Improved Synthesis of the C-Glucuronide/Glycoside of 4-Hydroxybenzylretinone (4-HBR)

Improvements in the synthesis of carbon-linked glucuronide/glucoside conjugates of cancer chemopreventive retinoids have been achieved starting with 2,3,4,6-tetra-O-benzyl-D-glucopyranose. The revised approach demonstrates better yields, eliminates the use of an expensive, carcinogenic protecting group reagent, and avoids much painstaking chromatography. The new approach should allow synthesis of larger quantities of the agents for detailed animal and mechanistic studies.