Thio-sugars. Part V. Rates of the nucleophilic substitution reactions of some 1,2:5,6-di-O-isopropylidene-3-O-tosyl-α-D-hexoses with potassium thiobenzoate
The rates of these reactions in dimethylformamide, monitored by 1H n.m.r. spectroscopy, have been measured for derivatives of gulose, allose, glucose, and galactose, and found to decrease in that order. From the reactions with the derivatives of gulose, allose, and glucose, 3-S-benzoyl-1,2:5,6-di-O-isopropylidene-3-thio-α-D-galactose, -glucose, and -allose, respectively, were isolated, and their 1H n.m.r. spectra are recorded.