CAL-B-mediated efficient synthesis of a set of valuable amides by direct amidation of phenoxy- and aryl-propionic acids

An efficient, easy and sustainable amidation of a set of non-activated carboxylic acids with anilines, assisted by CAL-B, as biodegradable catalyst, is reported. The enzymatic amidation reactions are performed on set of nonsteroidal anti-inflammatory drugs (NSAIDs), phenoxypropionic acid and protected-prolines by direct condensation of one equivalent of carboxylic acids and two equivalents of anilines derivatives in heptane after 72 h of reaction at 80 degrees C. The obtained carboxylic amides are recovered with isolated chemical yields varied between moderate and excellent. Fourteen from them are reported for the first time, and an X-ray crystal is obtained for: N-(4-iodophenyl)-2-(4-isobutylphenyl)propanamide 1d.