N-[9-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-3-O-[bis(1-methylethyl)aminophosphino]-2-deoxy-β-L-erythro-pentofuranosyl]-6,9-dihydro-6-oxo-1H-purin-2-yl]-2-methylpropanamide [ 141846-56-2 ]