[Synthesis of retinyl phosphate, its physico-chemical properties and biological activity].

Retinyl phosphate (RP) has been synthesized from retinol (R), using phosphodimorpholine chloride (PDMC) or POCl3. A method for isolating and purifying RP from the reaction mixture has been developed. The RP yield varies from 3 to 6% depending on the quantities of R and POCl3. The RP yield can be increased by 10--15% as a result of RP separation and rerun of the reaction. The resultant RP has an absorption maximum at 325 nm, is described by the formula C20H27PO4(NH4)2 and distributed between equal volumes of diethyl ester and 20% aqueous methanol at a ratio of 1:1. RP is alkaline-resistant and rapidly transforms into anhydroretinol (AR) in the acid medium. Eighteen hours after RP administration into the caudal vein or parenterally retinyl palmitate and R are accumulated in the liver of A-avitaminous rats.