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
Mn(i) phosphine-amino-phosphinites: a highly modular class of pincer complexes for enantioselective transfer hydrogenation of aryl-alkyl ketones
Jayaprakash, Harikrishnan
supporting information, p. 14115 - 14119 (2021/10/25)
A series of Mn(i) catalysts with readily accessible and more π-accepting phosphine-amino-phosphinite (P′(O)N(H)P) pincer ligands have been explored for the asymmetric transfer hydrogenation of aryl-alkyl ketones which led to good to high enantioselectivities (up to 98%) compared to other reported Mn-based catalysts for such reactions. The easy tunability of the chiral backbone and the phosphine moieties makes P′(O)N(H)P an alternative ligand framework to the well-known PNP-type pincers.
Method for refining chiral alcohol
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Paragraph 0102-0143, (2021/04/10)
The invention relates to a method for refining chiral alcohol shown as a formula (I). The method comprises the following steps: providing a crude product of the chiral alcohol shown as the formula (I); refining the crude product of chiral alcohol shown in the formula (I) by adopting a refining solvent to prepare a refined product of chiral alcohol shown in the formula (I); wherein the refining solvent is selected from at least one of diethyl ether, n-heptane, methyl tert-butyl ether and isopropyl ether; according to the refining method of the chiral alcohol, on the basis of ensuring the yield of the chiral alcohol, the residual quantity of process impurities can be controlled to be below 0.3%. The refining method is simple, special instruments and equipment are not needed, special operation skills are also not needed, and therefore the refining method is particularly suitable for industrial production and application.
A Cobalt(II) Complex Bearing the Amine(imine)diphosphine PN(H)NP Ligand for Asymmetric Transfer Hydrogenation of Ketones
Huo, Shangfei,Chen, Hong,Zuo, Weiwei
supporting information, p. 37 - 42 (2020/10/21)
Novel chiral cobalt complex a containing amine(imine)diphosphine PN(H)NP ligand and complex b containing bis(amine)diphosphine PN(H)N(H)P ligand were synthesized. The structures of two complexes were characterized by X-ray crystallography and high resolution mass spectrometry. The catalytic performances of cobalt complexes a and b for asymmetric transfer hydrogenation (ATH) of ketones under mild conditions were evaluated using 2-propanolisopropanol as solvent and hydrogen source after being activated by 8 equivalents of base. Complex a showed a good reactivity for reduction of ketones, with a turnover number (TON) of up to 555, and a maximum enantiomeric excess (ee) value of up to 91 %. Complex b exhibited inertness for hydrogenation of ketones. Electronic structure studies on a and b were conducted to account for the function of ligands on the catalytic performances.
