Novel Synthesis of Naphthopyranoisoxazoles and Versatile Access to Naphthopyranoisoxazolines
作者:George Varvounis、Theodoros Liaskopoulos、Stavroula Skoulika、Petros Tsoungas
DOI:10.1055/s-2008-1032178
日期:2008.3
2-(Alkenyloxy)naphthalene-1-carbaldehyde oximes are oxidized with potassium iodide, iodine and sodium bicarbonate directly to novel naphthopyranoisoxazoles. Naphthopyranoisoxazoles are also prepared from 2-(3-chloroallyloxy)naphthalene-1-carbaldehyde oxime or 2-(alkynyloxy)naphthalene-1-carbaldehyde oximes by oxidation with sodium hypochlorite and triethylamine. The oxidation of 2-(alkenyloxy)naphthalene-1-carbaldehyde oximes with sodium hypochlorite and triethylamine afforded novel naphthopyranoisoxazolines. The former reaction is tentatively proposed to occur via activation of the alkene side chain by means of an iodonium intermediate and either 1,3-dipolar interaction with a nitrile oxide side-group or cyclization with a hydroximic acid iodide side-group.
2-(烯酰氧基)萘-1-甲醛肟经碘化钾、碘和碳酸氢钠氧化后直接生成新型萘并吡喃异恶唑。用次氯酸钠和三乙胺氧化 2-(3-氯烯氧基)萘-1-甲醛肟或 2-(炔氧基)萘-1-甲醛肟,也能制备出萘并吡喃异恶唑。用次氯酸钠和三乙胺氧化 2-(烯酰氧基)萘-1-甲醛肟可得到新型萘并异噁唑类化合物。据初步推测,前一种反应是通过碘中间体活化烯侧链,然后与氧化腈侧基发生 1,3 双极作用,或与羟肟酸碘化侧基发生环化作用而发生的。