C(OC(=O)[NH:10][C:11]([CH3:23])([C:17]1[N:21]=[C:20]([CH3:22])[O:19][N:18]=1)[CH2:12][S:13]([CH3:16])(=[O:15])=[O:14])C1C=CC=CC=1.B(Br)(Br)Br.C(=O)([O-])[O-].[Na+].[Na+]>C(Cl)Cl>[CH3:16][S:13]([CH2:12][C:11]([NH2:10])([CH3:23])[C:17]1[N:21]=[C:20]([CH3:22])[O:19][N:18]=1)(=[O:14])=[O:15]To a solution of [2-Methanesulfonyl-1-methyl-1-(5-methyl-[1,2,4]oxadiazol-3-yl)-ethyl]-carbamic acid benzyl ester (Example 109c, 0.085 g, 241 μmol) in dry CH2Cl2 (1 ml) under argon atmosphere cooled down at 0° C. was slowly added a 1.0M solution of boron tribromide in dichloromethane (265 μl, 265 μmol). The reaction mixture was stirred at 0° C. for 20 minutes and stirred for 1 hour at room temperature The reaction was diluted with dichloromethane and an 2.0M aqueous solution of sodium carbonate was added. The two phases mixture was stirred at room temperature for 30 minutes and was poured into a separatory funnel and the organic phase was collected. The aqueous phase was back-extracted with dichloromethane. The combined organic phases were dried over sodium sulfate and evaporated down to dryness. The crude material was purified by flash chromatography on silica eluting with a dichloromethane/methanol gradient to yield the title compound (21 mg, 40%) as yellow oil. MS (ESI, m/z): 220.3 (M+H+).
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