Hydrochloric Acid → 6-Sulfanyl-2H-1,4-benzoxazin-3(4H)-one

HRID 1192257Notes

Reaction equation

HRID 1192257 reaction equation
[O:1]=[C:2]1[CH2:7][O:6][C:5]2[CH:8]=[CH:9][C:10]([S:12](Cl)(=O)=O)=[CH:11][C:4]=2[NH:3]1.Cl.[Sn].C(OCC)(=O)C>O1CCOCC1>[SH:12][C:10]1[CH:9]=[CH:8][C:5]2[O:6][CH2:7][C:2](=[O:1])[NH:3][C:4]=2[CH:11]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8857Ethyl AcetateHCID 52002293-oxo-3,4-dihydro-2H-1,4-benzoxazine-6-sulfonyl chlorideHCID 5352426Tin atom

Product 1

HCID 162277896-Sulfanyl-2H-1,4-benzoxazin-3(4H)-oneYield 16.1%

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

To a solution of 3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazine-6-sulfonyl chloride (5.8 g, 20.2 mmol), was added the hydrogen chloride in 1,4-dioxane (30 mL) followed by tin powder (12 g, 10.1 mmol). The resulting mixture was heated under reflux for 2 hours. After this time, the solvent of the reaction mixture was removed under vacuum to give the crude residue. The resulting residue was treated with ethyl acetate and washed with brine and water. The organic layer was separated, dried (Na2SO4) and concentrated. The crude material was purified by silica gel chromatography using a 60:40 mixture of hexane and ethyl acetate as eluent to afford the title product as a white solid (0.59 g, 16% yield). 1H NMR (400 MHz, d6-DMSO) δ: 10.82 (1H, s), 6.86 (2H, m), 6.81 (1H, m), 5.40 (1H, s), 4.53 (2H, s).

Workup

  1. temperatureThe resulting mixture was heated
  2. temperatureunder reflux for 2 hours
  3. customAfter this time, the solvent of the reaction mixture was removed under vacuum
  4. customto give the crude residue
  5. washwashed with brine and water
  6. customThe organic layer was separated
  7. dry with materialdried (Na2SO4)
  8. concentrationconcentrated
  9. customThe crude material was purified by silica gel chromatography
  10. additiona 60:40 mixture of hexane and ethyl acetate as eluent

Sources & evidence

ORD record
ord-f92917e49b9b4f7392d5cfea292906fd
Source dataset
uspto-grants-2014_03
Patent number
US08680139B2

Reaction notes

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