- Reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3as a reductant
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Herein, we report the first example of efficient reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3 as a catalyst and a reductant under mild conditions, affording various tertiary and secondary amines in excellent yields. A mechanistic study indicates that BH3N(C2H5)3 plays a dual function role of promoting imine and iminium formation and serving as a reductant in reductive amination. This journal is
- Zou, Qizhuang,Liu, Fei,Zhao, Tianxiang,Hu, Xingbang
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supporting information
p. 8588 - 8591
(2021/09/04)
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- A novel method for N-alkylation of aliphatic amines with ethers over ?3-Al2O3
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A novel and simple method for the N-alkylation of amines with different ethers as alkylating reagents has been developed, using cheap ?3-Al2O3 as the catalyst at atmospheric pressure in the temperature range of 260-320?°C. For example, the reaction of equ
- Chen, Hangeng,Zhang, Tao,Qian, Chao,Chen, Xinzhi
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p. 537 - 540
(2015/03/05)
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- Kinetics and Mechanisms of Nucleophilic Displacements with Heterocycles as Leaving Groups. Part 22. Reactions with Various Nucleophiles and a Study of the Effects of Substrate Concentrations, Traces of Water, ands Nature of the Gegenion on the Rates
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First- and second-order rate components for the nucleophilic displacements of a variety of N-(primary alkyl), N-(secondary alkyl), and N-benzyl substituents from mono-, bi-, and tri-cyclic pyridine leaving groups by various nucleophiles are independent of substrate concentration, of the nature of the gegenion, and of traces of water in the solvent.Thus assumptions implicit in the reasoning of earlier papers of this series are confirmed, and the conclusion that these nucleophilic displacements can proceed by five independent mechanistic pathways is strengthened.First-order rate components are invariant with the nature of the nuclephile.Second-order rate components vary with nucleophile nucleophilicity in a way that parallels Menschutkin reactions.Activation enthalpies for first-order components are less negative than those for second-order components, in agreement with previous data.
- Katritzky, Alan R.,Schultz, Hanna,Lopez-Rodriguez, Maria L.,Musumarra, Giuseppe,Cirma, Giuseppe
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- Conveniant Method for Replacement of Tertiary N-Methyl by Other Alkyl Groups: Application to Morphine Alkaloids
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The replacement of N-methyl of N-methylpiperidine (1), 4-methylmorpholine (4), 2-methyl-1,2,3,4-tetrahydroisoquinoline (7) and tropine (10) by n-propyl, n-butyl and isopropyl groups (3a-3c, 6c, 9a-9c and 12a-12c) has been achieved in high yields by quaternization of the respective tertiary amine with appropriate alkyl halide and demethylation of the resulting quaternary salt with thiophenoxide.It has been established that demethylation is strongly favoured over the removal of n-propyl and n-butyl groups, whereas deisopropylation occurs to some extent.Surprisingly, in the case of 11c, deisopropylation predominates.This method has been applied to morphine (13b), codeine (13d) and thebaine (14b) for similar replacements.The rapid quaternization of thebaine (14b) has been assigned to the absence of H-14 in this alkaloid.The fact that quaternary salts of thebaine, which are susceptible to aromatization of the nucleus by extrusion of the ethanamine chain, are smoothly demethylated to N-alkylnorthebaines (18a-18c) in good yields indicates that demethylation, a bimolecular nucleophilic displacement, competes very successfully with elimination reaction.
- Manoharan, T. Samuel,Madyastha, K. Madhava,Singh, B. B.,Bhatnagar, S. P.,Weiss, Ulrich
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- UNIMOLECULAR AND BIMOLECULAR TRANSFER OF N-SUBSTITUENTS FROM PYRIDINIUM CATIONS: EVIDENCE FOR A CLEAR MECHANISTIC CHANGEOVER
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N-Substituents in 2,4,6-triphenylpyridiniums are transferred to piperidine, morpholine and pyridine by unimolecular and/or bimolecular processes in chlorobenzene solution.These processes are quite distinct and afford no evidence for a mechanism intermediate between SN1 and SN2.
- Katritzky, Alan R.,Musumarra, Giuseppe,Sakizadeh, Kumars,El-Shafie, Sayed M. M.,Jovanovic, Bratislav
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p. 2697 - 2699
(2007/10/02)
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