Chlorotrimethylsilane → N2-Isobutyryl-2'-O-octadecylguanosine

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Reaction Steps

2′-O-Octadecylguanosine (1.9 g) in pyridine (150 ml) was cooled in an ice bath, and treated with trimethylsilyl chloride (2 g, 5 eq) and isobutyryl chloride (2 g, 5 eq). The reaction mixture was stirred for 4 hours, during which time it was allowed to warm to room temperature. The solution was cooled, water added (10 mL) and stirred for an additional 30 minutes. Concentrated ammonium hydroxide (10 mL) was added and the solution concentrated in vacuo. The residue was purified by silica gel chromatography (eluted with 3% MeOH/EtOAc) to yield 1.2 g of product. 1H NMR (DMSO-d6) δ 0.85 (t, 3, CH3), 1.15 (m, 38, O—CH2CH2(CH2)16 and CH(CH3)2), 2.77 (m, 1, CH(CH3)2), 4.25 (m, 2, 2′H, 3′H), 5.08 (t, 1, 5′-OH), 5.12 (d, 1, 3′-OH), 5.87 (d, 1, 1′-H), 8.27 (s, 1, 8-H), 11.68 (s, 1, NH2) and 12.08 (s, 1, NH2). Anal. Calcd. for C32H55N5O6: C, 63.47; H, 9.09; N, 11.57. Found: C, 63.53; H, 9.20; N, 11.52.

Provenance & Evidence