On the conversion of verapamil to carboxy verapamil
Gal, J.; Desai, D.M.; Bloedow, D.C.; Miller, L.V.; Murphy, R.C.
Research Communications in Chemical Pathology and Pharmacology 52(3): 387-390
1986
ISSN/ISBN: 0034-5164 PMID: 3738214 Document Number: 286105
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.