Cascade synthesis of indolizines and pyrrolo[1,2-<i>a</i>]pyrazines from 2-formyl-1-propargylpyrroles
作者:Carlos H. Escalante、Fernando A. Carmona-Hernández、Alberto Hernández-López、Eder I. Martínez-Mora、Francisco Delgado、Joaquín Tamariz
DOI:10.1039/d1ob01839f
日期:——
condensation/cyclization/aromatization reaction of substituted 2-formyl-N-propargylpyrroles with active methylene compounds such as nitromethane, alkyl malonates, methyl cyanoacetate and malononitrile. Under basic conditions, the reaction proceeded satisfactorily to provide the corresponding 6,7-disubstituted indolizines. The condensation of the pyrrolic analogues with ammonium acetate gave rise to pyrrolo[1,2-a]pyrazines
通过取代的 2-甲酰基-N-炔丙基吡咯与活性亚甲基化合物(如硝基甲烷、丙二酸烷基酯、氰基乙酸甲酯和丙二腈)的级联缩合/环化/芳构化反应,直接合成中氮茚和吡咯并[1,2- a ]吡嗪. 在碱性条件下,反应顺利进行,得到相应的6,7-二取代中氮茚。吡咯类似物与乙酸铵的缩合产生高产率的吡咯并[1,2- a ]吡嗪。N -Allenyl-2-formylpyrroles 作为比 2-formyl-N 更具反应性的底物-炔丙基吡咯,以更高的产量提供预期的中氮茚。因此,在环化反应之前,在一些N-炔丙基吡咯的反应机理中,可能生成了一种含有丙二烯基的中间体作为反应性物质。
The gold-catalyzed reaction of pyrrole and indole oximes having a propargylgroup attached to the nitrogen atom was studied. The selective 6-endo-dig mode of cyclization was observed for the terminal alkynes giving rise to the formation of pyrazine N-oxides in the presence of a gold catalyst. However, the reaction with substituted alkyne transferred the oxime functionality intramolecularly from one
Synthesis of Pyrrole-Fused <i>C</i>,<i>N</i>-Cyclic Azomethine Imines and Pyrazolopyrrolopyrazines: Analysis of Their Aromaticity Using Nucleus-Independent Chemical Shifts Values
derivative with various dipolarophiles resulted in the formation of cycloadducts having a pyrazolopyrrolopyrazine skeleton. The aromaticity of C,N-cyclic azomethine imines as well as that of pyrazolopyrrolopyrazines was determined by calculating of nucleus-independent chemical shifts values.
domino synthesis of pyrrolopiperazine fused with oxazine/imidazole by the reaction of pyrrole-derived δ-alkynyl aldehydes and nucleophilic amines was performed. This domino strategy involves the formation of two new C–N bonds and one C–O/C–N bond, resulting in the formation of two new interesting fused heterocycles. Some of the synthesized compounds exhibit promising growth inhibitory activity against
An Efficient One-Pot Synthesis of Novel Fused Pyrroles and Indoles by Dipolar Cycloaddition under Microwave and Conventional Conditions
作者:George Bashiardes、Imad Safir、Francis Barbot
DOI:10.1055/s-2007-982559
日期:2007.7
The straightforward synthesis of families of novel tri-cyclic and tetracyclic pyrrolino and indolino heterocycles in a one-pot [3+2]-cycloaddition reaction is described. The process enables the synthesis of diversified pyrroles or pyrrolines in high yields in a single step. Microwave and conventional thermal conditions were explored, with remarkable acceleration observed under the microwave conditions