Examinando por Autor "Matos, Ines"

Mostrando 1 - 2 de 2
  • Miniatura
    Publicación
    Acidic porous carbons involved in the green and selective synthesis of benzodiazepines
    (Elsevier, 2020-11-01) Godino Ojer, Marina; Matos, Ines; Bernardo, M.; Carvalho, R.; G.P. Soares, Olívia Salomé; Durán Valle, C.; Fonseca, I.M.; Pérez Mayoral, María Elena
    Eco-sustainable and recyclable porous carbons are reported as metal-free catalysts for the synthesis of benzodiazepines for the first time. The porous carbons were able to efficiently catalyse the synthesis of benzodiazepine 1 from o-phenylendiamine 2 and acetone 3 under mild conditions. Both acidic functions and the porosity of the catalysts were determinant features. High conversion values were obtained when using HNO3 oxidized carbons. The highest selectivity to benzodiazepine 1 was obtained in the presence of the most microporous catalyst N-N, which is indicative of the great influence of porous properties. Stronger acid sites and high microporosity of the carbon treated with H2SO4 yield benzodiazepine 1 with total selectivity.
  • Miniatura
    Publicación
    Porous carbons-derived from vegetal biomass in the synthesis of quinoxalines. Mechanistic insights
    (Elsevier, 2020-09-01) Godino Ojer, Marina; Blazquez García, R.; Matos, Ines; Bernardo, M.; Fonseca I.M.; Pérez Mayoral, María Elena
    We report herein for the first-time acid biomass-derived carbons from vegetal biomass, with high developed porosity, prepared through integrating method comprising pyrolysis and surface phosphonation, able to efficiently catalyze the synthesis of quinoxalines from 1,2-diamines and α-hydroxi ketones, under aerobic conditions. The obtained results indicate that the reaction is mainly driven by a combination of acid function strength and textural properties in terms of conversion and selectivity. Furthermore, our experimental and theoretical observations suggest that the preferred reaction pathway for this transformation, in the presence of the investigated acid carbon catalysts, involves cascade reactions including imination reaction between reactants, successive imine-enamine and keto-enol tautomerisms, heterocyclization followed by dehydration, and aromatization. While the acid sites seem to be a relevant role in each reaction step, the system formed by activated carbon and molecular oxygen could be behind the last oxidative reaction to give the corresponding nitrogen heterocycles.