Ultrasound‐Assisted Preparation of Copper(I) Oxide Nanocubes: High Catalytic Activity in the Synthesis of Quinazolines

Abstract

A facile and green ultrasound‐assisted synthesis of Cu2O nanocubes at room temperature is presented. The Cu2O nanocubes were characterized using XRD, SEM, TEM, energy‐dispersive X‐ray spectroscopy, UV/Vis spectroscopy, differential scanning calorimetry with thermogravimetric analysis, and FTIR spectroscopy. The Cu2O nanocubes were employed as a heterogeneous nanocatalyst and were found to be highly active in the preparation of quinazolines by the tandem cyclization of 2‐bromobenzaldehydes with amidines under ligand‐free conditions. Various quinazolines could be prepared in excellent yields within a very short reaction time. Furthermore, the Cu2O nanocatalyst could be recycled and reused up to four times without any significant loss of catalytic activity.

Chemical Insights Into the Synthetic Chemistry of Quinazolines: Recent Advances

“…Numerous quinazoline derivatives 20 could be synthesized in excellent isolated yields within a few minutes. Additionally, the cuprous oxide nanocatalytic system could be regenerated and recycled up to four times without any important loss of catalytic potency (Raut et al, 2017 ). Along the same line, Wang et al developed an effective one-pot procedure for the region-selective formation of functionalized quinazoline analogous 86 by using diaryl-λ 3 -iodanes 84 and nitriles 85 in the presence of cupric acetate and potassium tert -butoxide in dimethyl sulfoxide at 120°C (Wang et al, 2013 ).…”

Modern Development in Copper‐ and Nickel‐Catalyzed Cross‐Coupling Reactions: Formation of Carbon‐Carbon and Carbon‐Heteroatom bonds under Microwave Irradiation Conditions

“…[111] Derivatives of quinazolinone are valuable heterocyclic compounds originated in numerous natural and synthetic products with substantial biological or medicinal activities. During the last few years, several synthetic methods have been developed starting from 2-halobenzaldehydes, [112] 2halobenzamides [113] or 2-halobenzoic acids [114] in cascade reaction using copper catalyst and microwave-assisted conditions. For instance, the coupling reaction between 2-halobenzoic acids and guanidine hydrochloride using 10 mol % of Cu 2 O in DMF at 120 °C for 20 min, achieved moderate to high yields of quinazolinones, including new derivatives functionalized with fluorophores, nucleobases and hydrophobic chain.…”

Recent Advances in Metal-Nanoparticle-Catalyzed Coupling Reactions Assisted by Microwave Irradiation

“…Scheme 2 Pd-NiO/zeolite-NaY-catalyzed Suzuki-Miyaura coupling Bhanage et al achieved a facile synthesis of Cu 2 O nanocubes, which were used as a heterogeneous nanocatalyst for the synthesis of quinazolines. 11 The sequential reaction using 2-bromobenzaldehydes and amidines with Cu 2 O nanocubes in ethylene glycol as the solvent under microwave irradiation afforded various quinazolines in 81-96% yields (Scheme 3).…”