72407-64-8Relevant articles and documents
Efficient resolution of (R,S)-1-(1-naphthyl)ethylamine by Candida antarctica lipase B in ionic liquids
Wang, Bin,Zhang, Chao,He, Qinting,Qin, Hengfei,Liang, Guobin,Liu, Weiqiao
, p. 116 - 121 (2018/03/01)
The resolution of (R,S)-1-(1-naphthyl)ethylamine ((R,S)-NEA) by Candida antarctica lipase B (CALB) in ionic liquids (ILs) containing 1-alkyl-3-methylimidazolium cations ([Cnmim]+) and [Tf2N]?, [BF4]?, and [PF6]? anions was investigated. When the alkyl chain on the cation contained less than six carbons, the lipase activity corresponded with the hydrophobicity of the ILs, but further increase in the chain length suppressed the enzyme activity. The enzyme activity decreased depending on the anion, where [Tf2N]? > [PF6]? > [BF4]?. The effects of acyl donors, pH, temperature, water activity, and substrate concentration on the resolution were determined. Under the optimal conditions, the conversion of (R,S)-NEA and enantiomer excess of (R)-n-octyl acyl-NEA was 49.3% and 99.2%, respectively. The resolution kinetics of (R,S)-NEA by CALB in [C6mim][Tf2N] were studied and a ping-pong mechanism with a two substrate inhibition model was selected. The kinetic parameters of the fitting results were as follows: Michaelis constant of (R,S)-NEA Kma, 461.8 mmol/L; Michaelis constant of vinyl n-octanoateKmb, 262.1 mmol/L; inhibition constant of (R,S)-NEA Kia, 8737.2 mmol/L; inhibition constant of vinyl n-octanoateKib, 62336.8 mmol/L; maximum reaction rate rmax, 0.352 mmol/(mg min). Moreover, circular dichroism revealed that incubation of CALB in [C6mim][Tf2N] resulted in increased β-sheet content; its secondary structure was stable.
Chiral recognition and kinetic resolution of aromatic amines via supramolecular chiral nanocapsules in nonpolar solvents
Kida, Toshiyuki,Iwamoto, Takuya,Asahara, Haruyasu,Hinoue, Tomoaki,Akashi, Mitsuru
supporting information, p. 3371 - 3374 (2013/04/24)
Herein we report the first example of chiral recognition and kinetic resolution of aromatic amine guests using supramolecular nanocapsules assembled from cyclodextrin derivatives in nonpolar media. With these nanocapsules, an extremely high chiral recognition of 1-(1-naphthyl)ethylamine (1) in cyclohexane was achieved, with a binding selectivity of up to 41 for (S)-1(R)-1. In addition, kinetic resolution of 1 through enantioselective N-acylation was accomplished with an enantiomeric excess of up to 91%.
Palladium catalysts on alkaline-earth supports for racemization and dynamic kinetic resolution of benzylic amines
Parvulescu, Andrei N.,Jacobs, Pierre A.,De Vos, Dirk E.
, p. 2034 - 2043 (2008/02/03)
Palladium catalysts on alka-line-earth supports were studied as new heterogeneous catalysts for racemization of chiral benzylic amines such as 1-phenylethylamine. Particularly 5% Pd/BaSO4 and 5% Pd/CaCO 3 were able to selectively racemize amines, with minimal formation of secondary amines or hydrogenolysis to ethylbenzene. In contrast, these side reactions were pronounced on Pd/C. A reaction mechanism is proposed that is consistent with the reaction kinetics. The catalyst activity was found to depend on the number of available surface Pd atoms, determined by titration with CO. The selectivity crucially depends on the rate of condensation of the amine and the primary imine. which is highest on Pd/C. The racemization catalysts were combined in one pot with an immobilized lipase to perform dynamic kinetic resolution of chiral amines. High yields (up to 88%) of essentially enantiopure amides were obtained in a single step. The chemo-enzymatic catalyst system proved to be stable and could be reused without losing the initial activity.
