反应详情

To a solution of 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)pyridine-2-carboxylic acid, methyl ester (200 mg, 0.9 mmol) in ethanol (5 mL) was added a catalytic amount of titanium tetraisopropoxide and the solution heated under reflux for 2 hours. The solution was cooled and partitioned between ethyl acetate (10 mL) and water (10 mL) and the organic phase was dried (sodium sulfate) and concentrated. The residue was passed over a plug of silica gel (1:1 ethyl acetate:hexanes) to give 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)pyridine-2-carboxylic acid, ethyl ester (150 mg. 0.6 mmol): mp 74-75° C.

1. temperaturethe solution heated
2. temperatureunder reflux for 2 hours
3. temperatureThe solution was cooled
4. custompartitioned between ethyl acetate (10 mL) and water (10 mL)
5. dry with materialthe organic phase was dried (sodium sulfate)
6. concentrationconcentrated