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

HRID 1942330Notes

Reaction equation

HRID 1942330 reaction equation
[C:1]([NH2:10])(=[O:9])[C:2]1[C:3](=[CH:5][CH:6]=[CH:7][CH:8]=1)[OH:4].[C:11]1(C)[CH:16]=CC(S([O-])(=O)=O)=C[CH:12]=1.[NH+]1C=CC=CC=1.ClCCl.CO>COC(OC)(C)C>[CH3:12][C:11]1([CH3:16])[NH:10][C:1](=[O:9])[C:2]2[CH:8]=[CH:7][CH:6]=[CH:5][C:3]=2[O:4]1

Participants

6

Reactant 4

HCID 887MethanolHCID 5147SalicylamideHCID 6344DichloromethaneHCID 466102Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1)

Product 1

HCID 7174282,2-dimethyl-3,4-dihydro-2H-1,3-benzoxazin-4-oneYield 93.4%

Reagents, catalysts & solvents 1

HCID 64952,2-DimethoxypropaneSolvent

Procedure

To a solution of salicylamide (20.0 g, 0.146 mol; Aldrich Chemical Company, Inc., Milwaukee, Wis.) in 2,2-dimethoxypropane (300 mL) was added pyridinium p-toluenesulfonate (11.0 g, 0.044 mol) and then heated to reflux for 2 h. TLC (dichloromethane: methanol=20:1) indicated the reaction was complete. The solvent was removed and then the residue was taken up in ethyl acetate (150 mL). The solution was washed twice with sodium bicarbonate and once with brine. The organic layer was dried and concentrated under reduced pressure to afford (I-30a) (26.0 g, yield: 93.4%) as a yellow solid, which was used to next step without any purification.

Workup

  1. temperatureheated
  2. temperatureto reflux for 2 h
  3. customThe solvent was removed
  4. washThe solution was washed twice with sodium bicarbonate and once with brine
  5. customThe organic layer was dried
  6. concentrationconcentrated under reduced pressure
  7. customto afford (I-30a) (26.0 g, yield: 93.4%) as a yellow solid, which
  8. customwas used to next step without any purification

Sources & evidence

ORD record
ord-0d2c5847f5734ec3ad1b99976c217c87
Source dataset
uspto-grants-2013_03
Patent number
US08389552B2

Reaction notes

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