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

HRID 1168208Notes

Reaction equation

HRID 1168208 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-a092ab5350c0493ea3f6f68f4e2e4a08
Source dataset
uspto-grants-2003_09
Patent number
US06624152B2

Reaction notes

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