- Synthesis and in vitro biological evaluation of carbonyl group-containing analogues for σ1 receptors
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To identify the ligands for σ1 receptors that are potent and selective, analogues of prezamicol and trozamicol scaffolds of carbonyl-containing vesicular acetylcholine transporter (VAChT) inhibitors were explored. Of the 23 analogues synthesize
- Wang, Wei,Cui, Jinquan,Lu, Xiaoxia,Padakanti, Prashanth K.,Xu, Jinbin,Parsons, Stanley M.,Luedtke, Robert R.,Rath, Nigam P.,Tu, Zhude
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- Triphenylphosphine-Catalyzed Alkylative Iododecarboxylation with Lithium Iodide under Visible Light
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Under irradiation of 456 nm blue light-emitting diodes, PPh3 catalyzes the iododecarboxylation of aliphatic carboxylic acid derived N-(acyloxy)phthalimide with lithium iodide as an iodine source. The reaction delivers primary, secondary, and bridgehead te
- Fu, Ming-Chen,Shang, Rui,Wang, Jia-Xin
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supporting information
(2020/11/13)
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- Transamidation of: N -acyl-glutarimides with amines
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The development of new transamidation reactions for the synthesis of amides is an important and active area of research due to the central role of amide linkage in various fields of chemistry. Herein, we report a new method for transamidation of N-acyl-glutarimides with amines under mild, metal-free conditions that relies on amide bond twist to weaken amidic resonance. A wide range of amines and functional groups, including electrophilic substituents that would be problematic in metal-catalyzed protocols, are tolerated under the reaction conditions. Mechanistic experiments implicate the amide bond twist, thermodynamic stability of the tetrahedral intermediate and leaving group ability of glutarimide as factors controlling the reactivity of this process. The method further establishes the synthetic utility of N-acyl-glutarimides as bench-stable, twist-perpendicular, amide-based reagents in acyl-transfer reactions by a metal-free pathway. The origin of reactivity of N-acyl-glutarimides in metal-free and metal-catalyzed processes is discussed and compared.
- Liu, Yongmei,Achtenhagen, Marcel,Liu, Ruzhang,Szostak, Michal
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supporting information
p. 1322 - 1329
(2018/03/06)
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- Metal-Free Transamidation of Secondary Amides via Selective N-C Cleavage under Mild Conditions
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Nonplanar, electronically destabilized amides have emerged as powerful intermediates in organic synthesis. We report a highly selective method for transamidation of common secondary amides under mild, metal-free conditions that relies on transient N-selective functionalization to weaken amidic resonance. The combination of rational modification of the amide bond with nucleophilic addition mechanism, and the thermodynamic collapse of the resultant tetrahedral intermediate constitutes a two-step procedure to accomplish a challenging transamidation of secondary amides under mild conditions.
- Liu, Yongmei,Shi, Shicheng,Achtenhagen, Marcel,Liu, Ruzhang,Szostak, Michal
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p. 1614 - 1617
(2017/04/11)
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- A medium fluorous Grubbs-Hoveyda 2nd generation catalyst for phase transfer catalysis of ring closing metathesis reactions
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A fluorous Grubbs-Hoveyda metathesis catalyst supported on Teflon powder, that readily moves between the solid phase (Teflon) and the liquid phase (DMF) was prepared. By modulating the hydrophobicity of the reaction medium at the end of the reaction, the supported catalyst could be recovered by simple filtration even though the catalyst existed in a homogeneous state during the reaction. In RCM reactions, the catalyst could be reused up to three times with only a slight loss in reactivity with each subsequent cycle.
- Kobayashi, Yuki,Inukai, Sae,Kondo, Natsuki,Watanabe, Tomoko,Sugiyama, Yuya,Hamamoto, Hiromi,Shioiri, Takayuki,Matsugi, Masato
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supporting information
p. 1363 - 1366
(2015/03/04)
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- Palladium-catalyzed decarbonylative dehydration of fatty acids for the production of linear alpha olefins
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A highly efficient palladium-catalyzed decarbonylative dehydration reaction of carboxylic acids is reported. This method transforms abundant and renewable even-numbered natural fatty acids into valuable and expensive odd-numbered alpha olefins. Additionally, the chemistry displays a high functional group tolerance. The process employs a low loading of palladium catalyst and proceeds under solvent-free and relatively mild conditions.
- Liu, Yiyang,Kim, Kelly E.,Herbert, Myles B.,Fedorov, Alexey,Grubbs, Robert H.,Stoltz, Brian M.
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supporting information
p. 130 - 136
(2014/03/21)
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- PALLADIUM-CATALYZED DECARBONYLATION OF FATTY ACID ANHYDRIDES FOR THE PRODUCTION OF LINEAR ALPHA OLEFINS
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The present invention is directed to methods of forming olefins, especially linear alpha olefins from fatty acids or anhydrides, each method comprising: contacting an amount of precursor carboxylic acid anhydride with a palladium catalyst comprising a bidentate bis-phosphine ligand in a reaction mixture so as to form an olefin in a product with the concomittant formation and removal of CO and water from the reaction mixture, either directly or indirectly, wherein the reaction mixture is maintained with a sub-stoichiometric excess of a sacrificial carboxylic acid anhydride, an organic acid, or both, said sub-stoichiometric excess being relative to the amount of the precursor carboxylic acid anhydride. The precursor carboxylic acid anhydride may be added to the reaction mixture directly or formed in situ by the reaction between at least one precursor carboxylic acid with a stoichiometric amount of the sacrificial acid anhydride.
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Page/Page column
(2014/06/23)
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- The oxidative dealkylation of tertiary amides: Mechanistic aspects
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N-(But-3-enyl)-N-methylbenzamide 14a undergoes microsomal oxidation by rat liver microsomes to yield both N-methyl- and N-(but-3-enyl)benzamides 18a and 19, the products of N-dealkylation. Cyclic products, that could be derived from a carbon-centered radical formed by hydrogen atom abstraction from the N-methyl group, were not observed. When generated independently, this carbon-centred radical underwent cyclisation, the 5-exo-trig mode being preferred to 6-endo-trig by a factor of 5. In contrast, N-(but-3-ynyl)-N-methylbenzamide 15 undergoes microsomal oxidation to yield the products of dealkylation 18a and 23 and also N-benzoylpiperidone 24. Dealkylation is preferred by factor of 3 and the piperidone accounts for ca. 45% of the reaction at the N-methyl group. Piperidone formation is consistent with the generation of a carbon-centred radical α- to the amide nitrogen atom during dealkylation and implies that cyclisation proceeds preferentially via the 6-endo-dig mode. Generated independently the radical undergoes cyclisation by both 5-exo-dig and 6-endo-dig modes, the former being favoured by a factor of 10. Similarly, N,N-dimethylacrylamide 26 and N-methyl-N-(3-pyridyl)acrylamide 27 undergo microsomal oxidation to form, via the 5-endo-trig cyclisation mode, 3-hydroxy-N-methyl-2-pyrrolidone 33 and 3-hydroxycotinine ? 34, respectively, confirming the intermediacy of a carbon-centred radical in the dealkylation process. Attempts to trap N-acyliminium ions during microsomal dealkylation failed. Thus, although N,N-dimethylaniline 35 reacts in the presence of NaCN to form N-cyanomethyl-N-methylaniline 37 (Nu=CN), N,N-dimethylbenzamide undergoes dealkylation without forming N-cyanomethyl-N-methylbenzamide. Similarly, microsomal reaction of N,N-dimethylaniline in the presence of NaBD4 gives rise to multiple incorporation of deuterium atoms into the methyl groups of the starting material, whereas N,N-dimethylbenzamide undergoes dealkylation but with no such deuterium incorporation into the starting material. Further, microsomal oxidation of N,N-dimethylsalicylamide 38 yields N-methylsalicylamide 40 with no evidence for the formation of N-methyl-2,3-dihydro-4H-1,3-benzoxazin-4-one 39, the potential product of intramolecular cyclisation of the phenolic oxygen atom onto the putative N-aroylmethylene iminium ion.
- Iley, Jim,Tolando, Roberto
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p. 2328 - 2336
(2007/10/03)
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- Nonsymmetrical bipiperidyls as inhibitors of vesicular acetylcholine storage
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Introduction of a nitrogen atom into the cyclohexane ring of 2-(4- phenylpiperidinyl)cyclohexanol (vesamicol, AH5183) yielded two positional isomers, 5-azavesamicol (5, prezamicol) and 4-azavesamicol (6, trozamicol). As inhibitors of vesicular acetylcholi
- Efange,Khare,Parsons,Bau,Metzenthin
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p. 985 - 989
(2007/10/02)
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- Electrophilic α-amidoalkylation with enamides according to a new activation procedure using O,O'-dimethyldithiophosphoric acid
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The allylic amides 3a-d are rearranged to give enamides 4a-d using Pd-C as a catalyst. 4a-d and 10 are employed in an electrophilic α-amidoalkylation reaction with silyl enol ether 6 yielding the amido ketones 8a-d and 12. The enamides are activated for t
- Wanner,Wolf
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p. 799 - 802
(2007/10/02)
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- Tests of a Piperidino Mask for the Protection of Functionalized Carbon Sites in Multistep Syntheses
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Primary alkyl chlorides (R-Cl) are easily isolated in excellent yield after treatment of the appropriate N-alkylpiperidines (R-NC5H10) with α-chloroethyl chloroformate.The method is exemplified by the conversion of a variety of alkylpiperidines, including systems with other sensitive functionalities, to the respective chlorides in yields varying from 90 to 97percent.The potential significance of this process in drug congener preparation and in total synthesis is outlined.Similar fragmentations of N-sec-alkylpiperidines are described.
- Olofson, R. A.,Abbott, Duain E.
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p. 2795 - 2799
(2007/10/02)
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