Water → 1-(1,2,4-Trimethyl-1H-pyrrol-3-yl)ethanone

HRID 855614Notes

Reaction equation

HRID 855614 reaction equation
[OH-].[K+].[CH3:3][C:4]1[NH:5][CH:6]=[C:7]([CH3:12])[C:8]=1[C:9](=[O:11])[CH3:10].I[CH3:14].O>CS(C)=O>[CH3:14][N:5]1[CH:6]=[C:7]([CH3:12])[C:8]([C:9](=[O:11])[CH3:10])=[C:4]1[CH3:3]

Participants

6

Reactant 4

HCID 962WaterHCID 6328Methyl iodideHCID 14797Potassium HydroxideHCID 15163Ketone, 2,4-dimethylpyrrol-3-yl methyl

Product 1

HCID 149872381-(1,2,4-Trimethyl-1H-pyrrol-3-yl)ethanoneYield 96%

Reagents, catalysts & solvents 1

HCID 679Dimethyl SulfoxideSolvent

Procedure

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).

Workup

  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

Sources & evidence

ORD record
ord-959cebed967f4a7b9cf9b449f8d9a5f1
Source dataset
uspto-grants-2007_08
Patent number
US07262202B2

Reaction notes

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