50993-08-3Relevant academic research and scientific papers
α-Imino Iridium Carbenes from Imidoyl Sulfoxonium Ylides: Application in the One-Step Synthesis of Indoles
Burtoloso, Antonio C. B.,Caiuby, Clarice A. D.,De Jesus, Matheus P.
, p. 7433 - 7445 (2020/06/27)
Imidoyl sulfoxonium ylides are presented for the first time as potential precursors to generate α-imino metal-carbene intermediates and applied in direct C-H functionalization reactions catalyzed by [Ir(cod)Cl]2 (4 mol %) to provide 2-substituted indoles (up to 70% yield) in just one step. This class of sulfur ylide is successfully obtained from imidoyl chloride and dimethylsulfoxonium methylide (23 new examples in 45-85% yield) or by imino group formation from the corresponding β-keto sulfoxonium ylides and anilines in the presence of TiCl4 as a Lewis acid (9 examples in 33-94% yield).
Modulation of the carboxamidine redox potential through photoinduced spiropyran or fulgimide isomerisation
Andrews, M. Crawford,Peng, Ping,Rajput, Amit,Cozzolino, Anthony F.
, p. 432 - 441 (2018/04/26)
Carboxamidines functionalized with either a spiropyran or fulgimide photoswitch were prepared on multigram scales. The thermal, electrochemical, and photochemical ring isomerizations of these compounds were studied and the results compared with related systems. The photochemical isomerisations were found to be reversible and could be followed by 1H NMR and UV-vis spectroscopy. The spiropyran/merocyanine couple was thermally active and an activation enthalpy of 116 kJ mol-1 was measured for ring-opening. These measurements yielded an enthalpy difference of 25 kJ mol-1 between the open and closed states which is consistent with DFT calculations. DFT calculations predicted a charge transfer to the carboxamidine group upon ring closure in the fulgimide and a charge transfer from the carboxamidine group upon switching the spiropyran to the merocyanine form. This was confirmed experimentally by monitoring the change in the oxidation potential assigned to the carboxamidine group. The potential of these molecules to therefore act as a new class of photoresponsive ligands that can modulate the ligand field of a complex is discussed.
Transition Metal-Free Visible Light-Driven Photoredox Oxidative Annulation of Arylamidines
Shen, Zi-Chao,Yang, Pan,Tang, Yu
, p. 309 - 317 (2016/01/15)
A fast catalytic synthesis of multisubstituted quinazolines from readily available amidines via visible light-mediated oxidative C(sp3)-C(sp2) bond formation has been established. This reaction is a metal-free oxidative coupling catalyzed by a photoredox organocatalyst. The protocol features low catalyst loading (1 mol %).
Synthesis of 1,2-borazaronaphthalenes from imines by base-promoted borylation of C-H bond
Liu, Xinwang,Wu, Pengbo,Li, Jianfeng,Cui, Chunming
, p. 3737 - 3744 (2015/05/05)
A new route from benzylic imines permits the synthesis of 1,2-borazaronaphthalenes in good yields. The reaction involves formation of the enamidyl dibromoborane, which undergoes base-promoted borylation of the nearby aromatic C-H bond. Electrophilic attack of the boron species onto the benzylic arene is supported by the slow borylation of arenes substituted with electron-withdrawing groups. The resultant boron bromides can be easily substituted with lithium reagents to provide a range of products. The electronic properties of these 1,2-borazaronaphthalene derivatives have been investigated by UV-vis and fluorescence spectroscopy.
Facile synthesis of phosphaamidines and phosphaamidinates using nitrilium ions as an imine synthon
Van Dijk, Tom,Burck, Sebastian,Rong, Mark K.,Rosenthal, Amos J.,Nieger, Martin,Slootweg, J. Chris,Lammertsma, Koop
, p. 9068 - 9071 (2014/10/15)
Readily accessible nitrilium triflates are convenient imine building blocks for the expedient synthesis of a novel class of 1,3-P,N ligands as demonstrated for the reaction with primary phosphanes. This procedure allows variation of all substituents. X-ray crystal structures are reported for nitrilium ions, phosphaamidines, and three phosphaamidinate complexes. The lithium phosphaamidinate is N coordinated and its reaction with [AuCl(tht)] (tht=tetrahydrothiophene) gives a unique P-bridged gold trimer, while a P,N-bidentate complex results from [{RhCl(cod)}2]. The nitrilium ion methodology allows extension of the 1,3-P,N motive to bis(imino)phosphanes, which are the neutral phosphorus analogues of the valuable β-diketiminate ligand.
N'-Substituted N-Acyl- and N-Imidoyl-thioureas: Preparation and Conversion of N',N'-Disubstituted Compounds into 2-(N,N-Disubstituted Amino)thiazol-5-yl Ketones
Brindley, Jocelyn C.,Caldwell, Jennifer M.,Meakins, G. Denis,Plackett, Simon J.,Price, Susan J.
, p. 1153 - 1158 (2007/10/02)
Known methods were developed to give convenient general procedures for preparing N-acyl-N'-mono- and -N',N'-disubstituted thioureas from acid chlorides, and related N-imidoyl thioureas from imidoyl chlorides.In the products from three acid chlorides and ammonium thiocyanate the acyl isothiocyanates did not appear to be accompained by the isomeric thiocyanates.Treatment of N-(anilino)benzylidene-N',N'-disubstituted thioures with chloroacetone in the presence of triethylamine leads to 5-acetyl-4-phenyl-2-(N,N-disubstituted amino)thiazoles.In contrast, the corresponding N-benzoyl thioureas form only small amounts of these compounds; the main products are the 5-benzoyl-4-methyl isomers, and this unexpected outcome requires a revision of the literature.It is thought that formation of the 5-benzoyl-4-methylthiazoles involves N-C(4) fission of a cyclic intermediate to give an open-chain intermediate in which nucleophilic attack can occur at either the acetyl or the benzoyl group.One of the latter intermediates was generated directly from 2-acetyl-2-bromoacetophenone and N-methyl-N-phenylthiourea, and found to give the 5-benzoyl-4-methyl- and 5-acetyl-4-phenyl-thiazoles as the major and minor products, respectively.
