Br[C:2]1[CH:3]=[C:4]([N:8]([CH3:17])[C:9]([NH:11][CH2:12][CH2:13][CH2:14][CH2:15][CH3:16])=[O:10])[CH:5]=[CH:6][CH:7]=1.C[Li].C([Li])(C)(C)C.[B:25](OC)([O:28]C)[O:26]C>O1CCCC1.CCCCC>[CH3:17][N:8]([C:4]1[CH:3]=[C:2]([B:25]([OH:28])[OH:26])[CH:7]=[CH:6][CH:5]=1)[C:9]([NH:11][CH2:12][CH2:13][CH2:14][CH2:15][CH3:16])=[O:10]
In a manner similar to that of Example (18a), by reaction of 123 g (0.411 mol, 1 eq) of 1-(3-bromophenyl)-1-methyl-3-pentylurea in 1.23 L of tetrahydrofuran, 150 mL (0.452 mol, 1.1 eq) of methyllithium, 530 mL (0.904 mol, 2.2 eq) of a 1.7 M solution of tert-butyllithium in pentane and 115 mL (0.904 mol, 2.2 eq) of trimethyl borate, and after purification by chromatography on silica gel (50/50 heptane/ethyl acetate) and crystallization from ethyl acetate/heptane, 42.0 g of 3-(1-methyl-3-pentylureido)phenylboronic acid are obtained in the form of a pink-colored powder. Yield=39%
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