作者:Ke-Lai Li、Zong-Bo Du、Can-Cheng Guo、Qing-Yun Chen
DOI:10.1021/jo900267c
日期:2009.5.1
o-Acetaminophenols (2) reacted with Vilsmeier reagent under Meth-Cohn conditions to yield 2-formylpyrido[2,1-b]benzoxazoles (5) unexpectedly besides the known compounds 2-(benzoxazol-2′-yl)-3-dimethylaminoacroleins (4). Refluxing 4 in acetic anhydride gave 4-formylpyrido[2,1-b]benzoxazoles (6), an isomer of 5. Both 5a and 6a were structurally characterized by X-ray crystallography. A mechanism for
在已知的化合物2-(苯并恶唑-2'-基)-3-二甲基氨基丙烯醛中,邻乙酰氨基酚(2)与Vilsmeier试剂在Meth-Cohn条件下反应生成2-甲酰基吡啶并[2,1- b ]苯并恶唑(5) (4)。在乙酸酐中回流4得到4-甲酰基吡啶并[2,1- b ]苯并恶唑(6),其为5的异构体。两个图5a和6a中进行了结构表征通过X射线晶体学。5的形成机理 提出了包括顺序氯化,二聚化,分子内去除HCl形成恶唑环,两次甲酰化以及区域选择性分子内亲核环化以构建吡啶酮环的方法。