- Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
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The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]
- Huang, Changyu,Li, Jinpeng,Wang, Jiaquan,Zheng, Qingshu,Li, Zhenhua,Tu, Tao
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- Designing heterocyclic chalcones, benzoyl/sulfonyl hydrazones: An insight into their biological activities and molecular docking study
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The aim of this study is to investigate the antioxidant, anticholinesterase and the antiproliferative activities of some chalcones, benzoyl and sulfonyl hydrazones. The antioxidant activity was studied by way of four complimentary assays and the anticholinesterase activity was studied using the Ellman method. The antiproliferative activity of the compounds was determined using a BrdU cell proliferation ELISA assay. Compound 32 (IC50: 15.58 ± 0.01 μg/mL) against the brain (C6) and 29 (IC50: 5.02 ± 0.05 μg/mL) against cervical (HeLa) cancer cell lines exhibited higher antiproliferative activity than the other compounds. Two sulfonyl hydrazone derivatives 45 and 47 exhibited very good antioxidant activity. The results of anticholinesterase activity indicated that nine compounds 3, 8, 10, 14, 24, 25, 27, 38, and 45 significantly inhibited acetylcholinesterase enzymes and thirty-three compounds 1–4, 7–14, 22–28, 32–41, 44–47 inhibited butyrylcholinesterase enzymes (BChE) more than galantamine. In addition, virtual screening methods based on ligand 45 having the best activity against BChE was used to define new human BChE inhibitors. The interactions of ligand 8 against acetylcholinesterase (AChE) were also examined. Important key residues were determined and visualized on completion of the methodology. All calculations indicated the suitability of use of the molecular docking approach for understanding interaction mechanisms and crucial fragments of novel hit compounds such as the potential lead AChE and BChE inhibitor candidates.
- ?ztürk, Mehmet,Demirta?, Ibrahim,Iyido?an, Ay?egül Karakü?ük,Kur?un Aktar, Bedriye Seda,Oru?-Emre, Emine El?in,S?cak, Yusuf,Tok, Tu?ba Ta?k?n,Ya?l?o?lu, Ayse ?ahin
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- Design and Bioevaluation of Novel Hydrazide-Hydrazones Derived from 4-Acetyl-N-Substituted Benzenesulfonamide
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Abstract: In this research, a series of hydrazine-hydrazone derivatives (Ia–g), (IIa–h) were synthesized to discover new antioxidant and anticholinesterase agents. The structures of synthesized compounds were characterized by spectroscopic data using UV, IR, 1H, 13C NMR, mass spectroscopy, and elemental analysis. The bio-evaluation of the synthesized compounds (Ia–g), (IIa–h) were evaluated according to in vitro activity assays. The results of β-carotene/linoleic acid assay showed that among the synthesized compounds, the (Ib), (Ie), (IIb–IIe), and (IIh) compound exhibited higher activity for the lipid peroxidation inhibitory activity. In the DPPH free scavenging activity and the cation radical scavenging activity in ABTS?+ activity, compound (IIb) was found to be more active. In the CUPRAC reduced power assay, the A0.5 values of all synthesized compounds were better than α-TOC. In AChE assay, compound (IIb) exhibited the most activity with IC50 = 11.12 ± 0.74 μM, while the compounds (Ib–g) and (IIb–h), exhibited excellent activity than the positive standard galantamine (IC50 = 46.06 ± 0.10 μM) in the BChE assay.
- ?ztürk, M.,Bozkurt, E.,Iyido?an, A. Karakü?ük,Oru?-Emre, E. E.,S?cak, Y.
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p. 702 - 714
(2020/10/29)
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- Method of coupling, and the coupling method using the aromatic group-substituted heterocyclic compound
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Provided is an easy method (coupling method) capable of easily synthesizing a compound group in which aromatic molecules and aromatic molecules are coupled, a compound group in which aromatic molecules and alkene molecules are coupled, and the like without producing halogen waste and without the need to use scarce and expensive palladium. A compound (A) shown by general formula (A): Ar-H and a compound (B1) shown by general formula (B1): RaOCO-Ar', a compound (B2) shown by general formula (B2): RbCH=C(Ar")2, or a compound (B3) shown by general formula (B3): RcOCOCH=C(Ar")2 are reacted in the presence of a nickel compound.
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Paragraph 0202-0207
(2020/09/17)
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- Nickel-Catalyzed Decarbonylative Coupling of Aryl Esters and Arylboronic Acids
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A variety of functionalized biaryls can be accessed by coupling aryl and heteroaryl esters with boronic acids in Suzuki-Miyaura-type decarbonylative cross-coupling catalyzed by an affordable catalyst system composed of Ni(cod)2 and PCy3. The methodology is tolerant of a variety of functional groups and presents an attractive alternative to the use of palladium catalysis currently used in industry to acquire such bis(hetero)aryls, but also reveals challenges associated with nickel catalysis of esters in cross-coupling chemistry.
- Laberge, Nicole A.,Love, Jennifer A.
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supporting information
p. 5546 - 5553
(2015/09/01)
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- Decarbonylative C-H coupling of azoles and aryl esters: Unprecedented nickel catalysis and application to the synthesis of muscoride A
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A nickel-catalyzed decarbonylative C-H biaryl coupling of azoles and aryl esters is described. The newly developed catalytic system does not require the use of expensive metal catalysts or silver- or copper-based stoichiometric oxidants. We have successfully applied this new C-H arylation reaction to a convergent formal synthesis of muscoride A.
- Amaike, Kazuma,Muto, Kei,Yamaguchi, Junichiro,Itami, Kenichiro
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p. 13573 - 13576
(2012/10/08)
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