Unprotected Amino and Hydroxy Carboxylic Acids

Carboxylic Acids with Additional Electrophilic Croups 

Carboxylic acids with strongly electron-withdrawing groups, for example trifluoro-acetic or 2,4,6-trinitrobenzoic acid [22], are readily converted into esters or amides. The products can, however, be unusually sensitive toward attack by nucleophiles and can readily undergo hydrolysis, transesterification, or transamidation. 2,4,6-Tris(trifluoromethyl)benzoic acid has been reported to undergo conversion into the acyl chloride or esters only with difficulty [23]. 

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