Hydrochloric Acid → 7-benzenesulfonyl-2,2-dimethyl-3,4-dihydro-2H-benzo[1,4]oxazine

HRID 2224085Notes

Reaction equation

HRID 2224085 reaction equation
[C:1]1([S:7]([C:10]2[CH:22]=[CH:21][C:13]3[NH:14][C:15](=O)[C:16]([CH3:19])([CH3:18])[O:17][C:12]=3[CH:11]=2)(=[O:9])=[O:8])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.Cl.C(=O)(O)[O-].[Na+].C(=O)([O-])[O-].[K+].[K+]>C1COCC1.C(OCC)(=O)C>[C:1]1([S:7]([C:10]2[CH:22]=[CH:21][C:13]3[NH:14][CH2:15][C:16]([CH3:18])([CH3:19])[O:17][C:12]=3[CH:11]=2)(=[O:9])=[O:8])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 11430Potassium CarbonateHCID 516892Sodium BicarbonateHCID 586415337-benzenesulfonyl-2,2-dimethyl-4H-benzo[1,4]oxazin-3-one

Product 1

HCID 586415397-benzenesulfonyl-2,2-dimethyl-3,4-dihydro-2H-benzo[1,4]oxazineYield 95.8%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 8857Ethyl AcetateSolvent

Procedure

A solution of 7-benzenesulfonyl-2,2-dimethyl-4H-benzo[1,4]oxazin-3-one (0.570 g., 1.79 mmol) in 10 mL freshly distilled THF was cooled to 0° C., and borane-THF complex (5.39 mL of a 1 M solution in THF, 5.39 mmol) was added dropwise over 2 minutes. The resulting solution was warmed to reflux and stirred for 1 hour. Ethanolic hydrogen chloride (4 mL of 2 N solution, 8 mmol) was then added dropwise and the reaction was heated at reflux for an additional hour. The reaction mixture was cooled to room temperature and added to a mixture of 100 mL each ethyl acetate and 10% aqueous sodium bicarbonate. Potassium carbonate was added until the pH of the aqueous phase was roughly 7. The organic layer was separated, washed with 50 mL water and 50 mL brine, dried over sodium sulfate and concentrated in vacuo. The resulting crude oil was purified by flash chromatography (10 to 45% ethyl acetate in hexanes) to give 520 mg (94%) of 7-benzenesulfonyl-2,2-dimethyl-3,4-dihydro-2H-benzo[1,4]oxazine as a white powder. MS: 304 (M+H)+.

Workup

  1. temperatureThe resulting solution was warmed
  2. temperatureto reflux
  3. temperaturethe reaction was heated
  4. temperatureat reflux for an additional hour
  5. customThe organic layer was separated
  6. washwashed with 50 mL water and 50 mL brine
  7. dry with materialdried over sodium sulfate
  8. concentrationconcentrated in vacuo
  9. customThe resulting crude oil was purified by flash chromatography (10 to 45% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-cc1ccbffea0e40ef921f945e68d65492
Source dataset
uspto-grants-2008_05
Patent number
US07378415B2

Reaction notes

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