反应详情

In a nitrogen atmosphere, a solution of methyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide (4.0 g) and 5-amino-2-methoxy-2,4,6-cycloheptatrien-1-one (2.7 g) in xylene (100 ml) is refluxed for 6 hours. The reaction mixture is then allowed to stand at room temperature overnight. The crystals that have separated out are collected by filtration and purified by silica gel (40 g) column chromatography using methanol-dichloromethane (5:95) as the eluent. The resulting crude product is recrystallized from dioxane-methanol to give 4-hydroxy-2-methyl-N-(2-methoxy-1-oxo-2,4,6-cycloheptatrien-5-yl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide (0.3 g), m.p. 215°-218° C.

1. customThe crystals that have separated out
2. filtrationare collected by filtration
3. custompurified by silica gel (40 g) column chromatography
4. customThe resulting crude product is recrystallized from dioxane-methanol