4903-36-0Relevant articles and documents
Novel Conjugated s-Tetrazine Derivatives Bearing a 4H-1,2,4-Triazole Scaffold: Synthesis and Luminescent Properties
?wiatkowski, Marcin,Kudelko, Agnieszka,Maj, Anna
, (2022/01/20)
A series of new symmetrical s-tetrazine derivatives, coupled via a 1,4-phenylene linkage with a 4H-1,2,4-triazole ring, were obtained. The combination of these two rings in an extensively coupled system has significant potential applications, mainly in op
Br?nsted Base-Catalyzed Formal Reductive [3+2] Annulation of 4,4,4-Trifluorocrotonate and α-Iminoketones
Kondoh, Azusa,Terada, Masahiro
supporting information, p. 585 - 588 (2020/12/07)
A formal reductive [3+2] annulation of 4,4,4-trifluorocrotonate and α-iminoketones was developed under Br?nsted base catalysis. A single phosphazene base efficiently catalyzes the one-pot tandem reaction involving two mechanistically different elementary processes, namely the chemoselective reduction of an imine moiety of α-iminoketones with thiols as the reductant and the subsequent intermolecular Michael addition of an enolate of α-aminoketones concomitant with lactam formation. This operationally simple method provides β-trifluoromethyl-substituted γ-lactams with a tetrasubstituted carbon as a single diastereomer.
Synthesis of Imidoyl Chlorides Using Phosphorus Trichloride
Nguyen, T. L.,Popov, Yu. V.,Shishkin, E. V.,Shishkin, V. E.,Vo, T. L. Q.,Zotov, Yu. L.
, p. 849 - 851 (2021/06/12)
Abstract: The reaction of carboxamides with phosphorus trichloride under heating at 75–80°C for 1 h in the presence of a 4-dimethylaminopyridine catalyst was used to synthesize imidoyl chlorides in yields of 63–99%.
Regioselective Synthesis of Trisubstituted Quinoxalines Mediated by Hypervalent Iodine Reagents
Ito, Ryota,Miura, Kasumi,Suzuki, Noriyuki,Suzuki, Yumiko,Takehara, Ren
, p. 16892 - 16900 (2021/12/06)
A facile and regioselective synthesis of quinoxalines, an important motif in medicinal chemistry and materials sciences, was developed. Despite their prospective utility, the regioselective preparation of trisubstituted quinoxalines has not been previously established. In the reported system, hypervalent iodine reagents catalyzed the annulation between α-iminoethanones ando-phenylenediamines in a chemo/regioselective manner to afford trisubstituted quinoxalines. Excellent regioselectivities (6:1 to 1:0) were achieved using [bis(trifluoroacetoxy)iodo]benzene and [bis(trifluoroacetoxy)iodo]pentafluorobenzene as annulation catalysts.
Hydrogenation of Secondary Amides using Phosphane Oxide and Frustrated Lewis Pair Catalysis
K?ring, Laura,Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
supporting information, p. 14179 - 14183 (2021/09/03)
The metal-free catalytic hydrogenation of secondary carboxylic acid amides is developed. The reduction is realized by two new catalytic reactions. First, the amide is converted into the imidoyl chloride by triphosgene (CO(OCCl3)2) using novel phosphorus(V) catalysts. Second, the in situ generated imidoyl chlorides are hydrogenated in high yields by an FLP-catalyst. Mechanistic and quantum mechanical calculations support an autoinduced catalytic cycle for the hydrogenation with chloride acting as unusual Lewis base for FLP-mediated H2-activation.
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).
Silver-Catalyzed Cascade Cyclization Reaction of Isocyanides with Sulfoxonium Ylides: Synthesis of 3-Aminofurans and 4-Aminoquinolines
Liang, Yong-Xin,Yang, Ming,He, Bo-Wen,Zhao, Yu-Long
, p. 7640 - 7644 (2020/10/09)
A silver-catalyzed cascade cyclization reaction of isocyanides with sulfoxonium ylides has been developed for the first time. This reaction provides a new and efficient method for the construction of highly functionalized 3-aminofurans and 4-aminoquinolines from readily available starting materials in a single step.
Synthesis of Nitrogen-Containing Polyaromatics by Aza-Annulative π-Extension of Unfunctionalized Aromatics
Itami, Kenichiro,Ito, Hideto,Kawahara, Kou P.,Matsuoka, Wataru
supporting information, p. 6383 - 6388 (2020/03/13)
Nitrogen-containing polycyclic aromatic compounds (N-PACs) are an important class of compounds in materials science. Reported here is a new aza-annulative π-extension (aza-APEX) reaction that allows rapid access to a range of N-PACs in 11–84 % yields from readily available unfunctionalized aromatics and imidoyl chlorides. In the presence of silver hexafluorophosphate, arenes and imidoyl chlorides couple in a regioselective fashion. The follow-up oxidative treatment with p-chloranil affords structurally diverse N-PACs, which are very difficult to synthesize. DFT calculations reveal that the aza-APEX reaction proceeds through the formal [4+2] cycloaddition of an arene and an in situ generated diarylnitrilium salt, with sequential aromatizations having relatively low activation energies. Transformation of N-PACs into nitrogen-doped nanographenes and their photophysical properties are also described.
The impact of cation structure upon the acidity of triazolium salts in dimethyl sulfoxide
Konstandaras, Nicholas,Dunn, Michelle H.,Guerry, Max S.,Barnett, Christopher D.,Cole, Marcus L.,Harper, Jason B.
, p. 66 - 75 (2019/12/26)
A series of triazolium salts, selected for their varying electronic and steric properties, were prepared and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each systematic structural variation upon the acidity of the triazolium cation has been considered, in particular examining the effects of systematically altering electronic properties, quantified through the use of Hammett σ parameters. The first pKa value for an azolium salt that generates a mesionic carbene is also reported. These new data allow for the selection of appropriate bases for the deprotonation of such triazolium salts and the potential to correlate the pKa values determined herein with the nucleophilicity of the corresponding carbenes.
Dichloroimidazolidinedione-Activated Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
Gao, Yu,Liu, Jingjing,Li, Zhenjiang,Guo, Tianfo,Xu, Songquan,Zhu, Hui,Wei, Fulan,Chen, Siming,Gebru, Hailemariam,Guo, Kai
, p. 2040 - 2049 (2018/02/23)
A novel protocol for the activation of the Beckmann rearrangement utilizing the readily available and economical geminal dichloroimidazolidinediones (DCIDs) on a substoichiometric scale (10 mol %) has been developed. A unique self-propagating mechanism for the substoichiometric dichloroimidazolidinedione-activated transformation was proposed and validated. The substrate scope of the developed protocol has been demonstrated by 23 examples with good to excellent yields (mostly 90-98%) in a short time (mostly 10-30 min), including a substrate for synthesizing the monomer of nylon-12 and a complicated steroidal substrate on a preparative scale. This research not only unveils for the first time the synthetic potential of substoichiometric amounts of dichloroimidazolidinediones in promoting chemical transformation but also offers yet another important illustration of the self-propagating cycle in the context of the Beckmann rearrangement activated by a structurally novel organic promoter.
