6-Chloro-N-cyclopentyl-1-[5-O-[2-[[[(2-methoxyethoxy)carbonyl]oxy]methoxy]-2-oxido-6-oxo-3,5,7,10-tetraoxa-2-phosphaundec-1-yl]-β-D-ribofuranosyl]-1H-pyrazolo[3,4-d]pyrimidin-4-amine

6-Chloro-N-cyclopentyl-1-[5-O-(2-hydroxy-2-oxido-6-oxo-3,5,7-trioxa-2-phosphanon-1-yl)-β-D-ribofuranosyl]-1H-pyrazolo[3,4-d]pyrimidin-4-amine

6-Chloro-N-cyclopentyl-1-[5-O-[2-[[(ethoxycarbonyl)oxy]methoxy]-2-oxido-6-oxo-3,5,7-trioxa-2-phosphanon-1-yl]-β-D-ribofuranosyl]-1H-pyrazolo[3,4-d]pyrimidin-4-amine

6-Chloro-N-cyclopentyl-1-[5-O-(2-hydroxy-8-methyl-2-oxido-6-oxo-3,5,7-trioxa-2-phosphanon-1-yl)-β-D-ribofuranosyl]-1H-pyrazolo[3,4-d]pyrimidin-4-amine

6-Chloro-N-cyclopentyl-1-[5-O-[8-methyl-2-[[[(1-methylethoxy)carbonyl]oxy]methoxy]-2-oxido-6-oxo-3,5,7-trioxa-2-phosphanon-1-yl]-β-D-ribofuranosyl]-1H-pyrazolo[3,4-d]pyrimidin-4-amine