- Chirality-sensing binaphthocrown ether-polythiophene conjugate
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Abstract: An enantiomeric binaphthyl unit was tethered to adjacent thiophenes with oxyethylene linkers to give a chiral polythiophene with binaphthocrown ether cavities. Upon inclusion of a chiral cationic guest in the cavity of the chiral crown ether-polythiophene conjugate, the bithiophene unit was twisted to shorten the effective conjugation length of polythiophene backbone, enabling us to sense the guest binding by reading out the amplified optical signal gains arising from the backbone structure change. This strategy allowed us to discriminate the guest chirality without using chiroptical signals or a circular dichroism spectrometer to achieve the highest enantioselectivity of 7.3 for valine methyl ester with a 40-fold enhanced sensitivity compared with the corresponding monomeric sensor.
- Fukuhara, Gaku,Inoue, Yoshihisa
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- Synthesis of the C26-C32 Oxazole Fragment of Calyculin C: A Test Case for Oxazole Syntheses
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The synthesis of the C26-C32 oxazole fragment 4 and its C32 epimer 20 of serine/threonine protein phosphatase PP1 and PP2A inhibitor calyculin C is presented. The syn methyl arrangement in 4 was established through cyclic stereocontrol. Several methods for oxidizing the intermediate oxazolines 18 and 19 to the finished oxazole fragments were explored. The best results were obtained with oxidations proceeding through the corresponding ester enolate when the carbamate NH side chain was temporarily protected with a TMS group, or with CuBr2/DBU/HMTA-based oxidations. The finished oxazole fragment 4 was obtained in 21% overall yield, starting from Boc-D-alaninal.
- Pihko, Petri M.,Koskinen, Ari M. P.
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- New helical folds in α-peptides with alternating chirality
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In α-peptides, the 8/10 helix is theoretically predicted to be energetically unstable and has not been experimentally observed so far. Based on our earlier studies on 'helical induction' and 'hybrid helices', we have adopted the 'end-capping' strategy to induce the 8/10 helix in α-peptides by using short α/β-peptides. Thus, α-peptides containing a regular string of α-amino acids with alternating chirality were end capped by α/β-peptides with 11/9-helical motifs at the termini. Extensive NMR spectroscopy studies of these peptides revealed the presence of a hitherto unknown 8/10-helical pattern; the H-bonds in the shorter pseudorings were rather weak. The approach of using short helical motifs to induce new mixed helices in α-peptides could provide avenues for more versatile design strategies. A new twist: α-Peptides containing a regular string of α-amino acids with alternating chirality were end capped by α/β-peptides with 11/9-helical motifs at the termini. Extensive NMR spectroscopy studies of these peptides revealed the presence of a hitherto unknown 8/10-helical pattern in this hybrid helix (see figure); the H-bonds in the shorter pseudorings were rather weak. The addition of helix-stabilizing influences may enhance the propensity and stability of these uncommon folding patterns in oligomers of α-amino acids.
- Sharma, Gangavaram V. M.,Venkateshwarlu, Gajulapati,Reddy, Pothula Purushotham,Kunwar, Ajit C.
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- Rhodium-Catalyzed Enantioselective Synthesis of Oxazinones via an Asymmetric Ring Opening-Lactonization Cascade of Oxabicyclic Alkenes
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The rhodium-catalyzed asymmetric ring opening reaction of oxabicyclic alkenes is shown to be an efficient method for synthesizing chiral heterocycles. We demonstrate that the pairwise combination of chiral catalyst with chiral amino-acid-derived pronucleophiles results in a stereodivergent synthesis of diastereomeric hydroxyesters. A favorable conformational preference induces the subsequent lactonization of one diastereomer leading to the highly enantioselective synthesis of oxazinones.
- Yen, Andy,Pham, Anh Hoang,Larin, Egor M.,Lautens, Mark
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supporting information
p. 7549 - 7553
(2019/10/02)
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- A valsartan synthesis method of alkylation impurity (by machine translation)
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A valsartan synthesis method of alkylation impurities, is to L - valine that may exist in the impurity D - valine, alanine, leucine isoleucine amino acid as the raw material and the like, in thionyl chloride under the conditions of the esterification reaction with methanol, after the reaction by reducing pressure methanol, then with 2 - cyano - 4' - bromomethyl biphenyl in the reaction under alkaline conditions, after completion of the reaction, saturated salt water washing, adding hydrochloric acid to adjust the pH=1 - 2, the temperature of the crystallization, filtering to obtain the target product valsartan alkylation impurity. The present invention is to provide high-purity impurity, will its known impurity used for alkylation of valsartan in mass analysis, the position of the clear of impurities in the sample, the degree of impurity of the sample inspection, optimizes the analytical method, contribute to improving the quality of valsartan research, for the production of valsartan reducing impurity, improve the quality of the valsartan; at the same time, this invention has mild condition, the reaction yield is higher, convenient operation and the like. (by machine translation)
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Paragraph 0016; 0017
(2018/10/19)
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- Synthesis method for nitro group-containing natural product chrysamides B and diastereoisomer-compound thereof
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The invention belongs to the technical fields of medicinal chemistry and organic synthesis, and relates to a synthesis method for a nitro group-containing natural product chrysamides B, a chrysamidesB diastereoisomer-compound and a synthesis method and application thereof. According to the invention, a convergent synthesis method is adopted to condense chiral epoxy carboxylic acid and chiral dimethylpiperazine ring, and thereby the nitro group-containing natural product chrysamides B with a symmetrical structure and the chrysamides B diastereoisomer-compound are easily and efficiently synthesized. By three-step continuous oxidation, chiral epoxy carboxylic acid is prepared from p-nitrobenzaldehyde which is easy to obtain commercially, and dimethylpiperazine ring is prepared by reduction after alanine dimerization. The compound shows inhibitory activity on pasteurella multocida. Such a convergent synthesis route can be applied to the chemical synthesis of compounds with the similar structure and related derivatives, opening up a broad development space for novel antibiotic drugs.
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Paragraph 0024; 0025
(2018/11/22)
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- Chiral-pool synthesis of 1,2,4-trisubstituted 1,4-diazepanes as novel σ1 receptor ligands
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Starting from enantiomerically pure amino acids, 1,4-diazepanes with various substituents in 1, 2, and 4-position were synthesized following the late stage diversification strategy. The key step in the formation of the seven-membered ring was the intramolecular EDC coupling of amino acids 15, 26, and 39. The configuration in 2-position does not influence the σ1 affinity and selectivity over related receptors. A cyclohexylmethyl or a butyl group are the preferred substituents in 4-position, whereas a methyl moiety in 2-position and a (substituted) benzyl moiety in 1-position result in the highest σ1 affinity. These results fit nicely to the reported σ1 pharmacophore models. The compounds did not inhibit the structurally related fungal enzyme sterol Δ8,7-isomerase, but showed inhibition of diverse enzymes in late cholesterol biosynthesis at high concentrations. In a screening against more than 50 target proteins, (2S)-1-benzyl-4-(4-methoxybenzyl)-2-methyl-1,4-diazepane ((S)-28b, Ki(σ1) = 0.86 nM) showed a clean receptor profile. The dose dependent potentiation of electrically stimulated contractions of guinea pig vas deferens indicates σ1 agonistic activity of (S)-28b. Even at a dose of 100 mg/kg (S)-28b did not induce severe toxic or behavioral effects in the Irwin screen. Clear cognition enhancing effects were observed for (S)-28b after inducing amnesia by scopolamine.
- Fanter, Lena,Müller, Christoph,Schepmann, Dirk,Bracher, Franz,Wünsch, Bernhard
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p. 4778 - 4799
(2017/10/05)
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- Benzoxaborole Antimalarial Agents. Part 5. Lead Optimization of Novel Amide Pyrazinyloxy Benzoxaboroles and Identification of a Preclinical Candidate
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Carboxamide pyrazinyloxy benzoxaboroles were investigated with the goal to identify a molecule with satisfactory antimalarial activity, physicochemical properties, pharmacokinetic profile, in vivo efficacy, and safety profile. This optimization effort discovered 46, which met our target candidate profile. Compound 46 had excellent activity against cultured Plasmodium falciparum, and in vivo against P. falciparum and P. berghei in infected mice. It exhibited good PK properties in mice, rats, and dogs. It was highly active against the other 11 P. falciparum strains, which are mostly resistant to chloroquine and pyrimethamine. The rapid parasite in vitro reduction and in vivo parasite clearance profile of 46 were similar to those of artemisinin and chloroquine, two rapid-acting antimalarials. It was nongenotoxic in an Ames assay, an in vitro micronucleus assay, and an in vivo rat micronucleus assay when dosed orally up to 2000 mg/kg. The combined properties of this novel benzoxaborole support its progression to preclinical development.
- Zhang, Yong-Kang,Plattner, Jacob J.,Easom, Eric E.,Jacobs, Robert T.,Guo, Denghui,Freund, Yvonne R.,Berry, Pamela,Ciaravino, Vic,Erve, John C. L.,Rosenthal, Philip J.,Campo, Brice,Gamo, Francisco-Javier,Sanz, Laura M.,Cao, Jianxin
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p. 5889 - 5908
(2017/07/22)
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- Ferrocene-modified amino acids: synthesis and in vivo bioeffects on hippocampus
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A method for the ferrocene modification of amino acids of natural and synthetic origin has been developed. In the in vivo studies, the hippocampal electrical activity under the action of ferrocenyl(phenylpyrazolyl)glycine (1) was assessed. A meaningful rise (up to 25% compared to the control) in the response amplitudes of the focal potentials of the hippocampal region СА1 after intraperitoneal administration of compound 1 at the dose of 2.0 mg kg–1 was established.
- Rodionov,Snegur,Simenel,Dobryakova, Yu. V.,Markevich
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p. 136 - 142
(2017/07/05)
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- NR2B SELECTIVE NMDA-RECEPTOR ANTAGONISTS FOR TREATMENT OF IMMUNE-MEDIATED INFLAMMATORY DISEASES
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The present invention provides novel means and methods for treatment auf immunemediated inflammatory diseases.
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Paragraph 200; 230
(2017/03/21)
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- Catalysts and temperature driven melt polycondensation reaction for helical poly(ester-urethane)s based on natural L-amino acids
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Catalyst and temperature driven melt polycondensation reaction was developed for natural L-amino acid monomers to produce new classes of poly(ester-urethane)s. Wide ranges of catalysts from alkali, alkali earth metal, transition metal and lanthanides were developed for the condensation of amino acid monomers with diols to yield poly(ester-urethane)s. A-B Diblock and A-B-A triblock species were obtained by carefully choosing mono- or diols in model reactions. More than two dozens of transition metal and lanthanide catalysts were identified for the polycondensation to yield high molecular weight poly(ester-urethane)s. Theoretical studies revealed that the carbonyl carbon in ester possessed low electron density compared to the carbonyl carbon in urethane which driven the thermo-selective polymerization process. Optical purity of the L-amino acid residues in the melt polycondensation process was investigated using D- and L-isomers and the resultant products were analyzed by chiral-HPLC and CD spectroscopy. CD analysis revealed that the amino acid based polymers were self-assembled as β-sheet and polyproline type II secondary structures. Electron and atomic force microscopic analysis confirmed the formation of helical nano-fibrous morphology in poly(ester-urethane)s. The newly developed melt polycondensation process is very efficient and optimized for wide range of catalysts to produce diverse polymer structures from natural L-amino acids.
- Anantharaj, Santhanaraj,Jayakannan, Manickam
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p. 1065 - 1077
(2016/03/12)
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- Enantiomerically Pure 2-Methyltetrahydro-3-benzazepin-1-ols Selectively Blocking GluN2B Subunit Containing N-Methyl-d-aspartate Receptors
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A chiral pool synthesis was developed to obtain all four stereoisomeric 2-methyl-3-(4-phenylbutyl)tetrahydro-3-benzazepin-1-ols 21, 31, and 32 in a seven- to eight-step sequence. The phenols 32 reveal slightly higher GluN2B affinity than the methyl ethers 21. The GluN2B affinity increases in the order (1R,2S) (1S,2S) (1S,2R) (1R,2R). The stereoisomeric phenols (R,R)-32 and (S,R)-32 show the highest GluN2B affinity and the highest cytoprotective activity. Both compounds represent GluN2B selective allosteric NMDA receptor antagonists. Docking of the 3-benzazepin-1-ols into the ifenprodil binding site of the crystallized GluN1b/GluN2B N-terminal domains led to free binding energies, which correlate nicely with the experimentally determined GluN2B affinities. The similar GluN2B affinity of the stereoisomeric phenols (S,S)-32, (R,R)-32, and (S,R)-32 is explained by different binding modes of the 3-benzazepine scaffold. The benzyl ethers 31 reveal unexpectedly high GluN2B affinity but do not show cytoprotective effects. The additional benzyl moiety of 31 binds into a previously unrecognized lipophilic subpocket.
- Tewes, Bastian,Frehland, Bastian,Schepmann, Dirk,Robaa, Dina,Uengwetwanit, Tanaporn,Gaube, Friedemann,Winckler, Thomas,Sippl, Wolfgang,Wünsch, Bernhard
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supporting information
p. 6293 - 6305
(2015/08/24)
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- Chiral phosphanylferrocenecarboxamides with amino acid pendant groups as ligands for Cu-mediated asymmetric conjugate additions of diethylzinc to chalcones - Structural characterisation of precursors to the Cu catalyst
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A series of chiral phosphanylferrocenecarboxamides was prepared by treatment of either l'-(diphenylphosphanyl)ferrocene-1-carboxylic acid (Hdpf) or its planar-chiral 1,2isomers with amino acid methyl esters in the presence of peptide coupling agents. The compounds were characterised by spectroscopic methods, and the crystal structure of one representative was determined by X-ray diffraction. Catalytic testing of these donors in Cu-catalysed asymmetric conjugate additions of diethylzinc to chalcones revealed that the reaction outcomes were highly sensitive to the ligand structure and the reaction conditions (copper source and solvent), whereas the chalcone substituents (Me, MeO, or Cl in positions 4 or 4') had a less pronounced influence. Compounds based on Hdpf proved to be better ligands than their planarchiral analogues. Under optimised conditions, the reaction with L-valine-Hdpf conjugate, (S)-Ph2PfcCONHCH(CHMe2)CO2Me (fc = ferrocene-1,1'-diyl) and unsubstituted chalcone gave the alkylation product with complete conversion (20 °C/ 4 h) and in 87 % ee. The catalytic behaviour of the amidophosphane ligands was correlated to the results of a model coordination study and the crystal structure of [Cu(Ph2PfcCONHCH 2CO2Me)2](CF3SO3) ·2CHCl3.
- Tauchman, Jiri,Cisarova, Ivana,Stepnicka, Petr
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supporting information; experimental part
p. 4276 - 4287
(2010/10/21)
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- COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
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The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
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Page/Page column 45-49; 60
(2010/12/31)
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- NR2B-SELECTIVE NMDA-RECEPTOR ANTAGONISTS
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The present invention relates to compounds according to general formula (I) and pharmaceutical compositions comprising compounds according to general formula (I).
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Page/Page column 77-78
(2010/11/05)
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- New chiral building blocks of β-peptoid analogs
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The synthesis of chiral functionalized β-amino esters via the hydride reductive amination of chiral allenes was explored. These compounds can be regarded as β-peptoids building blocks bearing a chiral side chain at the nitrogen and at the same time retaining the β-amino acid side chain. β-Enamino esters were obtained from the nucleophilic addition of α-amino esters (l-Ala, d-Ala, l-Phe, l-Leu, l-Trp and d-Trp methyl esters) to 2,3-allenoates bearing a chiral auxiliary, which determines the stereochemistry outcome of the subsequent reduction reaction. It was also demonstrated that in the reduction of β-enamino esters derived from l-Pro and d-Pro methyl esters the chirality of the new chiral center is controlled by the α-amino ester moiety.
- Cardoso, Ana Lúcia,Lopes, Susana M.M.,Matos Beja, Ana,Ramos Silva, Manuela,de los Santos, Jesús M.,Pinho e Melo, Teresa M.V.D.,Palacios, Francisco
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body text
p. 9116 - 9124
(2010/01/16)
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- 3-AMIDO-PYRROLO[3,4-C]PYRAZOLE-5(1H, 4H,6H) CARBALDEHYDE DERIVATIVES AS INHIBITORS OF PROTEIN KINASE C
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The present invention relates to compounds and pharmaceutically acceptable salts of Formula (I): wherein X, R1, R2, R3, R4, R5, R6, R7, and R8 are as defined above. The invention further relates to pharmaceutical compositions comprising the compounds and pharmaceutically acceptable salts and to methods of treating diabetes mellitus and its complications (including in particular diabetic retinopathy, nephropathy or neuropathy), cancer, ischemia, inflammation, central nervous system disorders, cardiovascular disease, Alzheimer's disease and dermatological disease pression, viral diseases, inflammatory disorders, or diseases in which the liver is a target organ
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Page/Page column 20-21
(2008/12/08)
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- Novel glycine like amino acids from glyco-α-aminonitriles as building blocks for peptide synthesis
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Our interest in the glycoaminocyanation reaction led us to apply this methodology to introduce amino acids on a monosaccharide using the N-terminal position. The GAAs described in this paper are characterized by having the amino and carboxylic acid functionalities on a disubstituted position of the saccharide backbone leading to α,α-disubstituted glycines. These new sugar amino acids showed a restricted conformation involving a spontaneous intramolecular cyclization between the C- and N-terminal positions during hydrolysis or hydrogenolysis to give the corresponding oxopiperazine. Tripeptide mimics were obtained by the introduction of an additional amino acid using one-pot conditions starting from these cyclic by-products under basic media. We demonstrated that these pseudo tripeptides are good candidates for extension of the peptidic scaffold and cyclization.
- Ducatel, Helene,Van Nhien, Albert Nguyen,Postel, Denis
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- Relationship between the hydrophobicity of dipeptides and the Michaelis-Menten constant Km of their hydrolysis by carboxypeptidase-Y and carboxypeptidase-A
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The enzymatic hydrolysis of dipeptides by carboxypeptidase-Y and carboxypeptidase-A was investigated. In the enzymatic hydrolysis of the dipeptides, a good linear relationship (r = 0.997 and 0.999) was found between the Michaelis-Menten constant (Km) and the hydrophobicity of the substrates evaluated from relative elution volume in reversed-phase HPLC. The correlation suggests that the hydrophobicity of the C-terminal amino acid is a major factor in governing the stability of the enzyme-substrate complex. The difference in the slope of the linear-regression lines seems to reflect the degree of relative hydrophobicity of the binding pockets in carboxypeptidase-Y and carboxypeptidase-A.
- Kanosue, Yoshifumi,Kojima, Satoshi,Hiraga, Yoshikazu,Ohkata, Katsuo
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p. 1187 - 1193
(2007/10/03)
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- Asymmetric alkylations using SuperQuat auxiliaries - An investigation into the synthesis and stability of enolates derived from 5,5-disubstituted oxazolidin-2-ones
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Studies on the alkylation of enolates derived from a range of N-acyl-5,5-dimethyloxazolidin-2-ones and N-acyl-5,5-diphenyloxazolidin-2-ones reveal that high yields and high diastereoselectivities are best obtained when homochiral 4-isopropyl-5,5-dimethyloxazolidin-2-one is employed as a chiral auxiliary.
- Bull, Steven D.,Davies, Stephen G.,Jones, Simon,Sanganee, Hitesh J.
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p. 387 - 398
(2007/10/03)
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- Chiral Discrimination in the Liquid Phase: Excess Volumes of Binary Mixtures of Amino Acid Derivatives
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Volume changes on mixing the enantiomers of N-trifluoroacetylamino acid methyl esters (N-TFA-amino acid-OMe) were determined at 25 deg C by means of a high-precision vibrating-tube densimeter.The excess molar volume (VE) for the racemic mixtures of N-TFA-Ala-OMe 1, N-TFA-Val-OMe 2, and N-TFA-Leu-OMe 3, were found as VE = 0.0098, -0.0458, and 0.035 cm3 mol-1, respectively.For 2 and 3, these volumetric effects of discriminating interactions between enantiomers in the liquid phase are the largest ever observed.
- Lepori, Luciano,Koppenhoefer, Beenhard
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p. 6862 - 6864
(2007/10/02)
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- Syntheses of (1′R)-1′-methyl-cis-zeatin and its 9-β-D-ribofuranoside
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The cis isomers IIIb and IVb of the recently isolated cytokinins (1′R)-1′-methylzeatin (IIIa) and (1″R)-1″-methylzeatin 9-riboside (IVa) have been synthesized from D-alanine (V) through the intermediates VI, VII, IX, VIII, X, and XI.
- Fujii, Tozo,Ohba, Masashi,Sakari, Miwa
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p. 2077 - 2080
(2007/10/02)
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- ENANTIOSELECTIVE ELECTROPHILIC BOND CONSTRUCTION TO THE α-CARBON OF α-AMINOACIDS
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In this report, we describe three possibilities for aminoacid synthesis using an enantioselective electrophilic process.Thus, enantioselective carboxylation, alkylation and protonation of Schiff bases yield optically active aminoacids with e.e. up to 76percent.
- Duhamel, Lucette,Duhamel, Pierre,Fouquay, Stephane,Eddine, Jamal Jamal,Peschard, Olivier,et al.
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p. 5495 - 5506
(2007/10/02)
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- Synthesis of Optically Active 1,3,2-Oxazaphospholidine 2-Sulfides and 1,3,2-Benzodioxaphosphorin 2-Sulfides
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The optical isomers of ten kinds of insecticidal 1,3,2-oxazaphospholidine 2-sulfides (OS) and two kinds of 1,3,2-benzodioxaphosphorin 2-sulfides (BS), including the commercial insecticide salithion, were synthesized in high optical purity by using two optically active aryl methyl phosphorochloridothionates (AMPC) as chiral two-step phosphorylating reagents.Their configurations were assigned according to the reaction mechanism and supported by proton NMR information.
- Wu, Shao-Yong,Hirashima, Akinori,Kuwano, Eiichi,Eto, Morifusa
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p. 537 - 548
(2007/10/02)
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- Enzyme-Catalyzed Irreversible Formation of Peptides Containing D-Amino Acids
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Procedures have been developed for the preparation of dipeptides Z-L-Tyr-D-X and Z-L-Phe-D-X using Z-L-Tyr-OMe (or Z-L-Phe-OMe) and D-amino acid esters or amides (D-X) as substrates and soluble or immobilized α-chymotrypsin as a catalyst.The formation of each of these peptides in miscible or immiscible organic solvent-water systems in a kinetically controlled approach is virtually irreversible with no side reactions or racemization.Kinetic studies indicate that D-amino acid esters are about 100 times that of water and 10percent that of L-amino acid esters as a nucleophile in deacylation reactions.The effects of pH, organic solvents, temperature, and substrate and enzyme concentrations on the yield and the stability of the enzyme in syntheses have been studied and the results compared with those in the enzyme-catalyzed formation of L-L-dipeptides.
- West, J. Blair,Wong, Chi-Huey
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p. 2728 - 2735
(2007/10/02)
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- Anti-ulcer polypeptides containing L-aspartic acid and intermediates thereto
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This invention encompasses novel tetrapeptide amides and their intermediates containing an L-aspartic acid residue. These peptides are inhibitors of gastric acid secretion and therefore useful in the treatment of ulcers.
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