6587-24-2Relevant articles and documents
Visible-Light-Promoted Metal-Free Synthesis of (Hetero)Aromatic Nitriles from C(sp3)?H Bonds**
Murugesan, Kathiravan,Donabauer, Karsten,K?nig, Burkhard
supporting information, p. 2439 - 2445 (2020/12/07)
The metal-free activation of C(sp3)?H bonds to value-added products is of paramount importance in organic synthesis. We report the use of the commercially available organic dye 2,4,6-triphenylpyrylium tetrafluoroborate (TPP) for the conversion of methylarenes to the corresponding aryl nitriles via a photocatalytic process. Applying this methodology, a variety of cyanobenzenes have been synthesized in good to excellent yield under metal- and cyanide-free conditions. We demonstrate the scope of the method with over 50 examples including late-stage functionalization of drug molecules (celecoxib) and complex structures such as l-menthol, amino acids, and cholesterol derivatives. Furthermore, the presented synthetic protocol is applicable for gram-scale reactions. In addition to methylarenes, selected examples for the cyanation of aldehydes, alcohols and oximes are demonstrated as well. Detailed mechanistic investigations have been carried out using time-resolved luminescence quenching studies, control experiments, and NMR spectroscopy as well as kinetic studies, all supporting the proposed catalytic cycle.
Ligand-Promoted Non-Directed C?H Cyanation of Arenes
Liu, Luo-Yan,Yeung, Kap-Sun,Yu, Jin-Quan
supporting information, p. 2199 - 2202 (2019/01/24)
This article reports the first example of a 2-pyridone accelerated non-directed C?H cyanation with an arene as the limiting reagent. This protocol is compatible with a broad scope of arenes, including advanced intermediates, drug molecules, and natural products. A kinetic isotope experiment (kH/kD=4.40) indicates that the C?H bond cleavage is the rate-limiting step. Also, the reaction is readily scalable, further showcasing the synthetic utility of this method.
Methyl esters of 2-(N-hydroxycarbamimidoyl)benzoyl-substituted α-amino acids as promising building blocks in peptidomimetic synthesis: a comparative study
Tkachuk, Volodymyr A.,Hordiyenko, Olga V.,Omelchenko, Irina V.,Medviediev, Volodomir V.,Arrault, Axelle
, p. 2293 - 2309 (2018/11/02)
Abstract: An efficient and simple synthetic protocol for the synthesis of a number methyl esters of 2-(N-hydroxycarbamimidoyl)benzoyl-substituted (S)-α-amino acids via subsequent coupling and hydroxyamination of 2-cyanobenzamide derivatives has been developed. Comparative analysis of three pseudopeptide series based on 2-cyano- and 2-amidoxime-substituted benzoic acid and its pyridine and pyrazine counterparts has been provided and it has revealed a practical advantage of the benzoic acid derivatives due to their greater availability. The impact of the nitrogen atom in the aromatic ring on the trans/cis-amide equilibrium in the proline derivatives is discussed. Graphical abstract: [Figure not available: see fulltext.]
