SYNTHESIS AND MASS SPECTRAL REARRANGEMENTS OF SOME NEW MIXED VINYL SULPHIDE-SULPHONES AND DISULPHONES

Abstract

Abstract Stererospecifically prepared (E)-1-chloro-2-p-chlorophenylsulphonylstilbene (1) and (Z)-1-bromo-2-p-chlorophenylsulphonylstilbene (6) on reaction with sodium alkyl thiolates in abs. ethanol underwent nucleophilic displacement of halogens leading to the formation of (E)- and (Z)-1-alkylsulphenyl-2-p-chlorophenylsulphonylstilbenes (2 and 7). The sulphide-sulphones 2 and 7 on oxidation afforded the corresponding disulphones (3 and 8). Mass spectra of (E)- and (Z)-isomers of 1-butylsulphenyl-2-p-chlorophenylsulphonylstilbenes (2c and 7c) and their corresponding disulphones 3c and 8c are examined at 70 eV. Smiles type rearrangement is noticed only in 2c and 7c but not in 3c and 8c. McLafferty type rearrangement involving migration of hydrogen from aryl and/or alkyl groups to ethylenic carbon is observed both in sulphide-sulphones and in disulphones. Sulphonyl-sulphinate rearrangement with vinyl migration as the predominant pathway is a noted feature in both sulphide-sulphones and disulphones.