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

HRID 891044Notes

Reaction equation

HRID 891044 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>>[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

3

Reactant 2

HCID 180AcetoneHCID 5147Salicylamide

Product 1

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

Procedure

A solution of salicylamide (4.14 g, 30.2 mmol) and conc. sulfuric a-id (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-2865db88e25f40a18d825cac84754f22
Source dataset
uspto-grants-2006_02
Patent number
US07001921B1

Reaction notes

Loading…