127852-28-2Relevant articles and documents
Asymmetric Hydrogenation of 3,5-Bistrifluoromethyl Acetophenone in Pilot Scale with Industrially Viable Ru/Diphosphine-Benzimidazole Complexes
Xu, Liang,Huang, Zhi-Hong,Sandoval, Christian A.,Gu, Lian-Quan,Huang, Zhi-Shu
, p. 1137 - 1141 (2014)
A novel efficient asymmetric hydrogenation (AH) process was developed for the preparation of (R)-1-(3,5-bis(trifluoromethyl)phenyl)ethanol (3), using a catalyst Ru/(4R,5R)-(+)-4,5-bis(diphenylphosphinomethyl)-2,2-dimethyl-1,3-dioxoane-(R,R-Diop)-2R-(α-met
Efficient synthesis of (1R)-[3,5-bis(trifluoromethyl)phenyl] ethanol, a key intermediate for aprepitant, an NK-1 receptor antagonist
Vankawala, Pravinchandra J.,Kolla, Naveenkumar,Elati, Chandrashekar R.,Sreenivasulu,Kumar, K. Arun,Anjaneyulu, Yerrimilli,Venkatraman, Sundaram,Bhattacharya, Apurba,Mathad, Vijayavitthal T.
, p. 3439 - 3446 (2007)
Enzyme-catalyzed efficient synthesis of (1R)-[3,5-bis (trifluoromethyl) phenyl] ethanol (R)-(3), a key intermediate for aprepitant, via enantioselective transesterification of racemic 1-[3,5-bis (trifluoromethyl) phenyl] ethanol (RS)-3 using vinyl acetate as the acyl donor in the presence of Candida antarctica lipase-B (CAL-B) in an overall yield of 84% with >99% ee is described. Copyright Taylor & Francis Group, LLC.
Bioreduction of 3,5-bis(trifluoromethyl)acetophenone using ionic liquid as a co-solvent catalyzed by recombinant Escherichia coli cells
Wang, Nengqiang,Li, Jun,Sun, Jing,Huang, Jin,Wang, Pu
, p. 119 - 125 (2015)
We investigated the asymmetric bioreduction of 3,5-bis(trifluoromethyl) acetophenone (BTAP) to (R)-[3,5-bis(trifluoromethyl) phenyl] ethanol ((R)-BTPE) in a hydrophilic quaternary ammonium-based ionic liquid (IL)-containing system to improve the efficiency of bioreduction catalyzed by recombinant Escherichia coli cells overexpressing carbonyl reductase. Based on the low toxicity to microbial cells and moderately increased cell membrane permeability, tetramethylammonium cysteine ([N1,1,1,1][Cys]) was selected and employed as co-solvent. Some key reaction parameters involved in the bioreduction were also investigated in the [N1,1,1,1][Cys]-containing system. The optimum conditions for the process were found to be: 3.5% (w/v) [N1,1,1,1][Cys], 20% (v/v) isopropanol, 1. M BTAP, 12.7. g/L of recombinant E. coli cells, pH 6.8, reaction for 12. h at 30. °C. A 98.7% yield (with >99 % of enantiomeric excess (ee)) was obtained under the optimum conditions. The biocatalytic process was scaled up to a 5. L fermentor afforded high reaction yield in IL-containing system. The results demonstrated that the IL [N1,1,1,1][Cys] is a useful co-solvent to improve bioreduction process and may has potential applications in various biocatalytic reactions.
Identification of ketone reductase ChKRED20 from the genome of Chryseobacterium sp. CA49 for highly efficient anti-Prelog reduction of 3,5-bis(trifluoromethyl)acetophenone
Liu, Yan,Tang, Tuo-Xian,Pei, Xiao-Qiong,Zhang, Chao,Wu, Zhong-Liu
, p. 1 - 8 (2014)
A strain of Chryseobacterium sp. CA49 was isolated to perform efficient anti-Prelog reduction of 3,5-bis(trifluoromethyl)acetophenone (1a) to enantiopure (R)-3,5-bis(trifluoromethyl)-1-phenylethanol ((R)-1b), a key intermediate for the chiral drug Aprepit
Effective synthesis of (S)-3,5-bistrifluoromethylphenyl ethanol by asymmetric enzymatic reduction
Pollard, David,Truppo, Matthew,Pollard, Jennifer,Chen, Cheng-yi,Moore, Jeffrey
, p. 554 - 559 (2006)
The synthesis of (S)-3,5-bistrifluoromethylphenyl ethanol, a pharmaceutically important alcohol intermediate for the synthesis of NK-1 receptor antagonists, was demonstrated from a ketone via asymmetric enzymatic reduction. The isolated enzyme alcohol dehydrogenase from Rhodococcus erythropolis reduced the poorly water soluble substrate with excellent ee (>99.9%) and good conversion (>98%). The optimized process was demonstrated up to pilot scale using high substrate concentration (390 mM) using a straightforward isolation process achieving excellent isolation yields (>90%) and effective space time yield (100-110 g/L d). Process improvements, demonstrated at preparative scale, increased the substrate concentration to 580 mM achieving a space time yield of 260 g/L d.
Influence of cofactor regeneration strategies on preparative-scale, asymmetric carbonyl reductions by engineered escherichia coli
Dascier, Dimitri,Kambourakis, Spiros,Hua, Ling,David Rozzell,Stewart, Jon D.
, p. 793 - 800 (2014)
This study was designed to determine whether whole cells or crude enzyme extracts are more effective for preparative-scale ketone reductions by dehydrogenases as well as learning which cofactor regeneration scheme is most effective. Based on results from
High-yielding metalloenzymatic dynamic kinetic resolution of fluorinated aryl alcohols
Bogár, Krisztián,B?ckvall, Jan-E.
, p. 5471 - 5474 (2007)
Dynamic kinetic resolution (DKR) of various fluorinated aryl alcohols by a combination of lipase-catalyzed enzymatic resolution with in situ ruthenium-catalyzed alcohol racemization is described. (R)-Selective Candida antarctica lipase B (CALB) was employed for transesterification of different fluoroaryl alcohols in DKR reactions delivering the corresponding acetates in high yield (≥97%) with excellent enantiomeric excess (≥98%).
Half-sandwich ruthenium catalyst bearing an enantiopure primary amine tethered to an N-heterocyclic carbene for ketone hydrogenation
Wan, Kai Y.,Sung, Molly M. H.,Lough, Alan J.,Morris, Robert H.
, p. 6827 - 6842 (2017)
By using a copper transmetalation reagent [Cu-(Kaibene)2]I, the NHC ligand (S,S)-MeNC3H2NCHPhCHPhNH2 "Kaibene" was transferred to ruthenium to make a precatalyst [RuCp?(Kaibene)(MeCN)](PF6) (Cp? = 1,2,3,4,5-pentamethylcyclopentadienyl), 7, in high yield as a mixture of two diastereomers. Under relatively mild conditions (0.02 mol % Ru, 0.16 mol % KOtBu, iPrOH, 50 °C, 25 bar of H2), this compound catalyzes the hydrogenation of aryl ketones and one alkyl ketone effectively with excellent activity and productivity (TOF up to 48 s-1, TON up to 104). At higher hydrogenation pressure (46 bar), the catalytic hydrogenation of N-phenyl-benzylimine to the corresponding amine is efficiently achieved. The hydrogenation of prochiral ketones resulted in low ee (35% for 4-chloroacetophenone). NMR spectroscopy was used to observe diastereomeric hydrides RuCp?(Kaibene)(H) 13-R/S that were generated by reaction of 7 with H2 and base in THF-d8. Complementary DFT studies suggest that either the heterolytic splitting of dihydrogen to form 13-R/S or the hydride transfer to the substrate can be rate-determining depending on the substrate. Experimental and computational results support mechanisms that involve the heterolytic splitting of dihydrogen to the nitrogen of the amide-ligated form of Kaibene in THF or the heterolytic splitting to an outer-sphere alkoxide derived from the product alcohol or 2-PrOH solvent. An unusual feature is the rapid drop in ee of the product alcohol from as high as 60% (R) to 0% in some cases; this might be due to racemization of the Kaibene ligand in THF caused by the strong base or competitive inhibition of one diastereomer of the catalyst by reaction with the product (R)-alcohol.
Enantioselective ketone hydrogenation: From R&D to pilot scale with industrially viable Ru/phosphine-oxazoline complexes
Naud, Frederic,Spindler, Felix,Rueggeberg, Carsten J.,Schmidt, Andreas T.,Blaser, Hans-Ulrich
, p. 519 - 523 (2007)
The development of a pilot process for the enantioselective hydrogenation of 3,5-bistrifluoromethyl acetophenone (BTMA) using a Ru/phosphine-oxazoline complex in toluene in the presence of aqueous NaOH is described. Various reaction parameters and quality
Cobalt-catalyzed asymmetric hydrogenation of ketones: A remarkable additive effect on enantioselectivity
Du, Tian,Wang, Biwen,Wang, Chao,Xiao, Jianliang,Tang, Weijun
supporting information, p. 1241 - 1244 (2020/10/02)
A chiral cobalt pincer complex, when combined with an achiral electron-rich mono-phosphine ligand, catalyzes efficient asymmetric hydrogenation of a wide range of aryl ketones, affording chiral alcohols with high yields and moderate to excellent enantioselectivities (29 examples, up to 93% ee). Notably, the achiral mono-phosphine ligand shows a remarkable effect on the enantioselectivity of the reaction.
Effectiveness and Mechanism of the Ene(amido) Group in Activating Iron for the Catalytic Asymmetric Transfer Hydrogenation of Ketones
Xue, Qingquan,Wu, Rongliang,Wang, Di,Zhu, Meifang,Zuo, Weiwei
supporting information, p. 134 - 147 (2021/02/05)
I-interacting ligands of the diphosphino amido-ene(amido) type are effective in activating iron to resemble the properties of precious metals in the catalytic asymmetric transfer hydrogenation of ketones. To further verify the effectiveness of the ene(amido) group, we synthesized four amine(imine) diphosphine iron precatalyst complexes with substituents at α and β positions relative to imino groups (1-3) or with enlarged chelate ring sizes (5,5,6-membered rings) (4). In comparison with the parent trans-(R,R)-[Fe(CO)(Cl)(PPh2CH2CHaNCHPhCHPhNHCH2CH2PPh2)]BF4 (I), the introduction of a methyl group in 1 and 2 reduced the catalytic activity but led to undiminished enantioselectivity as reaction proceeded. In comparison to the iron complexes 1-3 with a 5,5,5-coordination geometry, the complex 4 derived from the new (R,R)-P-NH-NH2 tridentate ligand showed high reactivity comparable to that of I but was unfortunately not enantioselective. The catalytic reactivity of 1, 2, and 4 illustrates the effectiveness of the ene(amido) group. An electronic structure study on the important catalytic intermediate amido-ene(amido) complex 1b proved that iron was activated by an additional I-back-donation-interaction ligand to participate in the traditional metal-ligand bifunctional pathway in the asymmetric transfer hydrogenation reactions.
Tridentate nitrogen phosphine ligand containing arylamine NH as well as preparation method and application thereof
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Paragraph 0095-0102; 0105-0109, (2021/06/26)
The invention discloses a tridentate nitrogen phosphine ligand containing arylamine NH as well as a preparation method and application thereof, and belongs to the technical field of organic synthesis. The tridentate nitrogen phosphine ligand disclosed by the invention is the first case of tridentate nitrogen phosphine ligand containing not only a quinoline amine structure but also chiral ferrocene at present, a noble metal complex of the type of ligand shows good selectivity and extremely high catalytic activity in an asymmetric hydrogenation reaction, meanwhile, a cheap metal complex of the ligand can also show good selectivity and catalytic activity in the asymmetric hydrogenation reaction, and is very easy to modify in the aspects of electronic effect and space structure, so that the ligand has huge potential application value. A catalyst formed by the ligand and a transition metal complex can be used for catalyzing various reactions, can be used for synthesizing various drugs, and has important industrial application value.