K1L k1l 9-[(1~{R},6~{R},8~{R},9~{R},10~{R},15~{R},17~{R},18~{S})-8-(6-aminopurin-9-yl)-9-fluoranyl-3,12,18-tris(oxidanyl)-3,12-bis(oxidanylidene)-2,4,7,11,13-pentaoxa-3$l^{5},12$l^{5}-diphosphatricyclo[13.3.0.0^{6,10}]octadecan-17-yl]-3~{H}-purin-6-one K1L