5676-57-3Relevant articles and documents
Amino Acids: Nontoxic and Cheap Alternatives for Amines for the Synthesis of Benzoxazoles through the Oxidative Functionalization of Catechols
Aberi, Mahdi,Aboonajmi, Jasem,Sharghi, Hashem,Shekouhy, Mohsen
, p. 1064 - 1083 (2020/01/24)
The nano magnetic Fe3O4 (NM?Fe3O4) was applied for the synthesis of benzoxazoles via a C(aryl)?OH functionalization of catechol derivatives and amines in ethanol at room temperature. In the next step, amino acids have been applied as nontoxic and cheap alternatives for amines. The obtained products were similar with the regular amines case. This is the first report about the application of amino acids as alternatives for primary amines in organic synthesis. Furthermore, the presented method was successfully applied toward the synthesis of desired products in large scales. (Figure presented.).
Pd-Catalyzed Cross-Coupling Reactions Promoted by Biaryl Phosphorinane Ligands
Laffoon, Joshua D.,Chan, Vincent S.,Fickes, Michael G.,Kotecki, Brian,Ickes, Andrew R.,Henle, Jeremy,Napolitano, José G.,Franczyk, Thaddeus S.,Dunn, Travis B.,Barnes, David M.,Haight, Anthony R.,Henry, Rodger F.,Shekhar, Shashank
, p. 11691 - 11708 (2019/12/02)
We report the use of biaryl phosphorinanes as ligands for Pd-catalyzed cross-coupling reactions. A modular synthesis was developed that employs a double conjugate addition of primary biaryl phosphines into 1,1,5,5-tetraalkyl penta-1,4-diene-3-ones. Notably, this synthesis does not require the use of copper, a known contaminant in structurally related biaryl phosphane ligands. Using the synthetic strategy described above, we synthesized a library of biaryl phosphorinanes, varying their substitution about phosphorus and the steric and electronic nature of the biaryl motif. We then benchmarked their performance as ligands in Pd-catalyzed cross coupling reactions such as aryl sulfonamidation, aryl alkoxylation, and aryl amination in the presence of soluble organic bases. In each reaction studied, many ligands outperformed biaryl phosphanes known to promote the given transformation. Detailed substrate scopes were determined using high-throughput screening technology. Several biaryl phosphorinanes and their corresponding Pd(II) oxidative-addition complexes were extensively characterized using NMR spectroscopy and X-ray crystallography. General observations support that biaryl phosphorinanes promote reductive elimination and form robust catalysts with palladium. In many cases the use of these biaryl phosphorinanes may be advantageous over the use of biaryl phosphanes with respect to lower catalyst loadings, shorter reaction times, and robustness.
Synthesis of benzoxazoles from 2-aminophenols and β-diketones using a combined catalyst of br?nsted acid and copper iodide
Mayo, Muhammad Shareef,Yu, Xiaoqiang,Zhou, Xiaoyu,Feng, Xiujuan,Yamamoto, Yoshinori,Bao, Ming
, p. 6310 - 6314 (2014/07/21)
Cyclization reactions of 2-aminophenols with β-diketones catalyzed by a combination of Br?nsted acid and CuI are presented. Various 2-substituted benzoxazoles were obtained through these reactions. Different substituents such as methyl, chloro, bromo, nitro, and methoxy on 2-aminophenol are tolerated under the optimized reaction conditions.