title: On the conversion of verapamil to carboxy verapamil.
abstract: The reaction of verapamil with concentrated sulfuric acid was studied. It was found, in disagreement with a published report, that the reaction did not hydrolyze the nitrile group of the drug to the corresponding carboxylic acid, but, instead, produced a sulfonated derivative. Analysis of the product using several spectroscopic techniques indicated that the sulfonic acid moiety was introduced into the verapamil molecule at the 6-position of the 3,4-dimethoxyphenyl ring distant to the chiral center.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D007202:Indicators and Reagents; D014700:Verapamil / Q000031:analogs & derivatives*
chemical_list: D007202:Indicators and Reagents; C043220:carboxyverapamil; D014700:Verapamil