- 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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- 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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- Benzofuran derivatives, pharmaceutical composition containing the same, and a process for the preparation of the active ingredient
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The present invention is a piperazinylalkylbenzofuran derivative of the formula wherein R1 represents a C1-4 alkyl group, R2 stands for a hydrogen atom, X means an oxygen atom, Y is a hydroxyl group, Z represents a hydrogen atom, Ar′ represents a diphenylmethyl group, a pyridyl group, a partially saturated 5-membered heterocyclic group or a phenyl group, n has a value of 0 or 1, and pharmaceutically suitable acid addition salts thereof.
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- Asymmetric Hetero Diels-Alder Reactions in Aqueous Solution Using Amino Acid Esters as Chiral Auxiliaries
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(R)- and (S)-amino acid methyl ester hydrochlorides form with formaldehyde in THF/water mixtures iminium ions, which react already at 0 deg C as electron-deficient dienophiles in hetero Diels-Alder reactions with cyclopentadiene, cyclohexadiene, and open-
- Waldmann, Herbert
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p. 231 - 238
(2007/10/02)
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