α-异氰基丙酸乙酯 (I) 热环化生成 5-乙氧基-4-甲基恶唑 (II) 作为合成吡哆醇的中间体。也进行了几种新的α-异氰基羧酸烷基酯与相应的5-烷氧基-4-取代的恶唑的类似反应。研究了I的热环化反应产物。180℃环化5小时,主产物II的最大收率为20%;还得到了未反应的 I (30%)、α-氰基丙酸乙酯 (20%) 和 I 的二聚体 (5%)。α-异氰基琥珀酸乙酯 (X) 的 α-氢比 I 更容易去除,因此可以预期 X 更容易转化为 5-乙氧基-4-乙氧基羰基甲基恶唑 (XI),它也是吡哆醇。
Intramolecular Imidoylative Heck Reaction: Synthesis of Cyclic Ketoimines from Functionalized Isocyanide
作者:Jian Wang、Shi Tang、Qiang Zhu
DOI:10.1021/acs.orglett.6b01174
日期:2016.7.1
Efficient access to five- to seven-membered cyclic ketoimines, through palladium-catalyzed intramolecular imidoylative Heckreaction of alkene-containing isocyanides, has been developed. Consecutive isocyanide and alkene insertion into aryl or alkyl Pd(II) intermediates takes place in this process. No byproduct derived from monoinsertion or reversed sequence is detected.
Synthesis of Tetrazole-Derived Organocatalysts via Azido-Ugi Reaction with Cyclic Ketimines
作者:Olga I. Shmatova、Valentine G. Nenajdenko
DOI:10.1021/jo401428q
日期:2013.9.20
A newroute to tetrazole-derived cyclic amines based on the TMSN3-modified Ugi reaction with 2-substituted cyclic imines was elaborated. The reaction allows the direct preparation of five-, six-, and seven-membered cyclic amines substituted with a tetrazole ring, which are important types of organocatalysts. The scope and limitations of this method are discussed. In the case of the Ugi reaction with
Tetrazole-Substituted Five, Six, and Seven-Membered Cyclic Amines Bearing Perfluoroalkyl Groups - Efficient Synthesis by Azido-Ugi Reaction
作者:Olga I. Shmatova、Valentine G. Nenajdenko
DOI:10.1002/ejoc.201300861
日期:2013.10
azido-Ugi reactions was studied. It was shown that the reaction allows access to five-, six- and seven-membered perfluoroalkylated cyclic amines connected to a tetrazole ring. The scope and limitations of this approach are discussed. When benzyl isocyanide was used in the azido-Ugi reaction, it was shown that the tetrazole products could easily be debenzylated by catalytic hydrogenation to form 1H-tetrazoles