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]([NH2:34])([CH3:33])[CH3:32]>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]([CH3:33])[CH3:32])=[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 (750 mg, 1.44 mmole) was refluxed in ethanol (10 mL) with isopropylamine (1.22 mL, Aldrich) under nitrogen for 18 hours. A second portion of isopropylamine (1.22 mL) was added and reflux continued for an additional 24 hours. Volatiles were evaporated, the residue was redissolved in ethanol, 1N sodium hydroxide (1.44 mL) was added, and volatiles were reevaporated. The residue was chromatographed on a silica gel column. Title compound was eluted with 10% methanol-chloroform as a colorless glass. The glass was crystallized from ethyl acetate-hexanes to give (±)-(1R*, 2S*, 3S*, 5S*)-5-[5,6-dichloro-2-(isopropylamino)-1H-benzimidazol-1-yl]-3-(hydroxymethyl)-1,2-cyclopentanediol as white crystals (305 mg, 57%); m.p. 213°-214° C.; 1H-NMR(DMSO-d6) identical with that of the enantiomer described in Example 75.
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