89378-61-0

Upstream product

• 98-85-1 1-Phenylethanol 
• 141-75-3 butyryl chloride 
• 729-43-1 acetophenonazine 
• 107-92-6 butyric acid 
• 123-20-6 vinyl n-butyrate 
• 98-86-2 acetophenone 
• 100-52-7 benzaldehyde 
• 106-31-0 butanoic acid anhydride 
• 109-21-7 butyl butyrate 
• 93-54-9 1-Phenyl-1-propanol 
• 60-01-5 tributyrin 
• 57392-44-6 2,2,2-trichloroethyl butyrate 
• 623-42-7 butanoic acid methyl ester 
• 371-27-7 2,2,2-trifluoroethylbutyrate 

Downstream Products

• 541-35-5 butanamide 
• 1517-69-7 (R)-1-phenylethanol 
• 161024-76-6 (S)-α-methylbenzyl butyrate 
• 1445-91-6 (S)-1-phenylethanol 
• 107-92-6 butyric acid 

Relevant academic research and scientific papers

A one-step method for covalent bond immobilization of biomolecules on silica operated in aqueous solution

A simple, one-step method for covalent bond immobilization of biomolecules on silica operated in water is described. In the approach, an NHS-ester linked methallylsilane is utilized as a bifunctional linker to couple the biomolecule to the silica surface. Weak organic acid such as acetic acid activates the silica surface enough to react with bifunctional linker without destroying activity of biomolecule.

Discovery and Redesign of a Family VIII Carboxylesterase with High (S)-Selectivity toward Chiral sec-Alcohols

Highly enantioselective lipase has been widely utilized in the preparation of versatile enantiopure chiral sec-alcohols through kinetic or dynamic kinetic resolution. Lipase is intrinsically (R)-selective, and it is difficult to obtain (S)-selective lipase. Recent crystal structures of a family VIII carboxylesterase have revealed that the spatial array of its catalytic triad is the mirror image of that of lipase but with a catalytic triad that is distinct from lipase. We, therefore, hypothesized that the family VIII carboxylesterase may exhibit (S)-enantioselectivity toward sec-alcohols similar to (S)-selective serine protease, whose catalytic triad is also spatially arrayed as its mirror image. In this study, a homologous enzyme (carboxylesterase from Proteobacteria bacterium SG_bin9, PBE) of a known family VIII carboxylesterase (pdb code: 4IVK) was prepared, which showed not only moderate (S)-selectivity toward sec-alcohols such as 3-butyn-2-ol and 1-phenylethyl alcohol but also (R)-selectivity toward particular sec-alcohols among the substrates explored. Furthermore, the (S)-selectivity of PBE has been significantly improved by rational redesign based on molecular modeling. Molecular modeling identified a binding pocket composed of Ser381, Ala383, and Arg408 for the methyl substituent of (R)-1-phenylethyl acetate and suggested that larger residues may increase the enantioselectivity by interfering with the binding of the slow-reacting enantiomer. As predicted, substituting Ser381with larger residues (Phe, Tyr, and Trp) significantly improved the (S)-selectivity of PBE toward all sec-alcohols explored, even the substrates toward which the wild-type PBE exhibits (R)-selectivity. For instance, the enantioselectivity toward 3-butyn-2-ol and 1-phenylethyl alcohol was improved from E = 5.5 and 36.1 to E = 2001 and 882, respectively, by single mutagenesis (S381F).

Two Approaches for CAL-B-Catalyzed Enantioselective Deacylation of a Set of α-Phenyl Ethyl Esters: Organic Solvent with Sodium Carbonate and Micro-aqueous Medium

Herein, we report an efficient enantioselective cleavage of the acyl- moiety of a set of α- phenyl ethyl esters with different chain-lengths catalyzed by lipase B from Candida antarctica (CAL-B) by comparing two reactional approaches: anhydrous media with sodium carbonates and micro-aqueous medium. The deacylation is performed in organic solvent, in the presence of Na2CO3 in the first case, and by addition of a drop of phosphate buffer solution pH 7 in the second. The results show the high efficiency of the deacylation in the presence of the sodium carbonate for the enzymatic resolution of all the esters and that in term of reactivity (31% ≤ conv ≤ 50%) and selectivity (E > 200). While, during the hydrolysis in micro-aqueous media, the conversion is strongly affected by the length of the acyl-chain side, the conversion decreases from conv = 50% with the 1-phenylethyl acetate 1a to conv = 19% with 1-phenyethyl dodecanoate 6a, and this, even if the selectivity remains high (E > 89). In both conditions, the lipase CAL-B shows a high enantioselectivities in favor of (R)-1-phenyl ethanol enantiomer (conv > 45%, E > 200) but the reactivity is modulated by the form and the size of the acyl-chain side. Graphic Abstract: [Figure not available: see fulltext.].

Enhanced activity and modified substrate-favoritism of Burkholderia cepacia lipase by the treatment with a pyridinium alkyl-PEG sulfate ionic liquid

Three types of pyridinium salts, i.e., 1-ethylpyridin-1-ium cetyl-PEG10 sulfate (PYET), 1-butylpyridin-1-ium cetyl-PEG10 sulfate (PYBU), and 1-(3-methoxypropyl)pyridin-1-ium cetyl-PEG10 sulfate (PYMP), have been prepared and evaluated for their activation property of Burkholderia cepacia lipase by comparison to the control IL-coated enzymes, 1-butyl-2,3-dimethylimidazolium cetyl-PEG10 sulfate-coated lipase PS (IL1-PS). Among the tested pyridinium salt-coated lipases, the PYET-coated lipase PS (PYET-PS) exhibited the best results; the transesterification of 1-(pyridin-2-yl)ethanol, 1-(pyridin-3-yl)ethanol, 1-(pyridin-4-yl)ethanol, or 4-phenylbut-3-en-2-ol proceeded faster than those of the IL1-PS-catalyzed reaction while maintaining an excellent enantioselectivity (E > 200). This improved efficiency was found to be dependent on the increased Kcat value.

Facile covalent bio-conjugation of hydroxyapatite

Hydroxyapatite, which is a major component of the bone system in the human body, is an attractive material for bio-applications because it is nontoxic as well as biocompatible. In addition, many proteins are readily adsorbed on the surface of hydroxyapatite. The protein adsorption properties of hydroxyapatite have been employed for many bio-applications such as protein purification and nanomedical application. Nevertheless, the applications are not appropriate for proteins possessing hydrophobic surfaces because the surface of hydroxyapatite is charged. For applications with hydrophobic proteins, a covalent conjugation would be an alternative approach instead of physical adsorption. However, only a few examples of the covalent conjugation of proteins onto the surface of hydroxyapatite have been reported due to the lack of a convenient method for covalent conjugation. Herein, we report a facile process for the covalent conjugation of proteins on hydroxyapatite. We have successfully activated the surface of hydroxyapatite by a simple treatment with a peptide coupling reagent (for instance, N,N′-dicyclohexyl carbodiimide, N,N′-diisopropylcarbodiimide, or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide). Then, we directly conjugated enhanced green fluorescent protein (EGFP) as a model protein, and the conjugation was confirmed by a fluorescent microscope. We also employed the method for a hydrophobic surface protein, lipase. In this case, we found that a linker compound is required for the conjugation of lipase because of the distinct polarities of the surfaces of hydroxyapatite and lipase. The conjugated lipase on hydroxyapatite exhibited higher activity in organic solvents than the free form of lipase by a factor of up to 30 and can be recycled without a significant loss of the activity.

Improved Enantioselectivity of Subtilisin Carlsberg towards Secondary Alcohols by Protein Engineering

Generally, the catalytic activity of subtilisin Carlsberg (SC) for transacylation reactions with secondary alcohols in organic solvent is low. Enzyme immobilization and protein engineering was performed to improve the enantioselectivity of SC towards secondary alcohols. Possible amino-acid residues for mutagenesis were found by combining available literature data with molecular modeling. SC variants were created by site-directed mutagenesis and were evaluated for a model transacylation reaction containing 1-phenylethanol in THF. Variants showing high E values (>100) were found. However, the conversions were still low. A second mutation was made, and both the E values and conversions were increased. Relative to that shown by the wild type, the most successful variant, G165L/M221F, showed increased conversion (up to 36 %), enantioselectivity (E values up to 400), substrate scope, and stability in THF.

Easy and simple SiO2 immobilization of lipozyme CaLB-L: Its use as a catalyst in acylation reactions and comparison with other lipases

In this study, lipase from Candida antarctica B (Lipozyme CaLB-L) was successfully immobilized on SiO2 through adsorption and used to obtain (R)-(+)-esters derived from (R,S)-1-phenylethanol. The new immobilized enzyme was compared with commercially immobilized lipases (Novozyme 435, Lipozyme 435 and Pseudomonas cepacia (PSC-II and PSD-I)). Lipozyme CaLB-L adsorbed onto SiO2 was found to be a good catalyst and, under optimal conditions, esters could be obtained with conversion 44percent, enantiomeric excess of product (eep) > 99percent, enantiomeric excess of substract (ees) 77percent and enantiomeric ratio (E) > 200. The lipase maintained enantioselectivity under adverse conditions, such as in organic solvents, with an excess of substrate and at different temperatures. The immobilized lipase could be reused five times with no significant loss of the activity.

New air-stable iron catalyst for efficient dynamic kinetic resolution of secondary benzylic and aliphatic alcohols

We herein report a catalyst system for the dynamic kinetic resolution of secondary alcohols by combining the enzymatic resolution with an iron-catalyzed racemization. A new air-stable tricarbonyl (cyclopentadienone)iron complex is identified as the active racemization catalyst for this transformation without any additive. Various substrates including benzylic, heteroaromatic, aliphatic alcohols can be used and afford the corresponding esters in good yields and with excellent enantioselectivities.