5-Bromouracil → 1-(2,3,5-Tri-O-benzoyl-beta-L-ribofuranosyl)-5-bromouracil

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 1-O-acetyl-2,3,5-tri-O-benzoyl-β-L-ribofuranose (2.3 g, 4.55 mmol) in CH3CN (30 mL) was added to silylated 5-bromouracil [generated from 5-bromouracil (2.2 g, 14.3 mmol), HMDS (10 mL), and TMSCl (0.2 mL) by heating for 2 h at 80° C. followed by evaporation of the solvents], and the mixture cooled to 0° C. 1 M SnCl4 (13.6 mL) was added drop-wise, and the mixture stirred for 2 h at room temperature. The mixture was diluted with CHCl3 (100 mL) and quenched with cold saturated NaHCO3. The mixture was filtered over a Celite pad, and the organic phase separated, dried (MgSO4), and evaporated to give a white solid. The solid was washed with cold EtOAc and crystallized from EtOAc in hexanes to give the title compound (2.85 g, 98%) as a white crystals. 1H-NMR (CDCl3) δ 8.06 (1H, br s, NH), 8.06-7.29 (15H, m, Bz) 7.68 (1H, s, H-6), 6.29 (1H, d, H-1′, J=6 Hz), 5.81 (1H, m, H-3′), 5.65 (1H, t, H-2′, J=6 Hz), 4.77-4.62 (3H, m, H-4′, H-5′a, and 5′b).

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