150-30-1Relevant articles and documents
Systematic pH Study on the Acid- and Base-Catalyzed Racemization of Free Amino Acids To Determine the Six Constants, One for Each of the Three Ionic Species
Baum, Rocky,Smith, Grant Gill
, p. 7325 - 7327 (1986)
Computer analysis of pH profiles for racemization of four amino acids at 142 deg C led to the determination of the six absolute rate constants, one for each ionic species of amino acid in aqueoussolution catalyzed by hydronium and hydroxide ions.A comparison is made to show the effect of using all six constants to express the observed rate constants, as opposed to using only four in previous studies.The analyses also allowed the calculation of amino acid pKa values at elevated temperatures.
Stress degradation study of bortezomib: Effect of co-solvent, isolation and characterization of degradation products by UHPLC-Q-TOF-MS/MS and NMR and evaluation of the toxicity of the degradation products
Udutha, Suresh,Borkar, Roshan M.,Shankar,Sony,Jala, Aishwarya,Vamshi Krisna,Kiran Kumar,Misra,Prabhakar,Srinivas
, p. 8178 - 8191 (2021)
Bortezomib (BTZ) is a first-in-class, potent reversible inhibitor of proteasome used in the treatment of multiple myeloma, the second most common hematological cancer. Stress degradation studies were performed to investigate the inherent stability of the drug according to ICH recommended guidelines Q1A (R2). Stress experiments were carried out in two ways using acetonitrile and methanol as co-solvents under various conditions. A selective stability-indicating LC-MS method has been developed to separate all degradation products of the drug on a Hibar-Purospher STAR, C18 (250 × 4.6 mm, 5 μm) column using a mobile phase consisting of 0.1% formic acid and acetonitrile in the gradient mode. BTZ was found to undergo degradation under acidic, basic, neutral hydrolysis and oxidative conditions, whereas it was stable under other conditions. Thirteen degradation products (DP-1-DP-13) were identified using acetonitrile as a co-solvent. Additionally, three (DP-14-DP-16) degradation products were found where methanol was used as a co-solvent. A total of 16 (DP-1-DP-16) degradation products were characterized by liquid chromatography-tandem mass spectrometry (LC-ESI-Q-TOF/MS/MS) and high-resolution mass spectrometry (HRMS). Major degradation products, DP-3, DP-6, DP-9, DP-10, DP-11 and DP-12, formed under oxidation conditions were isolated using preparative HPLC and characterized by 1D and 2D NMR experiments. Furthermore, in vitro cytotoxicity of isolated DPs was tested on normal cell lines such as CHO-K1, HEK-293 and NRK-49F by MTT assays. This study revealed that they were around 2-6 times less toxic as compared with the standard control of the drug and DP-10 showed relatively more toxicity than other isolated DPs against rat kidney cells at 18.20 μM. In silico toxicity studies suggested that BTZ and its DPs can be hepatotoxic and genotoxic resulting in severe toxicity.
Catalytic amino acid production from biomass-derived intermediates
Deng, Weiping,Wang, Yunzhu,Zhang, Sui,Gupta, Krishna M.,Hülsey, Max J.,Asakura, Hiroyuki,Liu, Lingmei,Han, Yu,Karp, Eric M.,Beckham, Gregg T.,Dyson, Paul J.,Jiang, Jianwen,Tanaka, Tsunehiro,Wang, Ye,Yan, Ning
, p. 5093 - 5098 (2018)
Amino acids are the building blocks for protein biosynthesis and find use in myriad industrial applications including in food for humans, in animal feed, and as precursors for bio-based plastics, among others. However, the development of efficient chemical methods to convert abundant and renewable feedstocks into amino acids has been largely unsuccessful to date. To that end, here we report a heterogeneous catalyst that directly transforms lignocellulosic biomass-derived α-hydroxyl acids into α-amino acids, including alanine, leucine, valine, aspartic acid, and phenylalanine in high yields. The reaction follows a dehydrogenation-reductive amination pathway, with dehydrogenation as the rate-determining step. Ruthenium nanoparticles supported on carbon nanotubes (Ru/CNT) exhibit exceptional efficiency compared with catalysts based on other metals, due to the unique, reversible enhancement effect of NH3 on Ru in dehydrogenation. Based on the catalytic system, a two-step chemical process was designed to convert glucose into alanine in 43% yield, comparable with the well-established microbial cultivation process, and therefore, the present strategy enables a route for the production of amino acids from renewable feedstocks. Moreover, a conceptual process design employing membrane distillation to facilitate product purification is proposed and validated. Overall, this study offers a rapid and potentially more efficient chemical method to produce amino acids from woody biomass components.
New diketopiperazine derivatives from a deep-sea-derived Nocardiopsis alba SCSIO 03039
Zhang, Qingbo,Li, Sumei,Chen, Yuchan,Tian, Xinpeng,Zhang, Haibo,Zhang, Guangtao,Zhu, Yiguang,Zhang, Si,Zhang, Weimin,Zhang, Changsheng
, p. 31 - 36 (2013)
The strain SCSIO 03039 was isolated from a sediment sample in the Indian Ocean and was characterized as a Nocardiopsis alba species on the basis of its 16S rRNA gene sequence. Seven diketopiperazines (DKPs), including two new DKPs nocazines D (2a) and E (2b), and five known DKPs (1, 3-6), were isolated from N. alba SCSIO 03039, along with two known compounds 2-methoxy-1,4-naphthoquinone (7) and 1-hydroxy-4-methoxy-2-naphthoic acid (8). Their structures were elucidated by mass and NMR spectroscopic analyses. The structure of methoxyneihumicin (1), previously proposed in a conference poster lacking publicly available experimental data, was validated for the first time by detailed NMR analyses and X-ray diffraction study. The two enantiomers nocazines D (2a) and E (2b) were isolated as a mixture. Compounds 3 and 4 were only known as synthetic compounds before. Methoxyneihumicin (1) exhibited in vitro cytotoxicities against MCF-7 and SF-268 with IC 50 values of 4.6 and 12.7 μM, respectively, better than those of 6 (22.0 and 20.6 μM). The other compounds showed less pronounced cytotoxities against three tested human cancer cell lines and no compounds displayed antibacterial activities toward four indicator strains.
Primordial reductive amination revisited
Huber, Claudia,W?chtersh?user, Günter
, p. 1695 - 1697 (2003)
Amino acids are formed efficiently by reductive amination of α-keto acids under aqueous, conditions with freshly precipitated FeS or Fe(OH)2 and with NH3, CH3NH2 or (CH3)2NH at pH values near their pKa.
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Albertson,Tullar
, p. 502 (1945)
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Albertson,Archer
, p. 308 (1945)
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Collman,Buckingham
, p. 3039 (1963)
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Nummularine-O, a cyclopeptide alkaloid from Zizyphus nummularia
Pandey,Dwivedi,Shah,Eckhardt
, p. 2690 - 2691 (1986)
In addition to the known peptide alkaloid jubanine-B, a new peptide alkaloid, nummularine-O, has been isolated from the stem bark of Zizyphus nummularia and their structures have been elucidated by chemical and spectroscopic methods.
Primordial Amino Acids by Reductive Amination of α-Oxo Acids in Conjunction with the Oxidative Formation of Pyrite
Hafenbradi, D.,Keller, M.,Waechtershaeuser, G.,Stetter, K. O.
, p. 5179 - 5182 (1995)
The theory of an autotrophic origin of life postulates a primordial formation of amino acids by a mild and specific chemical energy source, namely by the reductive amination of α-oxo acids in conjunction with the oxidative formation of pyrite.Here we show experimental proof for this reaction, which involves carbon dioxide as catalyst.
Artificial Transaminase Carriyng a Synthetic Macrocyclic Binding Group
Winkler, Jeffrey,Coutouli-Argyropoulou, Evdoxia,Leppkes, Reinhard,Breslow, Ronald
, p. 7198 - 7199 (1983)
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Khan,Kidwai
, p. 822 (1973)
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Autorecycling System for the Synthesis of α-Amino-acids by the Reductive Amination of α-Keto-acids catalysed by 1,5-Dihydro-5-deazaflavin
Yoneda, Fumio,Kuroda, Kazunori
, p. 927 - 929 (1982)
An effective autorecycling system for the biomimetic synthesis of α-amino-acids by the reductive amination of α-keto-acids has been achieved for the first time using 10-aryl-5-deazaflavin, ammonium formate, and formic acid; each mole of the 5-deazaflavin catalyses the reduction, by formic acid, of up to 20 moles of the α-imino-acids formed in situ from the α-keto-acids and ammonium formate.
KINETIC STUDY OF A Zn2 + -CATALYZED TRANSAMINATION REACTION BETWEEN PYRIDOXAMINE ANALOGS WITH A PYRIDINOPHANE STRUCTURE AND alpha -KETO ACIDS.
Tachibana,Ando,Kuzuhara
, p. 2263 - 2266 (1983)
The kinetics of the nonenzymatic transamination reaction from pyridoxamine analogs with a pyridinophane structure to a-keto acids catalyzed by Zn**2** plus were investigated by monitoring the changes in the absorption spectra in methanol. It was found that these reactions obeyed first-order kinetics for the formation of the Zn**2** plus chelate of an aldimine. No appreciable change in the reaction rate was observed when the concentration of the a-keto acid was increased, indicating that the isomerization of the ketimine chelate to the aldimine chelate is the rate-determining step. There was a considerable enhancement of the reaction rate when the molar ratio of the zinc ion to the pyridoxamine analogs was reduced from 1/1 to 0. 5/1.
Method for the Racemization of Optically Active Amino Acids
Yamada, Shigeki,Hongo, Chikara,Yoshioka, Ryuzo,Chibata, Ichiro
, p. 843 - 846 (1983)
A practical method for the racemization of optically active amino acids has been developed.A wide variety of optically active α-amino acids, including neutral amino acids, acidic amino acids, basic amino acids, and imino acids, could be racemized by heating in a medium of acetic acid at 80-100 deg C for 1 h in the presence of 0.05 molar equiv of an aliphatic or an aromatic aldehyde.The factors influencing the racemization were investigated.Phenylglycine, (p-hydroxyphenyl)glycine, and serine could be racemized without complete dissolution of the optically active isomers.Thus, isolation of the racemic modification was easily achieved by simple filtration of the racemic modification suspended in the reaction mixture.The mechanism of the racemization is discussed.
Scope and limitations of reductive amination catalyzed by half-sandwich iridium complexes under mild reaction conditions
Nguyen, Dat P.,Sladek, Rudolph N.,Do, Loi H.
, (2020/07/15)
The conversion of aldehydes and ketones to 1° amines could be promoted by half-sandwich iridium complexes using ammonium formate as both the nitrogen and hydride source. To optimize this method for green chemical synthesis, we tested various carbonyl substrates in common polar solvents at physiological temperature (37 °C) and ambient pressure. We found that in methanol, excellent selectivity for the amine over alcohol/amide products could be achieved for a broad assortment of carbonyl-containing compounds. In aqueous media, selective reduction of carbonyls to 1° amines was achieved in the absence of acids. Unfortunately, at Ir catalyst concentrations of 1 mM in water, reductive amination efficiency dropped significantly, which suggest that this catalytic methodology might be not suitable for aqueous applications where very low catalyst concentration is required (e.g., inside living cells).
Synthesis of Unprotected 2-Arylglycines by Transamination of Arylglyoxylic Acids with 2-(2-Chlorophenyl)glycine
Inada, Haruki,Shibuya, Masatoshi,Yamamoto, Yoshihiko
, p. 11047 - 11059 (2020/10/12)
The transamination of α-keto acids with 2-phenylglycine is an effective methodology for directly synthesizing unprotected α-amino acids. However, the synthesis of 2-arylglycines by transamination is problematic because the corresponding products, 2-arylglycines, transaminate the starting arylglyoxylic acids. Herein, we demonstrate the use of commercially available l-2-(2-chlorophenyl)glycine as the nitrogen source in the transamination of arylglyoxylic acids, producing the corresponding 2-arylglycines without interference from the undesired self-transamination process.
