Acetic Anhydride → 5-Chloro-2-methyl-4H-3,1-benzoxazin-4-one

HRID 741550Notes

Reaction equation

HRID 741550 reaction equation
[NH2:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]([Cl:11])[C:3]=1[C:4]([OH:6])=[O:5].[C:12](OC(=O)C)(=O)[CH3:13]>>[Cl:11][C:7]1[C:3]2[C:4](=[O:6])[O:5][C:12]([CH3:13])=[N:1][C:2]=2[CH:10]=[CH:9][CH:8]=1

Participants

3

Reactant 2

HCID 7918Acetic AnhydrideHCID 750712-Amino-6-chlorobenzoic acid

Product 1

HCID 124789225-Chloro-2-methyl-4H-3,1-benzoxazin-4-oneYield 46%

Conditions

Temperature
120 °C

Procedure

2-amino-6-chlorobenzoic acid (25 g) dissolved in acetic anhydride (100 ml) was stirred at 120° C. for 2 hours. The mixture was cooled to room temperature and filtered off. The precipitate was washed with water and Na2CO3 (10%) and dissolved in CH2Cl2. The solution was dried with Na2SO4, filtered off and evaporated. The residue was crystallized twice from benzene, yielding 13 g (46%) of 5-chloro-2-methyl-4H-3,1-benzoxazin-4-one; mp. 148.7° C. (interm. 14).

Workup

  1. temperatureThe mixture was cooled to room temperature
  2. filtrationfiltered off
  3. washThe precipitate was washed with water and Na2CO3 (10%)
  4. dissolutiondissolved in CH2Cl2
  5. dry with materialThe solution was dried with Na2SO4
  6. filtrationfiltered off
  7. customevaporated
  8. customThe residue was crystallized twice from benzene

Sources & evidence

ORD record
ord-b5389765c6734447ac5744451fc56370
Source dataset
uspto-grants-1996_09
Patent number
US05552399

Reaction notes

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