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Synthesis of a novel cyclic sulfone dihydropyridine: An investigation of the isomerization reaction converting an exocyclic double bond isomer into a 1,4‐dihydropyridine
Author(s) -
Fenk Christopher J.,
Conley Richard A.,
Lindabery Gregory C.,
Stefanick Stephen M.,
Royster Thomas E.,
Dodd John H.,
Schwender Charles F.
Publication year - 1994
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570310216
Subject(s) - isomerization , chemistry , dihydropyridine , double bond , sulfone , reaction conditions , hydrochloride , medicinal chemistry , stereochemistry , organic chemistry , catalysis , calcium
An eight membered cyclic sulfone 1,4‐dihydropyridine, RWJ 22726, 1 , with remarkable cardiovascular activity was prepared by isomerization of an exocyclic double bond isomer using various reaction conditions. Under acidic and thermal isomerization conditions, an equilibrium mixture of products in an optimum ratio of 1:3.5 in favor of the desired 1,4‐dihydropyridine was obtained. Equilibration using basic reaction conditions could not be effected. Complete conversion to the 1,4‐dihydropyridine during the isomerization reaction was ultimately achieved by selective precipitation of the hydrochloride salt of the desired isomer.