Hydrochloric Acid → 2,5-dimethyl-2H-pyrazole-3-carboxylic acid phenethyl-amide

HRID 361599Notes

Reaction equation

HRID 361599 reaction equation
[CH3:1][N:2]1[C:6]([C:7]([O:9]CC)=O)=[CH:5][C:4]([CH3:12])=[N:3]1.Cl.[CH2:14]([NH2:22])[CH2:15][C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1>C(OCC)(=O)C.O.[Rh](Cl)(Cl)Cl>[CH2:14]([NH:22][C:7]([C:6]1[N:2]([CH3:1])[N:3]=[C:4]([CH3:12])[CH:5]=1)=[O:9])[CH2:15][C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 1001PhenethylamineHCID 1385761,3-Dimethyl-5-ethoxycarbonylpyrazole

Product 1

HCID 357640502,5-dimethyl-2H-pyrazole-3-carboxylic acid phenethyl-amide

Reagents, catalysts & solvents 2

HCID 24872Rhodium chlorideCatalystHCID 22728543Water ethylacetateSolvent

Procedure

A solution of 1.68 g of ethyl 2,5-dimethyl-2H-pyrazole-3-carboxylate in 3.8 ml of phenethylamine was treated with 0.10 g of rhodium(III) trichloride.trihydrate and heated to 140° C. while stirring for 21 h. Subsequently, the mixture was taken up in ethyl acetate/water, adjusted to pH 2-3 with 2N HCl and extracted three times with ethyl acetate. The combined organic phases were washed neutral with sat. aqueous sodium chloride solution, dried over sodium sulfate and evaporated. Chromatographic purification on silica gel with hexane/ethyl acetate 50:50 yielded 1.92 g (79%) of cryst. product of m.p. 97°-98° C. Recrystallization of a sample from tBuOMe gave 2,5-dimethyl-2H-pyrazole-3-carboxylic acid phenethyl-amide as colorless crystals of m.p. 97.5°-98.5° C.

Workup

  1. extractionextracted three times with ethyl acetate
  2. washThe combined organic phases were washed neutral with sat. aqueous sodium chloride solution
  3. dry with materialdried over sodium sulfate
  4. customevaporated
  5. customChromatographic purification on silica gel with hexane/ethyl acetate 50:50
  6. customyielded 1.92 g (79%) of cryst
  7. customRecrystallization of a sample from tBuOMe

Sources & evidence

ORD record
ord-896508e081f3421ba302f9c3c02181dd
Source dataset
uspto-grants-1999_02
Patent number
US05866583

Reaction notes

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