Ethyl Bromide → 1-Ethyl-4-nitro-1H-pyrazole
Reaction equation
[N+:1]([C:4]1[CH:5]=[N:6][NH:7][CH:8]=1)([O-:3])=[O:2].[H-].[Na+].Br[CH2:12][CH3:13]>CN(C=O)C.C(OCC)(=O)C>[CH2:12]([N:6]1[CH:5]=[C:4]([N+:1]([O-:3])=[O:2])[CH:8]=[N:7]1)[CH3:13]Participants
6
Reactant 3
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- -25 °C
Procedure
To a solution of 4-nitro-1H-pyrazole (5.0 g, 44.2 mmol) in anhydrous DMF (100 mL) was NaH (60% in oil) (1.94 g, 48.6 mmol) while being stirred at −25° C. under nitrogen. The mixture was stirred for 30 min before bromoethane (5.30 g, 48.6 mmol) was added. The mixture was continued to stir under nitrogen at −25° C. for 6 h. The solution was diluted with ethyl acetate (100 mL), washed with water (2×50 mL) and brine solution (50 mL), dried over magnesium sulfate, and filtered. The filtrate was concentrated under reduced pressure to afford crude 123a (5.0 g, 80%), which was used in next step without further purification. MS-ESI: [M+H]+ 142.0
Workup
- additionwas added
- stirringto stir under nitrogen at −25° C. for 6 h
- washwashed with water (2×50 mL) and brine solution (50 mL)
- dry with materialdried over magnesium sulfate
- filtrationfiltered
- concentrationThe filtrate was concentrated under reduced pressure
Sources & evidence
- ORD record
- ord-6f71280195714a51aa4cd4a804258729
- Source dataset
- uspto-grants-2014_06
- Patent number
- US08754077B2
Reaction notes
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