2940-19-4Relevant academic research and scientific papers
NIS-TBHP promoted oxidative coupling of C–N and C–O bonds: A metal-free approach to polysubstituted oxazoles
Li, Fei,Liu, Xiaolan,Yang, Shengxiang,Yang, Yuzhu
supporting information, (2020/04/08)
A metal-free approach to polysubstituted oxazoles via the oxidative coupling of readily available benzylamines and 1,3-dicarbonyl derivatives in the presence of an external base has been developed. A variety of functional groups on both of the starting materials are tolerated using this method, affording the corresponding oxazoles in moderate to good yields. Iodination was proposed as the initiation step of the reaction and a plausible mechanism has been proposed to explain the reaction pathway.
Practical Deoxygenation of Oxazole N-Oxides by PCl 3/Collidine
Shirinian, Valerii Z.,Lonshakov, Ilya A.,Zakharov, Alexey V.,Lvov, Andrey G.,Krayushkin, Mikhail M.
, p. 414 - 420 (2019/01/10)
A new chemoselective method for the synthesis of 2-aryl-1,3-oxazoles by deoxygenation of the corresponding N-oxides has been developed. As the deoxygenation reagent, a previously unknown complex of collidine with phosphorus trichloride in a 2:1 ratio has
A Highly Efficient Heterogeneous Copper-Catalyzed Oxidative Cyclization of Benzylamines and 1,3-Dicarbonyl Compounds to Give Trisubstituted Oxazoles
Cai, Mingzhong,Tuo, Yuxin,Wei, Li,You, Shengyong
, p. 3091 - 3100 (2019/08/07)
The heterogeneous copper-catalyzed cascade oxidative cyclization between benzylamines and 1,3-dicarbonyl compounds was achieved by using the 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized copper(II) complex [MCM-41-2N-Cu(OAc) 2 ] as catalyst and t -BuOOH (TBHP) as oxidant, with iodine as additive, under mild conditions, yielding a wide variety of 2,4,5-trisubstituted oxazoles in mostly good to excellent yields. This heterogeneous copper catalyst can be facilely prepared via a simple two-step procedure from readily available and inexpensive reagents and exhibits a slightly higher activity than Cu(OAc) 2. MCM-41-2N-Cu(OAc) 2 is also easy to recover and can be recycled up to eight times with almost consistent activity. The reaction is the first example of heterogeneous copper-catalyzed intermolecular cyclization for the construction of polysubstituted oxazoles.
Convenient route to trisubstituted oxazoles via a copper-catalysed tandem oxidative cyclisation by oxygen oxidation
Chen, Chengqun,Chen, Wenfu,Bao, Qianhong
, p. 7 - 10 (2015/02/05)
A novel copper-catalysed oxidative cyclisation has been developed for the synthesis of trisubstituted oxazoles, which is thought to proceed through cascade formation of C-N and C-O bonds by oxygen oxidation. The desired products can be obtained from readily available starting materials while avoiding hazardous materials. Therefore, a green synthetic method for the preparation of oxazoles has been found.
Synthesis and spectral properties of 3-(2-aryl-5-methyl-1,3-oxazol- 4-yl)-2-(2,5-dimethylthiophen-3-yl)cyclopent-2-en-1-ones
Lvov, Andrey G.,Shirinian, Valerii Z.,Kavun, Alexey M.,Krayushkin, Mikhail M.
supporting information, p. 277 - 279 (2015/01/16)
Alkylation of ethyl 4-(2,5-dimethylthiophen-3-yl)-3-oxobutanoate with 2-aryl-4-bromoacetyl-5-methyl-1,3-oxazole followed by decar-boxylation-cyclization of the intermediate diketo ester affords the title photochromic compounds. Relationship between the fl
Electrochemically promoted synthesis of polysubstituted oxazoles from β-diketone derivatives and benzylamines under mild conditions
Yuan, Gaoqing,Zhu, Zechen,Gao, Xiaofang,Jiang, Huanfeng
, p. 24300 - 24303 (2014/06/24)
An efficient electrochemical synthesis of poly-substituted oxazoles from readily available β-diketone derivatives and benzylamines is described. This electrochemical procedure does not need hazardous oxidants and transition metal catalysts as well as molecular I2 additives. Compared with the traditional thermo-chemical method, the present electrochemical method is greener and more efficient. The Royal Society of Chemistry 2014.
Iridium-catalyzed H/D exchange: Ligand complexes with improved efficiency and scope
Parmentier, Michael,Hartung, Thomas,Pfaltz, Andreas,Muri, Dieter
, p. 11496 - 11504 (2014/11/27)
Hydrogen isotope exchange (HIE) is one of the most attractive tools for the introduction of deuterium or tritium to an organic compound. Herein, iridium complexes with N,P-ligands, highly active catalysts for asymmetric double bond reductions, have been tested for their HIE capabilities. Electron-rich ligands, containing dicyclohexylphosphines or phosphinites, have been identified as excellent ligands for efficient deuterium incorporation. Substrates with strong directing groups, that is, pyridines, ketones, and amides, as well as weak ligating units, such as, nitro, sulfones, and sulfonamides, could be labeled efficiently. With the addition of tris(pentafluorophenyl) borane to the reaction mixture, also highly deactivating nitrile substituents were well tolerated in the reaction. Based on the excellent results obtained with the chiral ThrePhox ligand, a structurally simpler, achiral ligand was developed. The iridium complex containing this ligand, proved to be a powerful catalyst for HIE reactions. Uses beyond asymmetric catalysis: Iridium complexes with a wide variety of N,P-ligands were explored in hydrogen isotope exchange reactions (see scheme; pyr.=pyridine). Complexes with electron-rich ligands were found to be highly reactive, leading to efficient deuterium incorporation even in compounds bearing only weakly coordinating directing groups.
Metal-free, organocatalytic cascade formation of C-N and C-O bonds through dual sp3 C-H activation: Oxidative synthesis of oxazole derivatives
Xie, Jin,Jiang, Honglai,Cheng, Yixiang,Zhu, Chengjian
supporting information; experimental part, p. 979 - 981 (2012/02/04)
An organocatalytic cascade reaction that involves the formation of C-N, C-O and CN bonds in one process via dual sp3 C-H activation has been developed. This protocol affords a facile metal-free methodology for the synthesis of oxazole derivatives in air under mild conditions.
Synthesis of highly substituted oxazoles through iodine(III)-mediated reactions of ketones with nitriles
Saito, Akio,Hyodo, Nao,Hanzawa, Yuji
supporting information, p. 11046 - 11055 (2012/11/07)
In the presence of trifluoromethanesulfonic acid (TfOH) or bis(trifluoromethanesulfonyl) imide (Tf2NH), iodosobenzene (PhI=O) efficiently promoted the reactions of dicarbonyl compounds as well as monocarbonyl compounds with nitriles to give 2,4-disubstituted and 2,4,5-trisubstituted oxazole in a single step under the mild conditions.
Facile synthesis of polysubstituted oxazoles via A copper-catalyzed tandem oxidative cyclization
Wan, Changfeng,Zhang, Jintang,Wang, Sujing,Fan, Jinmin,Wang, Zhiyong
supporting information; experimental part, p. 2338 - 2341 (2010/08/04)
A highly efficient synthesis of polysubstituted oxazoles was developed via a copper-catalyzed tandem oxidative cyclization. The desired products can be obtained from readily available starting materials under mild conditions. This is an attractive alterna
