Acetic Anhydride → Ethyl 3-ethoxy-2-(2,4,5-trifluoro-3-methyl-6-nitrobenzoyl)acrylate
Reaction equation
[F:1][C:2]1[C:15]([CH3:16])=[C:14]([F:17])[C:13]([F:18])=[C:12]([N+:19]([O-:21])=[O:20])[C:3]=1[C:4]([CH2:6][C:7]([O:9][CH2:10][CH3:11])=[O:8])=[O:5].[CH:22]([O-])([O-])[O:23][CH2:24][CH3:25].C(OC(=O)C)(=O)C>>[CH2:24]([O:23][CH:22]=[C:6]([C:4](=[O:5])[C:3]1[C:12]([N+:19]([O-:21])=[O:20])=[C:13]([F:18])[C:14]([F:17])=[C:15]([CH3:16])[C:2]=1[F:1])[C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH3:25]Participants
4
Procedure
A mixture of 31.9 g of ethyl (2,4,5-trifluoro-3-methyl-6-nitrobenzoyl)acetate, 26.2 ml of ethyl orthoformate and 23.8 ml of acetic anhydride was heated under reflux for 1 hour. The reaction mixture was concentrated under reduced pressure to give 46.2 g of ethyl 3-ethoxy-2-(2,4,5-trifluoro-3 -methyl-6-nitrobenzoyl)acrylate as brown oil. To a solution of 45.4 g of the above compound in 328 ml of ethanol, 9.6 ml of cyclopropylamine was added dropwise with stirring under ice cooling, and then stirring was continued for 30 minutes at room temperature. The reaction mixture was concentrated under reduced pressure, and the residue was purified by column chromatography (silica gel, n-hexane-methylene chloride (1:1)) to give 28.8 g of yellow crystals. The crystals were recrystallized from isopropyl ether to give yellow needles, m.p. 115°-115.5° C.