p-Toluenesulfonic acid → 3-(2,5-dimethyl-1H-pyrrol-1-yl)-1-methyl-1H-pyrazole

HRID 2381287Notes

Reaction equation

HRID 2381287 reaction equation
[CH3:1][N:2]1[CH:6]=[CH:5][C:4]([NH2:7])=[N:3]1.[CH3:8][C:9](=O)[CH2:10][CH2:11][C:12](=O)[CH3:13].C1(C)C=CC(S(O)(=O)=O)=CC=1>C1C=CC=CC=1>[CH3:13][C:12]1[N:7]([C:4]2[CH:5]=[CH:6][N:2]([CH3:1])[N:3]=2)[C:9]([CH3:8])=[CH:10][CH:11]=1

Participants

5

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 80352,5-HexanedioneHCID 1372541-Methyl-3-aminopyrazole

Product 1

HCID 132489953-(2,5-dimethyl-1H-pyrrol-1-yl)-1-methyl-1H-pyrazoleYield 94.3%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Conditions

Temperature
115 °C

Procedure

A solution of 1-methyl-1H-pyrazol-3-ylamine (0.92 g, 9.5 mmol) in benzene (4.8 mL) was treated with hexane-2,5-dione (1.34 mL, 11.4 mmol) and para-toluenesulfonic acid (182 mg, 0.95 mmol) and was heated to 115° C. under Dean-Stark conditions for 4 h. After this time, the reaction was cooled to 25° C., concentrated in vacuo and dried under high vacuum overnight. The resulting residue was dissolved in methylene chloride (100 mL) and was washed with water (1×150 mL), dried over sodium sulfate, filtered and concentrated in vacuo. Silica gel column chromatography (ISCO, 80 g, 1:4 ethyl acetate/hexanes) afforded 3-(2,5-dimethyl-pyrrol-1-yl)-1-methyl-1H-pyrazole (1.57 g, 94%) as a green oil; ES+-HRMS m/e calcd for C10H13N3 [M+H+] 176.1182, found 176.1182.

Workup

  1. temperatureAfter this time, the reaction was cooled to 25° C.
  2. concentrationconcentrated in vacuo
  3. customdried under high vacuum overnight
  4. dissolutionThe resulting residue was dissolved in methylene chloride (100 mL)
  5. washwas washed with water (1×150 mL)
  6. dry with materialdried over sodium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-88a1e49199244bdebbea7f3ff643f909
Source dataset
uspto-grants-2012_09
Patent number
US08258134B2

Reaction notes

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