Acetic Anhydride → 5-Chloro-2-(3-fluorophenyl)-4H-3,1-benzoxazin-4-one
Reaction equation
[F:1][C:2]1[CH:3]=[C:4]([CH:18]=[CH:19][CH:20]=1)[C:5]([NH:7][C:8]1[C:9](=[C:13]([Cl:17])[CH:14]=[CH:15][CH:16]=1)[C:10]([OH:12])=[O:11])=O.C(OC(=O)C)(=O)C>>[F:1][C:2]1[CH:3]=[C:4]([C:5]2[O:11][C:10](=[O:12])[C:9]3[C:13]([Cl:17])=[CH:14][CH:15]=[CH:16][C:8]=3[N:7]=2)[CH:18]=[CH:19][CH:20]=1Participants
3
Procedure
29 parts of N-(3'-fluorobenzoyl)-6-chloroanthranilic acid in 250 parts of acetic anhydride are stirred under reflux for 21/2 hours. The mixture is evaporated down under reduced pressure, the residue is taken up in methylene chloride and this solution is washed with twice 100 parts by volume of 0.5 N sodium hydroxide solution and then with water. Thereafter, the solution is chromatographed on neutral alumina, giving 23.6 parts of 2-(3'-fluorophenyl)-5-chloro-4H-3,1-benzoxazin-4-one, of melting point 123°-125° C.; yield: 86.7% of theory.
Workup
- temperatureunder reflux for 21/2 hours
- customThe mixture is evaporated down under reduced pressure