反应详情

A mixture of 2.20 g (7.18 mmol) of 2-hydroxy-3-bromo-4-chloro-5-(1,1-dimethylethyl)benzaldehyde oxime and 3.12 g (14.72 mmol) of trifluoroacetic anhydride in 15 ml of tetrahydrofuran was cooled in an ice-water bath. A solution of 2.18 g (21.54 mmol) of triethylamine in 10 ml of tetrahydrofuran was added After refluxing for 2 hours, the solvent was evaporated and the residue was partitioned between saturated aqueous sodium bicarbonate solution and ether. The organic phase was washed with 1N hydrochloric acid, followed by water and brine. The organic phase was dried and evaporated. The residue was chromatographed on 100 g of silica gel using a gradient from 5:95 to 50:50 (v/v) ether:hexane as eluent. There was obtained 1.80 g (6.23 mmol, 87%) of 2-hydroxy-3-bromo-4-chloro-5-(1,1-dimethylethyl)benzonitrile; mp 105°-107° C.

1. temperaturewas cooled in an ice-water bath
2. temperatureAfter refluxing for 2 hours
3. customthe solvent was evaporated
4. customthe residue was partitioned between saturated aqueous sodium bicarbonate solution and ether
5. washThe organic phase was washed with 1N hydrochloric acid
6. customThe organic phase was dried
7. customevaporated
8. customThe residue was chromatographed on 100 g of silica gel using a gradient from 5:95 to 50:50 (v/v) ether