[(2R,3S,4R,5R)-5-(2-bromo-5,6-dichloro-3-formyl-indol-1-yl)-3,4-dihydroxy-tetrahydrofuran-2-yl]methyl acetate → 2-bromo-5,6-dichloro-1-[(2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl]indole-3-carbaldehyde

Participants

Reaction Steps

5,6-Dichloro-2-bromo-3-formyl-1-(5-O-acetyl-β-D-ribofuranosyl)indole (4.136, 101 mg, 0.22 mmol) was dissolved in dry MeOH (10 mL) to which was added sodium methoxide (25 mg, 0.46 mmol). The solution was stirred at room temperature for 15 min, until the starting material was consumed (TLC). Water (30 mL) was added and the solution evaporated until the MeOH was completely removed. The residual aqueous suspension was extracted with EtOAc (3×30 mL) and the combined organic extracts washed with brine (20 mL), dried over MgSO4, filtered and evaporated to yield a white solid. The solid was dissolved in MeOH (1 mL) and subjected to column chromatography (40×350 mm) on C18-reverse phase silica gel with 75% MeOH/H2O. Fractions containing product were pooled and evaporated to yield a white solid which was recrystallized from MeOH and H2O to yield 43 mg (47%) of 4.137 as a pale tan powder: mp 210-211° C.; Rf 0.2 (10% MeOH/CHCl3); 1H-NMR (500 MHz, DMSO-d6): δ 9.95 (s, 1H), 8.69 (s, 1H), 8.28 (s, 1H), 6.06 (d, 1H), 5.49-5.43 (m, 2H, D2O exch.), 5.31 (d, 1H, D2O exch.), 4.44 (q, 1H), 4.18 (m, 1H), 4.04 (d, 1H), 3.77-3.71 (m, 2H). 13C-NMR (125 MHz, DMSO-d6): δ 185.53, 134.05, 128.85, 126.58, 126.47, 125.31, 120.56, 116.00, 114.68, 90.27, 86.55, 71.69, 69.62, 60.98. HRMS (EI) m/z calcd. for C14H12BrCl2NO5 422.9276, found 422.9271. Anal calcd for C14H12BrCl2NO5: C, 39.56; H, 2.85; N, 3.30. Found: C, 39.77; H, 3.03; N, 3.32.

Provenance & Evidence