Synthesis, Structure Characterization And Biological Activity Of (3-substituted-4-amino-1,2,4-triazole-5-thio) Acylhydrazones

Substituted1,2,4-triazole derivatives which have been associated with various types ofbiological effects such as antiviral, antibacterial, anti-inflammatory and anticonvulsantactivity have important applications in the field of medicine and pesticide. So it attractsnumerous scientists for its research. In addition to these findings it is known thatacylhydrazones also have good biological activities because of its special unit and it is hot inmany research fields. Governed by these ideas and in line with our previous study, weefficiently synthesized two serieses of new acylhydrazones containing1,2,4-triazole moiety.Substituted aromatic acids are used as the starting materials, based on the methods ofesterification, hydrazinolysis, Reid and Heindl reactions, then4kinds of3-substituted-4-amino-5-mercapto-1,2,4-triazoles are obtained. The reaction of3-substituted-4-amino-5-mercapto-1,2,4-triazole with ethyl chloroacetate has given ethyl（3-substituted-4-amino-1,2,4-triazole-5-thio）acetate. The ester has been converted to the corresponding hydrazide whichhas given the target compounds by the reaction with para-substituted benzaldehydes oracetophenones. So that1,2,4-triazole is connected with acylhydrazone together organically. Inthis paper36target compounds and8intermediates have been synthesized which are newcompounds not been reported in the literature.The IR spectra, NMR spectra and elemental analysis were used to characterize thestructures of target compounds and intermediates. Some representative target compoundswere characterized in the2D and difference thermal NMR test for in-depth study oftautomerism. The investigation of NMR spectra demonstrated that target compounds behavesimilarly in dimethyl-d6sulfoxide solution. When dissolved in this solvent, the E geometricalisomers of target compounds undergo a rapid cis/trans equilibrium, with the trans conformerpredominating at room temperature.Preliminary biological activity tests have been carried out on all the target compounds.The auxin activity test （10ppm） of the target compounds showed that all the targetcompounds have poor effect on the wheat gemma and some compounds have a inhibitingeffect on the wheat gemma. The effects of compounds â…¢¹²⁰are better than compounds â…£_1¹6. The antibacterial activity was present in almost all the target compounds, but better activitywas observed against Staphylococcus aureus with the minimal inhibitory concentration（MIC）in the range3.13⁶.25μg/mL, and the MIC is similar with the comparison drug chloramphenicol. When R2is an electron withdrawing group of chlorine or a hydrophilichydroxyl group, it exhibites better antibacterial activity than other substituents.