14548-01-7Relevant articles and documents
Synthesis of heteroaromatic trifluoromethyl ethers with trifluoromethyl triflate as the source of the trifluoromethoxy group
Zhang, Qing-Wei,Hartwig, John F.
, p. 10124 - 10127 (2018)
A series of nitrogen-heterocycles have been transformed to the corresponding trifluoromethyl or higher perfluoroalkyl ethers by reaction of the corresponding N-oxides with trifluoromethyl or higher perfluoroalkyl triflate. Trifluoromethyl triflate, which has generally been used as a precursor to [OCF3]?, is used here as a bifunctional reagent to render the heteroarene more electrophilic and to deliver the trifluoromethoxy group. This reagent was easily prepared on a large scale (>100 grams) and is stable in either pure form or as a stock solution. Applications and limitations of this method are reported.
Phenanthridine-based nitrones as substrates for strain-promoted alkyne-nitrone cycloadditions
Strmiskova, Miroslava,Bilodeau, Didier A.,Chigrinova, Mariya,Pezacki, John Paul
, p. 1 - 6 (2019)
Over the past decade, bioorthogonal chemistry that facilitates the efficient conjugation of biomolecules has expanded from the copper-catalyzed alkyne-azide cycloadditions to a multitude of diverse reactions, varying additives and reactional partners, and most often offering better alternatives with faster rates and lower toxicity of employed reactants. Among these, the copper-free strain-promoted cycloaddition reactions have been demonstrated to be more promising, offering a reaction without toxic metal catalysts and with faster inherent kinetic rate constants. The strain-promoted alkyne-nitrone cycloadditions are easily tunable from both the (strained) alkyne and nitrone perspective, both compounds giving the opportunity to modulate the rate of reaction by substituting various positions. Previously, acyclic nitrones have been evaluated in the strain-promoted alkyne-nitrone reactions; however, they were notably prone to hydrolysis. Some five-membered ring endocyclic nitrones developed concomitantly offered the advantage of relatively fast kinetics and better resistance to degradation in aqueous conditions and have been successfully used for labelling of biomolecules in living systems. Herein, we have prepared and studied nitrones inspired by the phenanthridine scaffold that efficiently undergo strain-promoted alkyne-nitrone reactions. Phenanthridine nitrones react fast with strained cyclooctynes with large bimolecular rate constants while maintaining bioorthogonality and resistance to hydrolysis.
2-Position-selective C[sbnd]H fluoromethylation of six-membered heteroaryl N-oxides with (fluoromethyl)triphenylphosphonium iodide
Hu, Chen-Chen,Hu, Wei-Qiang,Qing, Feng-Ling,Xu, Xiu-Hua
, (2020/12/14)
A mild and efficient method for the regioselective C[sbnd]H fluoromethylation of heteroaryl N-oxides with (fluoromethyl)triphenylphosphonium iodide is presented. With LiOt-Bu as the base and DMSO as the solvent, this reaction delivers a series of C2-fluor
Deoxygenative Amination of Azine-N-oxides with Acyl Azides via [3 + 2] Cycloaddition
Ghosh, Prithwish,Han, Sang Hoon,Han, Sangil,Kim, Dongeun,Kim, In Su,Kim, Saegun,Kwon, Na Yeon,Mishra, Neeraj Kumar
, p. 2476 - 2485 (2020/03/13)
A transition-metal-free deoxygenative C-H amination reaction of azine-N-oxides with acyl azides is described. The initial formation of an isocyanate from the starting acyl azide via a Curtius rearrangement can trigger a [3 + 2] dipolar cycloaddition of polar N-oxide fragments to generate the aminated azine derivative. The applicability of this method is highlighted by the late-stage and sequential amination reactions of complex bioactive compounds, including quinidine and fasudil. Moreover, the direct transformation of aminated azines into various bioactive N-heterocycles illustrates the significance of this newly developed protocol.
Co(III)-Catalyzed C-H Amidation of Nitrogen-Containing Heterocycles with Dioxazolones under Mild Conditions
Dhiman, Ankit Kumar,Thakur, Ankita,Kumar, Inder,Kumar, Rakesh,Sharma, Upendra
, p. 9244 - 9254 (2020/08/14)
A cobalt(III)-catalyzed C-8 selective C-H amidation of quinoline N-oxide using dioxazolone as an amidating reagent under mild conditions is disclosed. The reaction proceeds efficiently with excellent functional group compatibility. The utility of the current method is demonstrated by gram scale synthesis of C-8 amide quinoline N-oxide and by converting this amidated product into functionalized quinolines. Furthermore, the developed catalytic method is also applicable for C-7 amidation of N-pyrimidylindolines and ortho-amidation of benzamides.
Visible-Light-Mediated C-H Alkylation of Pyridine Derivatives
Rammal, Fatima,Gao, Di,Boujnah, Sondes,Gaumont, Annie-Claude,Hussein, Aqeel A.,Lakhdar, Sami
supporting information, p. 7671 - 7675 (2020/10/09)
We report herein a visible-light-mediated C-H alkylation of pyridine derivatives that proceeds by simple combination of a large variety of N-alkoxypyridinium ions with alkanes in the presence of 2 mol % of fac-Ir(ppy)3 under blue illumination. The mild reaction conditions together with the high group functional tolerance make of this process a useful synthetic platform for the construction of structurally strained heterocycles. Detailed mechanistic investigations, including density functional theory calculations and quantum yield measurement, allowed us to understand factors controlling the reactivity and the selectivity of the reaction.
Rh/O2-Catalyzed C8 Olefination of Quinoline N-Oxides with Activated and Unactivated Olefins
Sharma, Ritika,Kumar, Rakesh,Sharma, Upendra
, p. 2786 - 2797 (2019/02/26)
The rhodium/O2 system-catalyzed distal C(sp2)-H olefination of quinoline N-oxides is developed. Molecular oxygen has been explored as an economic and clean oxidant, an alternative to inorganic oxidants. A wide substrate scope with respect to quinoline N-oxides and olefins (activated acrylates and styrenes; unactivated aliphatic olefins) demonstrates the robustness of the developed catalytic method. Interestingly, 2-substituted quinoline N-oxides also afforded good yields of the corresponding C8-olefinated products. Kinetic isotope studies and deuterium-labeling experiments have been performed to understand the preliminary mechanistic pathway. The applicability of the developed method is demonstrated by utilizing natural product-derived substrates and by converting the C8-olefinated quinoline N-oxides into various other useful molecules.
2-Position-Selective Trifluoromethylthiolation of Six-Membered Heteroaromatic Compounds
Muta, Ryuhei,Torigoe, Takeru,Kuninobu, Yoichiro
supporting information, (2019/06/13)
The regioselective C-H trifluoromethylthiolation of six-membered heteroaromatic compounds via nucleophilic attack of a CF3S source on the electrophilically activated six-membered heteroaromatic ring was developed. The reaction proceeds in good yield with good functional group tolerance, even on a gram-scale. The key to the successful regioselective transformation is the presence of an additive (2,4-dinitrobenzenesulfonyl chloride). The regioselective trifluoromethylthiolation of quinidine derivative is also demonstrated. Trifluoromethylthiolation, followed by S-oxidation, affords the corresponding sulfones.
Electrochemical Deoxygenation of N-Heteroaromatic N -Oxides
Xu, H.-C.,Xu, P.
supporting information, p. 1219 - 1221 (2019/06/08)
An electrochemical method for the deoxygenation of N-heteroaromatic N -oxide to give the corresponding N-heteroaromatics has been developed. Several classes of N-heterocycles such as pyridine, quinoline, isoquinoline, and phenanthridine are tolerated. The electrochemical reactions proceed efficiently in aqueous solution without the need for transition-metal catalysts and waste-generating reducing reagents.
An organocatalytic enantioselective direct α-heteroarylation of aldehydes with isoquinoline: N -oxides
Bertuzzi, Giulio,Pecorari, Daniel,Bernardi, Luca,Fochi, Mariafrancesca
supporting information, p. 3977 - 3980 (2018/04/23)
A new protocol for the enantioselective direct α-heteroarylation of aldehydes with isoquinoline N-oxides, via chiral enamine catalysis, has been successfully developed. High enantiomeric excesses and moderate to good yields were achieved for a variety of α-heteroarylated aldehydes.
