Example 1C. Synthesis of 4-bromo-2-methoxycarbonylpyrrole: To a solution of methanol (100 mL) containing 1-(4-bromo-1H-pyrrol-2-yl)-2,2,2-trichloroacetophenone (20 g, 68 mmol) was added slowly and dropwise sodium methanol (1M solution in methanol, 34 mL, 34 mmol). The reaction mixture was stirred at room temperature for 1 hour and then diluted with water (300 mL) to separate the organic layer. The aqueous phase was extracted with dichloromethane (CH2Cl2), and the combined organic layer and extract were washed with water (2 x 50 mL), dried over anhydrous magnesium sulfate (MgSO4), and concentrated under reduced pressure. The residue was recrystallized by hexane to give 4-bromo-2-methoxycarbonylpyrrole (12 g, 85% yield) as a white solid.LC-MS analysis showed [M-H]+ peak at 203.1.1.1H NMR (DMSO-d6, 400 MHz) data were as follows: δ 12.31 (broad single peak, 1H), 7.16 (single peak, 1H), 6.81 (single peak, 1H ), 3.75 (single peak, 3H).
