- Preparation method of N-trimethyl silicon ethoxycarbonyl-N-methyl-L/D-leucine
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The invention relates to a preparation method of N-(trimethylsilyl) ethoxycarbonyl group-N-methyl-L/D-leucine. The preparation method comprises the following steps: adding N-methyl-L/D-leucine hydrochloride, a trimethylsilylethoxycarbonyl protecting group reagent and alkali into a mixed solution of a polar solvent and water, and carrying out a reaction, so as to obtain the N-trimethylsilylethoxycarbonyl-N-methyl-L/D-leucine. According to the preparation method, the N-trimethyl silicon ethoxycarbonyl-N-methyl-L/D-leucine with high chiral purity, high chemical purity and high yield can be obtained, the chiral purity and the chemical purity can reach 99% or above, the yield can reach 60% or above, and the preparation method is simple in process, mild in condition and suitable for being applied to large-scale industrial production.
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Paragraph 0084-0086; 0090-0092
(2021/06/02)
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- Optical resolution of N-(t-butoxycarbonyl)leucine through mixed ligand complex formation with (R)-N-(2-pyridylmethyl)pipecolatocopper(II)
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A copper(II) complex of (R)-N-(2-pyridylmethyl)pipecolate (pmpi) was prepared, and its structure was revealed by X-ray crystal structure analysis. Mixed ligand complexes were then prepared from this complex and (R)- and (S)-N-(t-butoxycarbonyl)leucinate (BocLeu). The (R)-BocLeu complex is less soluble in aqueous acetonitrile and more soluble in acetone than the (S)-BocLeu complex, and the reason was discussed on the basis of their structures. Recrystallization of the reaction mixture consisting of Cu(II) ion, pmpi, and (RS)-BocLeu from aqueous acetonitrile gave the (R)-BocLeu complex and that from acetone gave the (S)-BocLeu complex.
- Yajima, Tatsuo,Fukushima, Takeo,Yamada, Atsuya,Shiraiwa, Tadashi
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p. 451 - 455
(2017/07/11)
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- D-amino acid position influences the anticancer activity of galaxamide analogs: An apoptotic mechanism study
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Galaxamide, an extract from Galaxaura filamentosa, is a cyclic pentapeptide containing five L-leucines. Due to the particular cyclic structure and the excellent anticancer activity, synthesis of Galaxamide and its analogs and their subsequent bio-applications have attracted great attention. In the present work, we synthesized six Galaxamide analogs by replacing one of the L-leucines with phenylalanine and varying the D-amino acid position. The anticancer effect of the synthesized Galaxamide analogs was tested against four in vitro human cancer cell lines, human hepatocellular cells (HepG2), human breast cancer cell (MCF-7), human breast adenocarcinoma cells (MDA-MB-435) and a human cervical carcinoma cell line (Hela). Results showed that Galaxamide analogs with differentD-amino acid positions displayed distinct anticancer potential. The Galaxamide analog containing D-amino acid at position 5 (Analog-6) presented the strongest anticancer activity. The mechanism study revealed that Analog-6 could cause the early apoptosis of HepG2 cells by inhibiting their growth in the sub-G1 stage of the cell cycle and induce the chromatin condensation and fragmentation, which can be seen as 68% of HepG2 cells inhibited in the sub-G1 stage. Moreover, a mitochondria-mediated pathway was found to be involved in the apoptotic process of Analog-6 on HepG2 cells.
- Bai, Defa,Yu, Siming,Zhong, Shenghui,Zhao, Bingxin,Qiu, Shaoling,Chen, Jianwei,Lunagariya, Jignesh,Liao, Xiaojian,Xu, Shihai
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- PROLINAMIDE DERIVATIVE AS THROMBIN INHIBITOR, PREPARATION METHOD AND APPLICATION THEREOF
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Provided are a compound of formula (I), pharmaceutically acceptable salts thereof, preparation methods and applications thereof for inhibiting thrombin, and applications in the treatment and prevention of thrombin-mediated and thrombin-related diseases.
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Paragraph 0185
(2013/09/26)
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- PROLINAMIADE DERIVATIVES AS THROMBIN INHIBITOR, PREPRARATION METHOD AND APPLICATION THEREOF
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Provided are a compound of formula (I), pharmaceutically acceptable salts thereof, preparation methods and applications thereof for inhibiting thrombin, and applications in the treatment and prevention of thrombin-mediated and thrombin-related diseases.
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Page/Page column
(2013/11/19)
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- Synthetic Studies of Tamandarin B Side Chain Analogues
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The syntheses of three tamandarin B analogues are described. The goal of these studies was to prepare material to determine their relative therapeutic index and to gain an oversight as to their potential for clinical applications.
- Lassen, Kenneth M.,Lee, Jisun,Joullie, Madeleine M.
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experimental part
p. 3027 - 3036
(2010/07/13)
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- Synthesis and biological evaluation of chiral α-aminoanilides with central antinociceptive activity
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Tocainide and related optically active chiral α-aminoanilides were synthesized and tested in vivo via the hot plate test to evaluate their central analgesic action. The aims of the study were to verify if a) the increase in lipophilicity, obtained by the introduction of an alkyl group on the steric center (3f-i), and the replacement of the C=O group with the C=S (10) group as well as the introduction of a methyl or ethyl group on the amidic nitrogen atom (8a-c) would produce an increase in central analgesic efficacy with respect to Tocainide; b) the 2,6-xylidide moiety is crucial for high analgesic activity (3b-e); c) the hydrogen atom bonded to the amidic nitrogen moiety is an essential pharmacophoric element for analgesic activity. Among all the synthesized compounds, 3f showed antinociceptive properties with a good enantioselective index.
- Corbo, Filomena,Franchini, Carlo,Lentini, Giovanni,Muraglia, Marilena,Ghelardini, Carla,Matucci, Rosanna,Galeotti, Nicoletta,Vivoli, Elisa,Tortorella, Vincenzo
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p. 1907 - 1915
(2008/02/01)
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- Synthetic studies on chlorofusin: Synthesis of the cyclic peptide portion
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The cyclic peptide portion of chlorofusin was synthesized by condensation of the five segments, d-Ada-OTMSE, Boc-l.-Orn(Cbz), Boc-l-Thr-l-Ala, l-Asn(Tr)-d-Asn(Tr)-d-Leu-OTMSE, and Boc-l-Thr-d-Leu, followed by cyclization at the amide bond between d-Ada an
- Mori, Tomonori,Miyagi, Marie,Suzuki, Kengo,Shibasaki, Mitsuhito,Saikawa, Yoko,Nakata, Masaya
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p. 275 - 291
(2008/03/12)
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- Enzymatic approach to both enantiomers of N-Boc hydrophobic amino acids
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Protease catalysed hydrolysis of N-Boc-amino acid esters allows us to obtain N-Boc l-acids and d-esters of amino butanoic acid, nor-leucine, nor-valine, leucine and t-leucine in excellent ee. The reaction occurs in short reaction times and high concentrations. When a biphasic system (buffer-MTBE) is employed, a strong solvent effect is observed. This method could be of significance for the preparation of d-t-leucine, for which a practical method is currently unavailable.
- Agosta, Eleonora,Caligiuri, Antonio,D'Arrigo, Paola,Servi, Stefano,Tessaro, Davide,Canevotti, Renato
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p. 1995 - 1999
(2007/10/03)
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- The role of the disulfide bond in amyloid-like fibrillogenesis in a model peptide system
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Three terminally protected short peptides Bis[Boc-D-Leu(1)-Cys(2)-OMe] 1, Bis[Boc-Leu(1)-Cys(2)-OMe] 2 and Bis[Boc-Val(1)-Cys(2)-OMe] 3 exhibit amyloid-like fibrillar morphology. Single crystal X-ray diffraction analysis of peptide 1 clearly demonstrates that it adopts an overall extended backbone molecular conformation that self-assembles to form an intermolecular hydrogen-bonded antiparallel supramolecular β-sheet structure in crystals. Scanning electron microscopic (SEM) images, transmission electron microscopic (TEM) images and Congo red binding studies vividly demonstrate the amyloid-like fibril formation of peptides 1, 2 and 3. However, after reduction of the disulfide bridge of peptides 1, 2 and 3, three newly generated peptides Boc-D-Leu(1)-Cys(2)-OMe 4, Boc-Leu(1)-Cys(2)-OMe 5 and Boc-Val(1)-Cys(2)-OMe 6 are formed and all of them failed to form any kind of fibril under the same conditions, indicating the important role of the disulfide bond in amyloid-like fibrillogenesis in a peptide model system. The Royal Society of Chemistry 2005.
- Das, Apurba Kumar,Drew, Michael G. B.,Haldar, Debasish,Banerjee, Arindam
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p. 3502 - 3507
(2007/10/03)
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- ARYLGLYCINE DERIVATIVES FOR USE AS GLYCINE TRANSPORT INHIBITORS
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The present invention relates to compounds of Formula (I) and salts solvates and hydrates thereof. The invention further relates to pharmaceutical compositions containing said compounds and methods of treating neurological and neuropsychistric disorders using said compounds.
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Page 150; 151
(2010/02/06)
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- Facile synthesis of D-amino acids from an L-serine-derived aziridine
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Using the concept that L-serine can be converted into a desymmetrized γ-diol derivative, five D-amino acids were synthesized from a common aziridine intermediate by a general, high-yielding three-step process. The key 2-t-butyldimethylsiloxymethyl N-t-butoxycarbonyl aziridine intermediate was synthesized in four steps and 65% overall yield.
- Travins, Jeremy M.,Etzkorn, Felicia A.
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p. 9389 - 9392
(2007/10/03)
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- Highly practical methodology for the synthesis of D- and L-α-amino acids, N-protected α-amino acids, and N-methyl-α-amino acids
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Full details are provided for an exceedingly practical method to synthesize D- and L-α-amino acids, N-protected α-amino acids, and N-methyl-α-amino acids, employing as a key step the asymmetric alkylation of pseudoephedrine glycinamide (1) or pseudoephedrine sarcosinamide (2). Practical procedures for the synthesis of 1 and 2 from pseudoephedrine and glycine methyl ester or sarcosine methyl ester, respectively, are presented. Optimum protocols for the enolization and subsequent alkylation of 1 and 2 are described. Alkylation reactions of 1 and 2 are found to be quite efficient with a wide range of alkyl halide substrates, and the products are formed with high diastereoselectivity. The products of these alkylation reactions are hydrolyzed efficiently and with little to no racemization simply by heating in water or water-dioxane mixtures. This protocol provides an exceedingly practical method for the preparation of salt-free α-amino acids of high enantiomeric purity. Alternatively, the alkylation products may be hydrolyzed in high yield and with little to no racemization by heating with aqueous sodium hydroxide. The alkaline hydrolyzate can then be treated with an acylating reagent to provide directly highly enantiomerically enriched N-protected derivatives such as N-Boc and N-Fmoc. Key features necessary for the successful execution of these experimental procedures are identified.
- Myers, Andrew G.,Gleason, James L.,Yoon, Taeyoung,Kung, Daniel W.
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p. 656 - 673
(2007/10/03)
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- Asymmetric Synthesis of α-Amino Acids and α-N-Hydroxyamino Acids from N-Acylbornane-10,2-sultams: 1-Chloro-1-nitrosocyclohexane as a Practical +> Equivalent
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Successive treatment of N-acylsultams 3 with sodium hexamethyldisilazide, 1-chloro-1-nitrosocyclohexane (1), and aq.HCl gave diastereoisomerically pure, crystalline N-hydroxyamino-acid derivatives 5.These were converted into various amino acids 7, N-hydroxyamino acids 8, and an N-Boc-amino acid 9. (S,S)-Isoleucine (17) and (S,S)-2-acetamido-3-phenylbutyric acid (23) were obtained from N-crotonoylsultam 15 via 1,4-addition of an organomagnesium or organocopper reagent followed by enolate 'amination' with 1.
- Oppolzer, Wolfgang,Tamura, Osamu,Deerberg, Joerg
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p. 1965 - 1978
(2007/10/02)
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- Asymmetric synthesis of α-amino acids and α-N-hydroxyamino acids via electrophilic amination of bornanesultam-derived enolates with 1-chloro-1-nitrosocyclohexane
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Successive treatment of N-acylsultams 3 with NaN(TMS)2, 1-chloro-1-nitrosocyclohexane (1) and 1N aq. HCl gave diastereomerically pure, crystalline N-hydroxyamino acid derivatives 4. Products 4 were converted to various amino acids 6, an N-BOC-amino acid 8 and to N-hydroxyamino acids 9. (S,S)-Isoleucine (16) was obtained from N-crotonoylsultam 13 via an organomagnesium-1,4-addition/enolate trapping process generating two stereogenic centers.
- Oppolzer,Tamura
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p. 991 - 994
(2007/10/02)
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- Aggregation Behavior of Amphiphiles Functionalized with Dipeptide Segments and Enantioselective Ester Hydrolysis in Their Bilayer Membranes
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Four amphiphiles having dipeptide segments, which consist of one histidyl residue and another amino acid residue, and the dihexadecyl moiety for the double-chain segment (N+C5AlaHis2C16, N+C5LeuHis2C16, N+C5PheHis2C16, and N+C5HisAla2C16) were synthesized, and the aggregate morphology of them was characterized by electron microscopy and differential scanning calorimetry.The amphiphiles, which have the histidyl residue bound to the dihexadecylamine component (N+C5AlaHis2C16, N+C5LeuHis2C16, and N+C5PheHis2C16) formed both multi- and single-walled aggregates in the aqueous dispersion state, while their sonicated solutions involved only single-walled vesicles.On the other hand, the amphiphile, which has the alanyl residue bound to the dihexadecylamine component (N+C5HisAla2C16) afforded tubular aggregates in the aqueous dispersion.The hydrolysis of enantiomeric esters of various hydrophobic nature, which was carried out in the single-walled vesicles, showed relatively small enantioselectivity.The reasons for such catalytic performance of the vesicles were discussed from the kinetic and mechanistic viewpoints; the kinetic analysis being carried out on the basis of the organic pseudo-phase concept.
- Murakami, Yukito,Nakano, Akio,Ikeda, Hidetsugu,Imori, Toru,Akiyoshi, Kazunari
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p. 172 - 180
(2007/10/02)
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