反应详情

A solution of 2-chloro-3,6-difluoro-benzaldehyde (16.5 g, 93 mmol) in ethanol (80 ml) was treated with hydroxylamine HCl (7.80 g, 112 mmol) and sodium acetate (9.20 g, 112 mmol). The mixture was heated under reflux for 16 h, then the solvent was evaporated, and the residue stirred with water. The precipitate was filtered and dried to afford 2-chloro-3,6-difluoro-benzaldehyde oxime. It was dissolved in acetic anhydride (140 ml) and refluxed for 16 h, then the mixture was evaporated to afford 2-chloro-3,6-difluoro-benzonitrile as a light brown liquid (10.6 g, 65%). In analogy to example 5a, this compound was reacted with 4-methylimidazole and potassium carbonate for 20 h at 90° C. Aqueous workup, extraction with Ethyl acetate followed by chromatography (SiO2, dichloromethane:methanol=100:0 to 97:3) afforded the title compound as a white solid (yield: 6%). MS: m/e=336.1 [M+H]+.

1. temperatureThe mixture was heated
2. temperatureunder reflux for 16 h
3. customthe solvent was evaporated
4. filtrationThe precipitate was filtered
5. customdried