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The Three‐Component Biginelli Reaction: A Combined Experimental and Theoretical Mechanistic Investigation |
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| Authors: | Rodrigo O. M. A. De Souza Prof. Dr. Eduardo T. da Penha Humberto M. S. Milagre Prof. Dr. Simon J. Garden Pierre M. Esteves Marcos N. Eberlin Prof. Dr. Octavio A. C. Antunes |
| Affiliation: | 1. Institute of Chemistry, Federal University of Rio de Janeiro, Cidade Universitária CT bloco A, RJ 21941‐909 (Brazil), Fax: (+55)?21‐2562‐7559;2. Department of Biochemistry and Microbiology, S?o Poulo State University, 13506‐900, Rio‐Claro SP (Brazil);3. ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, State University of Campinas—UNICAMP, 13084‐971, Campinas SP (Brazil) |
| Abstract: | Biginelli reactions have been monitored by direct infusion electrospray ionization mass spectrometry (ESI‐MS) and key cationic intermediates involved in this three‐component reaction have been intercepted and further characterized by tandem MS experiments (ESI‐MS/MS). Density functional theory calculations were also used to investigate the feasibility of the major competing mechanisms proposed for the Biginelli reaction. The experimental and theoretical results were found to corroborate the iminium mechanism proposed by Folkers and Johnson, whereas no intermediates directly associated with either the more energy demanding Knoevenagel or enamine mechanisms could be intercepted. |
| Keywords: | Biginelli reaction density functional calculations electrospray mass spectrometry heterocyclic compounds reaction mechanisms |