Synthesis of acetamides via oxidative C–C bond cleavage of ketones catalyzed by Cu‐immobilized magnetic nanoparticles

Abstract

Copper supported on magnetite nanoparticles modified with environmentally friendly ligand tricine was devised for synthesis of acetamides via C–C oxidative cleavage of ketones with amines. The catalyst was characterized using different techniques, including Fourier transform infrared, X‐ray diffraction, scannin electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, and energy dispersive x‐ray spectroscopy. The protocol showed relatively high yields of acetamide products. Furthermore, the magnetic recovery of the catalyst rendered the overall process fast and efficient. It was used in the reaction for six consecutive cycles with negligible loss of catalytic activity. This research is the first report of application of magnetic nanocatalysts for synthesis of acetamides from ketones of low activity through a C–C bond cleavage strategy.

Ni(OH)2 nanoparticles as a recyclable catalyst in acceptorless dehydrogenation of alcohols to acids/acid salts under aerobic conditions

“…The reaction delivered benzoic acid in 10 % yield, which indicates that Ni(OH) 2 nanoparticles are serving as an active catalyst in this acceptorless dehydrogenation of alcohols to acids/acids salts. Besides, the heterogeneous nature of the catalyst was further examined by a hot–filtration test [28] . For this purpose, the reaction of benzyl alcohol with KOH in the presence of the catalyst was performed in optimized reaction conditions for 12 h, and thereafter resulting carboxylate salt (54 % benzoic acid was obtained after an acidic workup) and the solid catalyst was removed by filtration and the filtrate was transferred to another reaction vessel.…”

“…After 24 h, upon acidic workup, the reaction delivered a 86 % yield of benzoic acid (Table 1, entry 1). As we are aware, the nature and dosage of bases play a significant role in acceptorless dehydrogenation of alcohols to acids, [26,27,28,29] we initially emphasized on investigating the influence of different bases and their quantity on the reaction outcome. It was noticed that decreasing the amount of base has a detrimental impact on the reaction yield.…”

“…Although the yield of benzoic acid can be improved by employing a heterogeneous Pd/C catalyst, [24] it needs to carry out the reaction in reduced pressure to realize optimal yields of products and thus it provided an operational difficulty to perform the reaction. Moreover, the reaction can easily be carried out in the presence of catalytic systems such as ZnO, [26] in‐situ generated Ag nanoparticles, [29] magnetic Ag nanoparticles, [28] zeolite imidazolate framework‐8, Co‐clusters decorated with N‐doped carbon nanotube (Co/N‐CNTs), [27,33] palladium nanoparticles supported on NiO, [32] self‐supported Ru‐NHC single site catalyst [14k] in the presence of either NaOH or KOH base. Remarkably, a graphene‐supported Ru‐NHC catalytic system has been employed to synthesize a multitude of acids from corresponding alcohols in an aqueous basic medium [14l] .…”

“…Moreover, cumbersome synthetic protocols for the catalysts and the requirement of expensive ligands are serious drawbacks associated with these catalytic systems. Hence, to mitigate these issues, a few heterogeneous catalytic systems of Pd, [24] Rh, [25] Ru, [14k] Zn, [26] Co, [27,33] and in‐situ generated Ag nanoparticles [28,29] have been employed for the synthesis of acids from corresponding primary alcohols via an acceptorless dehydrogenation strategy. However, these catalytic protocols required either high catalyst loadings (20 mol % of Rh in Rh/C) or high temperature (164 °C), and an excess amount of base (up to 4 equivalents KOH) to achieve efficiency.…”