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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Charge Tags for Most Comprehensive ESI-MS Monitoring of Morita-Baylis-Hillman (MBH)/aza-MBH Reactions: Solid Mechanistic View and the Dualistic Role of the Charge Tagged Acrylate

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Autor(es):
Galaverna, Renan [1] ; Camilo, Nilton S. [2] ; Godoi, Marla N. [3] ; Coelho, Fernando [2] ; Eberlin, Marcos N. [1]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Campinas UNICAMP, ThoMSon Mass Spectrometry Lab, Inst Chem, POB 6154, BR-13083970 Campinas, SP - Brazil
[2] Univ Campinas UNICAMP, Lab Synth Nat Prod & Drugs, Inst Chem, POB 6154, BR-13083970 Campinas, SP - Brazil
[3] Hlth Sci Fed Univ Porto Alegre UFCSPA, Dept Pharmacosci Sarmento Leite, BR-90050170 Porto Alegre, RS - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: Journal of Organic Chemistry; v. 81, n. 3, p. 1089-1098, FEB 5 2016.
Citações Web of Science: 8
Resumo

Neutral and charge tagged reagents were used to investigate the mechanism of the classical Morita-Baylis-Hillman (MBH) reaction as well as its aza-version using mass spectrometry with electrospray ionization (ESI-MS). The use of an acrylate (activated alkene) with a methylimidazolium ion as a charge tag eliminates the requirement for adding acids as ESI(+) additives, which are normally used to favor protonation and therefore detection of reaction partners (reagents, intermediates, and products) by ESI(+)-MS. For both charge tagged reactions (MBH/aza-MBH), most reactants, intermediates, and the final adducts were efficiently detected in the form of abundant doubly and singly charged ions. Characterization of the reactions partners was performed-via both tandem mass spectrometry (ESI(+)-MS/MS) and accurate m/z measurements. The charge tagged reactions also showed faster conversion rates when compare to the neutral reaction, indicating a dualistic role for the charge tagged acrylate. It acts as both the reagent and a cocatalyst due to the inherent ionic-coordination nature of the methylimidazolium ion, which stabilizes the zwitterionic intermediates and reagents through different types of coordination ion pairs. Hemiacetal intermediates for the rate-limiting proton transfer step were also intercepted and characterized for both classical and aza-MBH charge tagged reactions. (AU)

Processo FAPESP: 13/10449-5 - Adutos de Morita-Baylis-Hillman como blocos de contrução eficientes para a síntese de moléculas de interesse biológico
Beneficiário:Fernando Antonio Santos Coelho
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 12/10701-3 - Novas abordagens mecanísticas da reação de Morita-Baylis-Hillman (AZA, clássica e assimétrica) por espectrometria de massas
Beneficiário:Renan de Souza Galaverna
Linha de fomento: Bolsas no Brasil - Mestrado