- Elimination reactions of N-alkyl-N-chlorothenylamines promoted by MeONa-MeOH and Et2NH-MeCN. Effect of the β-aryl group on the imine-forming transition state
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Elimination reactions of N-alkyl-N-chlorothenylamines 1-4 with MeONa-MeOH and Et2NH-MeCN have been studied kinetically. The elimination reactions are regiospecific, producing only the conjugated imines. The reactions are second order and exhibit substantial values of Hammett ρ and k H/kD, and an E2 mechanism is evident. The relative rates of elimination for Me/Et/i-Pr/i-Bu substituents are 1/0.5/0.2/0.02 with MeONa-MeOH and 1/0.4/0.2/0.06 with Et2NH-MeCN. The transition state structure changes toward more product-like as the base is changed from MeONa-MeOH to Et2NH-MeCN. Comparison with existing data reveals that the structure of the transition state is relatively insensitive to the β-aryl group variation.
- Pyun, Sang Yong,Lee, Dong Choon,Seung, Yoon Je,Cho, Bong Rae
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- Mild Metal-Free Hydrosilylation of Secondary Amides to Amines
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The combination of amide activation by Tf2O with B(C6F5)3-catalyzed hydrosilylation with TMDS constitutes a method for the one-pot reduction of secondary amides to amines under mild conditions. The method displays a broad applicability for the reduction of many types of substrates, and shows good compatibility and excellent chemoselectivity for many sensitive functional groups. Reductions of a multifunctionalized α,β-unsaturated amide obtained from another synthetic methodology, and a C-H functionalization product produced the corresponding amines in good to excellent yield. Chemoselective reduction of enantiomeric pure (ee >99%) tetrahydro-5-oxo-2-furaneamides yielded 5-(aminomethyl)dihydrofuran-2(3H)-ones in a racemization-free manner. The latter were converted in one pot to N-protected 5-hydroxypiperidin-2-ones, which are building blocks for the synthesis of many natural products. Further elaboration of an intermediate led to a concise four-step synthesis of -epi-pseudoconhydrine.
- Huang, Pei-Qiang,Lang, Qi-Wei,Wang, Yan-Rong
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p. 4235 - 4243
(2016/06/09)
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- General and environmentally friendly synthesis of heterocyclic multidentate molecules based on microwave-assisted heating protocol
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An efficient microwave heating methodology for the synthesis of heterocyclic multidentate molecules is reported. Each compound was obtained with high yield and purity in a few minutes from easily available starting materials such as amines, heteroaldehydes and N-hydroxymethyl pyrazoles or triazoles. In addition, this approach allows synthesis without any solvent or organic and inorganic by-products.
- Regnier, Thomas,Lavastre, Olivier
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p. 155 - 159
(2007/10/03)
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- S-SUBSTITUTED N-1- (HETERO)ARYL ALKYL-N - (HETERO)ARYL ALKYLYSOTHIOCARBAMIDES, METHOD FOR THE PRODUCTION THEREOF, PHYSIOLOGICALLY ACTIVE S-SUBSTITUTED N-1- (HETERO )ARYL ALKYL-N - (HETERO)ARYL ALKYLYSOTHIOCARBAMIDES,A PHARMACEUTICAL COMPOUND AND CURING METHOD
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The invention relates to s-substituted N-1-[(hetero)aryl]alkyl-N-1-[(hetero)aryl]alkylysothio-carbamides and the physiologically active salts and bases thereof, embodied in the form of racemic mixtures (or stereoisomer mixture) or individual optical isomers. The specific physiological activity of said compounds makes it possible to use them in the form of molecular tools. Said invention also relates to Pharmaceutical compositions, containing said compounds and to a method for preventing and curing various diseases including neurodegenerative diseases as, for example Alzheimer's disease (AD). The pharmacological effect of said compounds is based on the combined cognitive-stimulating and neuroprotective action thereof, which is produced by acting on chemo-controlled calcium channels of neurone membranes, in particular the neurones regulated by glutamate receptors of the central neural system (CNS).
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Page/Page column 11
(2008/06/13)
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