C-5 bromination of some glucopyranuronic acid derivatives

Abstract

Treatment of methyl (phenyl tri-O–acetyl-1-thio-β-D-glucopyranosid)uronate with N-bromosuccinimide gave, as well as the expected hex-1-enopyranosid-3-ulose, the product of bromination at C-5. Methyl tetra-O–acetyl-β-D-glucopyranuronate on similar treatment gave a 5-C-bromo-derivative, in good yield. Methyl tri-O-acetyl-2,6-anhydro-L-gulonate afforded the 2-bromo-analogue which is the known glycosyl bromide of a derivative of L-xylo-hexulosonic acid and offers access to compounds in the L-ascorbic acid series and to the vitamin itself.