61624-15-5Relevant academic research and scientific papers
Synthetically useful variants of industrial lipases from: Burkholderia cepacia and Pseudomonas fluorescens
Yoshida, Kazunori,Ono, Masakazu,Yamamoto, Takahiro,Utsumi, Takashi,Koikeda, Satoshi,Ema, Tadashi
supporting information, p. 8713 - 8719 (2017/11/03)
Industrial enzymes lipase PS (LPS) and lipase AK (LAK), which originate from Burkholderia cepacia and Pseudomonas fluorescens, respectively, are synthetically useful biocatalysts. To strengthen their catalytic performances, we introduced two mutations into hot spots of the active sites (residues 287 and 290). The LPS-L287F/I290A double mutant showed high catalytic activity and enantioselectivity for poor substrates for which the wild-type enzyme showed very low activity. The LAK-V287F/I290A double mutant was also an excellent biocatalyst with expanded substrate scope, which was comparable to the LPS-L287F/I290A double mutant. Thermodynamic parameters were determined to address the origin of the high enantioselectivity of the double mutant. The ΔΔH? term, but not the ΔΔS? term, was predominant, which suggests that the enantioselectivity is driven by a differential energy associated with intermolecular interactions around Phe287 and Ala290. A remarkable solvent effect was observed, giving a bell-shaped profile between the E values and the log&P or ? values of solvents with the highest E value in i-Pr2O. This suggests that an organic solvent with appropriate hydrophobicity and polarity provides the double mutant with some flexibility that is essential for excellent catalytic performance.
Kinetic resolution of mandelate esters via stereoselective acylation catalyzed by lipase PS-30
Chen, Peiran,Yang, Wenhong
supporting information, p. 2290 - 2294 (2014/04/17)
By using lipase PS-30 as catalyst, the kinetic resolution of a series of racemic mandelate esters has been achieved via stereoselective acylation. The value of kinetic enantiomeric ratio (E) reached up to 197.5. Substituent effect is briefly discussed.
Urea-induced acid amplification: A new approach for metal-free insertion chemistry
Couch, Erica D.,Auvil, Tyler J.,Mattson, Anita E.
supporting information, p. 8283 - 8287 (2014/07/08)
The enhanced catalytic activity of difluoroboronate ureas proved to be essential as an acidity amplifier to promote metal-free O-H and S-H insertion reactions of α-aryldiazoacetates in high yield. This methodology was found to be generally applicable to a
Lipase activity of Lecitase Ultra: characterization and applications in enantioselective reactions
Mishra, Mithilesh Kumar,Kumaraguru, Thenkrishnan,Sheelu, Gurrala,Fadnavis, Nitin W.
experimental part, p. 2854 - 2860 (2010/04/05)
The general properties of Lecitase Ultra, a phospholipase manufactured and marketed by Novozymes, Denmark, have been studied after purification by ultrafiltration. The enzyme has a molecular mass of 35 KD, pH-optimum of 8.5, and appears to possess a single active site which exhibits both the lipase and phospholipase activities that increase in the presence of Ca2+ and Mg2+ ions. The enzyme is inhibited by heavy metal ions and surfactants, and does not accept p-nitrophenyl acetate and glycerol triacetate. Substrates, such as glycerol tributyrate and p-nitrophenyl palmitate, esters of N-acetyl-α-amino acids and α-hydroxy acids are readily accepted. Amino acids with aliphatic residues, such as alanine, isoleucine, and methionine, are hydrolyzed with high enantioselectivity for the l-enantiomer (E >100), but amino acids with aromatic residues such as phenylalanine and phenylglycine, and esters of α-hydroxy acids are hydrolyzed with low enantioselectivity (E = 1-5). Immobilization of the enzyme in a gelatin matrix (gelozyme) leads to a marginal improvement in the enantioselectivity for these substrates. However, a dramatic improvement in enantioselectivity is observed for ethyl 2-hydroxy-4-oxo-4-phenylbutyrate (E value increases from 4.5 to 19.5 with S-selectivity). Similarly, glycidate esters, such as ethyl trans-(±)-3-phenyl glycidate and methyl trans-(±)-3-(4-methoxyphenyl) glycidate, are selectively hydrolyzed with a remarkable selectivity towards the (2S,3R)-enantiomer providing unreacted (2R,3S)-glycidate esters (ee >99%, conversion 52-55%) by the immobilized enzyme.
Convenient synthesis of a new class of chiral hydroxymethyl-dihydrooxazole ligands and their application in asymmetric addition of diethylzinc to aromatic aldehydes
Li, Zhi-Ting,Li, Xin-Sheng,Li, Liang-Chao,Xu, Dong-Cheng
, p. 545 - 549 (2007/10/03)
A number of chiral hydroxymethyl-substituted dihydrooxazoles were synthesized from D- or L-mandelic acid and amino alcohols. The chiral ligands thus obtained were tested as catalyst in the asymmetric addition of diethylzinc to aromatic aldehydes, and the
BIPIPERIDINYL DERIVATIVES USEFUL AS INHIBITORS OF CHEMOKINE RECEPTORS
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Page/Page column 45, (2008/06/13)
In its many embodiments, the present invention provides a novel class of bipiperidinyl compounds as inhibitors of the CCR5 receptors, methods of preparing such compounds, pharmaceutical compositions containing one or more such compounds, methods of preparing pharmaceutical formulations comprising one or more such compounds, and methods of treatment, prevention, inhibition, or amelioration of one or more diseases associated with CCR5 using such compounds or pharmaceutical compositions. The invention also relates to the use of a combination of a compound of this invention and one or more antiviral or other agents useful in the treatment of Human Immunodeficiency Virus (HIV). The invention further relates to the use of a compound of this invention, alone or in combination with another agent, in the treatment of solid organ transplant rejection, graft v. host disease, arthritis, rheumatoid arthritis, inflammatory bowel disease, atopic dermatitis, psoriasis, asthma, allergies or multiple sclerosis.
Dynamic kinetic resolution of α-hydroxy acid Esters
Huerta, Fernando F.,Laxmi, Y.R. Santosh,Baeckvall, Jan-E.
, p. 1037 - 1040 (2007/10/03)
Enzymatic resolution in combination with ruthenium-catalyzed racemization of the substrate led to dynamic kinetic resolution of α-hydroxy esters in good yields and excellent ee's. Studies of different parameters showed that the best results were obtained
N-acylpyridinium trifluoromethanesulfonates and tetrafluoroborates: Shuttle reagents for the acylation of enantiopure secondary alcohols
Wagner, Rüdiger,Günther, Wolfgang,Anders, Ernst
, p. 883 - 888 (2007/10/03)
Several enanflopure alcohols are esterified with N-acyl-4- benzylpyfidinium trifluoromethanesulfonates 7b,d,f or tetrafluoroborates 7a,c,e. These reagents, which can be generated in situ, or isolated as stable salts, are synthesized from readily available 4-alkylpyridines 3, acyl chlorides 4 and strong protic acids 6. The acyl moiety is transferred under neutral conditions and in high yields. The heterocyclic component 3a can be re-isolated almost quantitatively. The acetate, benzoate and pivaloate groups were selected with regard to their application as frequently used protecting groups for hydroxy compounds. As shown by paramagnetic shift experiments with a chiral europium(III) complex, these acylations proceed without detectable racemization or epimerization.
Tritiated chiral alkanes as substrates for soluble methane monooxygenase from Methylococcus capsulatus (Bath): Probes for the mechanism of hydroxylation
Valentine, Ann M.,Wilkinson, Barrie,Liu, Katherine E.,Komar-Panicucci, Sonja,Priestley, Nigel D.,Williams, Philip G.,Morimoto, Hiromi,Floss, Heinz G.,Lippard, Stephen J.
, p. 1818 - 1827 (2007/10/03)
The tritiated chiral alkanes (S)-[1-2H1, 1-3H]ethane, (R)-[1-2H1, 1-3H]ethane, (S)-[1-2H1, 1-3H]butane, (R)[1-2H1, 1-3H]but
Photochemical reactions of alkyl phenylglyoxylates
Hu, Shengkui,Neckers, Douglas C.
, p. 6407 - 6415 (2007/10/03)
Three new photoproducts, ethyl O-benzoyl mandelate (5a), ethyl O-acetylmandelate (6a), and biphenyl triketone (7a) are isolated and identified in the reactions of ethyl phenylglyoxylate (1a) in benzene. Quantum yields and initial rate constants of product formation are shown to be concentration dependent. For the formation of carbonyl product 3 at lower starting material concentrations (N) and intermolecular H abstraction (k1) of methyl phenylglyoxylate (1d) are measured.
