- Enantioselective inclusion of pyrene-1-sulfonate salts of α-amino acids with crystals of α-cyclodextrin
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Enantioselective inclusion of α-amino acids with crystals of α-cyclodextrin (α-CD) has been achieved by converting the amino acids into sulfonate salts with pyrene-1-sulfonic acid (PyS). For example, crystals of α-CD selectively include L-leucine/PyS (1:1) salt in a host/guest ratio of ～1 with 92%ee from a solution of the racemic salt in ethanol/N-methylformamide (91:9) at 40 °C. Under conditions optimized for individual amino acids, the PyS salts of valine, phenylalanine, and methionine are also included with good enantioselectivities (up to 86%ee). Mechanistic studies for the inclusion of leucine/PyS salt reveals that the enantioselectivity originates from the difference in stability between the inclusion complexes of D- and L-leucine/PyS salts with α-CD in crystals.
- Hattori, Tetsutaro,Kitamoto, Yuichi,Maeda, Tetsuya,Miyoshi, Ikuko,Morohashi, Naoya
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supporting information
(2020/04/01)
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- Symmetric benzidine derivatives as anti-HCV agents: Insight into the nature, stereochemistry of the capping amino acid and the size of the terminal capping carbamates
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Novel symmetric molecules, bearing a benzidine prolinamide core, two terminal carbamate caps of variable sizes and nature, including natural and unnatural amino acids were developed. Several terminal N-carbamate substituents of the core structure, ranging from linear methyl, ethyl and butyl groups to branching isobutyl group; and an aromatic substituent were also synthesized. Series 1 has hydrophobic AA residues, namely S and R phenylglycine and a terminal carbamate capping group, whereas Series 2 bears sulphur containing amino acids, specifically S and R methionine and the natural R methylcysteine. The novel compounds were tested for their inhibitory activity (EC50) and their cytotoxicity (CC50), using an HCV 1b (Con1) reporter replicon cell line. Compound 4 with the unnatural capping residue, bearing D-Phenylglycine amino acid residue and N-isobutyloxycarbonyl capping group, was the most active within the two series, with EC50 = 0.0067 nM. Moreover, it showed high SI50 > 14788524 and was not cytotoxic at the highest tested concentration (100 μΜ), indicating its safety profile. Compound 4 also inhibited HCV genotypes 2a, 3a and 4a. Compared to the clinically approved NS5A inhibitor Daclatasvir, compound 4 shows higher activity against genotypes 1b and 3a, as well as improved safety profile.
- Abadi, Ashraf H.,Abdel Karim, Shereen E.,Abdel-Halim, Mohammad,Ahmed, Nermin S.,Frakolaki, Efseveia,Vassilaki, Niki,Youssef, Youssef H.,Zoidis, Grigoris
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- POLYCYCLIC TLR7/8 ANTAGONISTS AND USE THEREOF IN THE TREATMENT OF IMMUNE DISORDERS
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The present invention relates to compounds of Formula (I) and pharmaceutically acceptable compositions thereof, useful as toll-like receptor 7/8 (TLR7/8) antagonists. In Formula (I), Ring A is aryl or heteroaryl; Ring B is aryl or heteroary; and X is C(R4)2, O, NR4, S, S(R4), or S(R4)2.
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Paragraph 00400
(2017/07/06)
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- Cyclic hydroxamates, especially multiply substituted [1,2]oxazinan-3-ones
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Routes to putative N-acyl-D-ala-D-ala surrogates, beginning with the conversion of 4-, 5-, and 6-membered lactones into 5-, 6-, and 7-membered cyclic hydroxamates, are reported. The key step of the synthesis is trimethylaluminium-promoted cyclization of an ω-aminooxyester. The 7-membered cyclic hydroxamate crystallizes in a chair conformation. Extension of the reaction sequence to homoserine or homoserine lactone leads to cyclocanaline and N-acylated cyclocanalines. The 4-phenylacetamido derivative of cyclocanaline crystallizes in a boat conformation. The attachment of a 2-carboxypropyl substituent to the ring nitrogen of a 4-acylaminocyclocanaline has been effected, prior to cyclization, by coupling of the acyclic aminooxyester precursor to the triflate of benzyl lactate or, after cyclization, by coupling to tert-butyl α-bromopropionate in the presence of potassium fluoride - alumina, followed by removal of the protecting group in each case. A six-membered homolog of the antibiotic lactivicin has been synthesized by the reaction of 4-phenylacetamidocyclocanaline with benzyl 2-oxoglutarate in the presence of carbodiimide, followed by hydrogenolysis. Starting with methyl 2,4-dibromo-2,4-dideoxy-L-erythronate, which is available in two steps from L-ascorbic acid, these reaction sequences have been applied to the stereospecific synthesis of a D-alanine derivative whose nitrogen atom is enclosed within a 3,4-disubstituted [1,2]oxazinan-3-one.
- Wolfe, Saul,Wilson, Marie-Claire,Cheng, Ming-Huei,Shustov, Gennady V.,Akuche, Christiana I.
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p. 937 - 960
(2007/10/03)
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- Insecticidal Properties of Some Derivatives of L-Canavanine
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The canavanine derivatives D-canavanine and L-homocanavanine as well as the 1-methyl and 1-ethyl esters of L-canavanine were synthesized and evaluated for biological activity in fifth instar larvae of the tobacco hornworm, Manduca sexta .While L-homocanavanine did not increase intrinsic toxicity, it was as deleterious as L-canavanine.D-Canavanine was biologically active, as demonstrated by its ability to cause larval edema, but the D-enantiomer had little ability to elicit the larval growth inhibition and pupal deformity which are hallmarks of canavanine toxicosis and was postulated to be linked to aberrant protein production.The 1-methyl and 1-ethyl esters of L-canavanine were synthesized to determine if enhancing canavanine's hydrophobicity might increase its bioavailability.Our experiments revealed that these esters are less toxic than canavanine; the ethyl ester disrupted larval growth more than did the methyl analogue. - Keywords: L-Canavanine; D-canavanine; L-homocanavanine; 1-methyl-L-canavanine; 1-ethyl-L-canavanine; Manduca sexta
- Rosenthal, Gerald A.,Dahlman, D. L.,Crooks, Peter A.,Phuket, Supinan Na,Trifonov, L. S.
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p. 2728 - 2734
(2007/10/03)
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- Porcine Pancreatic Lipase Catalyzed Enantioselective Hydrolysis of Esters of N-Protected Unusual Amino Acids
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Porcine pancreatic lipase catalyzed the highly enantioselective hydrolysis of a kind of α-substituted carboxylic esters, i.e., the 2,2,2-trifluoroethyl esters of the N-benzyloxycarbonyl derivatives of unusual amino acids.
- Miyazawa, Toshifumi,Iwanaga, Hitoshi,Ueji, Shinichi,Yamada,Takashi,Kuwata, Shigeru
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p. 2219 - 2222
(2007/10/02)
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- Direct Optical Resolution of Carboxylic Acids by Chyral HPLC on Tris(3,5-dimethylphenylcarbamate)s of Cellulose and Amylose
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A variety of racemic carboxylic acids have been for the first time directly resolved by normal-phase, high-performance liquid chromatography using a hexane-2-propanol eluting system containing a small amount (ca. 1percent) of a strong carboxylic acid, like formic acid, trichloroacetic acid, and trifluoroacetic acid.
- Okamoto, Yoshio,Aburatani, Ryo,Kaida, Yuriko,Hatada, Koichi
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p. 1125 - 1128
(2007/10/02)
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- PAPAIN-ASSISTED RESOLUTION OF NATURAL AND XENOBIOTIC α-AMINO ACIDS
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A new and convenient method for the preparation of pure enantiomers of α-amino acids is described.Industrial papain, catalyzes the synthesis of L-Z-amino acid ethyl esters in ethanolic medium, with good yields.These esters are obtained from DL-Z-amino acids with 100percent optical purity.Unreactive D-Z-amino acids are readily isolated from reaction medium.Physical constants of natural and xenobiotic L-Z-amino acid esters and D-Z-amino acids are described.
- Moriniere, J. L.,Danree, B.,Lemoine, J.,Guy, A.
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p. 441 - 444
(2007/10/02)
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- UTILISATION DES HYDROLASES EN CHIMIE ORGANIQUE: SYNTHESE DE LIAISONS ESTER ET AMIDE CATALYSEE PAR LA PAPAINE INDUSTRIELLE
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The use of hydrolases in organic chemistry: synthesis of amide and ester bonds catalyzed by industrial papain.Industrial papain, which is readily available, catalyzed the synthesis of L-Z-alanine ethyl ester (L-ZAEt) in organic medium, under different conditions, with good yields.L-ZAEt was obtained from DL-Z-alanine with 100 percent optical purity.We studied the effects of pH, the solvent/substrate and papain/substrate ratios and the type of organic solvent added, on the L-ZAEt yield.Unreactive D-ZA was also easily isolated from the aqueous phase with good optical purity.This attractive method has been applied to other N-Z-amino acid esters with the same succes.This procedure has been developed for the preparation of peptides using carboxylic or phosphonic substrates.These peptides have anti-bacterial activity. enzymatic catalysis / papain / chymopapain / stereospecific esterification of carboxylic amino acids / dipeptides / phosphonopeptides / anti-bacterial activity
- Moriniere, Jean-Luc,Danree, Bernard,Guy, Alain
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p. 347 - 358
(2007/10/02)
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