Reaction Steps
2,5,6-Trichloro-3-formyl-1-(β-D-ribofuranosyl)indole (4.3, 109 mg, 0.29 mmol) was dissolved in MeOH (5 mL) to which was added acethydrazine (85 mg, 1.1 mmol). The resulting solution was heated on a 45 C oil bath for 16 h, then cooled to room temperature and poured into 15 mL of water. The resulting suspension was cooled to 4C, then filtered and the solids rinsed with cold water (25 mL). The solids were dissolved in DMF (0.5 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 crystalline solid, which was recrystallized from acetone/MeOH to yield 70 mg (56%) of 4.32 as a white microcrystalline solid which is an inseparable mixture of isomers in a ratio of 60:40: mp 270-271 C; Rf 0.2 (10% MeOH/CHCI3); 1H-NMR (500 MHz, DMSO-d6): (major isomer) δ 11.25 (s, 1H, D2O exch.), 8.56 (s, 1H), 8.27 (s, 1H), 8.18 (s, 1H), 5.94 (d, 1H), 5.40-5.36 (m, 2H, D2O exch.), 5.25 (d, 1H, D2O exch.), 4.42 (q, 1H), 4.13 (s, 1H), 3.98 (s, 1H), 3.70(s, 2H), 2.24 (s, 3H); (minor isomer) δ 11.41 (s, 1H, D2O exch.), 8.56 (s, 1H), 8.44 (s, 1H), 8.32 (s, 1H), 5.94 (d, 1H), 5.40-5.36 (m, 2H, D2O exch.), 5.25 (d, 1H, D2O exch.), 4.42 (q, 1H), 4.13 (s, 1H), 3.98 (s, 1H), 3.70(s, 2H), 1.95 (s, 3H). 13C-NMR (125 MHz, DMSO-d6): (major isomer) δ 171.39, 135.98, 133.15, 129.73, 126.01, 124.96, 123.86, 121.69, 115.41, 108.31, 88.78, 86.09, 71.41, 69.66, 61.10, 20.36; (minor isomer) δ 165.24, 138.70, 133.12, 129.82, 126.06, 124.96, 123.99, 122.17, 115.33, 108.51, 88.78, 86.09, 71.41, 69.66, 61.10, 21.67. HRMS (ES) m/z calcd. for C16H16Cl3N3O5·Na 458.0053, found 458.0043. Anal calcd for C16H16Cl3N3O5: C, 44.01; H, 3.69; N, 9.62. Found: C, 43.76; H, 3.75; N, 9.67.
