反应详情

10.0 g of 2,2-dioxo-4-methyl-1,2-benzoxathiin-8-ylsulfonamide are dissolved in 200 ml of tetrahydrofuran and the solution is hydrogenated with hydrogen for 21/2 hours, in the presence of 2.0 g of 5% palladium on carbon catalyst, under a pressure of 4 bar and at a temperature of 40° C. After removal of the catalyst the solution is concentrated and the residue is crystallised from 120 ml of 70% aqueous ethanol, affording 9.0 g of 3,4-dihydro-2,2-dioxo-3-methyl-1,2-benzoxathiin-8-ylsulfonamide of m.p. 185°-186° C.

1. custom2 hours
2. customat a temperature of 40° C
3. customAfter removal of the catalyst the solution
4. concentrationis concentrated
5. customthe residue is crystallised from 120 ml of 70% aqueous ethanol