Benzylhydrazine dihydrochloride → 1-benzyl-5-(3,4-dihydro-2H-1-benzopyran-6-yl)-3-(trifluoromethyl)-1H-pyrazole

HRID 591076Notes

Reaction equation

HRID 591076 reaction equation
Cl.Cl.[CH2:3]([NH:10][NH2:11])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.[O:12]1[C:17]2[CH:18]=[CH:19][C:20]([C:22](=O)[CH2:23][C:24](=O)[C:25]([F:28])([F:27])[F:26])=[CH:21][C:16]=2[CH2:15][CH2:14][CH2:13]1>C(#N)C>[CH2:3]([N:10]1[C:22]([C:20]2[CH:19]=[CH:18][C:17]3[O:12][CH2:13][CH2:14][CH2:15][C:16]=3[CH:21]=2)=[CH:23][C:24]([C:25]([F:28])([F:26])[F:27])=[N:11]1)[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1

Participants

4

Reactant 2

HCID 146540Benzylhydrazine dihydrochlorideHCID 708188081-(3,4-dihydro-2H-1-benzopyran-6-yl)-4,4,4-trifluorobutane-1,3-dione

Product 1

HCID 708554551-benzyl-5-(3,4-dihydro-2H-1-benzopyran-6-yl)-3-(trifluoromethyl)-1H-pyrazoleYield 39.7%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

A solution of benzylhydrazine dihydrochloride (394 mg, 2.03 mmol) and 1-(3,4-dihydro-2H-1-benzopyran-6-yl)-4,4,4-trifluorobutane-1,3-dione (49b) (500 mg, 1.84 mmol) in acetonitrile (80 mL) was refluxed for 16 hours. The mixture was concentrated in vacuo and the residue was taken up in ethyl acetate (5 mL). The organic layer was successively washed with water (10 mL) and brine (10 mL) before being dried over sodium sulfate and concentrated in vacuo. The oil was purified by preparative TLC (cyclohexane/ethyl acetate 100/0 to 90/10) to provide the desired pyrazole (49c) (260 mg, 0.73 mmol, 39%).

Workup

  1. concentrationThe mixture was concentrated in vacuo
  2. washThe organic layer was successively washed with water (10 mL) and brine (10 mL)
  3. dry with materialbefore being dried over sodium sulfate
  4. concentrationconcentrated in vacuo
  5. customThe oil was purified by preparative TLC (cyclohexane/ethyl acetate 100/0 to 90/10)

Sources & evidence

ORD record
ord-29eb6989148f4e43b5766646a4e9aa1c
Source dataset
uspto-grants-2016_01
Patent number
US09238026B2

Reaction notes

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