Hammick reaction
The Hammick reaction, named after Dalziel Hammick, is a chemical reaction in which the thermal decarboxylation of α-picolinic acids in the presence of carbonyl compounds forms 2-pyridyl-carbinols.
Using p-cymene as solvent has been shown to increase yields.Upon heating α-picolinic acid will spontaneously decarboxylate forming the so-called 'Hammick Intermediate', which can be viewed as an aromatic ylide. In the presence of a strong electrophile, such as an aldehyde or ketone, this species will undergo nucleophilic attack faster than proton transfer. After nucleophilic attack intramolecular proton transfer yields the desired carbinol.
The scope of the reaction is effectively limited to decarboxylating acids where the carboxyl group is α to the nitrogen, thus suitable substrates are limited to the derivatives of α-picolinic acid including the α-carboxylic acids of quinoline and isoquinoline.
