Adenosine, 2′-O-[2-[[2-[2-[(1,4-dioxopentyl)oxy]ethoxy]ethyl]amino]-2-oxoethyl]-5′-O-[ 1-(diphenylmethoxy)-3,3,3-trimethyl-1-[(trimethylsilyl)oxy]disiloxanyl]-N-( 2-methyl-1-oxopropyl)-