Acetic Anhydride → 6-Chloro-2-methyl-4H-3,1-benzoxazin-4-one

HRID 874716Notes

Reaction equation

HRID 874716 reaction equation
[NH2:1][C:2]1[CH:10]=[CH:9][C:8]([Cl:11])=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].[C:12](OC(=O)C)(=O)[CH3:13]>CC(O)C>[Cl:11][C:8]1[CH:9]=[CH:10][C:2]2[N:1]=[C:12]([CH3:13])[O:5][C:4](=[O:6])[C:3]=2[CH:7]=1

Participants

4

Reactant 2

HCID 7918Acetic AnhydrideHCID 124762-Amino-5-chlorobenzoic acid

Product 1

HCID 2911346-Chloro-2-methyl-4H-3,1-benzoxazin-4-oneYield 89%

Reagents, catalysts & solvents 1

HCID 3776IsopropanolSolvent

Procedure

A mixture of 2-Amino-5-chlorobenzoic acid (90 g, 524 mmole) and acetic anhydride (160 ml) was heated to reflux under nitrogen for 3 hours. The reaction became a solution during heating. The reaction was cooled to room temperature. Some solid came out during this period of time. The reaction mixture was slurried with 1 L IPA and filtered. The solid was washed with more IPA (50 ml) and dried under vacuum at room temperature for 18 hours. Product was collected as solid (91 g, yield: 89%). 1H NMR (CDCl3): 8.14 (d, J=6 Hz, 1H), 7.73 (dd, J=21 Hz, 6 Hz, 1H), 7.50 (d, J=21 Hz, 1H), 2.47 (s, 3H).

Workup

  1. temperaturewas heated
  2. temperatureto reflux under nitrogen for 3 hours
  3. temperatureduring heating
  4. waitSome solid came out during this period of time
  5. filtrationfiltered
  6. washThe solid was washed with more IPA (50 ml)
  7. customdried under vacuum at room temperature for 18 hours

Sources & evidence

ORD record
ord-34840b33fbcc41df96bceb3e6e9028c9
Source dataset
uspto-grants-2015_03
Patent number
US08980926B2

Reaction notes

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