- Trikoveramides A-C, cyclic depsipeptides from the marine cyanobacterium Symploca hydnoides
-
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
-
-
- 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
-
p. 3143 - 3151
(2020/03/23)
-
- Glycerol conversion to high-value chemicals: The implication of unnatural α-amino acid syntheses using natural resources
-
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)
-
- 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)
-
- A novel D-2-hydroxy acid dehydrogenase with high substrate preference for phenylpyruvate originating from lactic acid bacteria: Structural analysis on the substrate specificity
-
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
-
-
- Preparation method of chiral phenyllactic acid
-
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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-
- 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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-
- 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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- 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)
-
- 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)
-
- 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.
- -
-
Paragraph 0260-0262
(2015/09/22)
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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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- 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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p. 11225 - 11228,4
(2015/01/07)
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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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- 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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- 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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- 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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- 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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- 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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- 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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- Enantio-complementary deracemization of (±)-2-hydroxy-4- phenylbutanoic acid and (±)-3-phenyllactic acid using lipase-catalyzed kinetic resolution combined with biocatalytic racemization
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Deracemization of (±)-3-phenyllactic acid (1) and (±)-2-hydroxy-4-phenylbutanoic acid (2) was accomplished by lipase-catalysed kinetic resolution coupled to biocatalytic racemization of the non-reacting substrate enantiomers using Lactobacillus paracasei DSM 20008. Cyclic repetition of this sequence led to a single enantiomeric product from the racemate. Access to both enantiomers was achieved by switching between lipase-catalysed acyl-transfer and ester hydrolysis reactions. Both products constitute important building blocks for virus protease- and ACE-inhibitors, respectively.
- Larissegger-Schnell, Barbara,Glueck, Silvia M.,Kroutil, Wolfgang,Faber, Kurt
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p. 2912 - 2916
(2007/10/03)
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- Determination of the complete absolute configuration of petriellin A
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We report the full structural determination of the depsipeptide petriellin A. The absolute configuration of the amino acid residues, N-methyl isoleucine and N-methyl threonine, have been determined by a combination of HPLC and TLC comparison of synthetic Marfey's derivatives and Marfey's derivatives of the natural product hydrolysate. The configuration of the chiral centres in these two N-methylated residues was found to be the same as those of the common unmethylated l-amino acids. CSIRO 2006.
- Aurelio, Luigi,Brownlee, Robert T. C.,Dang, Jason,Hughes, Andrew B.,Polya, Gideon M.
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p. 407 - 414
(2008/02/04)
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- Synthesis of the key precursor of Hirsutellide A
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Hexadepsipeptide 2, the precursor of Hirsutellide A (1), was synthesized in an overall yield of 45% from N-Boc-Me-Gly via three coupling reactions using dicyclohexylcarbodiimide (DCC), O-(7-azabenzotriazol-1-yl)-N,N,N′, N′-tetramethyluronium hexafluorophosphate (HATU) and bis(2-oxo-3- oxazolidinyl)phosphinic chloride (BOP-Cl), respectively.
- Xu, Yanjie,Duan, Xuemin,Li, Meiling,Jiang, Liqin,Zhao, Guangle,Meng, Yi,Chen, Ligong
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p. 259 - 264
(2007/10/03)
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- Total synthesis of hirsutellide A
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The total synthesis of hirsutellide A 1 was described. The linear hexadepsipeptide precursor 2 was synthesized in 45% yield from N-Boc-Me-Gly by three coupling reactions with DCC, HATU and BOP-Cl, respectively. Macrocyclization was successfully performed on the fully deprotected amino acid 14 with BOP-Cl in 15% yield and with FDDP in 22% yield.
- Xu, Yanjie,Chen, Ligong,Duan, Xuemin,Meng, Yi,Jiang, Liqin,Li, Meiling,Zhao, Guangle,Li, Yang
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p. 4377 - 4379
(2007/10/03)
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- Biocatalytic racemization of aliphatic, arylaliphatic, and aromatic α-hydroxycarboxylic acids
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Biocatalytic racemization of a range of aliphatic, (aryl)aliphatic, and aromatic α-hydroxycarboxylic acids was accomplished by using whole resting cells of a range of Lactobacillus spp. The mild (physiological) reaction conditions ensured an essentially "clean" isomerization in the absence of side reactions, such as elimination or decomposition. Whereas straight-chain aliphatic 2-hydroxy-carboxylic acids were racemized with excellent rates (up to 85% relative to lactate), steric hindrance was observed for branched-chain analogues. Good rates were observed for aryl-alkyl derivatives, such as 3-phenyllactic acid (up to 59%) and 4-phenyl-2-hydroxybutanoic acid (up to 47%). In addition, also mandelate and its o-chloro analogue were accepted at a fair rate (45%). This biocatalytic racemization represents an important tool for the deracemization of a number of pharmaceutically important building blocks.
- Glueck, Silvia M.,Pirker, Monika,Nestl, Bettina M.,Ueberbacher, Barbara T.,Larissegger-Schnell, Barbara,Csar, Katrin,Hauer, Bernhard,Stuermer, Rainer,Kroutil, Wolfgang,Faber, Kurt
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p. 4028 - 4032
(2007/10/03)
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- Synthesis of brassinosteroids of varying acyl side chains and evaluation of their brassinolide-like activity
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Brassinosteroids containing various side chain moieties were synthesized and their activity was determined as the reciprocal logarithm of the ED 50 (50% effective dose per plant in moles) in the rice lamina inclination assay using synergist indole-3-acetic acid (IAA). The introduction of a hydroxyl group in the α-position to the carbonyl group of the ester structure significantly enhanced the activity. 2α,3α-Dihydroxy- 17β-[(2R,3S)-2-hydroxy-3-methylpentanoyl]oxy-B-homo-7-oxa-5α- androstan-6-one showed the highest activity, for which the pED50 was determined to be 10.5 under synergistic conditions with IAA. Under identical conditions, the pED50 values of brassinolide and castasterone were determined to be 13.6 and 12.3 respectively. With respect to the α-carbon of the acyl moiety, the R-form was 10 times more potent than the corresponding S-form. Substituting the terminal structure (Et) of the side chain to that of the most potent compound, brassinolide (i-Pr), did not increase the activity.
- Uesusuki, Shinya,Watanabe, Bunta,Yamamoto, Shuji,Otsuki, Junko,Nakagawa, Yoshiaki,Miyagawa, Hisashi
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p. 1097 - 1105
(2007/10/03)
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- NOVEL OPTICALLY ACTIVE COMPOUNDS, METHOD FOR KINETIC OPTICAL RESOLUTION OF CARBOXYLIC ACID DERIVATIVES AND CATALYSTS THEREFOR
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The present invention provides a method of kinetic optical resolution of carboxylic acid derivatives using specific optically active catalysts. A racemic or diastereomeric mixture of carboxylic acid derivatives of the formula (A) is reacted with a nucleophile in the presence of an optically active catalyst to form an optically active nucleophile derivative of the formula (B). The catalyst is an optically active compound represented by the formula (C) or (D) [wherein R1 is a substituted or unsubstituted, saturated or unsaturated, straight-chain, branched or alicyclic aliphatic hydrocarbon group which can have a heteroatom, R2 is ethyl or vinyl, and R5 is hydrogen or methoxy respectively].
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-
Page 19; 22; 24
(2008/06/13)
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- Process research of (R)-cyclohexyl lactic acid and related building blocks: A comparative study
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(S)-Cyclohexyl lactic acid is a component of the selective E-selectin inhibitor 2 ((S)-cHexLact-2-0-(3-Galβ(1→3)ddGlc-(4→1)αFuc). We describe the evaluation of various synthetic routes to this building block: (A) diazotation of phenylalanine followed by phenyl ring hydrogenation; (B) phenyl ring hydrogenation of phenyl alanine followed by diazotation; (C) acidic hydrolysis of the cyanohydrin derived from phenylacetaldehyde, enantiomeric resolution of the resulting, racemic phenyl lactic acid via diasteromeric salt formation and phenyl ring hydrogenation; (D) enantioselective dihydroxylation of a cinnamate ester, followed by hydrogenation of the benzylic hydroxy group and the aromatic nucleus; (E) enantioselective biocatalytic reduction of phenylpyruvic acid, followed by phenyl ring hydrogenation. The development of (2R)-2-0-(4-nitrophenyl)sulfonyl-cyclohexyl lactic acid p-bromobenzylester 21 as a buidling block with improved crystallinity and stability is also described.
- Storz, Thomas,Dittmar, Peter,Fauquex, Pierre Francois,Marschal, Philippe,Lottenbach, Willy Urs,Steiner, Heinz
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p. 559 - 570
(2013/09/05)
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- Dynamic kinetic resolution via dual-function catalysis of modified cinchona alkaloids: Asymmetric synthesis of α-hydroxy carboxylic acids
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A highly enantioselective catalytic transformation of racemic α-hydroxy acids to optically active α-hydroxy acids is reported. A new procedure was developed for the condensation of racemic α-hydroxy acids with trichloromethyl chloroformate (diphosgene) at room temperature in the presence of activated charcoal to form 5-substituted-1,3-dioxolane-2,4-diones in 90-100% yield. An efficient dynamic kinetic resolution of 5-aryl dioxolanediones was realized via a modified cinchona alkaloid-catalyzed alcoholytic opening of the dioxolanedione ring, generating a variety of optically active α-hydroxy esters in 91-96% ee and 61-85% chemical yield. In this dynamic kinetic resolution, the modified cinchona alkaloid was found to serve dual catalytic roles, mediating both the rapid racemization of the 5-aryl dioxolanediones and the enantioselective alcoholytic ring opening of the 5-aryl dioxolanediones. Consequently, both enantiomers of the 5-aryl dioxolanediones were converted to highly enantiomerically enriched aromatic α-hydroxy esters in yields (61-85%), far exceeding the maximum of 50% for a normal kinetic resolution. This development not only represents an expansion of the scope of asymmetric acyl-transfer catalysis of synthetic catalysts but also provides a new approach for the development of efficient chemical dynamic kinetic resolutions promoted by a single catalyst. 5-Alkyl dioxolanediones were resolved by a conventional but highly enantioselective kinetic resolution to provide α-hydroxy acids and esters in high optical purity and good yields. Copyright
- Tang, Liang,Deng, Li
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p. 2870 - 2871
(2007/10/03)
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- A practical synthesis of (1S,2R)-1-amino-2-indanol, a key component of an HIV protease inhibitor, indinavir
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A synthesis of (1S,2R)-1-amino-2-indanol (1), a key component of an HIV protease inhibitor, was accomplished through (R)-2-hydroxy-1-indanone ((R)- 3), which was prepared by an intramolecular Friedel-Crafts acylation of (R)2- acetoxy-3-phenylpropanoic acid readily available from D-(R)-phenylalanine. Alternatively, (R)-3 was obtained by an enzymatic resolution of (±)-2- acetoxy-1-indanone. Ketone (R)-3 was convened into 1 through an oxime formation and diastereoselective hydrogenation.
- Kajiro, Hiroshi,Mitamura, Shuichi,Mori, Atsunori,Hiyama, Tamejiro
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p. 1093 - 1100
(2007/10/03)
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- Enantioselective synthesis of α-hydroxy carboxylic acids: Direct conversion of α-oxocarboxylic acids to enantiomerically enriched α-hydroxy carboxylic acids via neighboring group control
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α-Oxocarboxylic acids can be reduced to the corresponding α-hydroxy carboxylic acids employing DIP-CI(TM) as a reducing agent. The α-carboxylic substituent exerts a remarkable neighboring group effect on the reduction. The reaction presumably proceeds in an intramolecular fashion through a 'rigid' bicyclic transition state assembly, which produces enantioselectivities approaching 99%.
- Wang, Zhe,La, Brittany,Fortunak, Joseph M.,Meng, Xian-Jun,Kabalka, George W.
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p. 5501 - 5504
(2007/10/03)
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- Stereoselective hetero-claisen rearrangement of camphor derived oxazoline-N-oxides
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Camphor derived oxazoline-N-oxides in the presence of various acylating agents afforded α-acyloxyoxazolines resulting from a diastereoselective [3,3] rearrangement. The configuration of the newly formed asymmetric center was established by chemical correlation. The observed diastereoselectivity accounts a concerted rather than a stepwise process.
- Dalko, Peter I.,Langlois, Yves
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p. 2107 - 2110
(2007/10/03)
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- Quantitative transformation of racemic 2-hydroxy acids into (R)-2-hydroxy acids by enantioselective oxidation with glycolate oxidase and subsequent reduction of 2-keto acids with D-lactate dehydrogenase
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The enzymatic resolution of chiral 2-hydroxy acids 1 by enantioselective oxidation with molecular oxygen in the presence of glycolate oxidase from spinach (Spinacia oleracea) and subsequent asymmetric reduction of 2-oxo acids 2 with D-lactate dehydrogenase from Lactobacillus leichmannii leads to enantiomerically pure (R)-2-hydroxy acids in up to 89% yield based on the racemate.
- Adam, Waldemar,Lazarus, Michael,Saha-Moeller, Chantu R.,Schreier, Peter
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p. 351 - 355
(2007/10/03)
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- Synthesis of optically active α-hydroxy acids by kinetic resolution through lipase-catalyzed enantioselective acetylation
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The lipase-catalyzed acetylation of a broad spectrum of racemic 2-hydroxy acids 1 to their 2-acetoxy acids 2 was shown to proceed with high enantioselectivity. Thus, the microbial lipases, in particular from Candida antarctica and Burkholderia species, are convenient biocatalysts for the synthesis of optically active 2-hydroxy acids in excellent enantioselectivity (ee values up to 99%). The absolute configurations of the 2-hydroxy acids 1 were assigned by comparison of the gas-chromatographic data with that of literature-known reference compounds, or by means of the exciton-coupled circular dichroism method (ECCD) on their bichromophoric 2-naphthoate 9-anthrylmethyl derivatives 3. These results establish that (S)-2-hydroxy acids 1 were preferentially acetylated by microbial lipases.
- Adam, Waldemar,Lazarus, Michael,Schmerder, Alexandra,Humpf, Hans-Ulrich,Saha-M?ller, Chantu R.,Schreier, Peter
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p. 2013 - 2018
(2007/10/03)
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- A practical synthesis of (1S, 2R)-1-amino-2-indanol, a key component of HIV protease inhibitor, indinavir
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The synthesis of (1S,2R)-1-amino-2-indanol, a key component of HIV protease inhibitor, is accomplished in eight steps from D-phenylalanine. The starting material is converted into 2-acetoxy-1-indanone in four steps involving intramolecular Friedel-Crafts cyclization. The stereochemically labile α-acetoxy ketone is hydrolyzed to 2-hydroxy-1-indanone using a catalytic amount of scandium triflate without any loss of the optical purity. Diastereoselective hydrogenation of α-hydroxy oxime, derived from the α-hydroxy ketone, gives the amino alcohol in 96% cis-selectivity. Optical purity of the starting material is perfectly retained throughout the transformations.
- Kajiro, Hiroshi,Mitamura, Shu-Ichi,Mori, Atsunori,Hiyama, Tamejiro
-
-
- Ribosome-mediated incorporation of hydrazinophenylalanine into modified peptide and protein analogues
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(S)-α-Hydrazinophenylalanyl-tRNA(Phe), an aminoacyl-tRNA derivative containing the unnatural amino acid (S)-α-hydrazinophenylalanine, was prepared in an effort to examine the stereochemical requirements of the A- site of the ribosome during in vitro protein synthesis. The (S)-α- hydrazinophenylalanine moiety was of interest because it contains two nucleophilic centers, the secondary nitrogen attached to C(α), which is normally acylated during the course of peptide bond formation, and the sterically less hindered primary nitrogen. To determine the position of acylation, (S)-α-hydrazinophenylalanyl-tRNA(Phe) was tested in an Escherichia cull in vitro protein biosynthesizing system lacking elongation factor G, such that only dipeptide products were formed. The dipeptide product mixture was analyzed by HPLC in direct comparison with authentic synthetic standards. The dipeptide assay utilizing (S)-α- hydrazinophenylalanyl-tRNA(Phe) as the A-site tRNA established that the analogue functioned well as an acceptor tRNA; HPLC analysis of the products showed that both dipeptides were formed in approximately equal amounts. When attached to a suppressor tRNA transcript, (S)-α-hydrazinophenylalanine was also incorporated into position 27 of dihydrofolate reductase in an E. coli protein synthesizing system by readthrough of a nonsense codon. This finding expands the currently accepted model of peptide bond formation at the ribosome and adds to the repertoire of peptide-like products shown to form at the peptidyltransferase center of the ribosome.
- Killian, Jennifer A.,Van Cleve, Mark D.,Shayo, Yuda F.,Hecht, Sidney M.
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p. 3032 - 3042
(2007/10/03)
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- (R)- and (S)-3-Hydroxy-4,4-dimethyl-1-phenyl-2-pyrrolidinone as chiral auxiliaries for the asymmetric synthesis of α-hydroxy acids
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Rac-α-bromo acids, rac-4, have been converted into(R)- or(S)-α-hydroxy acids, (R)- or (S)-9 by DCC-induced esterification with the chiral auxiliaries (R)or (S)-1, followed by reaction with sodium p-methoxyphenoxide in the presence of tetra-n-hexylammonium iodide, conditions of dynamic kinetic resolution, to give quite diastereoselectively the (αR,3S)- or (αS,3R)-α-(p-methoxyphenoxy) esters, 7, which were then oxidized with eerie ammonium nitrate and hydrolyzed under controlled acid conditions.
- Camps, Pelayo,Perez, Francesc,Soldevilla, Nuria
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p. 1877 - 1894
(2007/10/03)
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- Conversion of a Cyanhydrin Compound into S-( - )-3-Phenyllactic Acid by Enantioselective Hydrolytic Activity of Pseudomonas sp. BC-18
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A Pseudomonas strain, named BC-18, which can convert racemic phenylacetaldehyde-cyanhydrin (3-phenyllactonitrile) enantioselectively to S-( - )-3-phenyllactic acid (S-PLA), was isolated from soil. Although PLA produced with intact cells contained the S enantiomers of approximately 75% enantiomeric excess (% e.e.), repeated crystallization gave a higher purity (99.8% e.e.) of the S configuration product. Production of S-PLA was significantly increased when 2.0% (w/v) of calcium chloride were added to the reaction mixture for precipitation of S-PLA. Chemical mutagenesis yielded a mutant strain, named BC348-9, with 16 times higher activity (40mU/OD630), compared with that of the parent strain (2.5mU/OD630). When the mutant strain BC348-9 was used, approximately 18g/OD630 was produced, which is 12 times higher than that of the parent strain. The final accumulation of PLA exceeded 6.0%, 1.2 times higher than that of the parent strain.
- Hashimoto, Yoshihiro,Kobayashi, Etsuko,Endo, Takakazu,Nishiyama, Makoto,Horinouchi, Sueharu
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p. 1279 - 1283
(2007/10/03)
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- Building units for N-backbone cyclic peptides. 2. Synthesis of protected N-(ω-thioalkylene) amino acids and their incorporation into dipeptide units
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A new family of amino acids which contain an ω-thioalkylene group on the N(α)-amino nitrogen was synthesized by alkylation of ω-thioalkylamines with triflates of α-hydroxy acids. The reaction proceeded with inversion of configuration yielding optically pure products. The N(α)-(ω-thioalkylene)amino acids were orthogonally protected to allow their incorporation into peptides by solid-phase peptide synthesis (SPPS) methodology. In addition some of these new protected N(α)-(ω-thioalkylene)amino acids were incorporated into dipeptides by 'solution' techniques.
- Bilan, Gal,Gilon, Chaim
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p. 10513 - 10522
(2007/10/02)
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