compounds 7f and 7g exhibited inhibitory rates of 81.6% and 80.9% against C. arachidicola, and A. solani, respectively, better than that of the commercial fungicide thifluzamide with corresponding inhibitory rates of 75.0% and 78.6%. Besides, against G. zeae, most of the target compounds displayed better antifungal activity than the positive control thifluzamide.