The synthesis and characterization of uridine 5'-(beta-L-rhamnopyranosyl diphosphate) and its role in the enzymic synthesis of rutin.

Uridine 5'-(beta-L-rhamnopyranosyl diphosphate) was synthesized by the condensation of uridine 5'-diphenylpyrophosphate and beta-L-rhamnopyranosyl phosphate. That sugar 1-phosphate was made via the phosphitylation of the hemiacetal hydroxyl group of 2,3,4-tetra-O-acetyl-beta-L-rhamnopyranose. An enzyme preparation from the primary leaves of mung bean (Phaseolus aureus) was shown to catalyze the transfer of L-rhamnose from UDP-beta-L-rhamnose to the flavonol D-glucoside isoquercitrin to form rutin.