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.
Asymmetric synthesis of amino acids by Cr(II) complexes of natural amino acids
Micskei, Károly,Holczknecht, Orsolya,Hajdu, Csongor,Patonay, Tamás,Marchis, Valér,Meo, Milena,Zucchi, Claudia,Pályi, Gyula
, p. 143 - 148 (2003)
Stoichiometric reduction of the C,N double bond of oxime precursors of α-amino acids was performed in aqueous media by Cr(II) complexes of natural amino acids. The reduction of oximes of α-ketophenylacetic, α-keto-β-phenylpropionic and α-ketopropionic acids proceeded up to >90% conversion and 2-30% enantiomeric excess. 1:2 complexes of Cr(II) with l-alanine, l-valine, l-aspartic acid, l-histidine and l-phenylalanine were used as reducing agents. The reduction of α-(oximino)phenylacetic acid showed increasing e.e. (and decreasing conversion) with increasing temperature.
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.
Highly Efficient Synthesis of Amino Acids by Amination of Bio-Derived Hydroxy Acids with Ammonia over Ru Supported on N-Doped Carbon Nanotubes
Xie, Zhenbing,Chen, Bingfeng,Peng, Fangfang,Liu, Mingyang,Liu, Huizhen,Yang, Guanying,Han, Buxing
, p. 5683 - 5689 (2020)
The amino acids have extensive applications, and their productions from biomass-derived feedstocks are very attractive. In this work, the synthesis of amino acids by amination of bio-derived hydroxy acids with ammonia over different metallic nano-catalysts supported on various supports is studied. It is found that Ru nano-catalysts on the nitrogen-doped carbon nanotubes (Ru/N?CNTs) have an outstanding performance for the reaction. Different hydroxy acids can be catalytically converted into the corresponding amino acids with yields up to 70.0 % under mild conditions, which is higher than those reported. The reasons for the high efficiency of the catalyst are investigated, and the reaction pathway is proposed on the basis of control experiments.
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.
CYCLOPEPTIDE ALKALOIDS FROM ZIZYPHUS RUGOSA BARK
Tripathi, Y. C.,Maurya, S. K.,Spingh, V. P.,Pandey, V. B.
, p. 1563 - 1565 (1989)
The isolation of cyclopeptide alkaloids, nummularine-P, sativanine-H and rugosanine-B, a new 13-membered cyclopeptide alkaloid from the bark of Zizyphus rugosa is reported.The structure of the new alkaloid was elucidated by spectroscopic methods as well as by chemical degradation. Key Word Index-Zizyphus rugusa; Rhamnaceae; alkaloids; nummularine-P; sativanine-H; rugosanine-B.
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.
Stereoselectivity in Reactions of Metal Complexes VII. Asymmetric Synthesis of Amino Acids by Metal Ion-Promoted Transamination
Bernauer, Klaus,Deschenaux, Robert,Taura, Toshiaki
, p. 2049 - 2058 (1983)
Enantioselective synthesis of phenylalanine was performed by reacting phenylpyruvic acid with pyridoxamine followed by ketimine-aldimine isomerization of the Schiff base formed catalyzed by an optically active copper(II)-complex.By UV and CD measurements it was shown that the enantiomeric excess strongly depends on the reaction conditions and on the reaction time.In favorable cases it reached values up to 80percent.The selectivity of the reaction is discussed on the basis of possible structures of intermediate mixed ligand complex.
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.
Electrophilic amination of 2-azadienes
Gouverneur,Ghosez
, p. 7585 - 7598 (1996)
2-Azadienes 1 bearing a trialkylsilyloxy group on position 3 can be regarded as carboxylic acid synthons. Their cycloadditions with several classes of nitroso compounds have been studied in detail as well as the transformation of the adducts into α-amino acids. The study showed that arylnitroso compounds such as nitrosobenzene reacted with 2-azadienes to give adducts that are potential precursors of α-N-arylamino acids. We have outlined an important limitation to the use of α-chloronitroso compounds. They are not compatible with highly functionalized dienes like 2-azadienes. On the other hand α-cyanonitroso and acylnitroso compounds reacted with azadienes to give adducts which were readily converted into α-amino acid derivatives.
