反应详情

Briefly, the benzoyl ester derivatives of formula II are prepared by reacting 5-fluoro-4-halo-2-nitrobenzoic acid with a chlorinating agent, such as thionyl chloride or trichlorophosphorous, followed by reacting the acid chloride so formed with a dialkylmalonate. The 4,5-difluoro-2-nitrobenzoic acid starting material can be prepared by nitration in mixed acid of 3,4-difluorobenzoic acid, which is obtained by oxidation 3,4-difluoroacetophenone. The 4- chloro-5-fluoro-2-nitrobenzoic acid starting material can be obtained by the following process: