反应详情

温度

25 °C

To an appropriate flask equipped for reflux and/or distillation, 900 ml xylene, 40 grams (0.149 moles) methyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide and 19.94 grams (0.203 moles) of 3-amino-5-methylisoxazole are added. The mixture is refluxed for 13-18 hours. At 1 hour intervals, about 3-4% of the solvent volume is distilled off. Every 4 to 5 hours fresh xylene is added, equal in amount to that distilled during this period. At the end of the heating period, the reaction is cooled to 25°C., filtered and the cake is washed with xylene. After drying, the crude product weighed 43.8 grams (88%). This material could be recrystallized from about 40-50 volumes of dioxane with an 80-85% recovery of acceptable material. An alternate procedure for the purification of crude product is as follows:

1. customTo an appropriate flask equipped
2. temperaturefor reflux
3. additionare added
4. temperatureThe mixture is refluxed for 13-18 hours
5. distillationAt 1 hour intervals, about 3-4% of the solvent volume is distilled off
6. additionEvery 4 to 5 hours fresh xylene is added, equal in amount to
7. distillationthat distilled during this period
8. filtrationfiltered
9. washthe cake is washed with xylene
10. customAfter drying
11. customThis material could be recrystallized from about 40-50 volumes of dioxane with an 80-85% recovery of acceptable material
12. customAn alternate procedure for the purification of crude product