100784-99-4Relevant academic research and scientific papers
The Synthesis and Chemistry of Azolenines. Part 4. Preparation and Rearrangement of some 3,5-Diaryl-2H-pyrrole-2,2-dicarboxylic Esters
Sammes, Michael P.,Chung, Margaret W. L.,Katritzky, Alan R.
, p. 1773 - 1780 (2007/10/02)
Oxidation of diethyl 3,5-diaryl-3,4-dihydro-2H-pyrrole-2,2-dicarboxylates (3) with chloranil in refluxing xylene gives not the 3,5-diaryl-2H-pyrrole-2,2-dicarboxylates (4) as reported by an earlier group, but instead the rearranged, isomeric, 1H-pyrrole-1,2-dicarboxylates (5). 2H-Pyrroles (4) may be obtained from the dihydropyrroles (3) using DDQ in benzene at room temperature; they rearrange to the isomers (5) in boiling xylene via an acyl -sigmatropic shift from carbon to nitrogen, a novel process in the 2H-pyrrole series.Thermal analyses indicate that the rearrangement is concerted with negligible charge separation in the transition state.Other novel 3,5-diaryl-1H-pyrrole-2-carboxylic acid derivatives are described.
