Acetone → 2,2-dimethyl-3,4-dihydro-2H-1,3-benzoxazin-4-one

HRID 987114Notes

Reaction equation

HRID 987114 reaction equation
[C:1]([NH2:10])(=[O:9])[C:2]1[C:3](=[CH:5][CH:6]=[CH:7][CH:8]=1)[OH:4].[CH3:11][C:12]([CH3:14])=O>S(=O)(=O)(O)O>[CH3:11][C:12]1([CH3:14])[NH:10][C:1](=[O:9])[C:2]2[CH:8]=[CH:7][CH:6]=[CH:5][C:3]=2[O:4]1

Participants

4

Reactant 2

HCID 180AcetoneHCID 5147Salicylamide

Product 1

HCID 7174282,2-dimethyl-3,4-dihydro-2H-1,3-benzoxazin-4-oneYield 47%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidCatalyst

Procedure

A solution of salicylamide (4.14 g, 30.2 mmol) and conc. sulfuric acid (3 drops) in acetone (40 mL) was refluxed for 5 h. The reaction was concentrated and the residue taken up in ethyl acetate. The organic solution was washed with 1 N NaOH (2×), 1 N HCl (2×), H2O , then sat. aq. NaCl, dried (MgSO4) and concentrated to afford 2,2-dimethyl-4-keto-1,3-benzoxazine (2.50 g, 47%) as a white solid: 1H NMR (CDCl3, 300 MHz, ppm) 7.92 (d, 1H), 7.60 (bs, 1H), 7.47 (m, 1H), 7.06 (m, 1H), 6.92 (d, 1H), 1.65 (s, 6H).

Workup

  1. concentrationThe reaction was concentrated
  2. washThe organic solution was washed with 1 N NaOH (2×), 1 N HCl (2×), H2O
  3. dry with materialsat. aq. NaCl, dried (MgSO4)
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-e1d55b6767c44f9e877e240cf696d5ff
Source dataset
uspto-grants-2003_10
Patent number
US06630512B2

Reaction notes

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