1223461-63-9Relevant academic research and scientific papers
Hetero-Diels-Alder Reactions of Quinone Methides: The Origin of the α-Regioselectivity of 3-Methylene-1,2,4-naphthotriones
Delarmelina, Maicon,Delarmelina, Maicon,Ferreira, Sabrina B.,Da Silva, Fernando De C.,Ferreira, Vitor F.,Ferreira, Vitor F.,Carneiro, José Walkimar De M.
, p. 7001 - 7013 (2020/07/07)
The regioselective formation of α-and β-lapachone via hetero-Diels-Alder reactions was investigated by experimental and computational approaches. The experimentally observed α-selectivity was explored in detail, revealing that the lower energy barrier for the formation of α-lapachone is a result of lower Pauli repulsion throughout the reaction path, when compared to the β-isomer. By comparing equivalent points on both α-and β-lapachone potential energy surfaces (PES), according to the activation strain model (ASM) and energy decomposition analysis (EDA), we were able to demonstrate that the Pauli repulsion term increases more significantly when going from reactants to TSβ than to TSα, resulting in lower interaction energy in the early stages of the reaction path and in a later transition state for β-lapachone. Moreover, we confirmed that regio-and diastereoselectivity trends previously reported for other quinone methide intermediates are also observed for 3-methylene-1,2,4-naphthotriones, such as small endo/exo diastereoselectivity, as well as pronounced ortho/meta regioselectivity for reactions performed with dienophile containing electron-releasing groups. The results presented here provide a deeper understanding of the reactivity of quinone methide derivatives, aiding the future rational design of the reaction condition, structural modification of possible quinone methide intermediates, and the development of more selective synthetic routes for quinone derivatives.
Synthesis and anti-Trypanosoma cruzi activity of β-lapachone analogues
Ferreira, Sabrina Baptista,Salom?o, Kelly,De Carvalho Da Silva, Fernando,Pinto, Ant?nio Ventura,Kaiser, Carlos Roland,Pinto, Angelo C.,Ferreira, Vitor Francisco,De Castro, Solange L.
experimental part, p. 3071 - 3077 (2011/06/27)
The available chemotherapy for Chagas disease, caused by Trypanosoma cruzi, is unsatisfactory; therefore, there is an intense effort to find new drugs for the treatment of this disease. In our laboratory, we have analyzed the effect on bloodstream trypoma
Synthesis of α- and β-pyran naphthoquinones as a new class of antitubercular agents
Ferreira, Sabrina B.,Da Silva, Fernando De Carvalho,Bezerra, Flavio A. F. M.,Lourenco, Maria C. S.,Kaiser, Carlos R.,Pinto, Angelo C.,Ferreira, Vitor F.
experimental part, p. 81 - 90 (2010/06/22)
A series of α- and β-pyran naphthoquinones (lapachones) have been synthesized and evaluated for their in-vitro antibacterial activity against Mycobacterium tuberculosis strain H37Rv (ATCC 27294) using the Alamar-Blue susceptibility test; the activity was expressed as the minimum inhibitory concentration (MIC) in μg/mL. The synthetic methodology consisted of the formation of methylene and aryl o-quinone methides (o-QMs) generated by Knoevenagel condensation of 2-hydroxy-1,4-naphthoquinone with formaldehyde and arylaldehydes. These o-QMs then undergo facile hetero Diels-Alder reactions with dienophiles in aqueous ethanol media. Some naphthoquinones exhibited inhibition with MIC values of 1.25 μg/mL, similar to that of pharmaceutical concentrations currently used in tuberculosis treatment. These results justify further research into the value of these quinones as part of an original treatment for tuberculosis.
