- Site-Selective Modification of α-Amino Acids and Oligopeptides via Native Amine-Directed γ-C(sp3)-H Arylation
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Site-selective modification of chemically and biologically valuable α-amino acids and peptides is of great importance for biochemical study and pharmaceutical development. Few methods based on remote C(sp3)-H functionalization of aliphatic side-chains of peptides has been disclosed in recent years. In this report, we developed a novel approach for γ-C(sp3)-H and γ-/δ-C(sp2)-H arylation of α-amino acids with α-hydrogen by native amine-directed C-H functionalization and further realized the γ-C(sp3)-H arylation of N-terminally unprotected peptides.
- Yuan, Feipeng,Hou, Zhen-Lin,Pramanick, Pranab K.,Yao, Bo
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supporting information
p. 9381 - 9385
(2019/11/28)
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- Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions
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We report here on the use of ethyl nitroacetate as a glycine template to produce α-amino esters. This started with a study of its condensation with various arylacetals to give ethyl 3-aryl-2-nitroacrylates followed by a reduction (NaBH4 and then zinc/HCl) into α-amino esters. The scope of this method was explored as well as an alternative with arylacylals instead. We also focused on various [2 + 3] cycloadditions, one leading to a spiroacetal, which led to the undesired ethyl 5-(benzamidomethyl)isoxazole-3-carboxylate. The addition of ethyl nitroacetate on a 5-methylene-4,5-dihydrooxazole using cerium(IV) ammonium nitrate was also explored and the synthesis of other oxazole-bearing α-amino esters was achieved using gold(I) chemistry.
- Gagnot, Glwadys,Hervin, Vincent,Coutant, Eloi P.,Desmons, Sarah,Baatallah, Racha,Monnot, Victor,Janin, Yves L.
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p. 2846 - 2852
(2018/11/27)
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- IMIDAZOPYRAZINE DERIVATIVES, PROCESS FOR PREPARATION THEREOF, AND THEIR USES AS LUCIFERINS
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The present invention is in the field of bioluminescence in biology and/or medicine. In particular, the invention provides imidazopyrazine derivatives, processes for preparation thereof, and their uses as luciferins.
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Page/Page column 64
(2018/11/22)
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- Site-Selective γ-C(sp3)?H and γ-C(sp2)?H Arylation of Free Amino Esters Promoted by a Catalytic Transient Directing Group
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The first selective PdII-catalysed γ-C(sp3)?H and γ-C(sp2)?H arylation of free amino esters using a commercially available catalytic transient directing group. A variety of free amino esters, including α-amino esters and β-amino esters, amino monoesters and amino bis-esters, are shown to react with a diverse range of simple aryl and heteroaryl iodide reagents.
- Lin, Hua,Wang, Chao,Bannister, Thomas D.,Kamenecka, Theodore M.
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supporting information
p. 9535 - 9541
(2018/07/14)
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- Kinetic study of the alkaline degradation of imidapril hydrochloride using a validated stability indicating HPLC method
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An aqueous alkaline degradation study was performed for imidapril hydrochloride (IMD) drug in the presence of its degradation products and an isocratic stability indicating method was presented using a HPLC technique. The separations were performed using an ACE Generix 5C8, 150 × 4.6 mm column and a mobile phase consisting of buffer solution (0.1 M potassium dihydrogen phosphate and 0.02 M tetra-N-butyl ammonium hydrogen sulphate of pH = 4.5 with 1 N HCl) and acetonitrile 60:40 (v/v). The wavelength of the detector was adjusted at 210 nm. The method showed high sensitivity concerning accuracy, precision, linearity and specificity within the acceptable range from 0.1 to 100 μg mL-1 and the limit of quantification was found to be 0.0211 μg mL-1 for IMD. The proposed method was used to determine the drug in its pharmaceutical formulation and to investigate the degradation kinetics of the drug's alkaline-stressed sample. The reactions were found to follow a first-order reaction. The activation energy could also be estimated. The optimized stability indicating HPLC method was validated according to ICH guidelines.
- Abdulla, Shabaan A.,Frag, Eman Y.,Ahmed, Heba E.
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p. 69239 - 69250
(2016/08/05)
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- Copper-Catalyzed Addition of Alkylboranes to Iminoacetates: Access to α-Alkyl Branched α-Amino Acids
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A copper(I)-catalyzed addition of alkylborane reagents to α-iminoacetates has been developed to assemble both acyclic and cyclic α-branched α-amino carboxylic acid derivatives in good yields. A wide variety of unactivated alkenes are well tolerated in this transformation. (Figure presented.).
- Xiao, Xinsheng,Zhang, Wei,Lu, Xiaoxia,Deng, Yuanfu,Jiang, Huangfeng,Zeng, Wei
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p. 2497 - 2509
(2016/08/16)
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- Resolution of N-protected amino acid esters using whole cells of Candida parapsilosis ATCC 7330
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Whole cells of Candida parapsilosis ATCC 7330 were used for the resolution of N-acetyl amino acid esters. Excellent enantioselectivities (E = 40 to >500) were achieved for the resolution of N-protected protein and non-protein amino acid esters giving good yields (28-50%) and high enantiomeric excesses (up to >99%) for both enantiomers.
- Stella, Selvaraj,Chadha, Anju
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experimental part
p. 457 - 460
(2010/06/21)
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- SUBSTITUTED BETA-PHENYL-ALPHA-HYDROXY PROPANOIC ACID, SYNTHESIS METHOD AND USE THEREOF
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The present invention relates to a compound of the formula (I), wherein R1, R2 and R3 are each independently selected from H, OH, F, Cl, Br, methoxy and ethoxy; or alternatively, R1 and R2 together form -OCH2O-, R3 is selected from H, OH, methoxy, ethoxy and halogens; R4 is OH or acyloxy; R5 is cycloalkoxyl, amino and substituted amino, and when R5 is selected from amino, at least one of R1, R2 and R3 is not H. The present invention further relates to a process for synthesizing a compound of the formula (I), and use of the compound of the formula (I) in the manufacture of a medicament for the prevention or treatment of cardiovascular or cerebrovascular diseases.
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Page/Page column 10
(2009/02/10)
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- Asymmetric transfer hydrogenation of β,γ-alkynyl α-lmino esters by a bronsted acid
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Asymmetric synthesis of trans-alkenyl α-amino esters was realized by chiral phosphoric acid catalyzed transfer hydrogenatlon of β,γ- alkynyl α-imino esters. Utilizing Hantzsch esters as the hydrogen donor, both the alkyne and Imine moieties of β,γ-alkynyl
- Kang, Qiang,Zhao, Zhuo-An,You, Shu-Li
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scheme or table
p. 2031 - 2034
(2009/04/10)
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- Practical synthesis of (-)-α-aminobenzolactam via nitration-cyclization of L-homophenylalanine ethyl ester
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A practical synthesis of chiral (-)-α-aminobenzolactam (2) is described. The target compound (2) was prepared from commercially available L-homophenylalanine ethyl ester hydrochloride (LHPE-HCl 1) with a highly enantiomeric purity (>98% e.e.) by employing
- Y.U., Luoting,Huang, Jiling,Chang, Ching-Yao,Yang, Teng-Kuei
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p. 323 - 330
(2008/02/09)
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- Method for transferring amino acid into ketone acid(ester)
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A method for transferring amino acid into ketone acid (ester) may obtain ketone acid (ester) at low cost. The method uses sodium hypochlorous acid as oxidizing agent and proceeds oxidation reaction with amino acid or its derivatives so as to obtain ketone acid and its derivatives. The sodium hypochlorous acid is easily to get with low cost and the conditions of the reaction are mild so that the method meets the needs of the industry.
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Page/Page column 2
(2008/06/13)
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- Kinetic resolution of a intermediate useful in the production of benazepril and analogues thereof
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The present invention provides an efficient synthetic process for making benazepril and analogues thereof by having an intermediate compound undergo epimerization and kinetic resolution.
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- Synthesis of 4-carboethoxy-4-oxazolin-2-ones from 3-nosyloxy-2-ketoesters
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3-Nosyloxy-2-ketoesters, available from 2-ketoesters, react efficiently with methyl carbamate and tosic acid in refluxing toluene to provide 4-carboalkoxy-4-oxazolin-2-ones in good yields (41-84%).
- Hoffman, Robert V.,Johnson, M. Catherine,Okonya, John F.
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p. 1283 - 1286
(2007/10/03)
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- Ethyl N-(diphenylmethylene)glycinate as anionic glycine equivalent. Monoalkylation, dialkylation and michael additions under solid-liquid phase-transfer catalysis
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Ethyl N-(diphenylmethylene)glycinate, 1, undergoes monoalkylations, dialkylations and Michael additions to ethylenic and acetylenic acceptors under appropriate solid-liquid phase transfer catalysis conditions. Further transformations of the α-disubstituted ketimines lead to α-alkylated aspartic and glutamic acid derivatives 10, 15, 19 and 26, to bicyclic amino acids or derivatives featuring pyrazolone and isoxazolone moieties 30 and 33, and to α-substituted (E)-3,4-dehydroglutamic acids. Copyright
- Lopez, Anna,Moreno-Manas, Marcial,Pleixats, Roser,Roglans, Anna,Ezquerra, Jesus,Pedregal, Concepcion
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p. 8365 - 8386
(2007/10/03)
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- A β-Lactam Framework as a β-Alanyl Dication Equivalent: New Synthesis of α-Amino Acid N-carboxy Anhydrides (NCAs) Derived from β-Substituted Alanines
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Optically pure 4-formyl-3-hydroxy β-lactams are transformed into 4-methylaryl and 4-(2-ethylaryl) derivatives and converted into β-substituted alanine-derived NCAs through oxidation and Baeyer-Villiger rearrangement of the resulting α-keto β-lactams.
- Palomo, Claudio,Aizpurua, Jesus M.,Ganboa, Inaki,Maneiro, Elena,Odriozola, Beatriz
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p. 1505 - 1508
(2007/10/02)
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- Compounds for treating hypertension
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Compounds of the formula STR1 and their pharmaceutically acceptable salts, wherein the substituents are as defined herein, having antihypertensive activity.
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- COMPOUNDS FOR TREATING HYPERTENSION
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Compounds of the formula STR1 and their pharmaceutically acceptable salts, wherein the substituents are as defined herein, having antihypertensive activity.
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