- Can Heteroarenes/Arenes Be Hydrogenated Over Catalytic Pd/C Under Ambient Conditions?
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Hydrogenation of over a dozen aromatic compounds, including both heteroarenes and arenes, over palladium on carbon (Pd/C, 1–100 molpercent) with H2-balloon pressure at room temperature is reported. Analyses using pyridine as a model substrate revealed that acetic acid was the best solvent, as using only 1 molpercent Pd/C provided piperidine quantitatively. Substrate scope analysis and density functional theory calculations indicated that reaction rates are highly dependent on frontier molecular orbital characteristics and the steric bulkiness of substituents. Moreover, the established method was used for the concise synthesis of the anti-Alzheimer drug donepezil (Aricept?).
- Tanaka, Nao,Usuki, Toyonobu
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p. 5514 - 5522
(2020/07/24)
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- Scalable and Straightforward Synthesis of All Isomeric (Cyclo)alkylpiperidines
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An efficient approach towards introducing (cyclo)alkyl substituents at C-2, C-3 or C-4 positions of the piperidine ring was described. The method relied on the straightforward two-step reaction sequence based on the formal sp3–sp3 re
- Subota, Andrii I.,Lutsenko, Anton O.,Vashchenko, Bohdan V.,Volochnyuk, Dmitriy M.,Levchenko, Vitalina,Dmytriv, Yurii V.,Rusanov, Eduard B.,Gorlova, Alina O.,Ryabukhin, Sergey V.,Grygorenko, Oleksandr O.
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p. 3636 - 3648
(2019/06/13)
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- Synthetic Cathinone Analogues Structurally Related to the Central Stimulant Methylphenidate as Dopamine Reuptake Inhibitors
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Synthetic cathinones are, primarily, stimulant drugs of abuse that act at monoamine transporters (e.g., the dopamine transporter or DAT) as releasing agents or as reuptake inhibitors. In the past few years, the emergence of >150 new synthetic cathinones has attracted considerable attention from medical and law enforcement communities. threo-Methylphenidate (tMP), used clinically for the treatment of ADHD and narcolepsy, is also a DAT reuptake inhibitor. tMP is somewhat structurally similar to abused cathinone stimulants, and the structure-activity relationships (SAR) of tMP have been well-defined. Hence, available tMP literature might assist in understanding the SAR of synthetic cathinones, about which less is known. In the present study, we synthesized and examined eight 2-benzoylpiperidine analogues (4, 6-12) to determine if tMP SAR might be applicable to cathinone SAR. The benzoylpiperidine analogues were evaluated in a competition assay using live-cell imaging against APP+ in HEK293 cells stably expressing hDAT and in cells coexpressing DAT and voltage-gated Ca2+ channels. All compounds were found to be DAT reuptake inhibitors, and a significant correlation was obtained between the potency of the benzoylpiperidines and tMP binding data (r = 0.91), suggesting that the SAR of tMP analogues might be directly applicable to certain synthetic cathinones as DAT reuptake inhibitors.
- Yadav-Samudrala, Barkha J.,Eltit, Jose M.,Glennon, Richard A.
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p. 4043 - 4050
(2019/09/07)
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- Hydrogenation of Pyridines Using a Nitrogen-Modified Titania-Supported Cobalt Catalyst
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Novel heterogeneous catalysts were prepared by impregnation of titania with a solution of cobalt acetate/melamine and subsequent pyrolysis. The resulting materials show an unusual nitrogen-modified titanium structure through partial implementation of nitrogen into the support. The optimal catalyst displayed good activity and selectivity for challenging pyridine hydrogenation under acid free conditions in water as solvent.
- Chen, Feng,Li, Wu,Sahoo, Basudev,Kreyenschulte, Carsten,Agostini, Giovanni,Lund, Henrik,Junge, Kathrin,Beller, Matthias
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supporting information
p. 14488 - 14492
(2018/10/26)
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- Regio- and Stereoselective Alkylation of Pyridine-N-oxides: Synthesis of Substituted Piperidines and Pyridines
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Regio- and stereoselective addition of alkyl Grignard reagents to pyridine-N-oxides gave C2-alkylated N-hydroxy-1,2,5,6-tetrahydropyridines and trans-2,3-disubstituted N-hydroxy-1,2,5,6-tetrahydropyridines in good to excellent yields. These intermediates were aromatized or alternatively reduced in one-pot methodologies for efficient syntheses of alkylpyridines or piperidines, respectively. These reactions have a broad substrate scope and short reaction times.
- Barange, Deepak Kumar,Johnson, Magnus T.,Cairns, Andrew G.,Olsson, Roger,Almqvist, Fredrik
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supporting information
p. 6228 - 6231
(2016/12/23)
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