共查询到20条相似文献,搜索用时 15 毫秒
1.
Hideaki Hioki Mizuki Fukutaka Miwa Kubo Mitsuaki Kodama Keiko Ideta 《Tetrahedron》2005,61(45):10643-10651
A new traceless linker was developed to synthesize a library of 42 compounds possessing an azomethine linkage using combinatorial solid-phase parallel synthesis. The loading of the substrates on a solid support and cleavage from the solid support were performed by an imine synthesis and by imine-exchanged process under mild conditions, respectively. Thioesters with a hydroxy group on the central core exhibited liquid crystalline properties with the widest transition temperatures in the library. 相似文献
2.
Niloufar BibakJoseph Hajdu 《Tetrahedron letters》2003,44(31):5875-5877
A new stereospecific synthesis of lysophosphatidylcholines is reported. The sequence relies on orthogonal protection of hydroxyl groups derived from glyceric acid, using fluorenylmethylcarbonate versus tetrahydropyranyl ether functions, that allow regiospecific introduction of substituents to obtain the target phospholipid compound. 相似文献
3.
Quaternization of (S)-α-bromophenylacetic acid amide (8) with hexamethylentetramine (hexamine) preceded with ca. 80% inversion of configuration. Accordingly, starting from the trimethylsilylester of N-(S)-(α-bromo-α-phenylacetyl)-6-aminopenicillanic acid (4) quaternization with hexamine and subsequent hydrolysis afforded N-(R)-α-phenylglycyl-6-aminopenicillanic acid (1, ampicillin). Some other model reactions have been investigated. 相似文献
4.
《Tetrahedron letters》1987,28(41):4901-4904
N-Indolylethyl-2-pyridones bearing appropriate β-dicarbonyl substituents in the 3-position have been cyclised to pentacyclic indoles via spirocyclic indolenines by catalysis with trifluoroacetic anhydride. 相似文献
5.
Alejandro Cordero-Vargas Béatrice Quiclet-Sire Samir Z. Zard 《Tetrahedron letters》2004,45(39):7335-7338
A new strategy has been developed for the synthesis of C-aryl glycosides based on a xanthate-mediated free radical addition-cyclization sequence of an acetophenone xanthate to a vinylic carbohydrate followed by aromatization. 相似文献
6.
Seyyed Ali Moghaddas Zinatossadat Hossaini Daryoush Zareyee 《Journal of heterocyclic chemistry》2020,57(11):3856-3867
In this study, a new, easy and high yield procedure is investigated for the generation of pyrazine containing pyrrolo[2,1-a]isoquinoline derivatives using multicomponent reaction of phthalaldehyde or its derivatives, primary amines, α-haloalketones, electron deficient acetylenic compounds, ammonium acetate and KF/Clinoptilolite nanoparticles (KF/CP NPs) as catalyst in water at room temperature. The reactions of 2-hydroxy phthalaldehyde, primary amines, α-haloketones, electron deficient acetylenic compounds, and ammonium acetate in the presence of KF/CP NPs as catalyst in water at room temperature produce pyrazine derivatives in good yields. Also, in this work, antioxidant ability was studied for a number of prepared compounds employing the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and power of compounds for reducing of ferric ion experiments and evaluating results with synthetic antioxidants (TBHQ and BHT). Comfortable, simple, fast and fresh procedure is the advantages of this study. 相似文献
7.
《Journal of Saudi Chemical Society》2023,27(4):101670
Designing of molecules for drugs is important topic from many decades. The search of new drugs is very hard, and it is expensive process. Computer assisted framework can provide the fastest way to design and screen drug-like compounds. In present work, a multidimensional approach is introduced for the designing and screening of antioxidant compounds. Antioxidants play a crucial role in ensuring that the body's oxidizing and reducing species are kept in the proper balance, minimizing oxidative stress. Machine learning models are used to predict antioxidant activity. Three hydroxycinnamates are selected as standard antioxidants. Similar compounds are searched from ChEMBL database using chemical structural similarity method. The libraries of new compounds are generated using evolutionary method. New compounds are also designed using automatic decomposition and construction building blocks. The antioxidant activity of all designed and searched compounds is predicted using machine learning models. The chemical space of searched and generated compounds is envisioned using t-distributed stochastic neighbor embedding (t-SNE) method. Best compounds are shortlisted, and their synthetic accessibility is predicted to further facilitate the experimental chemists. The chemical similarity between standard and selected compounds is also studied using fingerprints and heatmap. 相似文献
8.
A new germanium-based linker for solid phase synthesis of aromatics: synthesis of a pyrazole library
An efficient synthesis of chlorogermane linker 12 is described. Economic introduction of germanium into this linker is accomplished by insertion of dichlorogermylene [from germanium(IV) chloride] into the homobenzylic C-Cl bond of 4-(2-chloroethyl)phenol 1. Using linker 12, transmetalation with lithiated 4-acetophenone, 3-acetophenone, and 4-(4'methoxy)biphenyl followed by Mitsunobu-type coupling to Argogel gives functionalized resins 14, 16, and 18, respectively. Treatment of resin 18 with TFA, ICl, Br2, or NCS effects clean ipso-degermylation releasing biphenyls 19-22, respectively. Resins 14 and 16 are employed for the parallel synthesis of a library of pyrazoles by enaminone formation (using Bredereck's reagent), condensative ring-closure (using a series of monosubstituted hydrazines), and cleavage (using TFA and Br2). Analysis of this library reveals the influence of the hydrazine substituent on both the regioselectivity of ring-closure and the propensity for electrophilic substitution at the 4-position of the pyrazoles during ipso-degermylative cleavage. 相似文献
9.
A. E. Trofimov I. S. Stepanova A. V. Ten’kovtsev 《Russian Journal of Applied Chemistry》2007,80(4):615-618
The possibility of preparation of nanocomposite materials with improved physicomechanical properties by polycondensation of spirocyclic silicates and diisocyanates was elucidated. The thermomechanical, spectral, and thermogravimetric properties of the resulting materials were examined. 相似文献
10.
James H. Rigby 《Tetrahedron letters》1982,23(18):1863-1866
A 2-substituted dihydrotropone is converted into a cis-hydroazulene intermediate via a novel Lewis acid catalyzed olefin cyclization. 相似文献
11.
12.
A. M. d'A Rocha Gonsalves Jorge M. T. B. Varejo Mariette M. Pereira 《Journal of heterocyclic chemistry》1991,28(3):635-640
A general analysis of the steps of the Rothemund reaction, allowed for a better understanding and a significant improvement of this reaction as a synthetic method in some of the previously known difficult syntheses. 相似文献
13.
A synthetic route was devised for a sugar based α-chloroketone, which was subsequently used to generate a family of C-nucleosides via parallel synthetic methodology. 相似文献
14.
Philippe Geoffrey Marie-Christiane Carre Paul Caubere Sandra Ianelli Mario Nardelli 《Journal of heterocyclic chemistry》1989,26(1):65-69
Benzocyclobutenols 1 were transposed by boron trifluoride etherate in the presence of triethylsilane into a new family of heterocycles 2 . 相似文献
15.
A new high performance parallel implementation of the general Effective Fragment Potential (EFP) method in a form of a portable software library called libefp is presented. The libefp library was designed to provide developers of various quantum chemistry software packages with an easy way to add EFP functionality to the program of their choice. The general overview of the library is presented and various aspects of interfacing the library with third party quantum chemistry packages are considered. The reference implementation of common methods of computational chemistry such as geometry optimization and molecular dynamics on top of libefp is delivered in the form of efpmd program. Results of molecular dynamics simulation of liquid water using the developed software are described. © 2013 Wiley Periodicals, Inc. 相似文献
16.
Xiao Wang 《Tetrahedron》2007,63(27):6141-6145
A small tri-β-peptide library was prepared starting from three enantio- and diastereopure azido acids. Fluorous tagging followed by two cycles of azide reduction, fluorous solid phase extraction (f-SPE), peptide coupling with the original azido acids, and f-SPE provided 27 protected azido peptides. Reduction and HPLC purification provided 25 of the 27 targeted tri-β-peptides in acceptable yields and excellent purities. 相似文献
17.
Shah N Gao M Tsutsui K Lu A Davis J Scheuerman R Fitch WL Wilgus RL 《Journal of combinatorial chemistry》2000,2(5):453-460
Combinatorial chemistry is a powerful tool to enhance drug discovery efforts in the pharmaceutical industry. One type of combinatorial chemistry, parallel synthesis, is now widely used to prepare numerous compounds of structural diversity. A novel high-throughput method for quality control of parallel synthesis libraries has been developed. The method uses flow injection MS, for proof of structure and estimation of purity, and a novel direct injection CLND technique for quantitation of amount. Following the synthesis of a small molecule library, compounds analyzed using this technique were characterized by mass spectrometry, and an accurate concentration of the compound was assessed by CLND. Characterization of one compound is completed in 60 s, allowing for up to 1000 compounds to be analyzed in a single day. The data is summarized using pass/fail criteria using internally developed software. 相似文献
18.
Emmanuelle Dubost Silvia Stiebing Thibault Ferrary Thomas Cailly Frédéric Fabis Valérie Collot 《Tetrahedron》2014
A set of variously substituted indazoles and hetero-aromatic derivatives were synthesized from o-halo-(het)arylaldehydes using a palladium catalyzed amination followed by cyclization. Starting from phenones, this process was extended to give 3-substituted indazoles. Moreover, N-1-substituted-indazoles can be reached by this strategy using an optional selective N-1-alkylation step during the process. This methodology offers a general and easy route for the synthesis of regioselectively substituted indazoles. 相似文献
19.
(S)-Malic acid diethyl ester was converted into a precursor of the lactonic portion of compactin and mevinolin. The substance was coupled with benzyl -tolyl sulfone and elaborated into the chiral lactone system of the natural products. 相似文献