The acylation of quercetin (I) with acetic anhydride in sulfuric acid gives the pentaacetate (II), which by reaction with KI, K2CO3 and benzyl chloride in refluxing butanone yields the 3'-acetoxy tetrabenzyloxy compound (III). The hydrolysis of the acetate group of (III) with NaOH in refluxing methanol/acetone/water affords the 3'-hydroxy compound (IV), which is condensed with ethyl 2-(isocyanato)acetate (V) and TEA in hot THF to provide the carbamate (VI). Cleavage of the benzyloxy groups of (VI) with H2 over Pd/C in THF gives the tetrahydroxy compound (VII), which is finally hydrolyzed with sulfuric acid in refluxing THF to yield the target prodrug.