Benzyl Bromide → 2-benzyl-7,8-dihydrocyclopenta[e]indazol-6(2H)-one
Reaction equation
[CH:1]1[C:9]2[C:8]3[CH2:10][CH2:11][C:12](=[O:13])[C:7]=3[CH:6]=[CH:5][C:4]=2[NH:3][N:2]=1.[CH2:14](Br)[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1>CN(C)C=O>[CH2:14]([N:2]1[CH:1]=[C:9]2[C:4]([CH:5]=[CH:6][C:7]3[C:12](=[O:13])[CH2:11][CH2:10][C:8]=32)=[N:3]1)[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 100 °C
Procedure
To a suspension of 7,8-dihydrocyclopenta[e]indazol-6(3H)-one (6.00 g, 34.8 mmol) in 60 mL of dimethylformamide was added benzyl bromide (5.40 mL, 45.5 mmol) and the mixture was heated to 100° C. After 15 hours, the solution was cooled to room temperature and partitioned between chloroform and saturated aqueous NaHCO3. The organic phase was washed with water (3×) and brine and dried over Na2SO4. The solution was concentrated to low volume under vacuum and flash chromatographed on silica gel eluting with EtOAc/dichloroethane (0:100 to 20:80) which removed a minor amount (˜10%) of the faster eluting regioisomer 3-benzyl-7,8-dihydrocyclopenta-[e]indazol-6(3H)-one and gave 2-benzyl-7,8-dihydrocyclopenta[e]indazol-6(2H)-one as a pale yellow solid.
Workup
- temperaturethe solution was cooled to room temperature
- custompartitioned between chloroform and saturated aqueous NaHCO3
- washThe organic phase was washed with water (3×) and brine
- dry with materialdried over Na2SO4
- concentrationThe solution was concentrated to low volume under vacuum and flash
- customchromatographed on silica gel eluting with EtOAc/dichloroethane (0:100 to 20:80) which
- customremoved a minor amount (˜10%) of the
- washfaster eluting regioisomer 3-benzyl-7,8-dihydrocyclopenta-[e]indazol-6(3H)-one
Sources & evidence
- ORD record
- ord-962b433aba76496e8318e7e94da739d2
- Source dataset
- uspto-grants-2011_04
- Patent number
- US07923568B2
Reaction notes
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