6-N-(4-Monomethoxytrityl)-9-(3,5-di-O-benzoyl-2-deoxy-beta-L-threo-pentofuranosyl)adenine → 6-N-(4-Monomethoxytrityl)-9-(2-deoxy-beta-L-threo-pentofuranosyl)adenine

Participants

Reaction Steps

Compound 5 (0.95 g, 1.30 mmol) was treated with a solution (saturated at −10° C.) of methanolic ammonia (40 mL), at room temperature overnight. After concentration, the residue was dissolved in dichloromethane (60 mL) and washed with water (30 mL). The aqueous layer was extracted twice with dichloromethane (10 mL). The combined organic layer was dried, filtered and concentrated. The residue was purified by silica gel column chromatography (0-5% MeOH in dichloromethane) to give pure 6 (0.67 g, 98%) as a foam: 1H NMR (CDCl3): δ 2.6-2.9 (m, 2H, H-2′ and H-2″), 3.5 (br s, 1H, OH-5′), 3.55 (s, 3H, OCH3), 3.9-4.0 (m, 3H, H-4′, H-5′ and H-5″), 4.5-4.6 (m, 1H, H-3′), 6.03 (dd, 1H, H-1′, J1′,2′=4.0 Hz, J1′,2″=8.8 Hz), 7.0 (br s, 1H, NH-6), 6.7-6.8 and 7.1-7.4 (2m, 14H, MMTr), 7.40 (d, 1H, OH-3′, JH,OH =10.6 Hz), 7.80 and 7.99 (2s, 2H, H-2 and H-8); ms: matrix G/T, (FAB+) m/z 524 [M+H]+, 408 [BH2]+, (FAB−), m/z 1045 [2M−H]−, 522 [M−H]−, 406 [B]−; UV (95% ethanol): λmax 275 nm (ε 12300), λmin 247 nm (ε 3600); [α]D20=+28 (c 0.94, DMSO).

Provenance & Evidence