反应详情

A solution of 10.15 g (43 mmol) of methyl 3,4-dimethylbenzo-thiazol-2-one-5-carboxylate in 100 ml of tetrahydrofuran and 100 ml of water was admixed with 2.06 g (86 mmol) of lithium hydroxide. The solution was then heated at reflux for 2 hours. After cooling, the tetrahydrofuran was removed under reduced pressure, the remaining aqueous solution was acidified and the precipitated solid was filtered off with suction and dried. More product was obtained by extracting the mother liquor with ethyl acetate. This gave a total of 8 g (36 mmol, 83% yield) of 3,4-dimethylbenzothiazol-2-one-5-carboxylic acid of m.p. 235° C.-239° C.

1. temperatureThe solution was then heated
2. temperatureat reflux for 2 hours
3. temperatureAfter cooling
4. customthe tetrahydrofuran was removed under reduced pressure
5. filtrationthe precipitated solid was filtered off with suction
6. customdried
7. customMore product was obtained
8. extractionby extracting the mother liquor with ethyl acetate