[Cl:1][C:2]1[C:10]2[CH:9]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])[O:8][B:7]([OH:17])[C:6]=2[CH:5]=[C:4]([OH:18])[CH:3]=1.IC.[C:21]([O-])([O-])=O.[K+].[K+]>CN(C=O)C>[Cl:1][C:2]1[C:10]2[CH:9]([CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])[O:8][B:7]([OH:17])[C:6]=2[CH:5]=[C:4]([O:18][CH3:21])[CH:3]=1To a mixture of ethyl 2-(4-chloro-1,6-dihydroxy-1,3-dihydrobenzo[c][1,2]oxaborol-3-yl)acetate (150 mg, 0.55 mmol) and iodomethane (254 mg, 2.22 mL) in anhydrous DMF (2 mL) was added anhydrous K2CO3 (380 mg, 2.75 mmol). The reaction mixture was stirred for 10 h and concentrated under reduced pressure. The residue was purified by prep HPLC to give the title compound as a yellow oil (49.1 mg. Yield: 31%). 1H NMR (400 MHz, DMSO-d6) δ 9.45 (s, 1H), 7.22-7.23 (d, J=4.0 Hz, 1H), 7.14-7.15 (d, J=4.0 Hz, 1H), 5.45-5.48 (m, 1H), 4.03-4.09 (m, 2H), 3.81 (s, 3H), 3.21-3.25 (m, 1H), 2.39-2.45 (m, 1H), 1.14-1.17 (m, 3H).
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