反应详情

KOH (818 mg, 14.6 mmol) was partially dissolved in DMSO (115 mL) and stirred for 5 min. 1-(2,4-dimethyl-1H-pyrrol-3-yl)-ethanone (1 g, 7.3 mmol) was added in small portions and the mixture was stirred for 45 min. Iodomethane (0.54 mL, 8.75 mmol) was added dropwise at such a rate as to maintain the internal temperature ≦30° C. The mixture was stirred for a further 45 min then poured into H2O (50 mL) and extracted with Et2O (3×60 mL). The combined organic extracts were washed (brine), dried (MgSO4), filtered, and evaporated in vacuo to afford 1-(1,2,4-trimethyl-1H-pyrrol-3-yl)-ethanone (1.06 g) as a pink solid. This was suspended in 1,1-bis-dimethylamino-3,3-dimethyl-butan-2-one (3.6 mL, 17.5 mmol) in a N2-flushed flask and heated at 70° C. for 36 h. The mixture was evaporated in vacuo and the residue triturated in EtOAc. The titled compound (973 mg) was obtained as a reddish solid. 1H-NMR (DMSO-d6) δ: 1.30 (s, 3H, CH3), 1.51 (s, 3H, CH3), 2.20 (br. s, 6H, CH3), 2.66 (s, 3H, CH3), 4.57 (d, 1H, J=12.5 Hz, CH), 5.53 (s, 1H, pyrrolyl-H), 6.72 (d, 1H, J=12.7 Hz, CH).

1. stirringthe mixture was stirred for 45 min
2. temperatureto maintain the internal temperature ≦30° C
3. stirringThe mixture was stirred for a further 45 min
4. extractionextracted with Et2O (3×60 mL)
5. washThe combined organic extracts were washed (brine)
6. dry with materialdried (MgSO4)
7. filtrationfiltered
8. customevaporated in vacuo