An efficient, ligand-free, heterogeneous supported copper hydroxide catalyst for the synthesis of n,n-bicyclic pyrazolidinone derivatives.
An efficient, ligand-free, heterogeneous supported copper hydroxide catalyst for the synthesis of n,n-bicyclic pyrazolidinone derivatives.
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DOI：
10.1002/chem.201002793
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发表时间：
2011-03
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影响因子：
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通讯作者：
Kazuaki Yoshimura;T. Oishi;K. Yamaguchi;N. Mizuno
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文献类型：
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作者：
Kazuaki Yoshimura;T. Oishi;K. Yamaguchi;N. Mizuno
吡唑烷酮和吡唑啉酮杂环化合物的合成非常重要，因为它们被用作染料、颜料、药物和农用化学品。特别地，N，N-双环吡唑烷酮衍生物显示出非常重要的生物活性，并且已经作为杀虫剂、除草剂和b-内酰胺抗生素如青霉素和头孢菌素的类似物被广泛研究。由多恩和奥托于1968年首次报道的偶氮甲亚胺与炔的1，3-偶极环加成反应（类似于Huisgen 1，3-偶极环加成反应）是合成N，N-双环吡唑烷酮衍生物的最有用的方法之一，因为许多官能团在偶氮甲亚胺和炔的存在下保持完整。然而，在不对称取代的炔的情况下，这种非催化的环加成得到区域异构体的混合物;例如，当在反应式（1）中描述的条件下进行1-亚苄基-3-氧代-1-吡唑烷鎓-2-化物（Ia）与丙炔酸乙酯（2a）的热诱导环加成时，得到3aa和3aa '的区域异构体混合物。
The synthesis of pyrazolidinone and pyrazolone heterocycles is of great importance because they have been used as dyes, color pigments, pharmaceuticals, and agricultural chemicals. In particular, N,N-bicyclic pyrazolidinone derivatives show very important bioactivities and have been widely investigated as pesticides, herbicides, and analogues of b-lactam antibiotics such as penicillin and cephalosporin. The 1,3-dipolar cycloaddition of azomethine imines to alkynes (an analogous reaction to the Huisgen 1,3-dipolar cycloaddition), first reported by Dorn and Otto in 1968, is one of the most useful procedures for the synthesis of N,N-bicyclic pyrazolidinone derivatives because many functional groups remain intact in the presence of azomethine imines and alkynes. However, this uncatalyzed cycloaddition gives a mixture of regioisomers in the case of unsymmetrically substituted alkynes; for example, when the thermally induced cycloaddition of 1-benzylidene-3-oxo-1-pyrazolidinium-2-ide (1 a) to ethyl propiolate (2 a) was carried out under the conditions described in Equation (1), a regioisomeric mixture of 3 aa and 3 aa’ was obtained.