10.1016/j.tet.2018.03.048
The study focuses on the selective synthesis of 1,4,5-trisubstituted imidazoles from α-imino ketones, which are prepared through N-heterocyclic-carbene (NHC)-catalyzed aroylation of imidoyl chlorides with aromatic aldehydes. The research outlines a straightforward methodology that involves NHC-catalyzed aroylation, followed by chemoselective reduction of the imino group, and subsequent annulation with formamide to form the imidazole ring. This approach allows the rapid and regioselective synthesis of imidazole derivatives with potential applications in pharmaceuticals and agrochemicals. The study demonstrates the substrate scope and optimization of reaction conditions, highlighting the importance of this method in creating chemical libraries for further application.
10.1016/j.tetlet.2008.06.095
The research focuses on the development and application of a new amine borane complex, 5-ethyl-2-methylpyridine borane (PEMB), for reductive amination reactions of ketones and aldehydes. The study compares PEMB to other reagents like pyridine borane (PYB) and 2-picoline borane (PICB) in terms of efficiency, cost-effectiveness, and reaction conditions. The experiments involved using PEMB in various reductive amination reactions with different aldehyde or ketone/amine pairs, employing a 2:2:1 ratio for the carbonyl, amine, and PEMB, and in some cases, without solvent to increase volume productivity and reduce waste. The reactions were typically carried out at ambient temperature, with some requiring heating to increase the rate. The study analyzed the yields and reaction times of these processes, finding that PEMB was highly effective, selective, and faster than PICB in solvent-less conditions. The analyses used included gas chromatography (GC) to determine yields and nuclear magnetic resonance (NMR) to characterize the products.
