- Synthesis of 3-Aryl-1-aminopropane Derivatives: Lithiation-Borylation-Ring-Opening of Azetidinium Ions
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In situ generated 2-phenyl-azetidinium ylides react with boronic esters to form acyclic γ-dimethylamino tertiary boronic esters. The transformation is believed to involve the formation of a zwitterionic boronate, which subsequently undergoes ring-opening 1,2-migration, which is promoted by the relief of ring strain. Owing to the configurational instability of the initially formed ylides, which appear to be in equilibrium with the open-chain carbene form, the reaction is not stereospecific. The C-B bond of the γ-dimethylamino tertiary boronic esters can be transformed into a variety of functional groups (C-OH, C-vinyl, C-H, C-BF3), thus giving a diverse selection of 3-aryl-1-aminopropanes, which represent a privileged motif among drug molecules.
- Casoni, Giorgia,Myers, Eddie L.,Aggarwal, Varinder K.
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p. 3241 - 3253
(2016/09/12)
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- Conformations and Conformational Processes of Hexahydrobenzazocines by NMR and DFT Studies
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Conformational processes that occur in hexahydrobenzazocines have been studied with the 1H and 13C dynamic nuclear magnetic resonance (DNMR) spectroscopy. The coalescence effects are assigned to two different conformational processes: the ring-inversion of the ground-state conformations and the interconversion between two different conformers. The barriers for these processes are in the range of 42-52 and 42-43 kJ mol-1, respectively. Molecular modeling on the density functional theory (DFT) level and the gauge invariant atomic orbitals (GIAO)-DFT calculations of isotropic shieldings and coupling constants for the set of low-energy conformations were compared with the experimental NMR data. The ground-state of all compounds in solution is the boat-chair (BC) conformation. The BC form adopts two different conformations because the nitrogen atom can be in the boat or chair parts of the BC structure. These two conformers are engaged in the interconversion process.
- Musielak, Bogdan,Holak, Tad A.,Rys, Barbara
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p. 9231 - 9239
(2015/09/28)
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- EVOLUTION THERMIQUE DE DERIVES DES HEXAHYDROBENZAZOCINES-2 ET DES HEXAHYDRO-1H-BENZAZONINES-2 N-QUATERNARISES (AMMONIUMS, N-OXYDES)
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La thermolyse des hydroxydes d'ammonium derives des hexahydrobenzazocines-2 et de la methyl-2-hexahydro-1H benzazonine-2 conduit a un melange de composes ethyleniques .Les N-oxydes de N-methyl hexahydrobenzazocines-2 se decomposent thermiquement en derives de l'oxa-2 hexahydro-1H-benzazonines-3 souilles de la benzazocine de depart.
- Elmasmodi, Abdellatif,Barbry, Didier,Hasiak, Bruno,Couturier, Daniel
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p. 2767 - 2774
(2007/10/02)
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