Guanosine, N-benzoyl-5′-O-[(2-cyanoethoxy)mercaptophosphinyl]-2′-O-[(1,1-dimethylethyl)dimethylsilyl]-N,7-(1,3-propanediyl)-P-thio-7-deazaadenylyl-(3′→5′)-3′-O-[(1,1-dimethylethyl)dimethylsilyl]-N-(2-methyl-1-oxopropyl)-, cyclic nucleotide