反应详情

7 g (=0.035 m) of 2-chloro-2H-1,4-benzothiazine-3(4H)-one, 6.2 g of N-(4-methylpyridin-2-yl)-piperazine, and 7 g of triethylamine were heated at reflux with stirring for 5 hours in 100 ml of toluene. The suspension was worked up by diluting it with 200 ml of toluene, and the resulting precipitate was filtered out and dissolved in 20% strength aqueous hydrochloric acid solution. The solution was rendered alkaline by adding an ammonium hydroxide solution, and the resulting precipitate was filtered out, washed with water and dried. 2 g of beige-colored crystalline 2-[4-(4-methylpyridin-2-yl)-piperazin-1-yl]-2H-1,4-benzothiazine-3(4H)-one having a melting point of 245° C. were obtained.

1. temperatureat reflux
2. filtrationthe resulting precipitate was filtered out
3. dissolutiondissolved in 20% strength aqueous hydrochloric acid solution
4. additionby adding an ammonium hydroxide solution
5. filtrationthe resulting precipitate was filtered out
6. washwashed with water
7. customdried