Study On The Preparation Technology Of3-amino-5-methylphenyl-4H-1,2,4-triazole For Antibacterial Agents

3-Amino-5-methylphenyl-4H-1,2,4-triazole was synthesized successfully through three step in this paper,which is one kind of the three thiazole class derivatives with lots of bactericidal activity.For the first step,2-methyl benzoic acid methyl ester was synthesized using2-methyl benzoic acid and methyl alcohol.The second step was to synthesize2-toluene formex hydrazine using2-methyl benzoic acid methyl ester and hydrazine hydrate.The last step was the synthesis of the target produst,3-amino-5-thylphenyl-4H-1,2,4-triazole using2-toluene formex hydrazine and s-methyl-iso-thiourea sulfate in the solution of tetrahydrofuran.The structures of the products were chatacterised and the purity was determined by the use of gas chromatograph-mass spectrometer(GC-MS),nuclear magnetic resonance spectrometer(NMR),melting point mensuration,infrared spectrometer(IR),high performance liquid chromatograph(HPLC) and so on.The reaction conditions were optimized by the Single-factor experimentation and Orthogonal experimentation.Under optimized conditions(the reactant mole ratio of n(2-methyl benzoic acid):n(methyl alcohol)=1.0:18.5reacted at65℃for10h,the yield of the2-methyl benzoic acid methyl ester was84.1%with98.6%purity.Then reaction of2-toluene formex hydrazine with6.6equiv.Hydrazine hydrate at20℃for fourteen hours gave2-toluene formex hydrazine in the yield of71.2%with87.3%purity.After optimization,3-amino-5-methylphenyl-4H-1,2,4-triazole was finally obtained in the yield of73.5%with97.1%purity from reaction of s-methyl-iso-thiourea sulfate and1.0equiv.dimethylamine at100℃for six hours.