Study On Synthesis And Application Of 1,2,4-triazole Derivatives

Triazole compounds have been widely developed and applied in medicine,pesticides,and materials due to their represent versatile biological activities and excellent optical stabilities.Related researches in developing new structural types of triazole compounds have been a extremely acute topic in heterocyclic chemistry field.In this paper,a series of 1,2,4-triazole derivatives were designed and synthesized,including four new compounds that were not reported in the literature.Nuclear magnetic resonance spectroscopy,mass spectrometry and infrared spectroscopy characterized the structures of the compounds.The synthesized compounds were evaluated for insecticidal activity,ultraviolet absorption properties and thermal stability.Specific work could be divided into following aspects:1.Using salicylic acid,thionyl sulfoxide and salicylamide as starting materials,the key intermediate(A)was synthesized by one-pot boiling method,and the nucleophilic addition reaction proceeded with hydrazine or its substitutes under the catalysis of acetic acid.And then the cyclization reaction of C-N occurs to produce 10 kinds of 13,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazole derivatives,of which compounds(VI?VII?VIII?X)have not been reported in the literature.2.The UV absorbance and thermal stability of the target compounds were determined by UV-Vis absorption spectra,fluorescence spectra and thermogravimetric analysis.The experimental results show that the target compound has strong UV absorption at 275-325 nm,and the thermal stability is good.Among them,compound I can meet the requirements of UV absorber in terms of UV absorption,light stability,light transmittance and thermal stability.Obviously,it has potential application value.The molar absorption coefficient of compound(I)is 3105 L/mol·cm,the light transmittance in the visible light region at 400 nm and 450 nm is 98.08% and 99.85%,respectively,and the initial decomposition temperature is 284°C.3.The target compounds were tested for insecticidal activity using three-day-old broad bean tapeworms.The experimental results showed that all compounds reached a 100% insecticidal rate at a test concentration of 200 mg/L;the insecticidal rate of all compounds was exceeded 98% at a test concentration of 100 mg/L.The insecticidal activity of Compound IV at 10 mg/L and 1 mg/L is comparable to the new generation of ultra-efficient insecticide dinotefuran.The main innovation of this paper is described as follows: 1.A detailed exploration and optimization of the synthesis process of key intermediates(A)for 1,2,4-triazole compounds was carried out.The innovative method of gradient heating was used to eliminate the reaction process in the raw material salicylic acid.Poly-problems;the yield is also 8.4% higher than that reported in the literature.2.The UV absorption and thermal stability of 3,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazole derivatives have not been reported.The results show that the compounds of this structure type can be used as potential The development of UV absorbers further expanded the application of this class of compounds.3.The 1,2,4-triazole compounds synthesized in this paper show excellent insecticidal activity,and there is no report on the application of these compounds in insecticides.The excellent insecticidal activity of Compound IV has potential application value,and it can also be a lead for the development of new structure type pesticides.