反应详情

6-Ethoxybenzothiazole-2-sulfonamide (1.72 g, 6.7 mmol) was dissolved in dichloroethane (26 ml) and cooled to 20°. Aluminum chloride (4 g) was added portionwise such that the temperature remained 20°. After complete addition, the mixture was stirred at room temperature for 24 hours. Stirring was discontinued and after 0.5 hour, the supernatant was decanted from a tarry-like residue. This residue was cooled in an ice-water mixture and a cold solution of concentrated HCl (3 ml) in water (40 ml) was added as rapidly as possible with stirring. The resulting mixture was stirred for an hour and filtered. The solid was washed with water and suction dried to give 0.5-0.8 g. This material was combined with that from further working of the supernatant and dissolved in 20% NaOH solution, diluted to 100 ml with water and filtered. The filtrate was slowly acidified with concentrated hydrochloric acid (pH 3) and the resulting tan solid was filtered, washed with water and dried at 60°-80° C. under vacuum: total yield 1.3 g, m.p. 225°-228° C.

1. temperaturecooled to 20°
2. customremained 20°
3. additionAfter complete addition
4. stirringStirring
5. waitwas discontinued and after 0.5 hour
6. customthe supernatant was decanted from a tarry-like residue
7. temperatureThis residue was cooled in an ice-water mixture
8. additiona cold solution of concentrated HCl (3 ml) in water (40 ml) was added as rapidly as possible
9. stirringwith stirring
10. stirringThe resulting mixture was stirred for an hour
11. filtrationfiltered
12. washThe solid was washed with water and suction
13. customdried
14. customto give 0.5-0.8 g
15. filtrationfiltered
16. filtrationthe resulting tan solid was filtered
17. washwashed with water
18. customdried at 60°-80° C. under vacuum