N-bromobutanimide → 6-Bromo-4H-furo[3,2-b]pyrrole-5-carboxylic acid methyl ester

関与物質

反応手順

To a cold solution (ice-water bath) of methyl 4H-furo[3,2-b]pyrrole-5-carboxylate (1.0 g, 6.05 mmol) in DCM (10 mL) was added TBAF (1.0 M in THF, 9.0 mL, 9.0 mmol) and NBS (1.5 g, 7.9 mmol). The resulting dark colored solution was stirred from 0° C. to rt overnight. The reaction mixture was diluted with 50 mL of CH2Cl2 and washed with water (100 mL) and brine (100 mL) and dried (Na2SO4). After filtration, the filtrate was concentrated by evaporation and the crude product was purified by silica gel chromatography (0-5% EtOAc/hexane) to afford a white solid. 1H NMR (400 MHz, CDCl3) δ (ppm) 8.84 (broad, 1H, NH), 7.54 (d, J=2.2 Hz, 1H), 6.48 (d, J=1.83 Hz, 1H), 3.92 (s, 3H) ppm; m+/z 244 (100%), 246 (100%).

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