反应详情

A mixture of 5.1 g (20 mmols) of methyl 4-hydroxy-2H-1,2-benzothiazine-3-carboxylate-1,1-dioxide, 3.0 g (23 mmols) of 2-amino-6-chloropyrazine and 400 ml of xylene was refluxed for 12 hours in a nitrogen atmosphere. The methanol formed by the reaction was removed with the aid of a 4 Å molecular sieve arranged in a Soxhlet attachment. After cooling, the reaction mixture was concentrated by evaporation, and the residue was purified by chromatography on a silicagel column, yielding 2.3 g (33% of theory) of N-(6-chloro-pyrazin-2-yl)-4-hydroxy-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide.

1. temperaturewas refluxed for 12 hours in a nitrogen atmosphere
2. customwas removed with the aid of a 4 Å molecular sieve
3. temperatureAfter cooling
4. concentrationthe reaction mixture was concentrated by evaporation
5. customthe residue was purified by chromatography on a silicagel column