反应详情

A solution of 10.1 g (0.05 mole) of methyl 2-methoxy-6-chloronicotinate in 20 ml of methanol is added dropwise at 70° C in the course of 30 minutes to 500 ml of 0.1 N aqueous sodium hydroxide solution. After completion of the addition, the mixture is refluxed for 1 hour. The clear solution is concentrated in vacuo to approx. 100 ml and acidified with 2 N hydrochloric acid to pH 3. The precipitate which has formed is collected by filtration, washed with a small amount of water and dried. The residue is recrystallized from benzene-petroleum ether to yield pure 2-methoxy-6-chloronicotinic acid with a melting point of 210°-215° C.

1. additionAfter completion of the addition
2. temperaturethe mixture is refluxed for 1 hour
3. concentrationThe clear solution is concentrated in vacuo to approx. 100 ml
4. customThe precipitate which has formed
5. filtrationis collected by filtration
6. washwashed with a small amount of water
7. customdried
8. customThe residue is recrystallized from benzene-petroleum ether