Solvent‐free synthesis of propargylamines via A³ coupling reaction and organic pollutant degradation in aqueous condition using Cu/C catalyst

Abstract

The present report focuses on the efficient and operationally simple synthesis of biomass‐derived carbon as support to immobilize copper particles as a catalyst for the one‐pot synthesis of propargylamines from furfural via the A3 coupling reaction. This new catalyst showed remarkable catalytic performance leading to a 97% yield within 5 h at 80 °C using 5 mg (0.0022 mmol Cu) of Cu/C catalyst under solvent‐free condition. Moreover, nitro‐substituted compounds such as 4‐nitrophenol (4‐NP) are highly toxic and not easily degradable. Hence, a quick and effective method is required to neutralize these toxic compounds. The synthesized active support Cu/C catalyst having various electron‐donating groups containing small amounts of Cu plays an essential role in the catalytic reduction of 4‐NP (0.1 g). Using only 3 mg (0.0013 mmol Cu) of Cu/C catalyst and NaBH4 (10 mmol), a 99% yield (100% selectivity) in the aqueous condition at 25 °C was achieved. The catalytic reduction follows the pseudo‐first‐order kinetics with reaction rate constant of 0.028 s−1. Moreover, results demonstrate that the Cu/C catalyst has superior catalytic activity due to the presence of electron‐donating molecules such as O, S, and N atoms, which enable synergistic effect in enhancing the overall catalytic performance. Notably, the recoverability and recyclability of the synthesized catalyst were evaluated for up to four cycles, which confirmed its stability in these cycles.

CuCl2‐Catalyzed one‐step protocol for the synthesis of novel propargylamine analogs under ultrasound irradiation

“…All synthesized compounds except product 4 q are new. Compound 4 q was reported with Cu/C catalyst in 5 h with a 91 % yield, [41] while in the present work derivative 4 q was obtained in 4.5 h with 86 % yield under reflux conditions and in 15 minutes with 97 % yield under ultrasonic conditions (Table 4).…”

α-Tertiary Propargylamine Synthesis via KA2-Type Coupling Reactions under Solvent-Free CuI-Zeolite Catalysis

“…Even though anilines are known to undergo A 3 coupling reactions, no successful example has so far been reported for KA 2 reactions since anilines generally led to complex reaction mixtures. Therefore, we looked at the suitability of anilines as coupling partners under our conditions.…”

Exploring amine-rich supramolecular silver(i) metallogels for autonomous self-healing and as catalysts for a three component coupling reaction

“…A three-component reaction, namely A 3 coupling, of an aldehyde, a terminal acetylene and an amine leading to propargylamines is an atom-and step-economic transformation. [37][38][39][40][41][42] Although gold-and silver-based homogeneous catalysts display outstanding performance, they are expensive and not reusable. 37,38,41 Recently, a few polymer-and/or other functional material-supported copper catalysts have been reported to be heterogeneous and recyclable catalysts for three component coupling.…”

“…37,38,41 Recently, a few polymer-and/or other functional material-supported copper catalysts have been reported to be heterogeneous and recyclable catalysts for three component coupling. 39,40,42 However, the tedious multistep synthesis of the requisite catalyst supports often restricts their large-scale applications. In order to explore a simple, efficient and powerful strategy using recyclable multifunctional catalysts, we investigated the catalytic application of the synthesized AgGel1-AgGel3 by studying the three-component coupling of benzaldehyde (1a), morpholine (2a) and phenylacetylene (3a) to form propargylamine (4a) in DMSO.…”