Ni(II)螯合物在氨基酸合成中的应用

Ni(II)螯合物诱导合成氨基酸是氨基酸合成方法中一类新颖且有工业生产价值的合成方法. 从合成方法学 、络合金属离子的优选、配体的改进、卤代片段的选择、合成氨基酸种类等方面介绍该合成方法的研究进 展.     

R(-)四氢噻唑-2-硫酮-4-羧酸对D,L-氨基酸酯拆分的研究

以新手性拆分试剂R(-)四氢噻唑-2-硫酮-4-羧酸[简称R(-)TTCA]对D,L-氨基酸酯进行手性拆分,分别得到(R)TTCA氨基酸酯盐1a_1f([α]_D²⁰＝-30.40°～-42.70°)及光学活性氨基酸酯2a-2f,其光学纯度为35.4%～75.8%.由1a_1f在碱存在下分解出2a-2f的对映体3a-3f,光学纯度为39.50%～69.10%.用半经验的量子化学PM3方法研究了氨基的碱性、中间产物铵盐生成热和稳定性.     

Asymmetric induction by helical poly(amino acid)s in cyanosilylation of aldehydes

It was first demonstrated that helical poly(amino acid)s have an ability to induce enantioselectivity in the cyanosilylation of aldehydes. The helicity of poly(amino acid)s and the N-terminal amino group were essential for the enantioinduction of the reaction.     

Molecular brushes based on poly(amino acid)s: synthesis,structures, and applications

Polymer science is witnessing rapid advancements in the precision construction of synthetic macromolecules. Beyond the impressive advances in molecular brush, the integration of poly(amino acid)s into bottlebrush architectures leads to a novel class of materials known as molecular brushes based on poly(amino acid)s (MBPAs). These materials not only possess biorelated functions but also enable the incorporation of the diverse secondary structures found in poly(amino acid)s into the bulk polymers. Here we present a comprehensive and critical summary of three synthetic strategies and three different constructions for MBPAs. Furthermore, we highlight their potential in the development of advanced materials for a broad range of applications, encompassing antimicrobial activity, pharmaceutical delivery, and bioimaging.     

Copper(II)salen catalysed, asymmetric synthesis of α,α-disubstituted amino acids

Cu(salen) complex 1 was found to be a versatile catalyst for the asymmetric alkylation of a range of enolates derived from α-amino acids, leading to α,α-disubstituted amino acids. The enantioselectivity of the process decreases as the size of the amino acid sidechain increases, but functionalized amino acids such as allylglycine and aspartic acid are substrates for the process. Benzylic bromides are found to be more enantioselective alkylating agents than propargylic bromides. As an example of the utility of this chemistry, an α-propargylic allylglycine derivative is prepared and subjected to ene-yne metathesis using Grubbs' catalyst to give a non-racemic cyclopentenyl amino acid.     

Theoretical Investigation on the Second-order Nonlinear Optical Properties of Chiral Amino Acid Zinc(Ⅱ) Porphyrins

Static second-order nonlinear optical effects of amino acid zinc(II) porphyrins 1, 2, 3 and 4 were calculated by the TDHF/PM3 method based on the molecular structures optimized at the semiempirical PM3 quantum chemistry level, showing due to the cancellation of symmetric center, these amino acid zinc(II) porphyrins exhibit second order nonlinear optical response. The analysis of β components indicated that these amino acid zinc(II) porphyrins are of multipolarizabilities, and they may be ascribed as the "mixture" of octupolar and dipoar molecules with ||βJ=3||/||βJ=1|| ≈ 5. It is found that there are no significant differences between the static β values of non-chiral and chiral amino acid zinc(II) porphyrins. However, the βxyz component, which is quite important to quadratic macroscopic х (2) susceptibility of chiral material, is increased significantly with the increase of side chain group of amino acids.     

高效液相色谱-电喷雾串联质谱法确证海洋微生物产生的新环肽的连接顺序

报道了采用高效液相色谱一电喷雾串联质谱技术测定由海洋内生真菌产生的2个新环五肽cyelo（Phe-Leu-Leu-Leu-Ile）和cyclo（Phe-Val-Leu-Leu-Leu）,串联质谱实验提供了丰富的结构信息,确证了环肽的氨基酸的种类和连接顺序。这种简单、快速、可靠的分析方法在对未知样品中环肽成分的检测中具有广阔的应用前景。     

Synthesis of N-phosphoryl amino acids using bis(9-fluorenylmethyl)phosphite

Bis(9-fluorenylmethyl)phosphite (BFMP) was found to be an effective reagent for the N-phosphorylation of various amino acid methyl esters. BFMP was prepared from N,N-diisopropyl phosphoramidous dichloride in a one-pot two-step reaction and was obtained as a crystalline solid. N-Phosphorylation of the methyl esters of seven representative amino acids with BFMP was high-yielding and generally resulted in crystalline products. Complete deprotection of both the 9-fluorenylmethylphosphosphate esters and the amino acid methyl esters was accomplished concomitantly with LiOH to give N-phosphoryl amino acids.     

The use of activated (S)-(+)-naproxen for the gas chromatographic resolution of some amino acid methyl esters

Summary A GC method has been elaborated for the separation of enantiomers of some amino acid methyl esters after derivatization with activated (S)-(+)-naproxen. Nine amino acid ester paris were completely resolvede in a single run on a fused silica capillary column.     

氨基酸改性聚乳酸

为了改善聚乳酸降解速度慢、细胞亲和性差等方面的不足,氨基酸对聚乳酸的改性工作正在得到人们越来越多的关注.本文综述了氨基酸对聚乳酸改性的各种方法,以及各种氨基酸改性聚乳酸材料的性能与应用.其中,较为常见的改性方法是合成聚(乳酸-氨基酸).展望氨基酸改性聚乳酸类生物降解材料的未来,降低合成成本是广泛应用的关键.因此,虽然目前广泛应用的聚(乳酸-氨基酸)合成途径是氨基酸环状衍生物(尤其是吗啉-2,5-二酮)开环聚合法,但经济有效地以氨基酸、乳酸等为原料的直接聚合法值得关注.     

Coprecipitation of Amino Acids with Mixed Hydroxide of Iron(III) and Copper(II)

Abstract

A coprecipitation method for concentrating amino acids from aquatic environments with a mixed hydroxide of iron(III) and copper(II) was developed. The percent coprecipitation of glycine, alanine, glutamic acid, aspartic acid, and lysine, being independent of pH in the range of 8.5 to 9.5, was more than 95%.     

Essential of Proline and Valine Residues in the Peptide Derived from Lactoferrin for Angiotensin Converting Enzyme Inhibition

We synthesized Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu, the peptide contained in lactoferrin (Lf), to identify the angiotensin converting enzyme (ACE) inhibition. In an attempt to know the structure‐activity relationship of this peptide, we replaced Pro (the third amino acid residues from N‐terminal) or Val (the fourth amino acid residues from N‐terminal) with Ala (neutral amino acid), Glu (acidic amino acid) or Lys (basic amino acid) to produce six peptides. From the in vitro ACE inhibition (IC₅₀) of these synthesized peptides, the original peptide (Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu) showed higher ACE inhibition than the replaced six peptides. Thus, replacement of Pro at the third amino acid residues or Val at the fourth position with Ala, Glu or Lys revealed the ACE inhibition to be lower than the original form of Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu. Otherwise, we added one peptide at the C‐terminal of Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu and found both products with an addition of Val (Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu‐Val) or Ile (Leu‐Arg‐Pro‐Val‐Ala‐Ala‐Glu‐Ile) showing a lower ACE inhibition than the original one. The ACE inhibitions produced by both replaced peptides were without significance. Also, deletion of the last peptide at the C‐terminal (Leu‐Arg‐Pro‐Val‐Ala‐Ala) failed to produce a marked change of ACE inhibition as compared to the original one. These results suggest that Pro and Val are essential in the peptide for inhibition of ACE activity.     

Analytical potential of 6-oxy-(N-succinimidyl acetate)-9-(2'-methoxycarbonyl) fluorescein for the determination of amino compounds by capillary electrophoresis with laser-induced fluorescence detection

The analytical potential of a fluorescein analogue, 6-oxy-(N-succinimidyl acetate)-9-(2'-methoxycarbonyl) fluorescein (SAMF), for the first time synthesized in our laboratory, as a labeling reagent for the labeling and determination of amino compounds by capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection was investigated. Biogenic monoamines and amino acids were chosen as model analytes to evaluate the analytical possibilities of this approach. The derivatization conditions and separation parameters for the biogenic amines were optimized in detail. The derivatization was performed at 30 degrees C for 6 min in boric acid buffer (pH 8.0). The derivatives were baseline-separated in 15 min with 25 mM boric acid running buffer (pH 9.0), containing 24 mM SDS and 12.5% v/v acetonitrile. The concentration detection limit for biogenic amines reaches 8 x 10(-11) mol.L(-1) (signal-to-noise ratio = 3). The application of CE in the analysis of the SAMF-derivatized amino acids was also exploited. The optimal running buffer for amino acids suggested that weak acidic background electrolyte offered better separation than the basic one. The proposed method was applied to the determination of biogenic amines in three different beer samples with satisfying recoveries varying from 92.8% to 104.8%. Finally, comparison of several fluorescein-based probes for amino compounds was discussed. With good labeling reaction, excellent photostability, pH-independent fluorescence (pH 4-9), and the resultant widely suited running buffer pH, SAMF has a great prospect in the determination of amino compounds in CE.     

固相萃取-高效液相色谱-电喷雾串联质谱技术分析大鼠血浆中的氨基酸及其在电离辐射损伤动物模型中的应用

建立了基于高效液相色谱-电喷雾串联质谱(HPLC-ESI MS/MS)与固相萃取(SPE)相结合的大鼠血浆中氨基酸的分析方法。以硅胶基质的强阳离子交换固相萃取柱(SCX-SPE)提取血浆中的氨基酸和降低基质效应,HPLC-ESI MS/MS进行测定。对SPE处理的样品pH值进行了优化,发现pH 2.8时SCX-SPE提取氨基酸的回收率和重现性比较令人满意。除赖氨酸和鸟氨酸外,氨基酸的总体回收率在33.6%～107.7%之间;除精氨酸外,氨基酸标准曲线的线性相关系数r2＞0.99; 25种氨基酸测定的日内精密度和日间精密度较好,相对标准偏差(RSD)分别低于9.0%和19.1%。此外,将该分析方法用于电离辐射对大鼠血浆氨基酸代谢的影响研究。结果表明,辐射可导致血浆中氨基酸代谢紊乱,并且其紊乱程度与电离辐射损伤程度正相关。研究结果为筛选新的急性辐射损伤标记物研究提供了实验依据。     

Enantioselektive Cyclopropanierung von 1,1-Diphenylethylen und Diazoessigester mit Kupfer-Katalysatoren

Copper(II) compounds catalyze the reaction of 1,1-diphenylethylene with diazoacetic acid ethylester. The main product is 2,2-diphenylcyclopropane carboxylic acid ethylester. The formation of the carbene dimerization products fumaric and maleic acid diethylester can be suppressed by the continuous addition of diazoacetic acid ester to 1,1-diphenylethylene.37 optically active ligands, partly new, were combined with copper(II)-acetate to givein-situ-catalysts. In five cases isolated copper complexes were used as catalysts. The best optical inductions in the formation of 2,2-diphenylcyclopro-pane carboxylic acid ethylester with up to 65.6% ee were achieved withSchiff base ligands, which derive from salicylaldehyde and amino alcohols, obtained from amino acid esters and phenylGrignard.

Prof. Dr.Karl Schlögl, Universität Wien, mit den besten Wünschen zum 60. Geburtstag gewidmet.     

二(2-乙基己基)磷酸对氨基酸的萃取平衡

二（２－乙基己基）磷酸对氨基酸的萃取平衡曹汉瑾,王德宝,刘沛妍,吴子生,严忠（东北师范大学化学系,长春,１３００２４）关键词氨基酸,二（２－乙基己基）磷酸,萃取平衡,分配比迄今为止,有关氨基酸溶剂萃取的文献报道还不多［１～３］．本实验以二（２－乙基己...     

谷氨酸在乳状液膜中的迁移行为

用氯化三等基·甲基铵（Ａｌｉｑｕａｔ ３３６）－Ｓｐａｎ８０－甲苯制成的乳状液膜体系对谷氨酸的迁移行为进行了研究,２ ｍｉｎ的迁移率可达９３％。在谷氨酸的最佳迁移条件下,油溶性好的苯丙氨酸迁移率较高,但油溶性低的甘氨酸和碱性氨基酸的迁移率明显较低。此法适用于微量氨基酸的提取和分离。     

STRUCTURE OF THE MITOCHONDRIAL URFA6L GENE AND tRNA~(Lys) GENE FROM CARP

The carp mitochondrial URFA6L gene consists of 165 base pairs. The overall structural organization of the gene is very similar to that of the Xenopus URFA6L gene. Their nucleotide sequences exhibit 68% homology. The carp URFA6L gene encodes a protein of 54 amino acids. The amino acid composition of the protein is unusual because almost half of the residues consist of 5 hydrophobic amino acids(proline, tryptophan, leueine, isoleueine and tyrosine). A comparison between the amino acid sequences of 5 vertebrate URFA6L proteins and the yeast ATPase8 showed that they have weak but very important common structural features, suggesting that the vertebrate URFA6L proteins may function asATPase8. The nucleotide sequence of the lysine tRNA gene from carp has been determined and represented in cloverleaf secondary structure. Similar to amphibian and mammalian mitochondrial tRNA~(Lys) genes, the carp mitochondrial tRNA~(Tys) gene also has some unusual structural features as compared with its cytoplasmic counterpart     

Synthesis,Crystal Structures and Catalysis of Dinuclear Cd(Ⅱ) Complexes Bridged by Unusual (N,O,O′)-Coordinated α-Amino Acids

Four dinuclear amino acid cadmium(Ⅱ) complexes [Cd₂(tren)₂(dl-alaninato)](ClO₄)₃·H₂O(Ⅰ), [Cd₂(tren)₂·(l-alaninato)](ClO₄)₃·H₂O(Ⅱ), [Cd₂(tren)₂(dl-phenylalaninato)](ClO₄)₃(Ⅲ) and [Cd₂(tren)₂(l-phenylalaninato)]· (ClO₄)₃(Ⅳ), constructed from mixed ligands of tris(2-aminoethyl)amine(tren) and racemic or natural amino acids( amino acids=dl- or l-alanine, and dl- or l-phenylalanine), have been synthesized and characterized by X-ray crystallography. The structural analysis of complexes Ⅰ and Ⅲ reveals that the cadmium centers are coordinated by one tren ligand and one amino acid molecule with the unusual (N,O,O′)-bridged mode, resulting in asymmetric chromophores of CdN₄O and CdN₅O in complex Ⅰ, CdN₄O₂ and CdN₅O in complex Ⅲ, respectively. The utility of the four complexes as efficient water-compatible Lewis acid catalysts for the direct aldol reaction in water was examined. The reaction proceeded smoothly to afford the corresponding β-hydroxy ketones in up to 99% yield. Moreover, the diastereoselectivity of the reaction favors the formation of the syn-isomers.     

Exploitation of Dimeric Cyclic Cysteine as Helix Inducer in Ultra-Short Peptides for Cu(II)-Catalyzed Asymmetric Michael Addition on Chalcones

A dimeric cyclic cysteine analogue, i.e. (1R,1′R,2R,2′R)-2,2′-disulfanediylbis (aminocyclohexane-1-carboxylic acid), was used as a constrained unnatural amino acid and as a folding inducer in ultra-short Leu-Val-containing peptide. Our results showed that both free dimer amino acid L1 and its peptide derivative L2 are able to chelate Cu(II). The obtained complexes resulted to be catalytically active in Michael addition reaction of nitromethane on different types of chalcones. L1-Cu(II) was shown more reactive in terms of conversion, while, in neat conditions, L2-Cu(II) allows to obtain an interesting 60 % e.e. on pyridine chalcone.