153-94-6Relevant articles and documents
A facile enantioseparation for amino acids enantiomers using β-cyclodextrins functionalized Fe3O4 nanospheres
Chen, Xin,Rao, Jinan,Wang, Jin,Gooding, J. Justin,Zou, Gang,Zhang, Qijin
, p. 10317 - 10319 (2011)
Herein is presented a strategy for the enantioseparation of amino acids enantiomers using β-CD functionalized Fe3O4 nanospheres, in which β-CD provides the ability to chirally discriminate amino acids enantiomers, while the Fe3O4 nanoparticles serve as magnetic separators.
Chiral separation of underivatized amino acids by reactive extraction with palladium-BINAP complexes
Verkuijl, Bastiaan J. V.,Minnaard, Adriaan J.,De Vries, Johannes G.,Feringa, Ben L.
, p. 6526 - 6533 (2009)
(Figure Presented) In answer to the need for a more economic technology for the separation of racemates, a novel system for reactive enantioselective liquid-liquid extraction (ELLE) is introduced. Palladium (S)-BINAP complexes are employed as hosts in the separation of underivatized amino acids. The system shows the highest selectivity for the ELLE of tryptophan with metal complexes as hosts reported to date and shows a good selectivity toward a range of natural and unnatural amino acids. Furthermore, the host can be prepared in situ from commerically available compounds. Bulk-membrane transport in the form of U-tube experiments demonstrates the enantioselective and catalytic nature of the transport. The dependency of the system on parameters such as pH, organic solvent, and host-substrate ratio has been established. 31P NMR spectroscopy has been used to confirm the preferred enantiomer in the extraction experiments. The intrinsic selectivity was deduced by determination of the association constants of the palladium complex with the tryptophan enantiomers.
Amino acid ionic liquids as chiral ligands in ligand-exchange chiral separations
Liu, Qian,Wu, Kangkang,Tang, Fei,Yao, Lihua,Yang, Fei,Nie, Zhou,Yao, Shouzhuo
, p. 9889 - 9896 (2009)
Recently, amino acid ionic liquids (AAILs) have attracted much research interest. In this paper, we present the first application of AAILs in chiral separation based on the chiral ligand exchange principle. By using 1alkyl-3-methylimidazolium L-proline (L-Pro) as a chiral ligand coordinated with copper(II), four pairs of underivatized amino acid enantiomers - DLphenylalanine (DL-Phe), DL-histidine (DL-His), DL-tryptophane (DL-Trp), and DL-tyrosine (DL-Tyr) - were successfully separated in two major chiral separation techniques, HPLC and capillary electrophoresis (CE), with higher enantioselectivity than conventionally used amino acid ligands (resolution (Rs) = 3.26-10.81 for HPLC; Rs = 1.34-4.27 for CE). Interestingly, increasing the alkyl chain length of the AAIL cation remarkably enhanced the enantioselectivity. It was inferred that the alkylmethylimidazolium cations and L-Pro form ion pairs on the surface of the sta-tionary phase or on the inner surface of the capillary. The ternary copper complexes with L-Pro are consequently attached to the support surface, thus inducing an ion-exchange type of retention for the DL-enantiomers. Therefore, the AAIL cation plays an essential role in the separation. This work demonstrates that AAILs are good alternatives to conventional amino acid ligands for ligand-exchange-based chiral separation. It also reveals the tremendous application potential of this new type of task-specific ILs.
D-Phenylglycine aminotransferase (d-PhgAT)-substrate scope and structural insights of a stereo-inverting biocatalyst used in the preparation of aromatic amino acids
Akhtar, M. Kalim,Campopiano, Dominic J.,De Cesare, Silvia,Loake, Gary J.,Marles-Wright, Jon,Serpico, Annabel
, p. 6533 - 6543 (2020)
Enantiopure amines are key building blocks in the synthesis of many pharmaceuticals, so a route to their production is a current goal for biocatalysis. The stereo-inverting d-phenylglycine aminotransferase (d-PhgAT), isolated from Pseudomonas stutzeri ST-201, catalyses the reversible transamination from l-glutamic acid to benzoylformate, yielding α-ketoglutarate and d-phenylglycine (d-Phg). Detailed kinetic analysis revealed a range of amine donor and acceptor substrates that allowed the synthesis of enantiopure aromatic d-amino acids at a preparative scale. We also determined the first X-ray crystal structure of d-PhgAT with its bound pyridoxal 5′-phosphate (PLP) cofactor at 2.25 ? resolution. A combination of structural analysis and site-directed mutagenesis of this class III aminotransferase revealed key residues that are potentially involved in the dual substrate recognition, as well as controlling the stereo-inverting behaviour of d-PhgAT. Two arginine residues (Arg34 and Arg407) are involved in substrate recognition within P and O binding pockets respectively. These studies lay the foundation for further enzyme engineering and promote d-PhgAT as a useful biocatalyst for the sustainable production of high value, aromatic d-amino acids. This journal is
Structure elucidation of a new natural diketopiperazine from a Microbispora aerata strain isolated from Livingston Island, Antarctica
Ivanova, Veneta,Laatsch, Hartmut,Kolarova, Mariana,Aleksieva, Krasja
, p. 164 - 170 (2013)
A new natural diketopiperazine (1) was obtained from the culture broth of Microbispora aerata strain imbas-11A, isolated from penguin excrements collected on the Antarctic Livingston Island. Compound 1 was purified consecutively by solvent extraction, silica gel column chromatography and preparative HPLC. The structure of the compound was elucidated by 1D and 2D NMR experiments and mass spectrometric investigations. The absolute configuration of compound 1 was determined by amino acid analysis and NOESY correlations. A low antiproliferative and cytotoxic effect of trans-cyclo-(D-tryptophanyl-L-tyrosyl) (1) was determined with L-929 mouse fibroblast cells, K-562 human leukemia cells and HeLa human cervix carcinoma. Trans-cyclo-(D-tryptophanyl-L-tyrosyl) (1) did not show antimicrobial activity at a concentration of 50 μg per disc against Bacillus subtilis, Staphylococcus aureus, Streptomyces viridochromogenes, Escherichia coli, Candida albicans and Mucor miehei.
Targeted Isolation of Asperheptatides from a Coral-Derived Fungus Using LC-MS/MS-Based Molecular Networking and Antitubercular Activities of Modified Cinnamate Derivatives
Chao, Rong,Hou, Xue-Mei,Xu, Wei-Feng,Hai, Yang,Wei, Mei-Yan,Wang, Chang-Yun,Gu, Yu-Cheng,Shao, Chang-Lun
, p. 11 - 19 (2021)
Under the guidance of MS/MS-based molecular networking, four new cycloheptapeptides, namely, asperheptatides A-D (1-4), were isolated together with three known analogues, asperversiamide A-C (5-7), from the coral-derived fungus Aspergillus versicolor. The planar structures of the two major compounds, asperheptatides A and B (1 and 2), were determined by comprehensive spectroscopic data analysis. The absolute configurations of the amino acid residues were determined by advanced Marfey's method. The two structurally related trace metabolites, asperheptatides C and D (3 and 4), were characterized by ESI-MS/MS fragmentation methods. A series of new derivatives (8-26) of asperversiamide A (5) were semisynthesized. The antitubercular activities of 1, 2, and 5-26 against Mycobacterium tuberculosis H37Ra were also evaluated. Compounds 9, 13, 23, and 24 showed moderate activities with MIC values of 12.5 μM, representing a potential new class of antitubercular agents.
Ultrasound-Controlled Chiral Separation of Four Amino Acids and 2,2,2-Trifluoro-1-(9-anthryl)ethanol
Lee, Jae Hwan,Ryoo, Jae Jeong
, p. 146 - 149 (2019)
Chiral separation of 4-hydroxyphenylglycine, phenylglycine, tryptophan, methionine, and 2,2,2-trifluoro-1-(9-anthryl)ethanol (TFAE) was performed under ultrasound reduction at room temperature and high temperature (50 °C). At high temperature (50 °C), both α and Rs were improved slightly under ultrasound reduction as compared to those under non-ultrasonic and ultrasonic irradiation (50 watt/L) conditions. Even at low temperatures, the largest α was observed under ultrasound reduction conditions, except in the case of methionine. However, at low temperature, Rs was reduced under ultrasound (50 watt/L) irradiation, but was improved under ultrasound reduction rather than under the continuous ultrasonic irradiation. Similar to the fact that gradient elution (based on solvent polarity) can improve α, ultrasound reduction can improve α and Rs. Ultrasound reduction is demonstrated to aid the rapid separation of chiral compounds with improved resolution, especially, at high temperatures. Although chromatographic separation using ultrasound has been rarely dealt with until now, ultrasound can be used as an external field in chromatography.
Coordination properties of 3-functionalised β-cyclodextrins: Thermodynamic stereoselectivity of copper(II) complexes of the 3-histamine derivative and its exploitation in ligand-exchange capillary electrophoresis
Giuffrida, Alessandro,Cucinotta, Vincenzo,MacCarrone, Giuseppe,Messina, Marianna,Rizzarelli, Enrico,Vecchio, Graziella
, p. 377 - 383 (2014)
A histamine derivative of β-cyclodextrin functionalised at the secondary rim was synthesised and characterised by optical and NMR spectroscopy. Its binary systems both with proton and copper(II) were thermodynamically characterised through pH-metric potentiometry. In addition, the ternary systems with the enantiomers of tryptophan, phenylalanine and alanine were investigated. Thermodynamic stereoselectivity was observed for both the tryptophan and phenylalanine enantiomers. The properties of the synthesised cyclodextrin derivative as a chiral selector were verified in chiral ligand-exchange capillary electrophoresis (CLECE) towards the enantiomeric pairs of some amino acids. A β-cyclodextrin histamine-functionalised at the secondary rim was synthesised and characterised as a chiral selector of aromatic amino acids.
Thermo-responsive adsorption and separation of amino acid enantiomers using smart polymer-brush-modified magnetic nanoparticles
Song, Ya-Ya,Song, Xiao-Dong,Yuan, Heng,Cheng, Chang-Jing
, p. 3194 - 3207 (2016)
Multifunctional magnetic nanoparticles simultaneously possessing thermo-responsive properties and chiral recognition ability show great potential in enantiomeric separation. In this study, a novel type of multifunctional magnetic Fe3O4 nanoparticle, decorated with smart polymer brushes consisting of poly(N-isopropylacrylamide-co-glycidyl methacrylate) chains with pendent β-cyclodextrin (β-CD) units, was fabricated as a chiral nanoselector for the thermo-sensitive selective adsorption and separation of three amino acid enantiomers. These smart polymer brushes were grafted on the surface of Fe3O4 nanoparticles via a combination of surface-initiated atom transfer radical polymerization and ring-opening reaction. The pendent β-CD units can serve as smart receptors for selectively recognizing enantiomeric molecules via formation of stable host-guest inclusion complexes. The thermo-sensitive poly(N-isopropylacrylamide) chains can act as microenvironmental adjustors for tuning the inclusion constants of β-CD toward enantiomeric guest molecules. The prepared multifunctional magnetic nanoparticles exhibit excellent thermo-responsive adsorption and decomplexation performances toward amino acid enantiomers. Via simply changing the operation temperature, the decomplexation of amino acid enantiomers and regeneration of the smart chiral magnetic nanoparticles can be easily achieved. Besides, the magnetic properties of the regenerated smart nanoparticles enable easy recovery under an external magnetic field for reuse. Such multifunctional magnetic nanoparticles with highly chiral recognition capability, excellent thermo-sensitive adsorption and decomplexation properties toward amino acid enantiomers, and recyclability show great potential in chiral separations.
Reversal of optical induction in transamination by regioisomeric bifunctionalized cyclodextrins
Fasella, Elisabetta,Dong, Steven D.,Breslow, Ronald
, p. 709 - 714 (1999)
Two isomeric compounds have been synthesized carrying a pyridoxamine on C-6 of β-cyclodextrin and an imidazole unit on C-6 of the neighboring glucose residue. Each one stereoselectively transaminates phenylpyruvic acid to produce phenylalanine, and with opposite stereochemical preferences. Structure determinations by X-ray crystallography and NMR spectroscopy indicate that the imidazole units serve to block proton addition from their side, rather than acting to protonate the transamination intermediates. Related cyclodextrin-pyridoxamine compounds had been reported carrying ethylenediamine units instead of imidazoles, and high enantioselectivities in transamination were claimed. Our work indicates that these claims are incorrect, and that only poor selectivities are seen that are often unrelated to the position of the ethylenediamine units. Neither of these transaminating systems yet approaches the enantioselectivity seen with a pyridoxamine carrying a chirally mounted internal base group. Copyright (C) 1999 Elsevier Science Ltd.
