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  • 1
    Language: English
    In: Tetrahedron, 11 March 2013, Vol.69(10), pp.2296-2301
    Description: New eunicellin-base diterpenoids, hirsutalins I–M ( – ), were isolated from the soft coral . Their structures were elucidated by spectroscopic methods, particularly in 1D and 2D NMR experiments. The absolute configuration of was determined by Mosher's method. These compounds did not exhibit cytotoxicity toward a limited panel of cancer cell lines but showed nitric oxide inhibitory activity in LPS-stimulated RAW264.7 macrophage cells. Among them, compound was found to possess the strongest NO inhibitory activity with an IC value of 9.8 μg/mL. Furthermore, was shown to significantly reduce the expression iNOS protein in the same cells. New eunicellin-based diterpenoids, were isolated from the soft coral, .
    Keywords: Eunicellin-Base Diterpenoids ; Hirsutalins I–M ; Cytotoxicity ; No Inhibitory Activity ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 2
    Language: English
    In: Tetrahedron, 25 November 2012, Vol.68(47), pp.9694-9700
    Description: Nine new steroids, sclerosteroids A–I ( , , , – ), along with 18 known metabolites ( – , , – ), were isolated from the soft coral These structures were elucidated on the basis of detailed spectroscopic analysis. The absolute configurations of sugar moieties in steroidal glycosides – were determined by HPLC analysis of the -tolylthiocarbamate derivatives of the liberated sugars from hydrolysis of these steroidal giycosides. Cytotoxic and anti-inflammatory activities of these compounds were measured in vitro.
    Keywords: Scleronephthya Gracillimum ; Sclerosteroids ; O-Tolylthiocarbamate ; Cytotoxic Activity ; Anti-Inflammatory Activity ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 3
    Language: English
    In: Tetrahedron, 22 July 2012, Vol.68(29), pp.5817-5823
    Description: The concomitant addition of a histone deacetylase inhibitor, suberoyl bis-hydroxamic acid, and a DNA methyltransferase inhibitor, RG-108, to the culture medium of , an entomopathogenic fungus, induced a significant increase in diversity of secondary metabolites. From the culture media were isolated two new highly oxidized ergosterols, formosterols A ( ) and B ( ), and five new isariotin analogs, 12′- -acetylisariotin A ( ), 1- -isariotin A ( ), and isariotins K–M ( – ), together with 22,23-epoxy-3,12,14,16-tetrahydroxyergosta-5,7-dien-11-one (named formosterol C) ( ), isariotins A ( ), C ( ), and E ( ), TK-57-164A ( ), and beauvericin ( ). The NMR spectra, X-ray single crystallographic diffraction, and chemical transformations revealed the structures of the two new formosterols and five new isariotins. The stereochemistry of formosterol C ( ) was deduced from its spectroscopic data. The side chains of formosterols A–C ( – ) contained -22,23-epoxide, which is rarely present in naturally occurring sterols and triterpenes.
    Keywords: Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 4
    Language: English
    In: Tetrahedron, 15 April 2015, Vol.71(15), pp.2290-2297
    Description: Copper-catalyzed oxidative coupling of ethers and salicylaldehydes, via the direct α-C(sp )–H bond functionalization of ethers in the presence -butyl hydroperoxide as an oxidant has been explored. The corresponding acetals were selectively formed in moderate to excellent yields. The sensitive formyl group of salicylaldehydes remained intact despite the oxidative reaction conditions.
    Keywords: Aldehydes ; Copper ; C–H Functionalization ; Oxidation ; C–O Bond Formation ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 5
    Language: English
    In: Tetrahedron, 05 August 2012, Vol.68(31), pp.6224-6230
    Description: Four benzodioxepanes – were prepared from reaction of 4-methoxy-3-hydroxybenzaldehyde via a series of reasonable transformations, including the regioselective PhBCl -mediated double allylation of , one-pot combination of ring-closing metathesis of skeleton and Baeyer–Villiger reaction, O-allylation of skeleton , Claisen rearrangement of skeleton , and one-pot combination of ring-closing metathesis and hydrogenation.
    Keywords: Benzodioxapane ; Ortho-Metalation ; Ring-Closing Metathesis ; Baeyer–Villiger Reaction ; Claisen Rearrangement ; O-Allylation ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 6
    Language: English
    In: Tetrahedron, 25 November 2012, Vol.68(47), pp.9616-9623
    Description: A novel synthetic route for the preparation of cyclohexane skeleton was developed via the one-pot domino Claisen–Schmidt condensation reaction/Michael addition/double aldol reaction of 1 equiv of functionalized arylaldehyde with 3 equiv of 2-acetylpyridine ( ).
    Keywords: Condensation ; Arylaldehyde ; 2-Acetylpyridine ; Cyclohexane ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 7
    Language: English
    In: Tetrahedron, 07 January 2013, Vol.69(1), pp.129-136
    Description: A facile synthetic route toward diversified benzo[ ]chrysenes starting with commercially available isovanillin ( ) or 3-hydroxybenzaldehyde ( ) in modest total yields is described via the transformations of Claisen rearrangement of , Grignard addition of , DBU-promoted cyclodehydration of , and photolytic Scholl oxidative annulation of . Skeleton is prepared via O-allylation of with -cinnamyl bromide.
    Keywords: Benzo[G]Chrysenes ; Claisen Rearrangement ; Grignard Addition ; Cyclodehydration ; Photolytic Scholl Oxidative Annulation ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 8
    Language: English
    In: Tetrahedron, Sept 16, 2013, Vol.69(37), p.7916(9)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.tet.2013.07.023 Byline: Meng-Yang Chang, Chieh-Kai Chan, Ming-Hao Wu Abstract: A one-pot synthetic route for preparing functionalized p-terphenyl derivatives 1 and 4 is developed. The route is easily carried from the treatment of cinnamyl aldehydes 2 with substituted allylsulfones 3 in good yields via the tandem intermolecular aldol condensation/intramolecular electrocyclization/oxidative dehydrogenation. Author Affiliation: Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan Article History: Received 30 May 2013; Revised 3 July 2013; Accepted 8 July 2013
    Keywords: Dehydrogenation
    ISSN: 0040-4020
    Source: Cengage Learning, Inc.
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  • 9
    Language: English
    In: Tetrahedron, 04 March 2014, Vol.70(9), pp.1800-1804
    Description: A four-component Ugi reaction (Ugi-4CR) utilizing formylphenyl boronic acids under mild condition was developed for the synthesis of arylboronic acid analogs. The reactions were performed in methanol and accelerated by microwave irradiation, which makes this strategy suitable for constructing boronic-containing chemical libraries. Two of the synthesized analogs were found to have cytotoxic activity against HepG2, MDA-MB231, and A549 cancer cell lines, demonstrating the potential application of this approach in developing novel boron-containing pharmaceuticals. In this study, an Ugi four-component reaction (Ugi-4CR) utilizing unprotected boronic acid building blocks under mild condition is developed. The described reactions were performed in methanol and accelerated by employing microwave irradiation. This strategy allows the direct generation of boronic acid analogs without protection and deprotection operations of boronic acid moiety, making it suitable for the preparation of boron-containing chemical libraries. The synthesized boronic acid analogs were subsequently evaluated for their cytotoxic activity by the MTT assay. Two potential lead compounds were found to be cytotoxic against HepG2, MDA-MB231, and A549 cancer cell lines, demonstrating the potential application of this approach in developing novel boron-containing pharmaceuticals.
    Keywords: Boronic Acids ; Ugi-4cr ; Multicomponent Reaction ; Microwave-Assisted Synthesis ; Acid/Base Extraction ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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  • 10
    Language: English
    In: Tetrahedron, 18 February 2016, Vol.72(7), pp.999-1004
    Description: Pinnigorgiols A–C ( – ), three novel 9,11-secosterols with a rare carbon skeleton arrangement, were isolated from a gorgonian coral identified as sp. Compounds – possess novel carbon skeletons, which include a tricyclo[5,2,1,1]decane ring. The structures of – were established on the basis of spectroscopic methods. The novel compounds – were tested for in vitro cytotoxicity in hepatic stellate cells (HSCs) and displayed inhibitory effects on the generation of superoxide anions and the release of elastase by human neutrophils. Proliferation of HSCs plays a key role in the pathogenesis of liver fibrosis.
    Keywords: 9,11-Secosterol ; Pinnigorgia ; Pinnigorgiol ; Hepatic Stellate Cell ; Superoxide Anion ; Elastase ; Chemistry
    ISSN: 0040-4020
    E-ISSN: 1464-5416
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