Preparation and reactions of 2-chloroethyl 1-thio-beta-D-glycopyranosides derived from D-galactose, D-glucose, and 2-acetamido-2-deoxy-D-glucose

Chloroethyl 1-thio-beta-D-glycopyranosides of the D-galacto and D-gluco configurations 5a-5c were prepared by alkylation of the corresponding 1-thio-beta-D-hexopyranoses 3a-3c with 1-bromo-2-chloroethane followed by deacetylation. The starting 1-thio-beta-D-hexopyranoses were obtained from the acetylated glycopyranosyl halides via isothiouronium salts. It was demonstrated that the chloroethyl thioglycosides 5a-5c undergo hydrolysis in aqueous solutions to give the 2-hydroxyethyl thioglycosides 6a-6c and reducing hexoses and that this hydrolysis proceeds via episulfonium salts. The hydrolysis was monitored by H-1 and C-13 NMR spectroscopy. In 1% aqueous solutions of sodium carbonate containing phenol or aniline, the thioglycosides 5a-5c provide, in addition to the above hydrolysis products, also the phenoxyethyl and phenylaminoethyl thioglycosides 9a, 10a and 9b, 10b, respectively.