The Research Of The Synthesis Of Diafenthiuron

Diafenthiuron is a new thioureas insecticide and miticide. This work is aimed at redesigning and optimizing the synthesis route of the product. The structure of the product is characterized by 1H MNR,13C NMR, MS, IR.4-bromo-2,6-diisopropylaniline was synthesized from 2,6-diisopropylaniline as the starting material, which is brominated under the action of hydrobromic acid and hydrogen peroxide. The purity was 97.1%, and the yield was 89.6% under the reaction conditions of n(H2O2):n(2,6-diisopropylaniline)=1.30:1, m(dichloroethane):m(2,6-diisopropylaniline)=12:1, reacted at 15 ℃ by 1.5 h.Xylene as solvent, potassium hydroxide as acid binding agent,4-bromo-2,6-diiso propyl aniline was reacted with phenol by Ullmann Coupling reaction employing copp er 8-hydroxyquinoline, copper,4-dimethylaminopyridine(DMAP) as catalyst systems to form 2,6-diisopropyl-4-phenolxyaniline. The yield was 89.6% under the reaction condit ions of n(4-bromo-2,6-diisopropylaniline):n(copper 8-hydroxyquinoline):n(DMAP):n(Cu)= 1:167.5:57.2:74.4, n(phenol):n(4-bromo-2,6-diisopropylaniline)=1.1:1, reacted at 145 ℃ by 3 h. The repeated times of catalysts was three.Water as solvent, PEG-600 as the catalyst, 2,6-diisopropyl-4-phenoxyaniline was r eacted with CS2 to from 2,6-diisopropyl-4-phenoxyphenyl dithiocarbamate. The purity was 91.3%, and the yield was 87.1% under the reaction conditions of n(2,6-diisopropy 1-4-phenoxyaniline):n(CS2):n(triethylamine)=1:3:3, reacted at 35 ℃ by 1.5 h.Dichloromethane as the solvent,2,6-diisopropyl-4-phenoxyphenyl isothiocyanate was synthesised by 2,6-diisopropyl-4-phenoxyphenyl dithiocarbamate and 4-toluene sulfonyl chloride(TsC1). The purity was 86.1%, and the yield was 79.7% under the reaction conditions of n(2,6-diisopropyl-4-phenoxy -phenyl dithiocarbamate):n(TsCl)=1:1.2, reacted at 35 ℃.Toluene as the solvent, diafenthiuron was synthesised by nucleophilic addition reaction of 2,6-diisopropyl-4-phenoxyphenyl isothiocyanate and t-butylamine. After purification, the purity was 98.6%, yield was 75.2% under the reaction conditions of n(t-butylamine): n(isothiocyanates)=1.4:1, the reaction was at room temprature for 12 h.