A study of reactions of 4-chloromethyl l, 4-dihydropyridines with nucleophiles.

Abstract

Reactions of 4-chloromethyl l,4-dihydropyridines with some nucleophiles have been studied. It was found that the nature of the reacting nucleophile determines the ring size of the product. Reaction with the thiocyanate, selenocyanate, and thiourea give dihydropyridine derivatives while ring expansion was effected by reaction with sulphite. -- A study of kinetics of reactions with thiocyanate and cyanide under identical conditions was attempted. Results indicate that thiocyanate reaction is Sn2 type. Reproducible results were not obtained for the reaction with cyanide. -- A method for the determination of thiocyanate in the presence of chloride suitable for the kinetics experiments was developed. -- An interesting rearrangement of the 4-chloromethyl l,4-dihydropyridine on reaction with urea was studied and from available evidence a pyrazolopyridone structure has been suggested for the product.