29055-08-1Relevant academic research and scientific papers
Bimetallic Bis-NHC-Ir(III) Complex Bearing 2-Arylbenzo[d]oxazolyl Ligand: Synthesis, Catalysis, and Bimetallic Effects
Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhan, Bing,Li, Zhi-Ming,Hou, Xiu-Feng
, p. 3514 - 3523 (2020/10/09)
Herein, an unprecedented bimetallic bis-NHC Cp*Ir complex 1 bearing 2-arylbenzo[d]oxazolyl and NHC ligands is reported. A significant increase in activity was observed for N-methylation of amines and reduction of aldehydes with MeOH catalyzed by 1 compared to the monometallic analogues (2-11). Under the optimal conditions, it showed to be highly effective in N-methylation of nitroarenes with MeOH as both C1 and H2 source. Substrates, including aromatic amines, ketones, and nitro compounds with various functional groups, can be well-tolerated. Mechanistic studies and DFT calculation highlight the significance of bimetallic centers cooperativity.
Bicyclobutane carboxylic amide as a cysteine-directed strained electrophile for selective targeting of proteins
Shindo, Naoya,Ojida, Akio,Tokunaga, Keisuke,Sato, Mami,Kuwata, Keiko,Miura, Chizuru,Fuchida, Hirokazu,Matsunaga, Naoya,Koyanagi, Satoru,Ohdo, Shigehiro
supporting information, p. 18522 - 18531 (2020/11/02)
Expanding the repertoire of electrophiles with unique reactivity features would facilitate the development of covalent inhibitors with desirable reactivity profiles. We herein introduce bicyclo[1.1.0]butane (BCB) carboxylic amide as a new class of thiol-reactive electrophiles for selective and irreversible inhibition of targeted proteins. We first streamlined the synthetic routes to generate a variety of BCB amides. The strain-driven nucleophilic addition to BCB amides proceeded chemoselectively with cysteine thiols under neutral aqueous conditions, the rate of which was significantly slower than that of acrylamide. This reactivity profile of BCB amide was successfully exploited to develop covalent ligands targeting Bruton's tyrosine kinase (BTK). By tuning BCB amide reactivity and optimizing its disposition on the ligand, we obtained a selective covalent inhibitor of BTK. The in-gel activitybased protein profiling and mass spectrometry-based chemical proteomics revealed that the selected BCB amide had a higher target selectivity for BTK in human cells than did a Michael acceptor probe. Further chemical proteomic study revealed that BTK probes bearing different classes of electrophiles exhibited distinct off-target profiles. This result suggests that incorporation of BCB amide as a cysteine-directed electrophile could expand the capability to develop covalent inhibitors with the desired proteome reactivity profile.
N -Methylation of ortho -substituted aromatic amines with methanol catalyzed by 2-arylbenzo [d] oxazole NHC-Ir(iii) complexes
Huang, Shuang,Hong, Xi,Cui, He-Zhen,Zhou, Quan,Lin, Yue-Jian,Hou, Xiu-Feng
, p. 5072 - 5082 (2019/04/17)
Seven new chelated cyclometalated Ir complexes of ABON,P, ABON,O, and ABON,C(carbene) based on a rigid and tunable 2-arylbenzo[d]oxazole backbone have been prepared for the N-methylation of amines. Among these three coordinated modes, ABON,C(carbene)-chelated iridium-based catalysts exhibited good performance in the monomethylation of aromatic amines with methanol (MeOH) as the green methylation reagent. The steric-modified synthesis of ABON,C(carbene) complexes was described. The most active ABON,C(carbene) complex with marginal steric hindrance as a catalyst was obtained from the benzoxazole ring without a substituent and methyl group of the benzimidazole ring on the N-heterocyclic carbene (NHC) ligand. A variety of amines including para- and meta-substituted aromatic amines, as well as heterocyclic amines, were formulated as suitable substrates. Importantly, this catalyst considerably promoted the yield of the N-methylation of ortho-substituted aromatic amines. Controlled kinetic experiments and deuterium-labeling reactions of these ortho-substituted amines were conducted under optimized conditions. On the basis of the experimental results, a plausible mechanism was proposed.
Aerobic C–C Bond Cleavage of Indoles by Visible-Light Photoredox Catalysis with Ru(bpy)32+
Ji, Xiaochen,Li, Dongdong,Wang, Zhongzhen,Tan, Muyun,Huang, Huawen,Deng, Guo-Jun
, p. 6652 - 6659 (2017/12/15)
Photoredox catalysis with Ru(bpy)32+ (2,2′-bipyridine) has been used to enable the activation of oxygen in the aerobic C–C cleavage/oxygenation reaction of indoles. A number of indole substrates that contain various functional groups were successfully employed in the reaction to give a wide range of ortho-aminobenzaldehyde derivatives. These products can then be used as versatile building blocks for further synthetic modifications. Mechanistic studies suggest that the reaction proceeds through a radical pathway.
Synthesis of Hydrazide-Containing Chroman-2-ones and Dihydroquinolin-2-ones via Photocatalytic Radical Cascade Reaction of Aroylhydrozones
Zhao, Yu,Chen, Jia-Rong,Xiao, Wen-Jing
supporting information, p. 6304 - 6307 (2016/12/23)
A general and efficient visible light photocatalytic α-amino carbon radical-based cascade reaction of aroylhydrazones has been described. This protocol tolerates a wide array of α-silylamines and aroylhydrazones to afford the corresponding diversely funct
Chemoselective Schwartz Reagent Mediated Reduction of Isocyanates to Formamides
Pace, Vittorio,De La Vega-Hernández, Karen,Urban, Ernst,Langer, Thierry
supporting information, p. 2750 - 2753 (2016/06/15)
Addition of the in situ generated Schwartz reagent to widely available isocyanates constitutes a chemoselective, high-yielding, and versatile approach to the synthesis of variously functionalized formamides. Steric and electronic factors or the presence of sensitive functionalities (esters, nitro groups, nitriles, alkenes) do not compromise the potential of the method. Full preservation of the stereochemical information contained in the starting materials is observed. The use of formamides in the nucleophilic addition of organometallic reagents (Chida-Sato allylation, Charette-Huang addition to imidoyl triflate activated amides, Matteson homologation of boronic esters) is briefly investigated.
2-Arylacetamides as Versatile Precursors for 3-Aminoisocoumarin and Homophthalimide Derivatives: Palladium-Catalyzed Cascade Double Carbonylation Reactions
Frutos-Pedre?o, Roberto,García-López, José-Antonio
supporting information, p. 2692 - 2700 (2016/08/30)
The synthesis of biologically relevant homophthalimide and 3-aminoisocoumarin nuclei via palladium-catalyzed carbonylation of 2-(2-iodoaryl)acetamides has been developed. The degree of N-substitution on the starting amide substrate dictates whether C?N or
Organocatalytic route to dihydrocoumarins and dihydroquinolinones in all stereochemical configurations
Engl, Oliver D.,Fritz, Sven P.,K?slin, Alexander,Wennemers, Helma
supporting information, p. 5454 - 5457 (2015/02/05)
A straightforward stereodivergent route to dihydrocoumarins and dihydroquinolinones based on cinchona alkaloid catalyzed addition reactions of monothiomalonates (MTMs) to functionalized nitroolefins followed by deprotection and chemoselective cyclization has been developed. The synthesis proceeds under mild conditions and yields heterocycles with adjacent quaternary and tertiary stereogenic centers in very high yields and stereoselectivities. Moreover, full control over the relative and absolute configuration is achieved by the use of (pseudo)enantiomeric catalysts and the difference in reactivity of thioester versus oxoester moieties. (Chemical Equation Presented).
Direct synthesis of cis-dihalido-bis(NHC) complex of nickel(ii) and catalytic application in olefin addition polymerization: Effect of halogen co-ligands and density functional theory study
Zhang, Dao,Zhou, Sen,Li, Zhiming,Wang, Quanrui,Weng, Linhong
, p. 12020 - 12030 (2013/09/02)
Two novel amine-containing N-heterocyclic carbene ligand precursors [H(1a-b)]Br have been prepared in good yield and fully characterized. Direct syntheses of cis- and trans-dihalido-bis(NHC) nickel complexes [Ni(NHC) 2X2] (X = Cl, Br
Mono-N-methylation of functionalized anilines with alkyl methyl carbonates over NaY faujasites. 4. Kinetics and selectivity
Selva, Maurizio,Tundo, Pietro,Foccardi, Tommaso
, p. 2476 - 2485 (2007/10/03)
(Chemical Equation Presented) In the presence of NaY faujasite as the catalyst, the reaction of bifunctional anilines (1-4: XC6H 4-NH2; X = OH, CO2H, CH2OH, and CONH2) with methyl alkyl carbonates [MeOCO2R′: R′ = Me or MeO(CH2)2O(CH2)2] proceeds with a very high mono-N-methyl selectivity (XC6H 4NHMe up to 99%), and chemoselectivity as well, with other nucleophilic functions (OH, CO2H, CH2OH, CONH2) fully preserved from alkylation and/or transesterification reactions. Aromatic substituents, however, modify the relative reactivity of amines 1-4: good evidence suggests that, not only steric and electronic effects, but, importantly, direct acid-base interactions between substituents and the catalyst are involved. Weakly acidic groups (OH, CH2OH, CONH2, pKa ≥ 10) may help the reaction, while aminobenzoic acids (pK a of 4-5) are the least reactive substrates. The solvent polarity also affects the reaction, which is faster in xylene than in the more polar diglyme. The mono-N-methyl selectivity is explained by the adsorption pattern of reagents within the zeolite pores: a BAl2 displacement of the amine on methyl alkyl carbonate should occur aided by the geometric features of the NaY supercavities. Different factors account for the reaction chemoselectivity. Evidence proves that the polarizability of the two nucleophilic terms (NH 2 and X groups) of anilines is relevant, although adsorption and confinement phenomena of reagents promoted by the zeolite should also be considered.
