Acetic Anhydride → 2-Acetoxy-3,5-dichlorobenzoic acid

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Reaction Steps

In one non-limiting example of a synthesis method for N-(2-hydroxy-3,5-dichlorobenzoyl)-L-phenylalanine, synthesis begins with reaction of 3,5-dichlorosalicylic acid with acetic anhydride to obtain 2-acetoxy-3,5-dichlorobenzoic acid which in turn is converted into the acid chloride by the action of oxalyl chloride. The 2-acetoxy-3,5-dichlorobenzoic acid chloride is then reacted in situ with phenylalanine ethyl ester hydrochloride, in the presence of triethylamine, to yield ethyl ester of N-(2-acetoxy-3,5-dichlorobenzoyl)-L-phenylalanine. The last step of the synthesis method introduces novel and highly specific hydrolysis of both ester functions of N-(2-acetoxy-3,5-dichloro benzoyl)-L-phenylalanine ethyl ester to obtain the OTA template, N-(2-hydroxy-3,5-dichlorobenzoyl)-L-phenylalanine (I) with 98% yield. This synthesis reaction is summarized in FIG. 2.

Provenance & Evidence