反应详情

To a solution of 4-methyl-5-(2-trifluoromethyl-phenyl)-1H-pyrrole-3-carboxylic acid methyl ester (2.9 g, 10.2 mmol) in anhyd THF (40 mL) was added lithium bis(trimethylsilyl)amide (1.0 M solution in THF, 12.3 mL, 12.3 mmol) slowly at 20° C. After stirring 0.5 h, iodomethane (0.96 mL, 15.4 mmol) was added and the mixture was stirred for 3 h at 20° C. After quenching with water, the organic layer was separated and the aqueous layer was extracted with EtOAc. The combined extracts were washed with water, dried (anhyd Na2SO4) and concentrated under reduced pressure to yield 1,4-dimethyl-5-(2-trifluoromethyl-phenyl)-1H-pyrrole-3-carboxylic acid methyl ester as an oil (2.8 g, 92%), which was used in the next step without purification. MS (ES): 298 (MH+). To a solution of 4-methyl-5-(2-trifluoromethyl-phenyl)-1H-pyrrole-3-carboxylic acid methyl ester (2.9 g, 10.2 mmol) in anhyd THF (40 mL) was added lithium bis(trimethylsilyl)amide C. To a solution of 1,4-dimethyl-5-(2-trifluoromethyl-phenyl)-1H-pyrrole-3-carboxylic acid methyl ester (2.5 g, 8.4 mmol) in MeOH (20 mL) was added 4N NaOH (10 mL) and the mixture was heated to reflux overnight. Evaporation of solvent gave a solid, which was re-dissolved in water. The solution was acidified with formic acid. The resulting solids were collected by filtration, washed with water and then dried under high vacuum to afford the title compound as an off-white solid (2.15 g, 90%). MS (ES): 284 (MH+).

1. customwas used in the next step without purification
2. temperaturethe mixture was heated
3. temperatureto reflux overnight
4. customEvaporation of solvent
5. customgave a solid, which
6. filtrationThe resulting solids were collected by filtration
7. washwashed with water
8. customdried under high vacuum