Synthesis of 4-chloro-2-trifluoroacetyl-aniline hydrochloride hydrate

The present invention relates to a method for the synthesis of efavirenz by an intermediate, particularly involving synthesis of 4-chloro-2-trifluoroacetyl-aniline hydrochloride hydrate, belonging to the field of pharmaceutical synthesis intermediates. Synthesis method comprising the steps of: at low temperature n-butyllithium solution was added dropwise 4-chloro-anilide -N- pivaloyl solution, the reaction solution to give the dilithium salt of 4-chloro aniline -N- pivaloyl, and low temperature to the solution with chlorine gas into the reaction trifluoroacetyl to give 4- chloro-2-trifluoroacetyl-aniline -N- pivaloyl, and finally the acetyl-4-chloro-2-trifluoromethyl -N- pivaloyl aniline in hydrolysis under acidic conditions to give the product 4- chloro-2-trifluoroacetyl-aniline hydrochloride hydrate. The present invention, with n-butyllithium as base in hydrochloric acid, and are substantially converted to the relatively high economic value of the lithium chloride solution, easy recycling, waste water treatment can be reduced difficulty; low cost using trifluoroacetyl chloride as starting materials can reduce production costs.