Synthesis Of Fenbuconazole And Optimization Of Preparation Technique

The fenbuconazole is a high efficient fungicide. A route was proposed here, and it started from 2-(4-chlorophenyl)acetic acid as a raw material, through six reactions included esterify, reduction, chlorination, two times of nucleophilic reactions and condensation reaction, fenbuconazole was eventually prepared. And an optimization of preparation technique was obtained in this paper, by wich could reach a high yield of fenbuconazole.2-(4-chlorophenyl)ethanol was obtained by the reduction of ethyl 2-(4-chlorophenyl) acetate which obtained from esterifying of 2-(4-chlorophenyl)acetic acid. A favorite reaction condition was obtained after we studied the influence of amount of SOCl₂, NaBH₄ and reaction temperature. Thus, the yield of the two steps reached 95%. In this paper, we developed a novel route, combined esterify and reduction reaction in one-pot, which simplified the operation and reached a high yield of product.2-(4-chlorophenyl)-l-chloroethane was obtained by the reaction with SOCl₂. Pyridine was used as a catalyst. A favorite reaction condition was obtained after we studied the influence of amount of SOCl₂. Thus, the yield of product reached 96%.4-(4-chlorophenyl)-2-phenyl-butanenitrile was obtained by the reaction with 2-(4-chlorophenyl)-l-chloroethane.NaH was used as reaction base. A favorite reaction condition was obtained after we studied the influence of kind of base, amount of reagent, ratio of reactant and reaction temperature. Thus, the yield of 4-(4-chlorophenyl)-2-phenyl-butanenitrile reached 82%, which was much higher than it was reported.2-bromomethyl-4-chlorophenyl-2-phenyl-butanenitrile was obtained by the reaction with dibromomethane. 30% NaOH was used as reaction base. A favorite reaction condition was obtained after we studied the influence of concentration of base, amount of reagent, ratio of reactant and temperature. Thus, the yield of 2-bromomethyl-4-chlorophenyl-2-phenyl-butanenitrile reached 93%.Fenbuconazole was eventually obtained by the reaction with potassium 1,2,4-triazol-1-ide. A favorite reaction condition was obtained after we studied the influence of kind of base, ratio of reactant and temperature. We got 99% fenbuconazole throughsalifying or recrystallizing in an appropriate solvent. The yield of fenbuconazole reached 81%. And, the yield of fenbuconazole reached 56.8% from the beginning raw material 2-(4-chlorophenyl)acetic acid.