Cathodic electrochemical regiospecific hydroxylation of isoquinoline and quinoline via their carboxylic acids

A new electrochemical regiospecific hydroxylation reaction with application to some aromatic benzopyridines is described. This hydroxylation is carried out by electrochemical reduction of isoquinoline or quinoline carboxylated derivatives at graphite electrode and in presence of water. The most important feature of this new process is that only one hydroxylated product is obtained from each carboxylated derivative. Three hydroxy derivatives of isoquinoline and quinoline have been obtained with moderate yields, between 45% and 73%. A plausible reaction route is proposed for the electrochemical process.