Guanosine, P-(2-aminoethyl)-N-benzoyl-5′-O-[bis(4-methoxyphenyl)phenylmethyl]-2′-deoxyguanylyl-(3′→5′)-2′-deoxy-N-(2-methylpropyl)-, 3′-[2-cyanoethyl N,N-bis(1-methylethyl)phosphoramidite]