Trifluoroacetic acid → 4-Nitroso-3-phenyl-3,4-dihydro-2H-1,4-benzoxazine

HRID 2415798Notes

Reaction equation

HRID 2415798 reaction equation
[C:1]1([CH:7]2[NH:12][C:11]3[CH:13]=[CH:14][CH:15]=[CH:16][C:10]=3[O:9][CH2:8]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.FC(F)(F)C(O)=O.[N:24](OCCCC)=[O:25].C(=O)([O-])[O-].[K+].[K+]>C(OCC)C.O>[N:24]([N:12]1[C:11]2[CH:13]=[CH:14][CH:15]=[CH:16][C:10]=2[O:9][CH2:8][CH:7]1[C:1]1[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1)=[O:25]

Participants

7

Reactant 4

HCID 6422Trifluoroacetic acidHCID 10996Butyl nitriteHCID 11430Potassium CarbonateHCID 124745723-phenyl-3,4-dihydro-2H-1,4-benzoxazine

Product 1

HCID 121486174-Nitroso-3-phenyl-3,4-dihydro-2H-1,4-benzoxazineYield 81.2%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 3283Diethyl EtherSolvent2×

Procedure

To a mixture of 3-phenyl-3,4-dihydro-2H-1,4-benzoxazine (17 g, 80.5 mmol) in ethyl ether (100 mL) is added trifluoroacetic acid (6.2 mL 80.5 mmol). The resulting solution is chilled to 5° C. in an ice bath, to which n-butyl nitrite (9.4 mL 80.5 mmol) is added dropwise. The mixture is stirred for 1 h and transferred to a separatory funnel to which is slowly added potassium carbonate (2.6 g, 18.8 mmol) in water (200 mL). Solids formed in the ether layer. The layers are separated and ethyl ether (100 mL) is added to dissolve the solids. The ether layer is washed twice with water (200 mL), dried over magnesium sulfate, filtered and concentrated. The resulting oil is chilled in the refrigerator overnight. The solids formed from the oil are ground-up in hexanes and collected by filtration to give 15.7 g (81%) of 4-nitroso-3-phenyl-3,4-dihydro-2H-1,4-benzoxazine.

Workup

  1. additionis added dropwise
  2. customtransferred to a separatory funnel to which
  3. customThe layers are separated
  4. additionethyl ether (100 mL) is added
  5. dissolutionto dissolve the solids
  6. washThe ether layer is washed twice with water (200 mL)
  7. dry with materialdried over magnesium sulfate
  8. filtrationfiltered
  9. concentrationconcentrated
  10. temperatureThe resulting oil is chilled in the refrigerator overnight
  11. customThe solids formed from the oil
  12. filtrationcollected by filtration

Sources & evidence

ORD record
ord-70beac0afb9e4807a2713feebb886ccb
Source dataset
uspto-grants-2004_11
Patent number
US06821970B2

Reaction notes

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