C([O:4][CH:5]1[CH:9]([N:10]2[C:14]3[CH:15]=[C:16]([Cl:20])[C:17]([Cl:19])=[CH:18][C:13]=3[N:12]=[C:11]2Br)[CH2:8][CH:7]([CH2:22][O:23]C(=O)C)[CH:6]1[O:27]C(=O)C)(=O)C.[CH:31]1([NH2:34])[CH2:33][CH2:32]1.CO.N>C(O)C>[Cl:19][C:17]1[C:16]([Cl:20])=[CH:15][C:14]2[N:10]([CH:9]3[CH:5]([OH:4])[CH:6]([OH:27])[CH:7]([CH2:22][OH:23])[CH2:8]3)[C:11]([NH:34][CH:31]3[CH2:33][CH2:32]3)=[N:12][C:13]=2[CH:18]=1(±)(1R*, 2S*, 3S*, 5S*)-3-(Acetoxymethyl)-5-(2-bromo-5,6-dichloro-1H-benzimidazol-1-yl)-1,2-cyclopentanediyl diacetate (500 mg, 0.958 mmol) was dissolved in absolute ethanol (5 mL) and cyclopropylamine (0.66 mL, 9.6 mmol) was added. The solution was refluxed under nitrogen for two hours. Additional cyclopropylamine (0.66 mL) was added and reflux continued for an additional 18 hours. The solution was cooled and methanol saturated with ammonia at 0° C. (5 mL) was added. After two days at ambient temperature, volatiles were removed in vacuo and the residue chromatographed on silica gel. (±)-(1R*, 2S*, 3S*, 5S*)-5-[5,6-Dichloro-2-(cyclopropylamino)-1H-benzimidazol-1-yl]-3-(hydroxymethyl)-1,2-cyclopentanediol was eluted with 7% methanol-chloroform and solidified from ethyl acetate-hexanes to white powder (210 mg, 59%), m.p. 223°-224° C.; 1H-NMR(DMSO-d6)δ: 7.64 and 7.46 (both s, 2, aromatic CH), 7.11 (m, 1, NH), 5.11 (t, J=4.3 Hz, 1, OH), 4.77 (d, J=7.0 Hz, 1, OH), 4.67 (d, J=3.7 Hz, 1, OH), 4.65-4.30 (m, 2, OCH and NCH), 3.85-3.75 (m, 1, OCH), 3.7-3.4 (m, 2, OCH2), 2.85-2.70 (m, 1, NCH of cyclopropyl), 2.15-1.80 (m, 3, CH2 and CH of cyclopentane), 0.80-0.50 (m, 4, 2 CH2 of cyclopropyl); mass spectrum (CI): 372(M+1).
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