- Direct β-Alkylation of Ketones and Aldehydes via Pd-Catalyzed Redox Cascade
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We report a direct β-alkylation of ketones and aldehydes with simple alkyl bromides through a Pd-catalyzed redox-cascade strategy. The use of a Cu cocatalyst is important for improved efficiency. The reaction is redox-neutral, without the need for strong acids or bases. Both cyclic and acyclic ketones, as well as α-branched aldehydes, are suitable substrates for coupling with secondary and tertiary alkyl bromides. Concise formal synthesis of Zanapezil is achieved using this β-alkylation method.
- Wang, Chengpeng,Dong, Guangbin
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p. 6057 - 6061
(2018/05/14)
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- Central Cholinergic Agents. 6. Synthesis and Evaluation of 3--1-(2,3,4,5-tetrahydro-1H-benzazepin-8-yl)-1-propanones and Their Analogs as Central Selective Acetylcholinesterase Inhibitors
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In an attempt to find central selective acetylcholinesterase (AChE) inhibitors, 3--1-(2,3,4,5-tetrahydro-1H-1-benzazepin-8-yl)-1-propanones 9 and their analogs were designed on the basis of our working hypothesis of the enzyme's active site.These compounds were prepared by regioselective Fridel-Crafts acylation of 2,3,4,5-tetrahydro-1H-1-benzazepines and related nitrogen heterocycles as a key step.Most compounds showed potent inhibitory activities with IC50s in the 10-300 nM range.In order to estimate their central selectivities, we examined their effects on the apomorphine-induced circling behavior in rats with unilateral striatal lesions.Among compounds with potent AChE inhibition, 3--1-(2,3,4,5-tetrahydro-1H-1-benzazepin-8-yl)-1-propanone fumarate (9a, TAK-147) (IC50 of AChE inhibition = 97.7 nM) inhibited the circling behavior at 3 mg/kg po, in which it had no significant effect on peripheral cholinergic effects.This demonstrates that 9a has favorable central selectivity.Furthermore, 9a significantly ameliorated diazepam-induced passive avoidance deficit at 1 mg/kg po.The benzazepine derivative 9a was selected as a candidate for clinical evaluation.
- Ishihara, Yuji,Hirai, Keisuke,Miyamoto, Masaomi,Goto, Giichi
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p. 2292 - 2299
(2007/10/02)
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