Nucleophilic displacement reactions in carbohydrates. Part VIII. Identification of the minor products from the reactions of 2,3-O-isopropylidene-5-O-methylsulphonyl-D-lyxofuranose and 2,3-O-isopropylidene-5-O-p-tolylsulphonyl-L-rhamnofuranose with sodium methoxide

Abstract

The minor products arising from the reaction of 2,3-O-isopropylidene-5-O-methylsulphonyl-D-lyxofuranose (1) with sodium methoxide in methanol have been shown to be 1,5-anhydro-2,3-O-isopropylidene-β-D-lyxofuranose (5), methyl 2,3-O-isopropylidene-α-D-lyxopyranoside (4a), methyl 2,3-O-isopropylidene-α-L-ribofuranoside (3b), and possibly methyl 2,3-O-isopropylidene-β-D-lyxopyranoside (4b). A minor product arising from similar treatment of 2,3-O-isopropylidene-5-O-p-tolylsulphonyl-α-L-rhamnofuranose was characterised as methyl 6-deoxy-2,3-O-isopropylidene-α-D-allofuranoside (8b).