反应详情

Methanesulfonic acid (99%, 318 g, 3.3 mole) was added slowly to a stirred mixture of 5-amino-2-chlorobenzoic acid (85%, 215 g, 1.1 mole) in 2-propanol (about 1100 ml). The mixture was heated under reflux with stirring for 6 hours, then the excess 2-propanol was evaporated under reduced pressure. Water (about 1000 ml) was added to the residue and the mixture was neutralized with solid sodium bicarbonate and extracted with methylene chloride (about 1200 ml). The extract was washed twice with water, dried over magnesium sulfate and evaporated to give a purple oil, which crystallized on seeding. The product was reprecipitated from dilute hydrochloric acid solution by slowly basifying with concentrated ammonium hydroxide and seeding. The resulting crystals after drying melted at 50.5°-52° C. (170 g, 75% yield).

1. temperatureThe mixture was heated
2. temperatureunder reflux
3. customthe excess 2-propanol was evaporated under reduced pressure
4. additionWater (about 1000 ml) was added to the residue
5. extractionextracted with methylene chloride (about 1200 ml)
6. washThe extract was washed twice with water
7. dry with materialdried over magnesium sulfate
8. customevaporated
9. customto give a purple oil, which
10. customcrystallized on seeding
11. customThe product was reprecipitated from dilute hydrochloric acid solution
12. customThe resulting crystals after drying melted at 50.5°-52° C. (170 g, 75% yield)