反应详情

5 g 2-(2,3-Dihydro-1,1-dioxido-3-oxo-1,2-benzisothiazol-2-yl)-5-hydroxy-2-methyl-valeramid are dissolved in 150 ml of xylene and the resulting solution is boiled under reflux for several hours, using a water separator. After the theoretical quantity of water has been separated off, the mixture is allowed to cool and concentrated in vacuo to a small volume. The precipitate is filtered off and recrystallized from n-butanol to give 3-(2,3-dihydro-1,1-dioxido-3-oxo-1,2-benzisothiazol-2-yl)-3-methyl-2-oxo-piperidine in the form of white crystals melting at 211° to 215° C., identical with the product obtained in example 1. The yield is 37% of the theoretical.

1. temperatureunder reflux for several hours
2. customAfter the theoretical quantity of water has been separated off
3. temperatureto cool
4. concentrationconcentrated in vacuo to a small volume
5. filtrationThe precipitate is filtered off
6. customrecrystallized from n-butanol