Syntheses with isoxazoles; the production of an isoxazolo[2,3-a]pyridinium salt, and the photochemical conversion of isoxazole-3-carboxylates into oxazole-2-carboxylates
作者:R. H. Good、Gurnos Jones
DOI:10.1039/j39710001196
日期:——
of 3-(4-ethoxybutyryl)isoxazole (6) gave 4,5,6,7-tetrahydro-4-oxoisoxazolo[2,3-a]pyridinium bromide (7). An attempt to aromatise the ketone (7) with boiling acetic anhydride was unsuccessful, but bromination gave a dibromo-ketone (9), which was dehydrobrominated to 5-bromo-4-hydroxyisoxazolo[2,3-a]pyridinium bromide (10). The photochemical conversion of isoxazole-3-carboxylates into the corresponding
3-(4-乙氧基丁酰基)异恶唑(6)的环化得到4,5,6,7-四氢-4-氧代异恶唑并[2,3- a ]溴化吡啶鎓(7)。尝试用沸腾的乙酸酐对酮(7)进行芳构化未成功,但是溴化反应生成了二溴代酮(9),将其脱氢溴化为5-溴代-4-羟基异恶唑并[2,3- a ]溴化吡啶鎓(10)。 。描述了异恶唑-3-羧酸盐到相应的恶唑-2-羧酸盐的光化学转化。