Acidic porous carbons involved in the green and selective synthesis of benzodiazepines

• Published in: Catalysis today Vol. 357; no. C; pp. 64 - 73
• Main Authors: Godino-Ojer, M., Matos, I., Bernardo, M., Carvalho, R., G.P. Soares, Olívia Salomé, Durán-Valle, C., Fonseca, I.M., Mayoral, E. Pérez
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2020; Elsevier
• Subjects: Activated carbons; Benzodiazepines; Heterocyclic chemistry; Heterogeneous catalytic systems; Heterogeneous catalytic systems; Heterocyclic chemistry; Activated carbons; Benzodiazepines
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2019.11.027

[Display omitted] •Acidic porous carbon efficiently catalyzes the synthesis of benzodiazepine 1.•Acid strength and porosity are key factors controlling the catalytic performance.•Total selectivity is observed by combining −SO3H functions and microporosity in sulfonated carbon catalyst. 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.