22286-82-4Relevant academic research and scientific papers
Enzymatic and microbial method of preparation of optically active (±) 3-methyl-4-phenyl-4,5-dihydroisoxazole-4-carboxylic acid
Zadrozna,Kurkowska,Makuch
, p. 4181 - 4191 (1997)
A racemic mixture of ethyl-3-methyl-4-phenyl-4,5-dihydroisoxasole-4-carboxylate was obtained in the 1,3-dipolar intermolecular cycloaddition of ethyl atroponate and aliphatic nitric oxide, which was then subjected to enzymatic and microbiological hydrolysis in order to obtain optically active acids.
A convenient new synthesis of a Naproxen precursor
Mahmood, Syed J.,Brennan, Courtney,Mahmun Hossain
, p. 1807 - 1809 (2002)
A precursor of Naproxen, 2-(6-methoxy-2-naphthyl)propenoic acid was synthesized in good yield from commercially available 6-methoxy-2-naphthaldehyde in three steps. The synthesis includes an unprecedented one-step reduction of acrylic acid ethyl ester to propenoic acid ethyl ester in high yield.
Copper-catalyzed intermolecular chloroazidation of α,β-unsaturated amides
Chen, Long,Xing, Haotian,Zhang, Huaibin,Jiang, Zhong-Xing,Yang, Zhigang
, p. 7463 - 7467 (2016)
A highly practical copper-catalyzed intermolecular chloroazidation of α,β-unsaturated amides has been described, giving a series of azidochlorides in good-to-excellent yields. The stable azidoiodine(iii) reagent and SOCl2 were used as azide and chlorine sources, respectively. The synthetic applications of this protocol were also explored by a variety of synthetically useful transformations.
Stereoselective Synthesis of Difluorinated 1,3-Dienes via Palladium-Catalyzed C-F Bond Activation of Tetrasubstituted gem-Difluoroalkenes
Wang, Yanhui,Ma, Qiao,Tsui, Gavin Chit
, p. 5241 - 5245 (2021/06/30)
A highly diastereoselective Pd(0)-catalyzed synthesis of difluorinated 1,3-dienes is described. Symmetrical 1,3-dienes containing a vicinal difluoro moiety can be obtained as single diastereomers from tetrasubstituted gem-difluoroalkenes. The reaction presumably proceeds through a stereoselective twofold Pd-catalyzed Miyaura borylation/Suzuki-Miyaura cross-coupling of the C-F bond. Moreover, modular synthesis of unsymmetrical difluorinated 1,3-dienes is also achievable by the coupling between gem-difluoroalkenes and borylated monofluoroalkenes.
Visible-Light-Promoted Hydroxydifluoroalkylation of Alkenes Enabled by Electron Donor–Acceptor Complex
Xie, Zhen-Zhen,Zheng, Yu,Tang, Kai,Guan, Jian-Ping,Yuan, Chu-Ping,Xiao, Jun-An,Xiang, Hao-Yue,Chen, Kai,Chen, Xiao-Qing,Yang, Hua
supporting information, p. 9474 - 9479 (2021/12/14)
A catalyst-free strategy for regioselective hydroxydifluoroalkylation of alkenes with alkyl bromides was developed, affording a series of difluoroalkylated tertiary alcohols in moderate to good yields. This photocatalyst-free protocol shows broad substrate scope under mild conditions. Moreover, mechanistic studies revealed that a newly identified electron donor–acceptor complex is crucial to this transformation.
Palladium-Catalyzed Stereoselective Hydrodefluorination of Tetrasubstituted gem-Difluoroalkenes
Ma, Qiao,Liu, Caroline,Tsui, Gavin Chit
supporting information, p. 5193 - 5197 (2020/07/04)
A highly stereoselective palladium(0)-catalyzed hydrodefluorination (HDF) of tetrasubstituted gem-difluoroalkenes is developed. By using catalytic Pd(PPh3)4 (2.5-5 mol percent) and hydrosilane Me2PhSiH, various trisubstituted terminal (E)-monofluoroalkenes can be synthesized with excellent E/Z selectivity (>99:1) and good functional group tolerability. The key stereocontrol should be exerted by an ester-directed C-F bond oxidative addition step in the catalytic cycle.
A Bond-Weakening Borinate Catalyst that Improves the Scope of the Photoredox α-C-H Alkylation of Alcohols
Kanai, Motomu,Oisaki, Kounosuke,Sakai, Kentaro
supporting information, p. 2171 - 2184 (2020/08/10)
The development of catalyst-controlled, site-selective C(sp 3)-H functionalization reactions is currently a major challenge in organic synthesis. In this paper, a novel bond-weakening catalyst that recognizes the hydroxy group of alcohols through formation of a borate is described. An electron-deficient borinic acid-ethanolamine complex enhances the chemical yield of the α-C-H alkylation of alcohols when used in conjunction with a photoredox catalyst and a hydrogen atom transfer catalyst under irradiation with visible light. This ternary hybrid catalyst system can, for example, be applied to functional-group-enriched-peptides.
Highly Selective Sub-Nanomolar Cathepsin S Inhibitors by Merging Fragment Binders with Nitrile Inhibitors
Schade, Markus,Merla, Beatrix,Lesch, Bernhard,Wagener, Markus,Timmermanns, Simone,Pletinckx, Katrien,Hertrampf, Torsten
supporting information, p. 11801 - 11808 (2020/11/26)
Pharmacological inhibition of cathepsin S (CatS) allows for a specific modulation of the adaptive immune system and many major diseases. Here, we used NMR fragment screening and crystal structure-aided merging to synthesize novel, highly selective CatS inhibitors with picomolar enzymatic Ki values and nanomolar functional activity in human Raji cells. Noncovalent fragment hits revealed binding hotspots, while the covalent inhibitor structure-activity relationship enabled efficient potency optimization.
Iodonium Ylides as Carbene Precursors in Rh(III)-Catalyzed C-H Activation
Jiang, Yuqin,Li, Pengfei,Li, Xingwei,Liu, Bingxian,Zhao, Jie
supporting information, p. 7475 - 7479 (2020/10/12)
The rhodium(III)-catalyzed coupling of C-H substrates with iodonium ylides has been realized for the efficient synthesis of diverse cyclic skeletons, where the iodonium ylides have been identified as efficient and outstanding carbene precursors. The reaction systems are applicable to both sp2 and sp3 C-H substrates under mild and redox-neutral conditions. The catalyst loading can be as low as 0.5 mol % in a gram-scale reaction. Representative products exhibit cytotoxicity toward human cancer cells at nanomolar levels.
Overcoming Scope Limitations in Cross-Coupling of Diazo Nucleophiles by Manipulating Catalyst Speciation and Using Flow Diazo Generation
Sullivan, Ryan J.,Freure, Garrett P.R.,Newman, Stephen G.
, p. 5623 - 5630 (2019/06/05)
The accessible scope of palladium-catalyzed diazo cross-coupling reactions has been expanded to include aryl chlorides by controlled diazo slow addition. The success of this strategy is based on manipulating speciation within the catalytic cycle through starvation of the diazo reagent to make the Pd(II) oxidative intermediate the resting state. The strategy is also applicable to cross-coupling reactions with aryl bromides and, in combination with safe, on-demand flow generation of nonstabilized diazo reagents, has been used to greatly expand the scope of applicable diazo compounds for this chemistry as well. Lastly, DFT calculations have provided insight into the mechanism and support for the proposed explanation for success of the slow addition strategy.
