79-50-5Relevant academic research and scientific papers
Adsorption and stability of chiral modifiers based on 1-(1-naphthyl)-ethylamine for Pt catalysed heterogeneous asymmetric hydrogenations
Meemken, Fabian,Steiger, Titian,Holland, Mareike C.,Gilmour, Ryan,Hungerbühler, Konrad,Baiker, Alfons
, p. 705 - 715 (2015)
Synthetic chiral modifiers suitable for modular build-up are highly desirable for tuning the efficiency and extending the versatility of asymmetric hydrogenations on chirally-modified metal catalysts. Adsorptive anchoring and structural stability of the simple chiral modifier (R)-1-(1-naphthyl)-ethylamine [(R)-NEA] and the upgraded, secondary amine chiral modifier (R,S)-pantoylnaphthylethylamine [(R,S)-PNEA] have been investigated under catalytic hydrogenation conditions. Using attenuated total reflection-infrared (ATR-IR) spectroscopy the adsorption modes of (R)-NEA and (R,S)-PNEA at the solid-liquid interface of a technical 5 wt% Pt/Al2O3 catalyst were investigated. In addition to the naphthalene group, (R,S)-PNEA is also anchored to Pt through its pantoyl moiety providing both enhanced anchoring and also a better defined chiral surface site for the asymmetric hydrogenation of ketopantolactone (KPL). Factors influencing the stability of NEA-based chiral modifiers are discussed. The recently discovered chiral fragmentation product of (R,S)-PNEA, (S)-amino-4,4-dimethyl-dihydrofuran-2-one [(S)-AF] is shown to play no role in conferring enantioselectivity in the asymmetric hydrogenation of KPL.
Synthesis process of D-pantolactone as D-calcium pantothenate intermediate
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Paragraph 0020; 0022-0032, (2021/06/23)
The invention provides a synthesis process of D-pantolactone serving as a D-calcium pantothenate intermediate. The process is characterized by comprising the following steps: S1, adding isobutyraldehyde, dimethyl oxalate, formaldehyde and sodium hydroxide into a reaction kettle according to an equal molar mass ratio, raising the temperature to 120 DEG C from 30 DEG C, keeping the temperature for 4 hours, and distilling to remove methanol in the product to obtain an intermediate D-pantolactone. According to the method, a catalyst is generated in situ under the condition of adopting Ir (COD) Hpo3] 2, a ligand and an alkaline additive, and under the condition of the catalyst, hydrogen is introduced to carry out asymmetric catalytic hydrogenation reaction on ketopantolactone, so that the chiral D-pantolactone with high reaction activity and selectivity can be obtained. The synthesis method is mild in hydrogenation reaction condition, and is suitable for various ketopantolactone derivatives; the substrate is wide in application range; and the reaction process causes little pollution to the environment.
Industrial kinetic resolution ofd,l-pantolactone by an immobilized whole-cell biocatalyst
Huang, Liu-Nv,Luo, Wen-Fang,Tang, Yi-Bin,Yang, Liu,Zhang, Qiu-Hua
, p. 30373 - 30376 (2021/10/20)
Immobilized whole-cells ofPichia pastorisharboring recombinantd-lactonase were entrapped in calcium alginate gels and used as an efficient biocatalyst for catalytic kinetic resolution ofd,l-pantolactone. The immobilized whole-cell biocatalyst exhibited good catalytic stability, which was applied for stereospecific hydrolysis ofd-pantolactone for up to 56 repeated batch reactions without obvious loss in the catalytic activity and enantioselectivity.
Preparation method of DL-pantoic acid lactone
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Paragraph 0042; 0046-0048; 0052-0054; 0058-0064, (2021/02/06)
The invention discloses a preparation method of DL-pantoic acid lactone, which comprises the following steps: reacting formaldehyde with isobutyraldehyde in the presence of a basic catalyst, slowly dropwise adding the reaction solution into sodium cyanide, adding an acid solution after the reaction is finished, and carrying out esterification reaction to obtain the DLpantoic acid lactone. The reaction is carried out in a water system, high-temperature and high-pressure reaction conditions are not needed, the process safety performance is high, the energy-saving and consumption-reducing effectsare obvious, and a high-content target product is obtained at a high yield, so that the production cost is reduced, and the method is a safe and simple DL-pantoic acid lactone production method.
Preparation method of hydroxyaldehyde and method for resolving optical isomer by using electrodialysis technology
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Paragraph 0265-0267, (2020/12/15)
The present invention provides a process for preparing hydroxyaldehydes using an immobilized catalyst, wherein the immobilized catalyst comprises a solid support and a tertiary amine-based functionalgroup. The invention also provides a method for preparing a polyhydroxy alcohol compound and a polyhydroxy acid compound. The invention further provides a method for splitting the optical isomer fromthe raceme through electrodialysis.
Catalyst Repurposing Sequential Catalysis by Harnessing Regenerated Prolinamide Organocatalysts as Transfer Hydrogenation Ligands
Bourgeois, Frederic,Medlock, Jonathan A.,Bonrath, Werner,Sparr, Christof
supporting information, p. 110 - 115 (2019/12/30)
A catalyst repurposing strategy based on a sequential aldol addition and transfer hydrogenation giving access to enantiomerically enriched α-hydroxy-γ-butyrolactones is described. The combination of a stereoselective, organocatalytic step, followed by an efficient catalytic aldehyde reduction induces an ensuing lactonization to provide enantioenriched butyrolactones from readily available starting materials. By capitalizing from the capacity of prolineamides to act as both an organocatalyst and a transfer hydrogenation ligand, catalyst repurposing allowed the development of an operationally simple, economic, and efficient sequential catalysis approach.
Synthesis method of chiral 2-hydroxy-1, 4-dicarbonyl compound and pantoic acid lactone
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Paragraph 0079-0081, (2020/11/10)
The invention discloses a chiral 2-hydroxy-1, 4-dicarbonyl compound synthesized by catalyzing asymmetric Aldol reaction of fatty aldehyde and glyoxylate or fatty aldehyde and acylformaldehyde monohydrate by taking tetrapeptide TP or an enantiomer ent-TP thereof as a chiral catalyst, and application of a synthetic product. The method for synthesizing the chiral 2-hydroxy-1, 4-dicarbonyl compound through the asymmetric Aldol reaction is shown as a formula 1 and a formula 2. The asymmetric Aldol reaction of fatty aldehyde and glyoxylate or fatty aldehyde and acylformaldehyde monohydrate is catalyzed to synthesize the optically active 2-hydroxy-1, 4-dicarbonyl compound, then the optically active pantoic acid lactone can be further synthesized, and the method has advantages of mild reaction conditions, easy operation, low catalyst consumption, high yield and the like, and can synthesize the 2-hydroxy-1, 4-dicarbonyl compounds with two configurations by using tetrapeptide and the enantiomerthereof.
STEREOSELECTIVE SYNTHESIS OF ENANTIOMERICALLY-ENRICHED PANTOLACTONE
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Page/Page column 15, (2019/12/25)
The present invention relates stereoselective synthesis of enantiomerically enriched pantolactone.
Wittig Rearrangements of Boron-Based Oxazolidinone Enolates
Zhang, Zirong,Collum, David B.
, p. 10892 - 10900 (2019/09/07)
[2,3]-Sigmatropic rearrangements (Wittig rearrangements) of α-alkoxy oxazolidinone enolates are described. Whereas alkali metal enolates fail, owing to facile deacylation, boron enolates generated from di-n-butylboron triflate and triethylamine rearranged in good yields and high selectivities with exceptions noted. IR and NMR spectroscopies show the boron is chelated by the α-alkoxy group rather than the more distal oxazolidinone carbonyl in the complex and enolate. The rearrangement product contains a boron alkoxide that remains unchelated by either carbonyl. Optimization was guided by density functional theory computations, suggesting that valine-derived oxazolidinones would be superior to the phenylalanine-derived analogues.
SYNTHESIS OF A RACEMIC MIXTURE OF PANTOLACTONE
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Page/Page column 9, (2019/12/25)
The invention relates to an improved synthesis of a racemic mixture of pantolactone (I).
