Boron Trichloride → (3S)-3-ethyl-7-fluoro-4-[(4-hydroxyphenyl)sulfonyl]-1-methyl-3,4-dihydroquinoxalin-2(1H)-one

HRID 898267Notes

Reaction equation

HRID 898267 reaction equation
[CH2:1]([C@@H:3]1[N:12]([S:13]([C:16]2[CH:21]=[CH:20][C:19]([O:22]C)=[CH:18][CH:17]=2)(=[O:15])=[O:14])[C:11]2[C:6](=[CH:7][C:8]([F:24])=[CH:9][CH:10]=2)[N:5]([CH3:25])[C:4]1=[O:26])[CH3:2].B(Cl)(Cl)Cl>[I-].C([N+](CCCC)(CCCC)CCCC)CCC.C(Cl)Cl>[CH2:1]([C@@H:3]1[N:12]([S:13]([C:16]2[CH:21]=[CH:20][C:19]([OH:22])=[CH:18][CH:17]=2)(=[O:14])=[O:15])[C:11]2[C:6](=[CH:7][C:8]([F:24])=[CH:9][CH:10]=2)[N:5]([CH3:25])[C:4]1=[O:26])[CH3:2]

Participants

5

Reactant 2

HCID 25135Boron TrichlorideHCID 69220473(3S)-3-ethyl-7-fluoro-4-[(4-methoxyphenyl)sulfonyl]-1-methyl-3,4-dihydroquinoxalin-2(1H)-one

Product 1

HCID 11639171(3S)-3-ethyl-7-fluoro-4-[(4-hydroxyphenyl)sulfonyl]-1-methyl-3,4-dihydroquinoxalin-2(1H)-oneYield 78.4%

Reagents, catalysts & solvents 2

HCID 67553Tetrabutylammonium IodideCatalystHCID 6344DichloromethaneSolvent2×

Conditions

Temperature
25 °C

Procedure

A solution of (3S)-3-ethyl-7-fluoro-4-[(4-methoxyphenyl)sulfonyl]-1-methyl-3,4-dihydroquinoxalin-2(1H)-one (0.27 g, 0.7 mmol)) and tetrabutylamonium iodide (0.77 g, 2.09 mmol) in methylene chloride (20 mL) was cooled to −78° C. and treated with a 1M solution of boron trichloride in methylene chloride (3.5 mL, 3.5 mmol) via syringe. The cooling bath was removed and the solution was stirred at 25° C. for 3 hours. The reaction was quenched with a saturated aqueous solution of ammonium chloride. The organic phase was separated, dried over magnesium sulfate and concentrated in vacuo. The crude oil was purified via flash column chromatography (SiO2, 40% ethyl acetate:hexane) to afford 0.2 g (78%) of (3S)-3-ethyl-7-fluoro-4-[(4-hydroxyphenyl)sulfonyl]-1-methyl-3,4-dihydroquinoxalin-2(1H)-one as white solid. MS (ESI) m/z 365 ([M+H]+); MS (ESI) m/z 363 ([M−H]−); Anal. Calcd for C17H17FN2O4S: C, 56.03; H, 4.70; N, 7.69. Found: C, 56.12; H, 4.03; N, 7.45.

Workup

  1. customThe cooling bath was removed
  2. customThe reaction was quenched with a saturated aqueous solution of ammonium chloride
  3. customThe organic phase was separated
  4. dry with materialdried over magnesium sulfate
  5. concentrationconcentrated in vacuo
  6. customThe crude oil was purified via flash column chromatography (SiO2, 40% ethyl acetate:hexane)

Sources & evidence

ORD record
ord-d5f8b475495a46bab4eedc65bc1e5b34
Source dataset
uspto-grants-2008_04
Patent number
US07351709B2

Reaction notes

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