Uridine, N-benzoyl-5′-O-[bis(4-methoxyphenyl)phenylmethyl]-P(O)-(2-cyanoethyl)-2′-O-(2-methoxyethyl)-5-methyl-P-thiocytidylyl-(3′→5′)-N-benzoyl-P-(2-cyanoethyl)-2′-O-(2-methoxyethyl)-5-methylcytidylyl-(3′→5′)-P(O)-(2-cyanoethyl)-2′-O-(2-methoxyethyl)-N-(2-methyl-1-oxopropyl)-P-thioguanylyl-(3′→5′)-2..