Fe₃O₄@SiO₂‐CeCl₃ Catalyzed Chemoselective Synthesis of Functionalized 3‐Substituted‐1,5‐Benzodiazepines via One‐pot Multicomponent and Domino Reactions

Abstract

Fe 3 O 4 @SiO 2-CeCl 3 catalyzed chemoselective synthesis of functionalized 3-substituted-1,5-benzodiazepines via one-pot multicomponent and domino reactions has been developed. During the one-pot synthesis process, one new cycle and four new bonds (one CC , two C-N and one C=C) were constructed by the nucleophilic addition and eliminate reaction (dehydration etc.) process, intramolecular proton transfer and cyclization process. The major advantages of the present method are good to excellent yields, shorter reaction time, simple experimental procedure, easy work up, mild reaction conditions, recyclability of the catalyst and ability to tolerate a variety of functional groups which gives economical as well as ecological rewards. K E Y W O R D S 3-substituted-1,5-benzodiazepines, catalysis, domino reaction, Fe 3 O 4 @SiO 2-CeCl 3 , one-pot multicomponent

Supported Metal Catalysts for the Synthesis of N-Heterocycles

“…In particular, in the context of the preparation of nitrogen-based heterocycles, very few works have been reported, and only very recently. In 2020, Wang et al described the preparation of a cerium(III) chloride catalyst supported on silica-coated magnetite nanoparticles (indicated as Fe 3 O 4 @SiO 2 -CeCl 3 ) by a rather simple, cost-effective and environmentally friendly procedure (Scheme 46); such material was then applied as a recoverable catalyst in a one-pot, three-component protocol and in a domino process for the synthesis of 3-substituted-1,5-benzodiazepines [116]. In the same year, Maleki and co-workers instead reported the preparation of a nickel catalyst supported on magnetic bentonite clay, obtained by introducing ferrite nanoparticles inside the porous structure of the mineral, which was then tested in the three-component condensation reaction of aldehydes, benzyl and ammonium acetate for the synthesis of imidazoles, performed at 80 • C in ethanol as the solvent and under ultrasound sonication [117].…”

“…material was then applied as a recoverable catalyst in a one-pot, three-component protocol and in a domino process for the synthesis of 3-substituted-1,5-benzodiazepines [116]. In the same year, Maleki and co-workers instead reported the preparation of a nickel catalyst supported on magnetic bentonite clay, obtained by introducing ferrite nanoparticles inside the porous structure of the mineral, which was then tested in the three-component condensation reaction of aldehydes, benzyl and ammonium acetate for the synthesis of imidazoles, performed at 80 °C in ethanol as the solvent and under ultrasound sonication [117].…”

NiFe2O4@SiO2@PrNH2–DPA–CeCl3: a cerium-based magnetic nano dual-acid catalyst with high efficacy and recyclability for domino sequential synthesis of lactam ring-fused 1,5-benzodiazepines

“…In 2020, Zolfigol et al published a magnetic nano single-acid catalyst Fe 3 O 4 @SiO 2 @(CH 2 ) 3 -NH(CH 2 ) 2 O 2 P(OH) 2 , and a series of benzo-[h]quinoline-4carboxylic acids were further catalytically synthesized. 51 Herein, our research team expresses unremitting interest in environment-friendly synthetic strategies; 52 in this protocol, a novel magnetic nano dual-acid catalyst (NiFe 2 -O 4 @SiO 2 @PrNH 2 -DPA-CeCl 3 ) was developed for the synthesis of aryl/carboxyl-substituted 1,5-benzodiazepines with a lactam structure. The catalyst doesn't use traditional Fe 3 O 4 as magnetic core and prepares a novel NiFe 2 O 4 magnetic core with analogously remarkable performance.…”

“…Herein, our research team expresses unremitting interest in environment-friendly synthetic strategies; 52 in this protocol, a novel magnetic nano dual-acid catalyst (NiFe 2 O 4 @SiO 2 @PrNH 2 –DPA–CeCl 3 ) was developed for the synthesis of aryl/carboxyl-substituted 1,5-benzodiazepines with a lactam structure. The catalyst doesn't use traditional Fe 3 O 4 as magnetic core and prepares a novel NiFe 2 O 4 magnetic core with analogously remarkable performance.…”