(2R,5R)-2-(6-aminopurin-9-yl)-5-ethyl-4-methoxyoxolan-3-ol;(2R,5R)-2-(6-aminopurin-9-yl)-5-(hydroxymethyl)-4-methoxyoxolan-3-ol;(2R,5R)-5-ethyl-4-methoxy-2-[6-[[(4-methoxyphenyl)-diphenylmethyl]amino]purin-9-yl]oxolan-3-ol;9-[(2R,5R)-5-ethyl-4-methoxy-3-methyloxolan-2-yl]-N-[(4-methoxyphenyl)-diphenylmethyl]purin-6-amine;[(2R,5R)-3-methoxy-5-[6-[[(4-methoxyphenyl)-diphenylmethyl]amino]purin-9-yl]-4-methyloxolan-2-yl]methanol