SYNTHESIS OF URIDINE 5'-(ALPHA-D-FUCOPYRANOSYL DIPHOSPHATE) AND (DIGITOXIGENIN-3-BETA-YL)-BETA-D-FUCOPYRANOSIDE AND ENZYMATIC BETA-D-FUCOSYLATION OF CARDENOLIDE AGLYCONES IN DIGITALIS-LANATA

The phosphorylation of 2,3,4-tri-O-acetyl-alpha-D-fucopyranose with o- phenylene phosphochloridate yielded alpha-D-fucopyranosyl phosphate wh ich was used for condensation with uridine 5'-monophosphomorpholidate to give uridine 5'-(alpha-D-fucopyranosyl diphosphate) (UDP-alpha-D-fu cose). A crude enzyme preparation from young leaves of Digitalis lanat a EHRH has been shown to catalyze the transfer of D-fucose from synthe tic UDP-alpha-D-fucose to cardenolide aglycones, such as digitoxigenin . The reaction product was identified and characterized by chemical sy nthesis, HPLC, and spectral methods as the 3 beta-O-beta-D-fucopyranos ide of digitoxigenin (digiproside). (C) 1994 Academic Press, Inc.