Reaction of pyrylium salts with nucleophiles. Part 25. Formation of pyridine-1-oxides, 2-isoxazolines and 1-pyrazoline-1-oxides
作者:Cornelia Uncuta、Miron Teodor Cǎproiu、Valentin Câmpeanu、Aurica Petride、Mariana G Dǎnilǎ、Marieta Plǎveti、Alexandru T Balaban
DOI:10.1016/s0040-4020(98)00530-4
日期:1998.8
The reaction of tri- and tetrasubstituted pyrylium salts with hydroxylamine affords acyclic keto-ketoximes (to be described in a separate paper) which cyclize yielding pyridine-1-oxides and/or 2-isoxazolines. Both these classes of compounds, with many possible applications, can thus be obtained simply and in good yield. The regioselectivity of 2-isoxazoline formation from unsymetrically substituted
三和四取代的吡啶鎓盐与羟胺的反应提供了无环酮-酮肟(将在另一篇论文中进行描述),其环化生成吡啶-1-氧化物和/或2-异恶唑啉。因此,这两种类型的化合物都有许多可能的应用,可以简单地以高收率获得。讨论了由不对称取代的吡啶鎓盐形成的2-异恶唑啉的区域选择性。前所未有的次要产物从形成2,6-二-吨丁基-4- methylpyrylium高氯酸盐和羟胺的两个分子是相应的1-吡唑啉-1-氧化物。提供了所有产品的机械合理性。