1′a-Carbaguanosine, 3′-deoxy-3′-fluoro-5′-O-(hydroxymercaptophosphinyl)-P-thioinosinylyl-(2′→5′)-2′-deoxy-2′-fluoro-1′a-methylene-, cyclic nucleotide, (2′ξ)-

1′a-Carbaguanosine, 3′-deoxy-3′,7-difluoro-5′-O-(hydroxymercaptophosphinyl)-P-thio-7-deazadenylyl-(2′→5′)-2′-deoxy-2′-fluoro-1′a-methylene-, cyclic nucleotide, (2′ξ)-