Regioselective synthesis of novel ethyl Z- and E-2-alkylidene-4-oxothiazolidine-5-acetate derivatives

Abstract

The syntheses of the title compounds containing an exocyclic double bond of exclusively the Z-configuration, via the regioselective base catalyzed reaction of the nitrile precursors possessing an acidic alpha-hydrogen with diethyl 2-mercaptobutanedioate in anhydrous ethanol, are described. The H-1-NMR data indicating the presence of both geometrical isomers in primarily nonpolar media favoring the E-form, are presented in terms of the solvent influence on intra- and intermolecular H-bonding and stereochemical outcome of the reaction.