C(C1NC=CN=1)(C1NC=CN=1)=O.[Br:13][C:14]1[CH:15]=[C:16]([CH:20]=[C:21]([C:23]([O:25][CH3:26])=[O:24])[CH:22]=1)[C:17]([OH:19])=O.[CH2:27]([NH:30][CH2:31][CH2:32][CH3:33])[CH2:28][CH3:29]>C1COCC1>[Br:13][C:14]1[CH:22]=[C:21]([CH:20]=[C:16]([C:17]([N:30]([CH2:31][CH2:32][CH3:33])[CH2:27][CH2:28][CH3:29])=[O:19])[CH:15]=1)[C:23]([O:25][CH3:26])=[O:24]Carbonyl diimidazole (3.0 g, 18 mmol) is added to a solution of 3-bromo-5-(methoxycarbonyl)benzoic acid (XIX, PREPARATION 2, 3.9 g, 15 mmol) in THF (30 mL). The mixture is stirred for 0.5 hours. Dipropylamine (AMINE, 4.2 mL, 30 mmol) is added to the mixture, which is then stirred for 24 hours. The solvent is then removed under reduced pressure and the mixture is partitioned between ethyl acetate and water. The organic phase is then washed with saline, dried over anhydrous magnesium sulfate, filtered, and concentrated. Column chromatography (silica gel; ethyl acetate/hexanes, 15/85) gives the title compound, IR (diffuse reflectance) 2968, 2958, 1714, 1637, 1479, 1440, 1422, 1321, 1310, 1288, 1273, 1252, 889, 772 and 718 cm−1; NMR (300 MHz, CDCl3) δ 8.21, 7.96, 7.70, 3.95, 3.46, 3.15, 1.69, 1.57, 1.00 and 0.78; MS (ESI+) for C15H20BrNO3 m/z (M+H)+=344.1.
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