反应详情

To a solution of N-((1H-pyrrol-2-yl)methylene)-N-methylmethanaminium chloride (45.0 g, 0.279 mol), aluminum trichloride (83.7 g, 0.63 mol) in DCE (90 mL) under nitrogen was added 2,2,2-trichloroacetyl chloride (32.4 mL, 0.093 mol). The mixture was heated to reflux for 4 h. After cooled to rt, MeOH (100 mL) was added followed by sodium methoxide solution [prepared with sodium (45.0 g, 1.98 mol) and MeOH (180 mL)]. The resulting mixture was then stirred at rt for 2 h. The solvent was then removed and the resulting residue was dissolved in water (100 mL), neutralized with 1 N HCl, and extracted with EtOAc (3×400 mL). The combined organic phases were washed with brine, dried, and concentrated to give methyl 5-formyl-1H-pyrrole-3-carboxylate (30.0 g, 60%). 1H NMR (DMSO-d6, 400 MHz) δ 12.62 (s, 1H), 9.48 (s, 1H), 7.66 (s, 1H), 7.30 (s, 1H), 3.67 (s, 3H).

1. temperatureThe mixture was heated
2. temperatureto reflux for 4 h
3. customThe solvent was then removed
4. dissolutionthe resulting residue was dissolved in water (100 mL)
5. extractionextracted with EtOAc (3×400 mL)
6. washThe combined organic phases were washed with brine
7. customdried
8. concentrationconcentrated