Chemical synthesis of all-trans retinoyl beta-glucuronide.

All-trans retinoyl fluoride reacts with the 3,6-lactone of glucuronic acid in slightly alkaline solution to give the lactone of retinoyl beta-glucuronide, along with other retinoyl glucurono-lactones, in about 60% yield. Hydrolysis of the lactone with very dilute alkali gives the free acid, retinoyl beta-glucuronide, in about 80% yield. Pure all-trans retinoyl beta-glucuronide (overall yield: 20-25%) was obtained free from other isomeric and anomeric forms by reverse-phase high pressure liquid chromatography. Retinoyl beta-glucuronide was characterized by UV-visible, infrared, and 1H-NMR spectra, by elementary analysis, by mass spectra, and by its susceptibility to hydrolysis by bacterial beta-glucuronidase.