反应详情

温度

25 °C

224.5 g of sulphuric acid (50% w/w) was dissolved in 300 ml of water and cooled to 25° C. while stirring under a mild nitrogen purge. 185.1 g (1 mole) of N-(5-chloro-2-hydroxyphenyl)acetamide prepared according to Example 1a was added to the diluted sulphuric acid and mixed intensively. 4 ml of nitric acid 65% w/w was added to the foam formed on top of the reaction mixture at low stirring speed. The stirring speed was increased and 75 ml of nitric acid 65% w/w was added in 45 minutes, while maintaining the temperature between 23 and 26° C. The mixture was stirred vigorously for an additional 1 hour at 23-26° C. Then the mixture was cooled to 0-5° C. and vigorously stirred at this temperature for 1 hour. The solid was filtered off quickly, washed three times with 300 ml of cold water, sucked for at least 30 minutes and dried at 50° C. and 100 mbar under a gentle nitrogen stream till dry.

1. custompurge
2. additionmixed intensively
3. customformed on top of the reaction mixture at low stirring speed
4. temperatureThe stirring speed was increased
5. temperaturewhile maintaining the temperature between 23 and 26° C
6. stirringThe mixture was stirred vigorously for an additional 1 hour at 23-26° C
7. temperatureThen the mixture was cooled to 0-5° C.
8. stirringvigorously stirred at this temperature for 1 hour
9. filtrationThe solid was filtered off quickly
10. washwashed three times with 300 ml of cold water
11. waitsucked for at least 30 minutes
12. customdried at 50° C.
13. customtill dry