Trifluoroacetic acid → 3,4-Dihydro-2H-1,4-benzoxazine

HRID 1765052Notes

Reaction equation

HRID 1765052 reaction equation
C(OC([N:8]1[C:13]2[CH:14]=[CH:15][CH:16]=[CH:17][C:12]=2[O:11][CH2:10][CH2:9]1)=O)(C)(C)C.FC(F)(F)C(O)=O>ClCCl>[O:11]1[C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=2[NH:8][CH2:9][CH2:10]1

Participants

4

Reactant 2

HCID 6422Trifluoroacetic acidHCID 15348605Tert-butyl 2,3-dihydro-1,4-benzoxazine-4-carboxylate

Product 1

HCID 5850963,4-Dihydro-2H-1,4-benzoxazine

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of dichloromethane (10 mL) containing N-(tertbutoxycarbonyl)-2,3-dihydro-benzo[1,4]oxazine (0.438, 1.86 mmol) at 0° C. was added slowly trifluoroacetic acid (1.0 mL, 7.44 mmol). The reaction mixture was stirred at this temperature during 5 h, then the solvent was removed in vaccuo. The crude product was dissolved in EtOAc (15 mL) and washed successively with 10% Na2CO3 solution and water. The organic layer was dried over MgSO4 and the solvent was removed under reduce pressure. The title compound was obtained pure as brown oil (0.245 g, 98%). Rf=0.31 (petrol/ether 5/5); LCMS m/z 136 ([M+1]+); 1H NMR (300 MHz, CDCl3): δ 3.43 (4H, m); 3.54 (1H, s); 4.27 (4H, m); 6.60-6.82 (4H, m); 13C NMR (75 MHz, CDCl3): δ 43.4; 67.7; 118.1; 119.2; 121.3; 123.7; 136.1; 146.6. IR (film): 3375; 1498; 741 cm−1.

Workup

  1. customthe solvent was removed in vaccuo
  2. dissolutionThe crude product was dissolved in EtOAc (15 mL)
  3. washwashed successively with 10% Na2CO3 solution and water
  4. dry with materialThe organic layer was dried over MgSO4
  5. customthe solvent was removed

Sources & evidence

ORD record
ord-a91af5e6f4b642fba07db9ed9902e3f8
Source dataset
uspto-grants-2007_06
Patent number
US07226918B2

Reaction notes

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