Boron Trichloride → (3R)-3-ethyl-7-fluoro-4-(4-hydroxybenzoyl)-1-methyl-3,4-dihydroquinoxalin-2(1H)-one

HRID 898215Notes

Reaction equation

HRID 898215 reaction equation
[CH2:1]([C@H:3]1[N:12]([C:13](=[O:22])[C:14]2[CH:19]=[CH:18][C:17]([O:20]C)=[CH:16][CH:15]=2)[C:11]2[C:6](=[CH:7][C:8]([F:23])=[CH:9][CH:10]=2)[N:5]([CH3:24])[C:4]1=[O:25])[CH3:2].B(Cl)(Cl)Cl>[I-].C([N+](CCCC)(CCCC)CCCC)CCC.C(Cl)Cl>[CH2:1]([C@H:3]1[N:12]([C:13](=[O:22])[C:14]2[CH:19]=[CH:18][C:17]([OH:20])=[CH:16][CH:15]=2)[C:11]2[C:6](=[CH:7][C:8]([F:23])=[CH:9][CH:10]=2)[N:5]([CH3:24])[C:4]1=[O:25])[CH3:2]

Participants

5

Reactant 2

HCID 25135Boron TrichlorideHCID 69223654(3R)-3-ethyl-7-fluoro-4-(4-methoxybenzoyl)-1-methyl-3,4-dihydroquinoxalin-2(1H)-one

Product 1

HCID 11709655(3R)-3-ethyl-7-fluoro-4-(4-hydroxybenzoyl)-1-methyl-3,4-dihydroquinoxalin-2(1H)-oneYield 88.6%

Reagents, catalysts & solvents 2

HCID 67553Tetrabutylammonium IodideCatalystHCID 6344DichloromethaneSolvent2×

Conditions

Temperature
0 °C

Procedure

To a stirred solution of (3R)-3-ethyl-7-fluoro-4-(4-methoxybenzoyl)-1-methyl-3,4 dihydroquinoxalin-2(1H)-one (0.19 g, 0.55 mmol) and tetrabutylammonium iodide (0.41 g, 1.1 mmol) in methylene chloride (5 mL), under nitrogen, at −78° C., was added a 1.0 M solution of boron trichloride in methylene chloride (2.8 mL, 2.8 mmol). Stirring was continued at −78° C. for 5 minutes, and the reaction was warmed to 0° C. where it was stirred for 5 h. The reaction was quenched by the addition of ice water, and the resulting mixture was stirred for 10 min. The layers were separated. The organic layer was washed with water and brine and dried over magnesium sulfate. Evaporation of the solvent and purification by eluting it through a short plug of silica gel with 75% hexane/EtOAc gave 0.16 g (88%) of (3R)-3-ethyl-7-fluoro-4-(4-hydroxybenzoyl)-1-methyl-3,4-dihydroquinoxalin-2(1H)-one. [α]D25=−300° (c=0.009 G/ML, DMSO); MS (ESI) m/z 329 ([M+H]+); MS (ESI) m/z 327 ([M−H]−); HRMS: calcd for C18H17FN2O3, 328.1223; found (ESI+), 329.13036; Anal. Calcd for C18H17FN2O3: C, 65.85; H, 5.22; N, 8.53. Found: C, 65.73; H, 5.46; N, 8.28.

Workup

  1. stirringwas stirred for 5 h
  2. customThe reaction was quenched by the addition of ice water
  3. stirringthe resulting mixture was stirred for 10 min
  4. customThe layers were separated
  5. washThe organic layer was washed with water and brine
  6. dry with materialdried over magnesium sulfate
  7. customEvaporation of the solvent and purification
  8. washby eluting it through a short plug of silica gel with 75% hexane/EtOAc

Sources & evidence

ORD record
ord-823f9168a24346eb86dfbb95ef91d0f9
Source dataset
uspto-grants-2008_04
Patent number
US07351709B2

Reaction notes

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