Cyclization of thiohydrazonate esters and azo-hydrazone tautomerism of 2-arylhydrazono-3-oxo-1,4-benzothiazines
作者:Ahmad S. Shawali、Said Elsheikh、Cyril Párkányi
DOI:10.1002/jhet.5570400202
日期:2003.3
4. Identical products (4) were obtained by refluxing 1 or 6 in ethanol in the presence of triethylamine. The structure of 4 was confirmed by their alternate synthesis starting with diethyl chloromalonate in ethanol in the presence of triethylamine which yielded the intermediate 1,4-benzothiazine derivatives 8. The subsequent coupling of 8 with diazotized anilines in ethanol in the presence of potassium
在三乙胺的存在下,在乙醇中使芳基肼基氯乙酸乙酯(1)与2-氨基硫代苯酚(2)反应,得到相应的硫代肼基甲酸乙酯(3)。类似地,芳基肼基氯乙酸甲酯(6)得到相应的硫代肼基甲酸甲酯(7)。用乙醇中的氯化氢处理3和7分别得到1,4-苯并噻嗪衍生物4。在三乙胺存在下,在乙醇中回流1或6,得到相同的产物(4)。4的结构通过在氯乙二酸二乙酯在乙醇中,在三乙胺的存在下进行交替合成,证实了它们的合成,从而得到中间体1,4-苯并噻嗪衍生物8。随后在氢氧化钾存在下,将8与重氮化苯胺在乙醇中偶联,得到4。