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.
[Image:Hammick Reaction Scheme.png|center|300px|The Hammick reaction]
Using p-cymene as solvent has been shown to increase yields.
Reaction mechanism
Upon heating α-picolinic acid will spontaneously decarboxylate forming the so-called 'Hammick Intermediate'. This was initially thought to be an aromatic ylide, but is now believed to be a carbene 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.[Image:Hammick-Reaktion M-v3.svg|650px|center|The mechanism of the Hammick reaction]
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.