Hydrolysis and saponification of methyl benzoates - A green procedure in high temperature water

We report a study of the hydrolysis and saponification of methyl benzoates, 1, in both water and slightly alkaline solution (2% KOH) at high temperatu re (200-300 degrees C). In this green, solvent-free procedure, we achieve p artial hydrolysis or quantitative saponification of sterically hindered and p-substituted methyl benzoates in 30 min. In addition, methyl 2,4,6-trimet hylbenzoate, 1a, and methyl p- aminobenzoate, 1g, can be selectively decarb oxylated or hydrolyzed by changing the temperature and/or pH of the reactio n medium. The enhancement of the nucleophilicity of diluted alkaline soluti on at high temperature is proved by the quantitative hydrolysis of the ster ically hindered ester, 1a, and the partial hydrolysis of the trifluoromethy l group to a carboxylic acid in methyl p-trifluoromethylbenzoate, 1e.