- Purification and partial characterization of Lactobacillus species SK007 lactate dehydrogenase (LDH) catalyzing phenylpyruvic acid (PPA) conversion into phenyllactic acid (PLA)
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Phenyllactic acid (PLA) is a novel antimicrobial compound synthesized by lactic acid bacteria (LAB), and its production from phenylpyruvic acid (PPA) is an effective approach. In this work, a lactate dehydrogenase (LDH), which catalyzes the reduction of PPA to PLA, has been purified to homogeneity from a cell-free extract of Lactobacillus sp. SK007 by precipitation with ammonium sulfate, ion exchange, and gel filtration chromatography. The purified enzyme had a dimeric form with a molecular mass of 78 kDa (size exclusion chromatography) or 39 kDa (SDS-PAGE). The ratio of enzyme activity with PPA to that with pyruvate being almost invariable at every purification step indicated that, in Lactobacillus sp. SK007, LDH is responsible for the conversion of PPA into PLA. HPLC profiles of PPA transformation into PLA by growing cells, cell-free extract, and purified LDH of Lactobacillus sp. SK007 were also investigated. Results showed that the presence of NADH was found to be necessary for the enzymatic production of PLA from PPA. The purified LDH displayed optimal activity for PPA at pH 6.0 and 40°C. The Km values of the enzyme for PPA and pyruvate were 1.69 and 0.32 mM, respectively. Moreover, because other screened LAB strains exhibiting relatively high LDH activity toward PPA produced also considerable amounts of PLA, LDH activity for PPA could be therefore used as a screening marker for PLA-producing LAB.
- Li, Xingfeng,Jiang, Bo,Pan, Beilei,Mu, Wanmeng,Zhang, Tao
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Read Online
- Trikoveramides A-C, cyclic depsipeptides from the marine cyanobacterium Symploca hydnoides
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Trikoveramides A – C, members of the kulolide superfamily of cyclic depsipeptides, were isolated from the marine cyanobacterium, Symploca hydnoides, collected from Bintan Island, Indonesia. Their planar structures were elucidated by a combination of NMR spectroscopy and HRMS spectral data. The absolute configurations of the amino acid and phenyllactic acid units were confirmed by Marfey's and chiral HPLC analyses, respectively, while the relative stereochemistry of the 3-hydroxy-2-methyl-7-octynoic acid (Hmoya) unit in trikoveramide A was elucidated by the application of the J-based configuration analysis and NOE correlations. The cytotoxic activity of the trikoveramides were evaluated against MOLT-4 human leukemia cells and gave IC50 values of 9.3 μM, 35.6 μM and 48.8 μM for trikoveramide B, trikoveramide C and trikoveramide A, respectively. In addition, trikoveramides A – C showed weak to moderate inhibition in the quorum sensing inhibitory assay based on the Pseudomonas aeruginosa lasB-gfp and rhlA-gfp bioreporter strains.
- Goh, Jun Xian,Katermeran, Nursheena Parveen,Phyo, Ma Yadanar,Tan, Lik Tong
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- Semirational Design of Fluoroacetate Dehalogenase RPA1163 for Kinetic Resolution of α-Fluorocarboxylic Acids on a Gram Scale
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Here the synthetic utility of fluoroacetate dehalogenase RPA1163 is explored for the production of enantiomerically pure (R)-α-fluorocarboxylic acids and (R)-α-hydroxylcarboxylic acids via kinetic resolution of racemic α-fluorocarboxylic acids. While wild-type (WT) RPA1163 shows high thermostability and fairly wide substrate scope, many interesting yet poorly or moderately accepted substrates exist. In order to solve this problem and to develop upscaled production, in silico calculations and semirational mutagenesis were employed. Residue W185 was engineered to alanine, serine, threonine, or asparagine. The two best mutants, W185N and W185T, showed significantly improved performance in the reactions of these substrates, while in silico calculations shed light on the origin of these improvements. Finally, 10 α-fluorocarboxylic acids and 10 α-hydroxycarboxylic acids were prepared on a gram scale via kinetic resolution enabled by WT, W185T, or W185N. This work expands the biocatalytic toolbox and allows a deep insight into the fluoroacetate dehalogenase catalyzed C-F cleavage mechanism.
- Chen, Bo,Li, Min,Li, Yanwei,Ma, Ming,Tian, Shaixiao,Tong, Wei,Wang, Jian-Bo,Xu, Guangyu,Yue, Yue,Zhang, Hongxia
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p. 3143 - 3151
(2020/03/23)
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- Oxalyl-CoA Decarboxylase Enables Nucleophilic One-Carbon Extension of Aldehydes to Chiral α-Hydroxy Acids
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The synthesis of complex molecules from simple, renewable carbon units is the goal of a sustainable economy. Here we explored the biocatalytic potential of the thiamine-diphosphate-dependent (ThDP) oxalyl-CoA decarboxylase (OXC)/2-hydroxyacyl-CoA lyase (HACL) superfamily that naturally catalyzes the shortening of acyl-CoA thioester substrates through the release of the C1-unit formyl-CoA. We show that the OXC/HACL superfamily contains promiscuous members that can be reversed to perform nucleophilic C1-extensions of various aldehydes to yield the corresponding 2-hydroxyacyl-CoA thioesters. We improved the catalytic properties of Methylorubrum extorquens OXC by rational enzyme engineering and combined it with two newly described enzymes—a specific oxalyl-CoA synthetase and a 2-hydroxyacyl-CoA thioesterase. This enzymatic cascade enabled continuous conversion of oxalate and aromatic aldehydes into valuable (S)-α-hydroxy acids with enantiomeric excess up to 99 %.
- Burgener, Simon,Cortina, Ni?a Socorro,Erb, Tobias J.
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supporting information
p. 5526 - 5530
(2020/02/20)
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- Controllable Intramolecular Unactivated C(sp3)-H Amination and Oxygenation of Carbamates
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Dual catalyst-controlled intramolecular unactivated C(sp3)-H amination and oxygenation of carbamates merging visible-light photocatalysis and earth-abundant transition metal catalysis have been reported. Useful amino alcohol and diol derivatives could be selectively obtained from readily available tertiary alcohol derivatives. The possible mechanisms have been proposed via a 1,5-HAT process followed by Lewis acid-controlled cyclization. The nickel and zinc catalysts inhibit the formation of oxygenation and amination products, respectively. An interesting phenomenon of chirality transfer is also observed.
- Guo, Qihang,Ren, Xiang,Lu, Zhan
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supporting information
p. 880 - 884
(2019/05/16)
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- Glycerol conversion to high-value chemicals: The implication of unnatural α-amino acid syntheses using natural resources
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Glycerol derivatives are an important class of compounds, which have great applications as basic structural building blocks in organic synthesis. O-Benzylglycerol was oxidised to produce a high-value compound in high yield using a NaOtBu-O2 system. Furthermore, the synthetic utility of the resulting product was demonstrated by its transformation into unnatural α-amino acids, thus showing the valorisation of glycerol biomass.
- Park, Yun Ji,Yang, Jung Woon
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p. 2615 - 2620
(2019/06/03)
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- Heterologous production of asperipin-2a: Proposal for sequential oxidative macrocyclization by a fungi-specific DUF3328 oxidase
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Asperipin-2a is a ribosomally synthesized and post-translationally modified peptide isolated from Asperigillus flavus. Herein, we report the heterologous production of asperipin-2a and determination of its absolute structure. Notably, the characteristic bicyclic structure was likely constructed by a single oxidase containing the DUF3328 domain.
- Ye, Ying,Ozaki, Taro,Umemura, Myco,Liu, Chengwei,Minami, Atsushi,Oikawa, Hideaki
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supporting information
p. 39 - 43
(2019/01/04)
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- A novel D-2-hydroxy acid dehydrogenase with high substrate preference for phenylpyruvate originating from lactic acid bacteria: Structural analysis on the substrate specificity
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2-Hydroxy acid dehydrogenases (2-HADHs) have been implicated in the synthesis of 2-hydroxy acids from 2-oxo acids that are used in wide areas of industry. D-lactate dehydrogenases (D-LDHs), a subfamily of 2-HADH, have been utilized to this purpose, yet they exhibited relatively low catalytic activity to the 2-oxo acids with large functional groups at C3. In this report, four putative 2-HADHs from Oenococcus oeni, Weissella confusa, Weissella koreensis and Pediococcus claussenii were examined for activity on phenylpyruvate (PPA), a substrate to 3-phenyllactic acid (PLA) with a C3 phenyl group. The 2-HADH from P. claussenii was found to have the highest kcat/Km on PPA with 1,348.03 s?1 mM?1 among the four enzymes with higher substrate preference for PPA than pyruvate. Sequential, structural and mutational analysis of the enzyme revealed that it belonged to the D-LDH family, and phenylalanine at the position 51 was the key residue for the PPA binding to the active site via hydrophobic interaction, whereas in the 2-HADHs from O. oeni and W. confusa the hydrophilic tyrosine undermined the interaction. Because phenyllactate is a potential precursor for pharmaceutical compounds, antibiotics and biopolymers, the enzyme could increase the efficiency of bio-production of valuable chemicals. This study suggests a structural basis for the high substrate preference of the 2-HADH, and further engineering possibilities to synthesize versatile 2-hydroxy acids.
- Lee, Hoe-Suk,Park, Jisu,Yoo, Young Je,Yeon, Young Joo
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- Preparative Asymmetric Synthesis of Canonical and Non-canonical α-amino Acids Through Formal Enantioselective Biocatalytic Amination of Carboxylic Acids
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Chemical and biocatalytic synthesis of non-canonical α-amino acids (ncAAs) from renewable feedstocks and using mild reaction conditions has not efficiently been solved. Here, we show the development of a three-step, scalable and modular one-pot biocascade for linear conversion of renewable fatty acids (FAs) into enantiopure l-α-amino acids. In module 1, selective α-hydroxylation of FAs is catalyzed by the P450 peroxygenase P450CLA. By using an automated H2O2 supplementation system, efficient conversion (46 to >99%; TTN>3300) of a broad range of FAs (C6:0 to C16:0) into valuable α-hydroxy acids (α-HAs; >90% α-selective) is shown on preparative scale (up to 2.3 g L?1 isolated product). In module 2, a redox-neutral hydrogen borrowing cascade (alcohol dehydrogenase/amino acid dehydrogenase) allowed further conversion of α-HAs into l-α-AAs (20 to 99%). Enantiopure l-α-AAs (e.e. >99%) including the pharma synthon l-homo-phenylalanine can be obtained at product titers of up to 2.5 g L?1. Based on renewables and excellent atom economy, this biocascade is among the shortest and greenest synthetic routes to structurally diverse and industrially relevant ncAAs. (Figure presented.).
- Dennig, Alexander,Blaschke, Fabio,Gandomkar, Somayyeh,Tassano, Erika,Nidetzky, Bernd
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supporting information
(2019/02/09)
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- Iridium-catalyzed efficient reduction of ketones in water with formic acid as a hydride donor at low catalyst loading
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A highly efficient and chemoselective transfer hydrogenation of ketones in water has been successfully achieved with our newly developed catalyst. Simple ketones, as well as α- or β-functionalized ketones, are readily reduced. Formic acid is used as a traceless hydride source. At very low catalyst loading (S/C = 10:000 in most cases; S/C = 50:000 or 100:000 in some cases), the iridium catalyst is impressively efficient at reducing ketones in good to excellent yields. The TOF value can be as high as up to 26:000 mol mol-1 h-1. A variety of functional groups are well tolerated, for example, heteroaryl, aryloxy, alkyloxy, halogen, cyano, nitro, ester, especially acidic methylene, phenol and carboxylic acid groups.
- Liu, Ji-Tian,Yang, Shiyi,Tang, Weiping,Yang, Zhanhui,Xu, Jiaxi
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supporting information
p. 2118 - 2124
(2018/05/24)
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- A Phenylpyruvic Acid Reductase Is Required for Biosynthesis of Tropane Alkaloids
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Solanaceous medicinal plants produce tropane alkaloids (TAs). We discovered a novel gene from Atropa belladonna, AbPPAR, which encodes a phenylpyruvic acid reductase required for TA biosynthesis. AbPPAR was specifically expressed in root pericycles and endodermis. AbPPAR was shown to catalyze reduction of phenylpyruvic acid to phenyllactic acid, a precursor of TAs. Suppression of AbPPAR disrupted TA biosynthesis through reduction of phenyllactic acid levels. In summary, we identified a novel enzyme involved in TA biosynthesis.
- Qiu, Fei,Yang, Chunxian,Yuan, Lina,Xiang, Dan,Lan, Xiaozhong,Chen, Min,Liao, Zhihua
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supporting information
p. 7807 - 7810
(2019/01/04)
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- Preparation method of chiral phenyllactic acid
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The invention relates to a preparation method of chiral phenyllactic acid. The preparation method comprises the steps: salifying (S)-phenethylamine serving as a resolving agent and DL-phenyllactic acid in a specific solvent, and carrying out recrystallization to obtain (S)-phenethylamine-D-phenyl lactate; salifying (R)-phenethylamine serving as a resolving agent and DL-phenyllactic acid in a specific solvent, and carrying out recrystallization to obtain (R)-phenethylamine-L-phenyl lactate; and carrying out acid dissociation to prepare the chiral phenyllactic acid. Compared with the prior art,the preparation method has the advantages that the adopted resolving agent is cheap, available and easy to recover, and the preparation method is suitable for industrial production.
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Paragraph 0044-0046
(2018/09/29)
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- An Atropos Biphenyl Bisphosphine Ligand with 2,2′-tert-Butylmethylphosphino Groups for the Rhodium-Catalyzed Asymmetric Hydrogenation of Enol Esters
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This is an update of our previous work concerning the development of Atropos biphenyl bisphosphine ligands. An unexpected Atropos structural property was confirmed by single crystal X-ray diffraction and this result is consistent with the computational calculations described in our previous work. This P-stereogenic bisphosphine ligand possessing a biphenyl backbone and 2,2′-tert-butylmethylphosphino groups has been applied to the Rh-catalyzed asymmetric hydrogenation of enol esters, which has not been widely studied and can be used for the synthesis of several important bioactive compounds. Although there is room for further improvement in enantioselectivity, the results reported herein provide a further understanding of such types of ligands. (Figure presented.).
- Jia, Jia,Fan, Dongyang,Zhang, Jian,Zhang, Zhenfeng,Zhang, Wanbin
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p. 3793 - 3800
(2018/09/20)
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- Highly Efficient Deracemization of Racemic 2-Hydroxy Acids in a Three-Enzyme Co-Expression System Using a Novel Ketoacid Reductase
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Enantiopure 2-hydroxy acids (2-HAs) are important intermediates for the synthesis of pharmaceuticals and fine chemicals. Deracemization of racemic 2-HAs into the corresponding single enantiomers represents an economical and highly efficient approach for synthesizing chiral 2-HAs in industry. In this work, a novel ketoacid reductase from Leuconostoc lactis (LlKAR) with higher activity and substrate tolerance towards aromatic α-ketoacids was discovered by genome mining, and then its enzymatic properties were characterized. Accordingly, an engineered Escherichia coli (HADH-LlKAR-GDH) co-expressing 2-hydroxyacid dehydrogenase, LlKAR, and glucose dehydrogenase was constructed for efficient deracemization of racemic 2-HAs. Most of the racemic 2-HAs were deracemized to their (R)-isomers at high yields and enantiomeric purity. In the case of racemic 2-chloromandelic acid, as much as 300 mM of substrate was completely transformed into the optically pure (R)-2-chloromandelic acid (> 99% enantiomeric excess) with a high productivity of 83.8 g L?1 day?1 without addition of exogenous cofactor, which make this novel whole-cell biocatalyst more promising and competitive in practical application.
- Xue, Ya-Ping,Wang, Chuang,Wang, Di-Chen,Liu, Zhi-Qiang,Zheng, Yu-Guo
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- Biocatalytic Synthesis of Chiral N-Functionalized Amino Acids
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N-Functionalized amino acids are important building blocks for the preparation of diverse bioactive molecules, including peptides. The development of sustainable manufacturing routes to chiral N-alkylated amino acids remains a significant challenge in the pharmaceutical and fine-chemical industries. Herein we report the discovery of a structurally diverse panel of biocatalysts which catalyze the asymmetric synthesis of N-alkyl amino acids through the reductive coupling of ketones and amines. Reactions have been performed on a gram scale to yield optically pure N-alkyl-functionalized products in high yields.
- Hyslop, Julia F.,Lovelock, Sarah L.,Sutton, Peter W.,Brown, Kristin K.,Watson, Allan J. B.,Roiban, Gheorghe-Doru
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supporting information
p. 13821 - 13824
(2018/09/27)
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- Alternating Sequence Controlled Copolymer Synthesis of α-Hydroxy Acids via Syndioselective Ring-Opening Polymerization of O-Carboxyanhydrides Using Zirconium/Hafnium Alkoxide Initiators
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The ring-opening polymerization (ROP) of O-carboxyanhydrides (OCAs) can give diverse poly(α-hydroxy acid)s (PAHAs) with different functional groups because of easy modification of the side group of OCAs, which can extend applications of PAHAs widely. The stereoselective polymerization of O-carboxyanhydrides and further sequence controlled alternating copolymerization of OCAs were still big challenges until now for lack of suitable catalysts/initiators. In this work, a highly syndioselective ROP of OCAs system as the first stereoselective example in this area is reported using zirconium/hafnium alkoxides as initiators with the highest Pr value up to 0.95. Furthermore, these initiators were successfully applied in the precisely alternating sequence controlled copolymerization of PheOCA and Tyr(Bn)OCA, and alternating copolymerization of LacOCA and PheOCA was also achieved.
- Sun, Yangyang,Jia, Zhaowei,Chen, Changjuan,Cong, Yong,Mao, Xiaoyang,Wu, Jincai
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supporting information
p. 10723 - 10732
(2017/08/15)
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- Investigating Substrate Scope and Enantioselectivity of a Defluorinase by a Stereochemical Probe
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The possibility of a double Walden inversion mechanism of the fluoracetate dehalogenase FAcD (RPA1163) has been studied by subjecting rac-2-fluoro-2-phenyl acetic acid to the defluorination process. This stereochemical probe led to inversion of configuration in a kinetic resolution with an extremely high selectivity factor (E > 500), showing that the classical mechanism involving SN2 reaction by Asp110 pertains. The high preference for the (S)-substrate is of synthetic value. Wide substrate scope of RPA1163 in such hydrolytic kinetic resolutions can be expected because the reaction of the even more sterically demanding rac-2-fluoro-2-benzyl acetic acid proceeded similarly. Substrate acceptance and stereoselectivity were explained by extensive molecular modeling (MM) and molecular dynamics (MD) computations. These computations were also applied to fluoroacetic acid itself, leading to further insights.
- Wang, Jian-Bo,Ilie, Adriana,Yuan, Shuguang,Reetz, Manfred T.
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p. 11241 - 11247
(2017/08/21)
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- Solvent-induced chirality switching in the enantioseparation of regioisomeric hydroxyphenylpropionic acids via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol
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The enantioseparation of three hydroxyphenylpropionic acid isomers via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol has been demonstrated. The racemates of all three acid isomers were successfully separated with high efficiency (0.56–0.84) after single crystallization. For 2-hydroxy-3-phenylpropionic acid 4, the configuration of the less-soluble salt was controlled by the crystallization solvent: the (R)-4 salt was crystallized from water, while 2-propanol afforded the (S)-4 salt. The chiral recognition mechanism of the three acids was discussed based on the crystal structures of the diastereomeric salts.
- Kodama, Koichi,Nagata, Jun,Kurozumi, Nobuhiro,Shitara, Hiroaki,Hirose, Takuji
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supporting information
p. 460 - 466
(2017/03/23)
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- Asymmetric Assembly of All-Carbon Tertiary/Quaternary Nonadjacent Stereocenters through Organocatalytic Conjugate Addition of α-Cyanoacetates to a Methacrylate Equivalent
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An efficient, highly diastereo- and enantioselective assembly of acyclic carbonyl fragments possessing nonadjacent all-carbon tertiary/quaternary stereoarrays is reported based on a Br?nsted base catalyzed Michael addition/α-protonation sequence involving α-cyanoacetates and 2,4-dimethyl-4-hydroxypenten-3-one as novel methacrylate equivalent.
- Iriarte, Igor,Vera, Silvia,Badiola, Eider,Mielgo, Antonia,Oiarbide, Mikel,García, Jesús M.,Odriozola, José M.,Palomo, Claudio
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supporting information
p. 13690 - 13696
(2016/09/13)
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- An efficient enzymatic aminolysis for kinetic resolution of aromatic α-hydroxyl acid in non-aqueous media
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A new and highly efficient enzymatic aminolysis approach for kinetic resolution of aromatic α-hydroxy acid in non-aqueous media has been developed. The corresponding α-hydroxyl acid ester was employed as the substrate, and commercially available Candida antarctica lipase B is used as the biocatalyst, anhydrous ammonia is the resolving agent. Reactions can be proceeded smoothly in organic solvent at ambient temperatures. High concentration of substrate is allowed due to the application of organic media and the products are obtained in yields of up to 49% with ee values of up to 99%, and with E value of >300, representing an appealing and promising protocol for large-scale preparations.
- Chen, Shan,Liu, Fuyan,Zhang, Kuan,Huang, Hansheng,Wang, Huani,Zhou, Jiaying,Zhang, Jing,Gong, Yiwei,Zhang, Dela,Chen, Yiping,Lin, Chang,Wang, Bo
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supporting information
p. 5312 - 5314
(2016/11/16)
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- Metal-free one-pot α-carboxylation of primary alcohols
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An efficient metal-free procedure for the formal α-carboxylation of primary alcohols has been developed. The method involves a one-pot oxidation/Passerini/hydrolysis sequence and provides access to α-hydroxy acids bearing a broad range of functional groups. A minor modification to the reaction conditions extends the range of accessible products to α-hydroxy esters.
- Van Der Heijden, Gydo,Kraakman, Jasper,Biemolt, Jasper,Ruijter, Eelco,Orru, Romano V. A.
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supporting information
p. 9716 - 9719
(2016/10/31)
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- Nitrilases, nucleic acids encoding them and methods for making and using them
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The invention relates to nitrilases and to nucleic acids encoding the nitrilases. In addition methods of designing new nitrilases and method of use thereof are also provided. The nitrilases have increased activity and stability at increased pH and temperature.
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Page/Page column 70
(2016/01/09)
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- Nitrilases
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The invention relates to nitrilases and to nucleic acids encoding the nitrilases. In addition, methods of designing new nitrilases and methods of use thereof are also provided. The nitrilases have increased activity and stability at increased pH and temperature.
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- Chiral separation of phenyllactic acid by helical structure from spring dextrin
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We performed the enzymatic synthesis of spring dextrin (SD) with a helical conformation and investigated its chiral-recognition properties in relation to the stereoselective phenyllactic acid (PLA), using reversed-phase high-performance liquid chromatography. The effects of column temperature, buffer pH and methanol content on enantioselective separation were investigated. Baseline chromatographic separation was achieved on an Inertsil ODS-SP column using 1 % SD as the chiral mobile-phase additive. Helical structure was necessary for chiral separation of PLA, according to visible spectroscopy. Molecular dynamic simulations to predict the interactions between SD and PLA showed that van der Waals attractions played an important role in enantiomer separation.
- Xu, Jin,Xu, Xueming,Wang, Qiang,Fan, Xuerong
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p. 515 - 521
(2016/02/26)
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- Fragmentation-Rearrangement of Peptide Backbones Mediated by the Air Pollutant NO2.
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The fragmentation-rearrangement of peptide backbones mediated by nitrogen dioxide, NO2., was explored using di-, tri-, and tetrapeptides 8-18 as model systems. The reaction, which is initiated through nonradical N-nitrosation of the peptide bond, shortens the peptide chain by the expulsion of one amino acid moiety with simultaneous fusion of the remaining molecular termini through formation of a new peptide bond. The relative rate of the fragmentation-rearrangement depends on the nature of the amino acids and decreases with increasing steric bulk at the α carbon in the order Gly>Ala>Val. Peptides that possessed consecutive aromatic side chains only gave products that resulted from nitrosation of the sterically less congested N-terminal amide. Such backbone fragmentation-rearrangement occurs under physiologically relevant conditions and could be an important reaction pathway for peptides, in which sections without readily oxidizable side chains are exposed to the air pollutant NO2.. In addition to NO2.-induced radical oxidation processes, this outcome shows that ionic reaction pathways, in particular nitrosation, should be factored in when assessing NO2. reactivity in biological systems.
- Gamon, Luke F.,Nathanael, Joses G.,Taggert, Bethany I.,Henry, Fraser A.,Bogena, Jana,Wille, Uta
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supporting information
p. 14924 - 14930
(2015/10/20)
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- Pd-catalyzed α-selective C(sp3)-H acetoxylation of amides through an unusual cyclopalladation mechanism
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We report the first example of Pd-catalyzed site-selective α-C(sp3)-H oxidation/acetoxylation of amides through an unusual [4,6]-bicyclic metallacycle intermediate with 1-aminoanthraquinone as a new bidentate directing group. In addition to the distinct mechanism and high efficiency, the reaction is highly appealing due to the ample commercial source, low-cost, as well as easy removal and recycling of the auxiliary group.
- Wang, Meining,Yang, Yang,Fan, Zhoulong,Cheng, Zhen,Zhu, Weiliang,Zhang, Ao
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supporting information
p. 3219 - 3222
(2015/06/01)
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- Solid-phase synthesis of tetrahydropyridazinedione-constrained peptides
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The design and solid-phase synthesis of tetrahydropyridazine-3,6-dione (Tpd) peptidomimetics derived from backbone-aminated peptides is reported. The described protocol features the synthesis of chiral α-hydrazino acids suitable for chemoselective incorporation into growing peptide chains. Acid-catalyzed cyclization to form the Tpd ring during cleavage affords the target peptidomimetics in good yield and purity. The scope of Tpd incorporation is demonstrated through the synthesis of constrained peptides featuring nucleophilic/electrophilic side chains and sterically encumbered α-substituted hydrazino acid residues. (Chemical Equation Presented).
- Kang, Chang Won,Ranatunga, Sujeewa,Sarnowski, Matthew P.,Del Valle, Juan R.
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supporting information
p. 5434 - 5437
(2015/02/19)
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- A chemoselective oxidation of monosubstituted ethylene glycol: Facile synthesis of optically active α-hydroxy acids
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A mild and efficient method for the synthesis of optically active α-hydroxy acids through chemoselective oxidation of monosubstituted ethylene glycols using the TEMPO-NaOCl reagent system is described. It is evident from our studies that the solvent, pH and reaction temperature are very crucial for the success of this oxidation. The versatility of this method has been demonstrated with a variety of aliphatic, aromatic and carbohydrate substrates bearing various functional groups. the Partner Organisations 2014.
- Chinthapally, Kiran,Baskaran, Sundarababu
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supporting information
p. 4305 - 4309
(2014/06/23)
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- Kinetic resolution of mandelate esters via stereoselective acylation catalyzed by lipase PS-30
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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.
- Chen, Peiran,Yang, Wenhong
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supporting information
p. 2290 - 2294
(2014/04/17)
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- Biocontrolled formal inversion or retention of L -α-amino acids to enantiopure (R)- or (S)-hydroxyacids
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Natural L-α-amino acids and L-norleucine were transformed to the corresponding α-hydroxy acids by formal biocatalytic inversion or retention of absolute configuration. The one-pot transformation was achieved by a concurrent oxidation reduction cascade in aqueous media. A representative panel of enantiopure (R)- and (S)-2-hydroxy acids possessing aliphatic, aromatic and heteroaromatic moieties were isolated in high yield (67-85 %) and enantiopure form (>99 % ee) without requiring chromatographic purification.
- Busto, Eduardo,Grischek, Barbara,Kroutil, Wolfgang,Richter, Nina
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supporting information
p. 11225 - 11228,4
(2015/01/07)
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- Optical control of enzyme enantioselectivity in solid phase
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A lipase was immobilized on transparent agarose microspheres and genetically engineered to specifically anchor photochromic molecules into its catalytic site. Several combinations of azobenzene and spiropyran groups were conjugated to cysteines introduced at different positions near the active center. Light modulated the catalytic properties of the resulting solid bioconjugates, and such modulation depended on both the nature of the photochromic compound and the anchoring position. Covalent anchoring of azobenzene derivatives to the residue 295 of the lipase 2 from Bacillus thermocathenolatus triggered lipase preference for the S isomer under UV light, whereas visible light promoted preference for the R isomer. Molecular dynamics simulations indicate that conjugating photochromic compounds into the catalytic cavity allows manipulating the steric hindrance and binding energy of the substrates, leading to an enantioselective molecular fit in certain cases. Using this approach, we report for the first time the control of enzyme properties using light in the solid phase.
- Bautista-Barrufet, Antoni,Lopez-Gallego, Fernando,Rojas-Cervellera, Victor,Rovira, Carme,Pericas, Miquel A.,Guisan, Jose M.,Gorostiza, Pau
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p. 1004 - 1009
(2014/04/03)
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- Increased catalyst productivity in α-hydroxy acids resolution by esterase mutation and substrate modification
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Optically pure α-hydroxy acids and their derivatives are versatile chiral building blocks in the pharmaceutical industry. In this study, the potential of a recombinant Pseudomonas putida esterase (rPPE01) for the enzymatic resolution of α-acetoxy acids was significantly improved by combinatorial engineering of both the biocatalyst and substrate. Semirational design based on homologous modeling and molecular docking provided a single-point variant, W187H, whose kcat/KM for sodium 2-acetoxy-2-(2′-chlorophenyl)acetate (Ac-CPA-Na) was increased 100-fold, from 0.0611 to 6.20 mM-1 s-1, while retaining its excellent enantioselectivity and broad substrate spectrum. Biocatalyst deactivation under the operating conditions was decreased by using the potassium salt of Ac-CPA instead of Ac-CPA-Na. With 0.5 g L-1 of lyophilized cells containing rPPE01-W187H, 500 mM (R,S)-Ac-CPA-K was selectively deacylated with 49.9% conversion within 15 h, giving satisfactory enantiomeric excesses (ee) for both the S product (>99% ee) and the remaining R substrate (98.7% ee). Consequently, the amount of (S)-2-hydroxy-2-(2′-chlorophenyl)acetate prepared per unit weight of lyophilized cells was improved by a factor of 18.9 compared with the original productivity of the wild-type esterase. Further enzymatic resolution of other important hydroxy acids at the 100 mL scale demonstrated that the rPPE01-W187H-based bioprocess is versatile and practical for the large-scale preparation of chiral α-hydroxy acids.
- Ma, Bao-Di,Kong, Xu-Dong,Yu, Hui-Lei,Zhang, Zhi-Jun,Dou, Shuai,Xu, Yan-Peng,Ni, Yan,Xu, Jian-He
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p. 1026 - 1031
(2014/04/03)
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- Enantioselective reduction of 3-aryl-2-oxo-propanoic acids: A comparison of enzymatic and transition-metal-catalyzed methods
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Phenyllactic acids are important constituents of depsipeptides, which are a large class of natural products expressing a wide range of biological activities. Despite there being several methods for the enantioselective synthesis of α-hydroxy acids, almost no studies are available addressing the substrate selectivity of transition-metal and enzyme-catalyzed methods for the preparation of substituted phenyllactic or more general aryllactic acids. We report herein comparative results for Rh-DiPAMP (DiPAMP = 1,2-ethandiylbis[(o- methoxyphenyl)phenylphosphane]) and lactate dehydrogenase catalyzed enantioselective reductions of several 3-aryl-2-oxopropanoic acids. Phenyllactic acids are important constituents of depsipeptides, which are a large class of natural products expressing a wide range of biological activities. A comparative study of transition-metal and lactate dehydrogenase catalyzed enantioselective reductions of several 3-aryl-2-oxopropanoic acids as valuable sources for enantiomerically pure phenyllactic acids is described. Copyright
- Luettenberg, Sebastian,Ta, Tien Dat,Von Der Heyden, Jan,Scherkenbeck, Juergen
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p. 1824 - 1830
(2013/06/04)
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- One-pot, single-step deracemization of 2-hydroxyacids by tandem biocatalytic oxidation and reduction
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A facile and efficient one-pot, single-step method for deracemizing a broad range of 2-hydroxyacids to (R)-2-hydroxyacids was established by combination of resting cells of an (S)-hydroxyacid dehydrogenase-producing microorganism and an (R)-ketoacid reductase-producing microorganism.
- Xue, Ya-Ping,Zheng, Yu-Guo,Zhang, Ya-Qin,Sun, Jing-Lei,Liu, Zhi-Qiang,Shen, Yin-Chu
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supporting information
p. 10706 - 10708
(2013/11/06)
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- Anthelmintic PF1022A: Stepwise solid-phase synthesis of a cyclodepsipeptide containing N-methyl amino acids
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Cyclodepsipeptides of the enniation-, PF1022-, and verticilide-family represent a diverse class of highly interesting natural products with respect to their manifold biological activities. However, until now no stepwise solid-phase synthesis has been accomplished due to the difficult combination of N-methyl amino acids and hydroxycarboxylic acids. We report here the first stepwise solid-phase synthesis of the anthelmintic cyclooctadepsipeptide PF1022A based on an Fmoc/THP-ether protecting group strategy on Wang-resin. The standard conditions of our synthesis allow an unproblematic adaption to an automated peptide synthesizer.
- Lüttenberg, Sebastian,Sondermann, Frank,Scherkenbeck, Jürgen
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scheme or table
p. 2068 - 2073
(2012/03/27)
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- Synthesis, characterization and activity of new phosphonate dipeptides as potential inhibitors of VanX
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VanX, a Zn(II)-dependent D-ala-D-ala dipeptidase, is essential for vancomycin resistance in Enterococcus faecium. The enzymatic activity of VanX was previously found to be inhibited competitively by 2-{[(1-aminoethyl) (hydroxy) phosphoryl]oxy} propanoic acid (1B). Here we report the synthesis and characterization of seven phosphonate dipeptide analogs of D-ala-D-ala with various substituent, the activity evaluation indicated that six of these phosphonate analogs inhibit VanX with IC50 of 0.48-8.21 mM. These data revealed a structure-activity relationship which is that the large substituent group on β-carbon resulted in low binding affinity of the phonphonate analog to VanX. This information will be helpful to guide the design and synthesis of the tightly-binding inhibitors for VanX.
- Jia, Chao,Yang, Ke-Wu,Liu, Cheng-Cheng,Feng, Lei,Xiao, Jian-Min,Zhou, Li-Sheng,Zhang, Yi-Lin
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supporting information; experimental part
p. 482 - 484
(2012/03/11)
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- Enantioseparation of typical pesticides using cellulose carbamate stationary phases by capillary liquid chromatography
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Cellulose-tris(3,5-dimethylphenylcarbamate) was initially synthesized as the chiral selector, then stable coated and bonded chiral stationary phases were prepared, respectively, using aminopropyl-functionalized silica gel as the support media. The prepared stationary phases were used for micro-column chiral separation by self-installed capillary high performance liquid chromatography system. Eighteen kind of chiral compounds including some typical pesticides were tested on both prepared chiral stationary phases and different chromatographic parameters such as resolution and retention time were comparatively investigated.
- Bai, Lian-Yang,Zhang, Yu-Ping,Deng, Pu-Hong,Zhang, Yi-Jun,Chen, Jun
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experimental part
p. 4917 - 4922
(2012/10/08)
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- MACROCYCLIC INHIBITORS OF HEPATITIS C PROTEASE
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The invention provides macrocyclic compounds inhibitory to the Hepatitis C viral protease, compositions and combinations including the compounds, methods of treatment of conditions wherein inhibition of the Hepatitis C viral protease is medically indicated, and methods of treatment of a Hepatitis C viral infection in a human patient.
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Page/Page column 92
(2010/04/25)
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- Peptide ligation assisted by an auxiliary attached to amidyl nitrogen
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New thiol-containing auxiliaries were developed for peptide ligation. They were placed at the amidyl N-atom in the second amino acid residue of a peptide fragment. With the new auxiliaries, peptide ligation could be conducted at non-Cys and non-Gly sites. Compared to other recently developed auxiliaries, an important feature of the present design was that the new auxiliaries were generally applicable and readily removable.
- Li, Juan,Cui, Hong-Kui,Liu, Lei
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body text
p. 1793 - 1796
(2010/06/13)
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- Serendipitous discovery of α-hydroxyalkyl esters as β-lactamase substrates
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O-(1-Carboxy-1-alkyloxycarbonyl) hydroxamates were found to spontaneously decarboxylate in aqueous neutral buffer to form O-(2-hydroxyalkylcarbonyl) hydroxamates. While the former molecules do not react rapidly with serine β-lactamases, the latter are quite good substrates of representative class A and C, but not D, enzymes, and particularly of a class C enzyme. The enzymes catalyze hydrolysis of these compounds to a mixture of the α-hydroxy acid and hydroxamate. Analogous compounds containing aryloxy leaving groups rather that hydroxamates are also substrates. Structure-activity experiments showed that the α-hydroxyl group was required for any substantial substrate activity. Although both d- and l-α-hydroxy acid derivatives were substrates, the former were preferred. The response of the class C activity to pH and to alternative nucleophiles (methanol and d-phenylalanine) suggested that the same active site functional groups participated in catalysis as for classical substrates. Molecular modeling was employed to explore how the α-hydroxy group might interact with the class C β-lactamase active site. Incorporation of the α-hydroxyalkyl moiety into novel inhibitors will be of considerable interest.
- Pelto, Ryan B.,Pratt
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experimental part
p. 10496 - 10506
(2011/10/18)
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- Biocatalytic racemization of α-hydroxycarboxylic acids using a stereo-complementary pair of α-hydroxycarboxylic acid dehydrogenases
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Biocatalytic racemization of aliphatic, (aryl)aliphatic and aromatic α-hydroxycarboxylic acids was achieved via a reversible oxidation-reduction sequence using a pair of stereo-complementary Prelog- and anti-Prelog d- and l-α-hydroxyisocaproate dehydrogenases from Lactobacillus confusus DSM 20196 and Lactobacillus paracasei DSM 20008, resp., overexpressed in Escherichia coli. The mild reaction conditions ensured essential 'clean' isomerization, undesired 'over-oxidation' of the substrate forming the α-ketoacid could be suppressed by exclusion of O2 and adjustment of the NAD+/NADH-ratio.
- Bodlenner, Anne,Glueck, Silvia M.,Nestl, Bettina M.,Gruber, Christian C.,Baudendistel, Nina,Hauer, Bernhard,Kroutil, Wolfgang,Faber, Kurt
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experimental part
p. 7752 - 7755
(2009/12/04)
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- Electroorganic synthesis in oil-in-water (O/W) nanoemulsion: TEMPO-mediated electrooxidation of amphiphilic alcohols in water
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Oil-in-water nanoemulsion which consisted of TEMPO, amphiphilic alcohols, and water offered unique reaction environments for electrooxidation of the alcohols to give the corresponding carboxylic acids in good to excellent yields.
- Kuroboshi, Manabu,Yoshida, Tomonori,Oshitani, Jun,Goto, Kuniaki,Tanaka, Hideo
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experimental part
p. 7177 - 7185
(2009/12/24)
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- METHOD FOR PRODUCING OPTICALLY ACTIVE HYDROXYCARBOXYLIC ACID DERIVATIVE OR SALT THEREOF
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The present invention has its object to provide a method for producing an optically active hydroxycarboxylic acid derivative which is an intermediate important for production of medicines, agrochemicals, chemical products, and so on. The production method of the present invention comprises: carrying out a hydrogen-transfer reduction of a ketocarboxylic acid or a salt thereof by the reaction of an optically active diamine complex to produce an optically active hydroxycarboxylic acid derivative. According to the present invention, it is possible to safely and efficiently produce an industrially-useful optically active hydroxycarboxylic acid derivative.
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Page/Page column 11
(2009/06/27)
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- Manganese-promoted regioselective ring-opening of 2,3-epoxy acid derivatives: a new route to α-hydroxy acid derivatives
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A simple and general methodology directed towards the synthesis 3-aryl-2-hydroxy amides, or esters with total regioselectivity from the easily available 2,3-epoxy amides or esters, promoted by active manganese is described. Utilizing enantiopure epoxy amides as starting materials, the corresponding 3-aryl-2-hydroxy amides in enantiopure form are also available. Some synthetic applications of selected examples of 3-aryl-2-hydroxy carboxylic acid derivatives are shown. A mechanism has been proposed to explain this novel reaction.
- Concellon, Jose M.,Bernad, Pablo L.,Rodriguez-Solla, Humberto,Diaz, Pamela
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experimental part
p. 2178 - 2184
(2009/12/31)
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- Solution-phase peptide synthesis; Synthesis of 'North-Western' and 'South Eastern' fragments of the antifungal cyclodepsipeptide petriellin A
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The solution-phase synthesis of two highly modified peptides, a hexamer and a heptamer, that constitute the two halves of the antifungal cyclic depsipeptide, Petriellin A, is reported. CSIRO 2008.
- Aurelio, Luigi,Brownlee, Robert T. C.,Hughes, Andrew B.
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p. 615 - 629
(2008/12/22)
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- Design and synthesis of novel 2-pyridone peptidomimetic falcipain 2/3 inhibitors
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The structure-based design, chemical synthesis and in vitro activity evaluation of various falcipain inhibitors derived from 2-pyridone are reported. These compounds contain a peptidomimetic binding determinant and a Michael acceptor terminal moiety capable of deactivating the cysteine protease active site.
- Verissimo, Edite,Berry, Neil,Gibbons, Peter,Cristiano, M. Lurdes S.,Rosenthal, Philip J.,Gut, Jiri,Ward, Stephen A.,O'Neill, Paul M.
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scheme or table
p. 4210 - 4214
(2009/04/10)
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- Trichosporon cutaneum-promoted deracemization of (±)-2-hydroxindan-1-one: a mechanistic study
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A mechanistic study of the deracemization of (±)-2-hydroxy-1-indanone mediated by the yeast Trichosporon cutaneum to afford pure (1S,2R)-1,2-indandiol is reported. The key aspect of the study was the use of pure (R)- and (S)-2-hydroxy-1-indanone enantiomers to ensure reliable conclusions. Experiments in the absence of yeast cells or using dead cells disclosed that the pure enantiomers were not racemized, which suggest that the whole dynamic kinetic resolution process is enzymatic in character. When living yeast cells were used the (R)-substrate was smoothly converted to (1S,2R)-1,2-indandiol, whilst the (S)-2-hydroxy-1-indanone was converted to the same diol through a more complex fashion, which requires a more lengthy oxidation-reduction pathway having the 1,2-indanedione as an achiral intermediate. An unexpected observation was that 1,2-indanone acts as a moderate inhibitor of the reductive enzymes acting in the conversion of (R)-2-hydroxy-1-indanone to (1S,2R)-1,2-indandiol.
- Cazetta, Tarcila,Lunardi, Ines,Conceicao, Gelson J.A.,Moran, Paulo J.S.,Rodrigues, J. Augusto R.
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p. 2030 - 2036
(2008/02/11)
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- Electroorganic synthesis in oil-in-water nanoemulsion: TEMPO-mediated electrooxidation of amphiphilic alcohols in water
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Oil-in-water nanoemulsions, consisting of TEMPO, amphiphilic alcohols, and water, offer unique reaction environments for electrooxidation of the alcohols to give the corresponding carboxylic acids in good to excellent yields. Georg Thieme Verlag Stuttgart.
- Yoshida, Tomonori,Kuroboshi, Manabu,Oshitani, Jun,Gotoh, Kuniaki,Tanaka, Hideo
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p. 2691 - 2694
(2008/02/12)
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- A stable, convertible isonitrile as a formic acid carbanion [ -COOH] equivalent and its application in multicomponent reactions
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The application of 2-(2,2-dimethoxyethyl) phenyl isonitrile in Ugi, Passerini, and Ugi-Smiles reactions is described. The simple transformation to highly activated indolyl amides allows functional-group conversion of the isonitrile moiety into a variety of carboxylic acid derivatives, overall acting as a neutral, nucleophilic COOH equivalent. Georg Thieme Verlag Stuttgart.
- Kreye, Oliver,Westermann, Bernhard,Wessjohann, Ludger A.
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p. 3188 - 3192
(2008/09/20)
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- Biocatalytic racemization of (hetero)aryl-aliphatic α- hydroxycarboxylic acids by Lactobacillus spp. proceeds via an oxidation-reduction sequence
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The biocatalytic racemization of a range of (hetero)aryl- and (di)aryl-aliphatic α-hydroxycarboxylic acids has been achieved by using whole resting cells of Lactobacillus spp. The essentially mild (physiological) reaction conditions ensure the suppression of undesired side reactions, such as elimination, decomposition or condensation. Cofactor/inhibitor studies using a cell-free extract of Lactobacillus paracasei DSM 20207 reveal that the addition of redox cofactors (NAD+/NADH) leads to a distinct increase in the racemization rate, while strong inhibition is observed in the presence of Thio-NAD+, which suggests that the racemization proceeds by an oxidation-reduction sequence rather than involvement of a "racemase" enzyme. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Nestl, Bettina M.,Glueck, Silvia M.,Hall, Melanie,Kroutil, Wolfgang,Stuermer, Rainer,Hauer, Bernhard,Faber, Kurt
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p. 4573 - 4577
(2007/10/03)
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