for the following products
6-Chloro-9-beta-D-(2,3-isopropylidene)ribofuranosylpurine | 6-Chloro-9-[2,3-O-(1-methylethylidene)-beta-D-ribofuranosyl]-9H-purine | 6-Chloropurine-9-(2,3-isopropylidene-beta-D-ribofuranoside) and 6-Chloro-9-[2.3-0-(isopropylidene)-beta-D-ribofuronosyl]-9H-purine