Methylhydrazine → (2R,3R,4S,5R)-2-(6,7-dichloro-3-methyl-pyrazolo[3,4-b]indol-4-yl)-5-(hydroxymethyl)tetrahydrofuran-3,4-diol

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Reaction Steps

2,5,6-Trichloro-3-formyl-1-(β-D-ribofuranosyl)indole (4.3, 82 mg, 0.22 mmol) was dissolved in methanol (4 mL) to which was added methylhydrazine (0.5 mL). The solution was stirred at room temperature for 16 h, then the solvent was removed under vacuum. The residue was suspended in 20 mL of brine and extracted with EtOAc (2×20 mL). The combined organic extracts were dried over MgSO4, filtered and evaporated to yield a yellow oil. The oil was subjected to column chromatography (40×350 mm) on C18-reverse phase silica gel with 75% MeOH/water. Fractions containing product were pooled and evaporated to yield 29 mg (33%) of 4.36 as a pale yellow solid: mp 135-138° C.; Rf0.6 (20% MeOH/CHCl3); 1H-NMR (500 MHz, DMSO-d6): δ 8.25 (s, 1H), 7.94 (s, 1H), 7.73 (s, 1H), 5.95 (d, 1H), 5.38 (d, 1H, D2O exch.), 5.25 (m, 2H, D2O exch.), 4.21 (q, 1H), 4.13 (m, 1H), 4.05 (s, 3H), 3.97 (m, 1H), 3.74 (m, 2H). 13C-NMR (125 MHz, DMSO-d6): δ 146.23, 139.94, 128.98, 123.94, 122.80, 120.16, 119.24, 115.28, 109.15, 88.91, 85.71, 71.94, 68.75, 60.89, 37.81. HRMS (ES) m/z calcd. for C15H15Cl2N3O4.Na.MeOH 426.0599, found 426.0593. Anal calcd for C15H15Cl2N3O4: C, 48.40; H, 4.06; N, 11.29. Found: C, 48.13; H, 4.16; N, 11.12.

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