Hi. We have 4- (phenylcarbamoyl) -1,2-phenylene dibenzoate. I need to remove benzoyl groups and obtain 3,4-dihydroxy-N-phenylbenzamide. Can I make it using an acid saponification?
Try using base hydrolysis instead. K2CO3 in methanol at rt, or LiOH in THF/H2O at rt. You may need to optimise the solvent to find something that dissolves your compound.
Thanks, but while using base hydrolysis pyrocatechol fragment can oxidized
Dear V. N. Anishchenko
A mild alkaline hydrolysis may solve this problem
Base on the fact that amide bond is stronger than the ester bond, so base hydrolysis of the ester can be achieved by alkaline hydrolysis using NaHCO3 or diluted NaOH at room temperature
I think no need to reflux or heat because this type of ester of this type can be hydrolyzed even when the compounds expose to moisture like what is happening in aspirin hydrolysis
I think you have to try different dilution of the basic solution and you can reach the optimum concentration of the base which can selectively hydrolyze the ester without affective the amide bond
For selective hydrolysis of the ester in the presence of amide bond, please read the following article
Spinola, M.; Jeanloz, R. W. JBC 1970, 245, 4158.
Scheme 1
Although I have not tried this hydrolysis of the ester using aniline as a weak nucleophile. But theoretically you can try refluxing your compound with aniline in methanol. Beside the target compound you search for, a single by product (N-phenylbenzamide) is expected. You can get the target amide by several methods such as crystallization of column chromatography.
Scheme 2
Finally, although I am not sure if you are interested in chemical synthesis, but your target compound can be achieved simply from the reaction of aniline with methyl 3,4-dihydroxybenzoate or ethyl 3,4-dihydroxybenzoate, all are readily available in Sigma.
Scheme 3
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