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  • 1
    Language: English
    In: The Journal of organic chemistry, 04 April 2014, Vol.79(7), pp.3206-14
    Description: A diverse library of novel carbamates was synthesized utilizing copper-catalyzed oxidative C-O coupling of formamides and salicylaldehydes. Sensitive aldehyde groups remained intact in the presence of an oxidant and a transition-metal salt. Salicylaldehydes bearing electron-donating, electron-withdrawing, and halogen groups as well as 1-hydroxy-2-naphthaldehydes provided the desired carbamates in good to excellent yields.
    Keywords: Aldehydes -- Chemistry ; Carbamates -- Chemical Synthesis ; Copper -- Chemistry ; Formamides -- Chemistry
    ISSN: 00223263
    E-ISSN: 1520-6904
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  • 2
    Language: English
    In: Tetrahedron Letters, 27 November 2013, Vol.54(48), pp.6529-6532
    Description: Xanthine oxidase (XO) is a key enzyme in purine metabolism with an important role in various pathologies. Several flavonoids have been reported for their capacity to inhibit this enzyme, and, for these compounds, the ability to adopt a planar 3D structure has been accepted as fundamental prerequisite for such activity. Here we report the in vitro investigation of a series of non-planar protoflavone derivatives as XO inhibitors, among which protoapigenone 1′- -propargyl ether was found to be an efficient competitive inhibitor of the enzyme with an IC value of 3.61 μM, significantly ( 〈0.001) stronger than the anti-gout drug allopurinol (IC = 8.72 μM). Methoxy substitution at C-7, however, resulted in complete loss of activity. In silico docking supported the observed structure–activity relationships, based on which a ‘planar structure’ itself can no longer be considered as a criterion for flavonoid-type inhibitors of XO.
    Keywords: Xanthine Oxidase Inhibitor ; Flavonoid ; Protoflavone ; Protoapigenone ; Structure–Activity Relationships ; Docking Study ; Chemistry
    ISSN: 0040-4039
    E-ISSN: 1873-3581
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  • 3
    Language: English
    In: Tetrahedron Letters, 18 September 2013, Vol.54(38), pp.5162-5166
    Description: 1,5-Diphenylpent-3-en-1-yne derivatives were isolated in minor quantities from terrestrial plants and exhibited strong anti-inflammatory activity. A cross coupling reaction between -benzyl-9-BBN and chloroenynes under mild condition was developed resulting in the formation of different 1,5-diphenylpent-3-en-1-yne derivatives with a full control on the / selectivity. Several substrates bearing electron-donating and electron-withdrawing substituents were tolerable under the reaction conditions affording the corresponding products in good yields. This is the first study to report the synthesis of a vast array of novel 1,5-diphenylpent-3-en-1-yne derivatives paving the way for the preparation of tailored derivatives on mass scale necessary for biological studies and drug development.
    Keywords: Henna ; Palladium ; B-Benzyl-9-Bbn ; B-Alkyl Suzuki Coupling ; Aqueous Reaction ; Chemistry
    ISSN: 0040-4039
    E-ISSN: 1873-3581
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  • 4
    Language: English
    In: European Journal of Organic Chemistry, August 2012, Vol.2012(24), pp.4533-4540
    Description: An efficient method for the synthesis of flavones and γ‐benzopyranones has been developed utilizing a mild Sonogashira coupling and 18‐crown‐6 ether mediated 6‐ cyclization of ‐alkynoylphenyl acetates. By using this strategy, flavones and γ‐benzopyranones bearing electron‐donating groups, halogens, and simple alkyl substituents were synthesized in satisfactory yields. A facile, mild, and selective method for the synthesis of flavones and γ‐benzopyranones is reported. ‐Alkynoylphenyl acetates were obtained from either acyl chloride derivatives or substituted salicylates. Upon removing the acetate group, flavones and γ‐benzopyranones were synthesized within 15 min with the aid of 18‐crown‐6 ether. A library of flavones and γ‐benzopyranones was established.
    Keywords: Synthetic Methods ; Oxygen Heterocycles ; Cross‐Coupling ; Cyclization ; Michael Addition
    ISSN: 1434-193X
    E-ISSN: 1099-0690
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  • 5
    Language: English
    In: 2012, Vol.7(10), p.e45113
    Description: Recent studies of infectious diseases have attempted to construct more realistic parameters of interpersonal contact patterns from diary-approach surveys. To ensure that such diary-based contact patterns provide accurate baseline data for policy implementation in densely populated Taiwan, we collected contact diaries from a national sample, using 3-stage systematic probability sampling and rigorous in-person interviews. A representative sample of 1,943 contact diaries recorded a total of 24,265 wide-range, face-to-face interpersonal contacts during a 24-hour period. Nearly 70% of the contacts occurred outside of respondents' households. The most active age group was schoolchildren (ages 5–14), who averaged around 16–18 daily contacts, about 2–3 times as many as the least active age groups. We show how such parameters of contact patterns help modify a sophisticated national simulation system that has been used for years to model the spread of pandemic diseases in Taiwan. Based on such actual and representative data that enable researchers to infer findings to the whole population, our analyses aim to facilitate implementing more appropriate and effective strategies for controlling an emerging or pandemic disease infection.
    Keywords: Research Article ; Computer Science ; Medicine ; Social And Behavioral Sciences ; Public Health And Epidemiology ; Infectious Diseases ; Computer Science
    E-ISSN: 1932-6203
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  • 6
    Language: English
    In: PLoS ONE, 01 January 2011, Vol.6(8), p.e23922
    Description: Protoapigenone, a natural flavonoid possessing an unusual p-quinol moiety on its B-ring, is a novel prospective anticancer agent with low toxicity that is currently in development. The first economical, one-step synthesis of protoapigenone from...
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 7
    Language: English
    In: European Journal of Organic Chemistry, December 2012, Vol.2012(34), pp.6760-6766
    Description: Copper catalysed oxidative coupling reaction of formamides with β‐keto esters and 2‐carbonyl‐substituted phenols successfully proceeded through direct C–H bond activation of formamides. The corresponding carbamates were formed with high stereoselectivity under mild reaction conditions. This protocol was successfully applied to the synthesis of three novel halogenated carbamates and a carbaryl insecticide derivative. Our results suggest the use of 6.0 equiv. TBHP is crucial for this type of reaction. Synthesis of carbamates was accomplished through the reaction of β‐keto esters or 2‐carbonyl‐substituted phenols with formamides using copper chloride and an oxidant. Sixteen aliphatic as well as fourteen aromatic carbamates were prepared in good to excellent yields. The methodology was applied to the synthesis of halogenated carbamates and a carbaryl insecticide derivative.
    Keywords: Synthetic Methods ; Oxidation ; C–H Activation ; Regioselectivity ; Carb­amates ; Copper
    ISSN: 1434-193X
    E-ISSN: 1099-0690
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  • 8
    Language: English
    In: Bioorganic & Medicinal Chemistry, 01 July 2013, Vol.21(13), pp.3866-3872
    Description: The addition of a DNA methyltransferase inhibitor, 5-azacytidine, to fungus culture broth changed its secondary metabolites profile. Analysis of the culture broth extract led to the isolation of three new bisabolane-type sesquiterpenoids: (7 )-(+)-7- -methylsydonol ( ), (7 ,11 )-(+)-12-hydroxysydonic acid ( ) and 7-deoxy-7,14-didehydrosydonol ( ), along with eight known compounds. The isolated compounds were evaluated for their anti-diabetic and anti-inflammatory activities. Among the isolates, ( )-(+)-sydonol ( ) did not only potentiate insulin-stimulated glucose consumption but also prevented lipid accumulation in 3T3-L1 adipocytes. Additionally, ( )-(+)-sydonol ( ) exhibited significant anti-inflammatory activity through inhibiting superoxide anion generation and elastase release by fMLP/CB-induced human neutrophils. This is the first report on isolating a secondary metabolite with anti-diabetic and anti-inflammatory activities from microorganisms.
    Keywords: Epigenetic ; Aspergillus Sydowii ; Bisabolane-Type ; Anti-Diabetic ; Anti-Inflammatory ; Medicine ; Chemistry ; Anatomy & Physiology
    ISSN: 0968-0896
    E-ISSN: 1464-3391
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  • 9
    Language: English
    In: Tetrahedron: Asymmetry, 2009, Vol.20(12), pp.1407-1412
    Description: A series of phenylaluminum reagents AlPh Et (L) ( = 1–3) containing adduct ligand L [Et O, THF, OPPh , or 4-dimethylaminopyridine (DMAP)] were synthesized and characterized. NMR studies showed that AlPh Et (L) ( = 1 or 2) exists as an equilibrium mixture of 3–4 species in solution. Solid-state structures of the phenylaluminum reagents reveal a distorted tetrahedral geometry. Asymmetric additions of phenylaluminum to 2-chlorobenzaldehyde were examined employing a titanium(IV) complex [TiL (OPr ) ] (H L = (1 ,2 )-2-( -tolylsulfonylamino)-1,3-diphenyl-1-propanol) as a catalyst precursor. It was found that the adduct ligand L had a strong influence on the reactivity and the enantioselectivity in asymmetric phenyl additions to aldehydes. The phenylaluminum reagents with OPPh or DMAP were unreactive toward aldehydes, and AlPh (THF) was found to be superior to AlPh (OEt ) or AlPhEt (THF). Asymmetric aryl additions of AlAr (THF) to aldehydes employing a loading of 5 mol % titanium(IV) complex with a strategy of a slow addition of the aldehydes over 20 min were conducted, and the reactions produced optically active secondary alcohols in high yields with excellent enantioselectivities of up to 94% ee.
    Keywords: Chemistry
    ISSN: 0957-4166
    E-ISSN: 1362-511X
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  • 10
    Language: English
    In: ChemInform, 21 January 2014, Vol.45(3), pp.no-no
    Description: Byline: Da-Wei Chuang(1), Mohamed El-Shazly(1), Chin-Chau Chen(1), Yu-Ming Chung(1), Balaji D. Barve(1), Ming-Jung Wu(1), Fang-Rong Chang(1), Yang-Chang Wu(1) Keywords: alkynes (benzene compounds); alkenes (acyclic compounds); C-C bond formation; catalysis, phase-transfer catalysis ***** No abstract is available for this article. ***** Author Affiliation: (1)Grad. Inst. Nat. Prod., Kaohsiung Med. Univ., Kaohsiung 807, Taiwan
    Keywords: Alkynes Benzene Compounds ; Alkenes Acyclic Compounds ; C‐C Bond Formation ; Catalysis ; Phase‐Transfer Catalysis
    ISSN: 0931-7597
    E-ISSN: 1522-2667
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