Triethylamine → cis-2',3',5'-tri-O-benzoyl-2-chloro-N-(2-phenoxycyclopentyl)adenosine

Participants

Reaction Steps

cis-2-Phenoxycyclopentylamine (0.75 g, 4.23 mmol) was combined with 9-(2,3,5-tri- O-benzoyl-β-D-ribofuranosyl)-2,6-dichloro-9H-purine (2.95 g, 4.7 mmol) and triethylamine (0.64 g, 6.3 mmol) in dioxan (30 ml) and stirred for 50 h. The reaction mixture was filtered, evaporated and the residue dissolved in ethyl acetate and washed with water (2×50 ml). The organic phase was dried (MgSO4), evaporated and the residue coevaporated to give cis-2',3',5'-tri-O-benzoyl-2-chloro- N-(2-phenoxycyclopentyl)adenosine (3.1 g, 90%) as an amorphous foam, which was deprotected using saturated methanolic ammonia (50 ml). After 70 h at room temperature the reaction mixture was evaporated and the residue purified by flash chromatography on silica gel, eluting with a mixture of dichloromethane and methanol (19:1). The title cis-2-chloro- N-(2-phenoxycyclopentyl)adenosine (0.925 g, 53%) was obtained as an amorphous foam (a 1:1 mixture of diastereoisomers), 1H NMR (DMSO-d6)δ 1.58-2.15 (6H, 3m, --CH2CH2CH2 --), 3.51-3.60 (1 H, m, H-5'a), 3.62-3.71 (1H, m, H-5'b), 3.95 (1H, br q, H-4'), 4.12 (1H, br q, H-3'), 4.46-4.62 (2H, m, H-2' and --CH), 4.82-4.89 (1H, m, --CH), 5.07 (1H, br t, 5'-OH), 5.22, 5.49 (2H, 2d, 2'- and 3'-OH), 5.83 (1H, d, H-1'), 6.80-6.91 (3H, m, Ar--H), 7.15-7.24 (2H, t, Ar--H), 7.99, 8.22 (1H, d & m, N--H), 8.41, 8.45 (1 H, 2s, H-8).

Provenance & Evidence