共查询到20条相似文献,搜索用时 15 毫秒
1.
Markus Pietzsch Thomas Waniek Richard J. Smith Svetoslav Bratovanov Stefan Bienz Christoph Syldatk 《Monatshefte für Chemie / Chemical Monthly》2000,9(2):645-653
The sterospecificities of hydantoinases and N-carbamoyl amino acid amidohydrolases (N-carbamoylases) from different microbial sources were investigated for the stereoselective syntheses of the unnatural silicon-containing amino acids D- and L-3-trimethylsilyl-alanine (3) from the respective racemic hydantoin D,L-1. In a preparative biotransformation, whole resting cells of Agrobacterium sp. IP I 671, immobilized in a Ca-alginate matrix, were used for the synthesis of amino acid D-3 in 88% yield and 95% enantiomeric excess. Since the purified D-N-carbamoylase from Agrobacterium sp. IP I 671 was shown to be 100%D-selective, the enantiomeric purity of 95% of D-3 arising from the transformation with the immobilized cells must be explained by the participation of a further, L-selective N-carbamoylase or, which is more likely, by racemization of the final hydrolysis product by the action of an amino acid racemase. Isolated hydantoinases from Bacillus thermoglucosidasius, Thermus sp., Arthrobacter aurescens DSM 3745, and Arthrobacter crystallopoietes DSM 20117 turned out to be stereospecific for the conversion of the D-form of hydantoin D,L-1. The enantiomerically pure L-form of 3 was also prepared. It was synthesized from racemic N-carbamoyl amino acid D,L-2 by enantiomer-specific hydrolysis of the L-form in presence of L-N-carbamoylase from Arthrobacter aurescens DSM 3747. 相似文献
2.
Markus Pietzsch Thomas Waniek Richard J. Smith Svetoslav Bratovanov Stefan Bienz Christoph Syldatk 《Monatshefte für Chemie / Chemical Monthly》2000,131(6):645-653
Summary. The sterospecificities of hydantoinases and N-carbamoyl amino acid amidohydrolases (N-carbamoylases) from different microbial
sources were investigated for the stereoselective syntheses of the unnatural silicon-containing amino acids D- and L-3-trimethylsilyl-alanine (3) from the respective racemic hydantoin D,L-1. In a preparative biotransformation, whole resting cells of Agrobacterium sp. IP I 671, immobilized in a Ca-alginate matrix, were used for the synthesis of amino acid D-3 in 88% yield and 95% enantiomeric excess. Since the purified D-N-carbamoylase from Agrobacterium sp. IP I 671 was shown to be 100%D-selective, the enantiomeric purity of 95% of D-3 arising from the transformation with the immobilized cells must be explained by the participation of a further, L-selective N-carbamoylase or, which is more likely, by racemization of the final hydrolysis product by the action of an amino
acid racemase. Isolated hydantoinases from Bacillus thermoglucosidasius, Thermus sp., Arthrobacter aurescens DSM 3745, and Arthrobacter crystallopoietes DSM 20117 turned out to be stereospecific for the conversion of the D-form of hydantoin D,L-1. The enantiomerically pure L-form of 3 was also prepared. It was synthesized from racemic N-carbamoyl amino acid D,L-2 by enantiomer-specific hydrolysis of the L-form in presence of L-N-carbamoylase from Arthrobacter aurescens DSM 3747.
Received December 20, 1999. Accepted January 7, 2000 相似文献
3.
A novel and facile synthesis of 5-hydroxy-4-hydroxymethyl-2-cyclohexenylguanine 1 is described. The key steps involve a Diels-Alder reaction of ethyl (2E)-3-acetyloxy-2-propenoate 2 as dienophile with Danishefsky's diene 3 to build up the six-membered ring skeleton, a Fraser-Reid reductive rearrangement of the adduct using LiAlH(4), and base-moiety introduction using a Mitsunobu reaction. Optically pure D- and L-1 were obtained via resolution of intermediate 7 with (R)-(-)-methylmandelic acid. The synthetic procedure toward racemic 1 consists of only five steps and has proven to be highly efficient toward the synthesis of cyclohexenyl nucleosides. 相似文献
4.
The NAN-190 analogue 2-(2-(2-(4-(2-methoxyphenyl)piperazin-1-yl)ethoxy)ethyl)isoindoline-1,3-dione(1, C23H27N3O4, Mr = 409.48) was synthesized via a three-step reaction and characterized by 1H NMR, 13 C NMR, ESIMS and single-crystal X-ray diffraction. The crystal belongs to orthorhombic, space group Pna21 with a = 7.6445(15), b = 38.851(8), c = 7.1316(14) A, V = 2118.0(7) A3, Z = 4, Dc = 1.2840 mg/mm3, μ = 0.089 mm-1, F(000) = 872.4, R = 0.0545 and w R = 0.1681. The single-crystal X-ray structural analysis reveals that the piperazine ring in compound 1 presents a stable and minimum energy chair conformation. In addition, the preliminary cytotoxic assay shows that the title compound exhibits strong and selective inhibitory activity against DU145 cells(IC50 = 5.88 ± 1.02 μM). 相似文献
5.
Antonio Echavarren Amalia Galn Javier de Mendoza Armando Salmern Jean-Marie Lehn 《Helvetica chimica acta》1988,71(4):685-693
The optically active (4S,8S)-4, 8-bis(hydroxymethyl)-1,5,7-triazabicyclo[4.4.0]dec-5-ene ((S,S)- 1 ) has been synthesized in nine steps from L -asparagine with a total yield of 5.1%. Similarly, the enantiomer (R,R)- 1 has been prepared from D -asparagine. (S,S)- and (S,S)- 1 are representative examples of rigid and functionalized bicyclic guanidine systems and constitute useful intermediates in the construction of chiral selective anion-receptor molecules. 相似文献
6.
A cyclic analogue 4 of galardin, a known MMP inhibitor, is designed to improve its selectivity. The synthesis of 4 starts from dimethyl (S)‐malate using diaselective alkylation and subsequent cyclization and amide formation as key steps. The compound 4 showed MMP inhibitory activity on all MMPs tested with IC30, ranging from 20.1 μM to 104 μM. 相似文献
7.
Lead Structures for New Antibacterials: Stereocontrolled Synthesis of a Bioactive Muraymycin Analogue 下载免费PDF全文
Daniel Wiegmann Dr. Stefan Boettcher Agnes Mihalyi Prof. Timothy D. H. Bugg Prof. Christian Ducho 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15292-15297
Naturally occurring muraymycin nucleoside antibiotics represent a promising class of novel antibacterial agents. The structural complexity suggests the investigation of simplified analogues as potential lead structures, which can then be further optimized towards highly potent antimicrobials. Herein we report studies on muraymycin‐derived potential lead structures lacking an aminoribose motif found in most naturally occurring muraymycins. We have identified a 5′‐defunctionalized motif to be ideal in terms of stability and chemical accessibility and have synthesized a full‐length muraymycin analogue based on this structure using a novel fully stereocontrolled route. The obtained 5′‐deoxy analogue of the natural product muraymycin C4 showed good inhibitory properties towards the bacterial target protein MraY, sufficient pharmacokinetic stability and no cytotoxicity against human cells, thus making it a promising lead for antibacterial drug development. 相似文献
8.
G. A. Ermakova S. Ya. Skachilova N. I. Yurchenko 《Chemistry of Heterocyclic Compounds》1995,31(1):33-34
A new method was proposed for synthesis ofD,L-5-oxoproline from N-acetyl-L-glutamic acid in weakly acid medium in the presence of water, and hydrolysis of an acetyl and cyclization and total racemization of the acid simultaneously take place. The advantage of the method is the possibility of obtaining two individual amino acids with high yields in one chemical process usingL-glutamic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 39–41, January, 1995. 相似文献
9.
10.
D-、L-和DL-青霉胺的太赫兹时域光谱 总被引:8,自引:0,他引:8
利用太赫兹时域光谱技术(THz-TDS)对D-、L-和DL-青霉胺的研究发现, 三种样品在0.2 THz到1.8 THz波段的吸收光谱存在显著差异, 实验结果表明, THz吸收光谱能够鉴别青霉胺对映异构体, 这一特点将可以用于青霉胺药物的检测. 本文利用纯D-、L-青霉胺的THz吸收光谱, 对D-、L-青霉胺混合样品的THz吸收光谱进行拟合, 证明可以用THz光谱定量分析混合样品中D-、L-青霉胺的相对含量. 这项研究为手性药物分子检测和分析提供了新的实验方法, 也对深入了解手性药物与生物靶分子之间相互作用提供了启示. 相似文献
11.
12.
13.
K. K. Venter S. P. Korshunov L. I. Vereshchagin R. L. Bol'shedvorskaya D. O. Lolya S. A. Giller 《Chemistry of Heterocyclic Compounds》1966,1(4):415-416
Nitration of methyl furyl-2-propiolate in acetic anhydride at -25° gives methyl 5-nitrofuryl-2-propiolate in good yield. Methods for preparing furyl-2-propiolic acid and its methyl ester are described. 相似文献
14.
《Analytical letters》2012,45(5):813-826
Abstract In order to develop a better understanding of the mechanism of action of the cardioactive steroid glycoside digoxin, we have synthesized a fluorescent analogue of this drug which retains biological activity. Fluoroscein isothiocyanate has been coupled to digoxin via an ethyl lysine bridge, after mild periodate oxidation of the terminal glycase moiety. The conjugate can displace oubain from the plasma membrane digoxin receptor, Na+/K+ ATPase and can itself be displaced by native digoxin. The structure of the conjugate based on FAB mass spectroscopy is presented. 相似文献
15.
In continuation of our interest in the synthesis of glycosidase inhibitors, we report herein an efficient synthesis of three new polyhydroxylated amino cyclohexane derivatives (aminocyclitols) that may potentially possess important biological activities. The key step involved the highly stereoselective dihydroxylation of protected azido cyclohexene derivatives 5, 9, and 15, which were easily red from D-(-)-quinic acid. The subsequent hydrogenation step was conducted under acidic conditions to provide the target molecules in an efficient manner with high overall yields. 相似文献
16.
Synthesis of a nitro analogue of plakoric acid is presented. The peroxy bond was incorporated into the substrate structure through a boron trifluoride etherate catalyzed methoxy-hydroperoxy group partial exchange reaction in diethyl ether with urea-hydrogen peroxide complex (UHP, a commercially available solid reagent) as the source of the hydrogen peroxide. Under the given conditions, only one of the two methoxyl groups underwent the MeO—— OOH exchange and the resulting hydroperoxy hemiketal proceeded directly to the end product through an intramolecular Michael addition of the hydroperoxyl group to the nitro group activated carbon-carbon double bond. 相似文献
17.
18.
L. A. Shchukina R. G. Vdovina Yu. B. Shvetsov A. V. Karpova 《Russian Chemical Bulletin》1962,11(2):286-288
Summary A preparative method was developed for obtaining L-and D-2-hydroxy-3-methylbutyric acids by the separation of racemic 2-hydroxy-3-methylbutyric acid with the aid of D-and L-threo-2-amino-1-p-nitrophenyl-1,3-propanediols. 相似文献
19.
Jun LIU Qing Hua BIAN Ming An WANG Hong Chao GUO Min WANG 《中国化学快报》2006,17(5):606-608
Optically active TADDOL (α, α, α′, α′-tetraaryl-1, 3-dioxolane-4, 5-dimethanol) and the related ligands have played a significant role in asymmetric reactions1. Although several hundreds of different TADDOLs and TADDOL analogues have already been de 相似文献