[Na].C([O:5][CH:6]1[CH:10]([N:11]2[C:15]3[CH:16]=[C:17]([Cl:21])[C:18]([Cl:20])=[CH:19][C:14]=3[N:13]=[C:12]2Br)[CH2:9][CH:8]([CH2:23][O:24]C(=O)C)[CH:7]1[O:28]C(=O)C)(=O)C.[CH3:32][O-:33].[Na+].Cl>CO>[Cl:20][C:18]1[C:17]([Cl:21])=[CH:16][C:15]2[N:11]([CH:10]3[CH:6]([OH:5])[CH:7]([OH:28])[CH:8]([CH2:23][OH:24])[CH2:9]3)[C:12]([O:33][CH3:32])=[N:13][C:14]=2[CH:19]=1Sodium (spheres, 0.10 g, 4.8 mequiv) were added to dry methanol (15 mL). (±)-(1R*, 2S*, 3S*, 5S*)-3-(Acetoxymethyl)-5-(2-bromo-5,6-dichloro-1H-benzimidazol-1-yl)-1,2-cyclopentanediyl diacetate (0.560 g, 0.958 mmol) was added to the sodium methoxide in methanol and the solution stirred at ambient temperature under nitrogen for 5 hours. The solution was then neutralized with 1N hydrochloric acid and volatiles removed in vacuo. The residual solid was chromatographed on silica gel. (±)-(1R*, 2S*, 3S*, 5S*)-5-(5,6-Dichloro-2-methoxy-1H-benzimidazol-1-yl)-3-(hydroxymethyl)-1,2-cyclopentanediol was eluted with 10% methanol-chloroform as a white powder, after trituration with diethyl ether (0.211 g, 64%), m.p. 204°-206° C. dec; 1H-NMR(DMSO-d6)δ: 7.82 and 7.67 (both s, 2, aromatic CH), 4.9 (m, 2,2 OH), 4.7-4.6 (m overlapping d at 4.61, J=4.1 Hz, 2 total, NCH and OH), 4.4-4.3 (m, 1, OCH), 4.11 (s, 3, OCH3), 3.8 (m, 1, OCH), 3.6-3.4 (m, 2, OCH2), 2.1-2.0 (m, 2, CH2), 1.9-1.8 (m, 1, CH); mass spectrum (CI): 347(M+1).
Wird geladen…
