Guanosine, 2′-deoxy-P(S)-[(2,2-dimethyl-1-oxopropoxy)methyl]-5′-O-[[[(2,2-dimethyl-1-oxopropoxy)methyl]thio]hydroxyphosphinyl]-2′-fluoro-P-thioadenylyl-(3′→5′)-2′-deoxy-2′-fluoro-, cyclic nucleotide