- Aeruginosins 102-A and B, new thrombin inhibitors from the cyanobacterium Microcystis viridis (NIES-102)
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Aeruginosins 102-A and B were isolated from the freshwater cyanobacterium Microcystis aeruginosa (NIES-102). Their structures were elucidated to be 1 and 2 on the basis of 2D NMR data and chemical degradation. These peptides inhibited thrombin potently.
- Matsuda, Hisashi,Okino, Tatsufumi,Murakami, Masahiro,Yamaguchi, Katsumi
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Read Online
- 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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Read Online
- Synthesis of Weinreb amides using diboronic acid anhydride-catalyzed dehydrative amidation of carboxylic acids
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The first successful example of the direct synthesis of Weinreb amides using catalytic hydroxy-directed dehydrative amidation of carboxylic acids using the diboronic acid anhydride catalyst is described. The methodology is applicable to the concise syntheses of eight α-hydroxyketone natural products, namely, sattabacin, 4-hydroxy sattabacin, kurasoins A and B, soraphinols A and B, and circumcins B and C.
- Shimada, Naoyuki,Takahashi, Naoya,Ohse, Naoki,Koshizuka, Masayoshi,Makino, Kazuishi
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supporting information
p. 13145 - 13148
(2020/11/09)
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- Mechanistic study of the radical SAM-dependent amine dehydrogenation reactions
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The radical SAM enzyme NosL catalyzes the conversion of l-Trp to 3-methyl-2-indolic acid, and this reaction is initiated by the 5′-deoxyadenosyl (dAdo) radical-mediated hydrogen abstraction from the l-Trp amino group. We demonstrate here that when d-Trp was used in the NosL reaction, hydrogen abstraction occurs promiscuously at both the amino group and Cα of d-Trp. These results inspired us to establish the detailed mechanism of l-Trp amine dehydrogenation catalyzed by a NosL mutant, and to engineer a novel radical SAM-dependent l-Tyr amine dehydrogenase from the thiamine biosynthesis enzyme ThiH.
- Ji, Xinjian,Liu, Wan-Qiu,Yuan, Shuguang,Yin, Yue,Ding, Wei,Zhang, Qi
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p. 10555 - 10558
(2016/09/02)
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- Latifolicinin A from a Fermented Soymilk Product and the Structure-Activity Relationship of Synthetic Analogues as Inhibitors of Breast Cancer Cell Growth
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The functional components in soymilk may vary depending upon the fermentation process. A fermented soymilk product (FSP) obtained by incubation with the microorganisms of intestinal microflora was found to reduce the risk of breast cancer. Guided by the inhibitory activities against breast cancer cells, two cytotoxic compounds, daidzein and (S)-latifolicinin A, were isolated from the FSP by repetitive extraction and chromatography. Latifolicinin A is the n-butyl ester of β-(4-hydroxyphenyl)lactic acid (HPLA). A series of the ester and amide derivatives of (S)-HPLA and l-tyrosine were synthesized for evaluation of their cytotoxic activities. In comparison, (S)-HPLA derivatives exhibited equal or superior inhibitory activities to their l-tyrosine counterparts, and (S)-HPLA amides showed better cytotoxic activities than their corresponding esters. In particular, (S)-HPLA farnesyl amide was active to triple-negative MDA-MB-231 breast cancer cells (IC50 = 27 μM) and 10-fold less toxic to Detroit-551 normal cells.
- Ke, Yi-Yu,Tsai, Chen-Hsuan,Yu, Hui-Ming,Jao, Yu-Chen,Fang, Jim-Min,Wong, Chi-Huey
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p. 9715 - 9721
(2015/11/24)
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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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- Concise, protecting group free total syntheses of (+)-sattabacin and (+)-4-hydroxysattabacin
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The first asymmetric total syntheses of the antiviral natural products (+)-sattabacin and (+)-4-hydroxysattabacin are reported. Both total syntheses are remarkably concise and were completed without the use of protecting groups. These syntheses allowed the unambiguous assignment of the absolute configuration of both natural products. The syntheses of these natural products, which exhibit marked antiviral activity, are readily amenable to the preparation of structural analogs and progress in this regard is also reported.
- Aronoff, Matthew R.,Bourjaily, Neil A.,Miller, Kenneth A.
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scheme or table
p. 6375 - 6377
(2011/01/03)
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- 4,4-Dimethyl-1,2,3,4-tetrahydroquinoline-based PPARα/γ agonists. Part I: Synthesis and pharmacological evaluation
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Type-2 diabetes (T2D) is a complex metabolic disease characterized by insulin resistance in the liver and peripheral tissues accompanied by a defect in pancreatic β-cell. Since their discovery three subtypes of Peroxisomes Proliferators Activated Receptors were identified namely PPARα, PPARγ and PPARβ/(δ). We were interested in designing novel PPARγ selective agonists and/or dual PPARα/γ agonists. Based on the typical topology of synthetic PPAR agonists, we focused our design approach on 4,4-dimethyl-1,2,3,4-tetrahydroquinoline as novel cyclic tail.
- Parmenon, Cecile,Guillard, Jerome,Caignard, Daniel-Henri,Hennuyer, Nathalie,Staels, Bart,Audinot-Bouchez, Valerie,Boutin, Jean-Albert,Dacquet, Catherine,Ktorza, Alain,Viaud-Massuard, Marie-Claude
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p. 1617 - 1622
(2008/09/19)
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- METHOD FOR SYNTHESIS OF KETO ACID OR AMINO ACID BY HYDRATION OF ACETHYLENE COMPOUND
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An object of the present invention is to provide a method for synthesis of keto acids by hydration of an acetylene compound (acetylene-carboxylic acids) under mild conditions free from harmful mercury catalysts and a method for synthesis of amino acids from acetylene-carboxylic acids in a single container (one-pot or tandem synthesis). In one embodiment of the method according to the present invention for synthesis of keto acids, acetylene-carboxylic acids is hydrated in the presence of a metal salt represented by General Formula (1), where M1 represents an element in Group VIII, IX, or X of the periodic table, and X1, X2, or X3 ligand represents halogen, H2O, or a solvent molecule, and k represents a valence of a cation species, and Y represents an anion species, and L represents a valence of the anion species, and each of K and L independently represents 1 or 2, and k × m = L × n.
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Page/Page column 24
(2008/12/06)
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- An asymmetric synthesis of PPAR-γ agonist navaglitazar from (+)-methyl (2S,3R)-3-(4-methoxyphenyl)glycidate
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An asymmetric synthesis of navaglitazar, a peroxisome proliferator activated receptor (PPAR) γ agonist, from commercially available (+)-methyl (2S,3R)-3-(4-methoxyphenyl)glycidate, is described. The new synthesis features high overall yield, low solvent usage, crystalline intermediates and operational simplicity. Schweizerische Chemische Gesellschaft.
- Rizzo, John R.,Zhang, Tony Y.
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p. 580 - 583
(2007/10/03)
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- Synthesis of a peroxime proliferator activated receptor (PPAR) α/γ agonist via stereocontrolled Williamson ether synthesis and stereospecific SN2 reaction of S-2-chloro propionic acid with phenoxides
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The stereospecific synthesis of the PPAR α/γ agonist 1 was accomplished via ethylation of the optically pure trihydroxy derivative 6, itself derived via an enzymatic resolution. The ethylation can be accomplished without epimerization only under strict control of the reaction conditions and the choice of base (sodium tert-amylate), temperature (-30°C), order of addition, and solvent (DMF). The key diastereospecific SN2 reaction of the phenol 4 with S-2-chloropropionic acid is best achieved via the sodium phenoxide of 4 derived from Na0 as the reagent of choice. The structure elucidation and key purification protocols to achieve pharmaceutical purity will also be described
- Aikins, James A.,Haurez, Michael,Rizzo, John R.,Van Hoeck, Jean-Pierre,Brione, Willy,Kestemont, Jean-Paul,Stevens, Christophe,Lemair, Xavier,Stephenson, Gregory A.,Marlot, Eric,Forst, Mindy,Houpis, Ioannis N.
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p. 4695 - 4705
(2007/10/03)
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- Claisen condensation as a facile route to an α-alkoxy-cinnamate: Synthesis of ethyl (2S)-2-ethoxy-3-(4-hydroxyphenyl)propanoate
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The title compound was prepared from p-anisaldehyde and ethyl ethoxyacetate via a racemic synthetic route. The synthesis involves a Claisen-type condensation in which the elimination was unexpectedly promoted by an excess of the ester. The process has been successfully performed on a 2000-L scale with a total yield over seven steps of 19%.
- Linderberg, Mats T.,Moge, Mikael,Sivadasan, Sivaprasad
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p. 838 - 845
(2013/09/03)
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- pH-Dependent Chemoselective Synthesis of α-Amino Acids. Reductive Amination of α-Keto Acids with Ammonia Catalyzed by Acid-Stable Iridium Hydride Complexes in Water
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An acid-stable hydride complex [Cp*IrIII(bpy)H]+ {1, Cp* = η5-C5Me5, bpy = 2,2′-bipyridine} serves as the active catalyst for the highly chemoselective synthesis of α-amino acids by reductive aminatio
- Ogo, Seiji,Uehara, Keiji,Abura, Tsutomu,Fukuzumi, Shunichi
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p. 3020 - 3021
(2007/10/03)
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- Synthesis and antioxidant properties of a new lipophilic ascorbic acid analogue
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4-(4-Hydroxyphenyl)-5-(4-hydroxyphenylmethyl)-2-hydroxyfurane-2-one 1 was prepared by an acidic dimerisation of 4-hydroxyphenylpyruvic acid and some of its antioxidant and spectroscopic properties have been measured and compared to that of ascorbic acid. 1 is as good an antioxidant as ascorbic acid in the DPPH (2,2-diphenyl-1-picryl hydrazyl radical) test and the inhibition of hydroxyl radical and a powerful inhibitor of the Cu2+ or AAPH (2,2′-azobis-(2-amidinopropane) dihydrochloride) induced oxidation of human LDL. 1 gives a stable radical characterised by its ESR spectrum similarly to ascorbic acid but in lower concentration and with a different reactivity towards nitroxides. Theoretical calculations allow us to propose the structure for the radical formed from 1, to explain its lower stability than ascorbyl radical and to evaluate the lipophilicity of 1.
- Cotelle, Philippe,Cotelle, Nicole,Teissier, Elisabeth,Vezin, Herve
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p. 1087 - 1093
(2007/10/03)
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- Synthesis of microcin SF608
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The first total synthesis of aquatic peptide microcin SF608 is described. Coupling of L-Hpla with the dipeptide L-Phe-L-Choi followed by coupling with agmatine and a deprotection step gave microcin SF608. In addition, the levorotatory character of L-Hpla (5) was thoroughly established, and the conformational analysis of L-Choi containing peptides 1 and 8-10 was performed using NMR spectroscopy to examine the cis-trans isomer equilibrium of the L-Phe-L-Choi amide bond.
- Valls, Nativitat,Vallribera, Merce,Lopez-Canet, Meritxell,Bonjoch, Josep
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p. 4945 - 4950
(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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- Process for production of phenyllactic acid derivative
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A process for producing a phenyllactic acid derivative comprises hydrogenating a phenylpyruvic acid derivative in the presence of a catalyst containing at least one element selected from the Group VIII elements of the periodic table. The process provides a phenyllactic acid derivative useful as an intermediate in the production of pharmaceuticals and agricultural chemicals. The process uses as a starting material a phenylpyruvic acid derivative which is easily synthesized. The process is simpler in operation and provides a higher yield than conventional processes.
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- Selectivity and Specificity in Substrate Binding to Proteases: Novel Hydrolytic Reactions Catalysed by α-Chymotrypsin Suspended in Organic Solvents with Low Water Content and Mediated by Ammonium Hydrogen Carbonate
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α-Chymotrypsin suspended in organic solvents with low water content catalysed hydrolytic reactions in the presence of ammonium hydrogen carbonate.Molecular modelling studies were carried out and structure-reactivity relationships were established by studying the hydrolysis of amino acid derivatives and analogues.The enzyme was found to be stereoselective with respect to the hydrolysis of L-amino acid derivatives, but no stereoselectivity was observed when α-hydroxy esters were used as substrates.A general procedure for the resolution of aromatic amino acid esters is given.The results are interpreted in terms of molecular modelling based on X-ray crystallographic data and literature data.
- Ricca, Jean-Marc,Crout, David H. G.
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p. 1225 - 1234
(2007/10/02)
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- A modified synthesis of (±)-β-aryllactic acids
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The synthesis of racemic forms of the reportedly active principle of Danshen, namely (±)-β-(3,4-dihydroxyphenyl)lactic acid [(±)3-(3,4-dihydroxyphenyl)-2-hydroxypropanoic acid] and its seven racemic derivatives is reported.
- Wong,Xu,Chang,Lee
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p. 793 - 797
(2007/10/02)
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