Carboxylderivatives

Carboxylderivatives are compounds derived from carboxylic acids by replacing the hydroxyl group of the carboxyl moiety (-COOH) with various leaving groups, forming reactive acyl derivatives. The common feature is the acyl (R-CO-) group, which enables nucleophilic acyl substitution: a nucleophile attacks the carbonyl carbon and the leaving group departs. The reactivity of these derivatives toward nucleophiles and hydrolysis is largely governed by the identity of the leaving group.

Common examples include acyl chlorides (RCOCl), acid anhydrides (RCO-O-COR'), esters (RCOOR'), and amides (RCONR'R''), as well as thioesters and imides. In general, acyl chlorides are the most reactive toward nucleophiles, followed by anhydrides, esters, and amides, reflecting leaving-group ability. These derivatives can be prepared from carboxylic acids by converting the -OH into a better leaving group, such as using thionyl chloride to form acyl chlorides, dehydration or condensation to form anhydrides, alcoholysis to form esters, or coupling reagents to form amides.

Applications and significance: Carboxylderivatives are central to organic synthesis and materials science. They serve as intermediates in the preparation of esters and amides, which underpin polymers such as polyesters and polyamides, as well as a wide range of pharmaceuticals and agrochemicals. They participate in diverse reactions, including aminolysis, hydrolysis, transesterification, and acyl transfer, with the exact outcome governed by the leaving group and the reacting nucleophile.