Synthesis of the immunosuppressive agent 2-morpholinoethyl mycophenolate by a lipase-catalyzed transesterification

The synthesis of 2-morpholinoethyl mycophenolate was realized by an enzymatic transesterification of simple esters of mycophenolic acid with 2-morpholinoethanol. Best results were achieved by a Candida antarctica lipase B (CAL B) catalyzed transesterification of ethyl mycophenolate in toluene. CAL B showed to selectively transform only the ethyl ester function leaving unreacted the other functional groups present on the substrate. By this way 2-morpholinoethyl mycophenolate was obtained in satisfactory yields from mycophenolic acid (84%).