Search results for "Furan"
showing 10 items of 667 documents
Metal-Free Diastereo- and Enantioselective Dearomative Formal [3 + 2] Cycloaddition of 2-Nitrobenzofurans and Isocyanoacetate Esters
2022
The diastereo- and enantioselective dearomative formal [3 + 2] cycloaddition of 2-nitrobenzofurans and α-aryl-α-isocyanoacetate esters provides tricyclic compounds bearing the 3a,8b-dihydro-1H-benzofuro[2,3-c]pyrrole framework with three consecutive stereogenic centers. The reaction was enabled by a cupreine-ether organocatalyst. The reaction products were obtained with almost full diastereoselectivity and with excellent enantiomeric excesses for a number of substituted 2-nitrobenzofurans and isocyanoacetates.
Efficacy of 8 weeks elbasvir/grazoprevir regimen for naïve-genotype 1b, HCV infected patients with or without glucose abnormalities: Results of the E…
2022
Background and aim: Direct Acting Antivirals(DAAs) achieve the highest rate of sustained viral re- sponse(SVR) in patients with genotype-1b(G1b) Hepatitis C virus(HCV) infection. Reducing treatment du- ration can simplify the management and improve adherence of therapy. Patients and methods: The study evaluates the efficacy of 8 weeks of elbasvir/grazoprevir regimen in 75 treatment-naïve(TN), G1b patients with mild-moderate fibrosis(Liver Stiffness by Fibroscan®< 9.0 kPa). Viral load(VL) has been evaluated by Roche TaqMan RT-PCR(LLOQ < 15 IU/ml). Results: Mean age was 61.0 ±14.2 years, 44% were male, mean LS by Fibroscan®was 6.1 ±1.8 kPa. Twenty-eight patients(37.3%) had an HOMA > …
The Yeast RNA Polymerase II-associated Factor Iwr1p Is Involved in the Basal and Regulated Transcription of Specific Genes
2009
RNA polymerase II (RNA pol II) is a multisubunit enzyme that requires many auxiliary factors for its activity. Over the years, these factors have been identified using both biochemical and genetic approaches. Recently, the systematic characterization of protein complexes by tandem affinity purification and mass spectroscopy has allowed the identification of new components of well established complexes, including the RNA pol II holoenzyme. Using this approach, a novel and highly conserved factor, Iwr1p, that physically interacts with most of the RNA pol II subunits has been described in yeast. Here we show that Iwr1p genetically interacts with components of the basal transcription machinery …
Sphingobium aromaticiconvertens sp. nov., a xenobiotic-compound-degrading bacterium from polluted river sediment.
2007
A bacterial strain capable of degrading some monochlorinated dibenzofurans, designated RW16T, was isolated from aerobic River Elbe sediments. The strain was characterized based on 16S rRNA gene sequence analysis, DNA G+C content, physiological characteristics, polyamines, ubiquinone and polar lipid pattern and fatty acid composition. This analysis revealed that strain RW16T represents a novel species of the genus Sphingobium. The DNA G+C content of strain RW16T, 60.7 mol%, is the lowest yet reported for the genus. 16S rRNA gene sequence analysis placed strain RW16T as an outlier in the genus Sphingobium. The name Sphingobium aromaticiconvertens sp. nov. is proposed for this dibenzofuran-min…
Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry Analysis of Carbosulfan, Carbofuran, 3-Hydroxycarbofuran, and Other Metabolites in …
2007
The potential of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QqTOF-MS) to identify and confirm carbosulfan and seven of its main metabolites (carbofuran, 3-hydroxycarbofuran, 3-ketocarbofuran, 3-hydroxy-7-phenol carbofuran, 3-keto-7-phenolcarbofuran, 7-phenolcarbofuran, dibutylamine) at trace levels from food is explored for the first time. The analytical method developed consists of pressurized liquid extraction (PLE) and LC-QqTOF-MS in positive ion mode, which attains unequivocal identification and quantification of the studied compounds in food, at levels well below of those of concern (0.05 mg/kg for the sum of carbosulfan, carbofuran, and 3-hydroxycarbofuran).…
Determination of pesticides in soil samples by solid phase extraction disks
1993
A systematic study comparing the methodology and analytical results obtained in an investigation of seven pesticide residues (Molinate, Atrazine, Carbofuran, Pirimicarb, Prometryn, Malathion and Tetrachlorvinphos) in soil samples is reported. Solid-phase extraction (SPE) using glass columns and 47 mm disks of octyl and octadecyl-bonded silica was used in the pesticide analysis. The best extraction efficiency and clearest extracts are obtained with C8 disks. The analyses were carried out by capillary gas chromatography with nitrogen and phosphorus detection. Recovery experiments were performed at ppb levels in spiked soil samples. The average recoveries of the compounds were 53–77%. Detectio…
Direct derivative spectrophotometric determination of carbaryl and carbofuran in water samples
1990
Abstract Derivative absorption spectrophotometry has been applied to the direct determination of carbaryl and carbofuran in water samples. The use of the third derivative for carbaryl and the fourth derivative for carbofuran reduces the matrix effect and the seventh derivative provides, in both cases, accurate results for the determination of these pesticides, even working at low dilution levels of the samples. A limit of detection of 4 ppb and a variation coefficient of 0.1% have been obtained for the determination of carbaryl. Carbofuran can be determined with a limit of detection of 5 ppb and a variation coefficient of 0.02%.
Synthese und eigenschaften von oxydo-p-oligophenylenen. 18. Mitteilung über poly- und oligophenylene
1965
Oxydosubstituierte p-Oligophenylene leiten sich vom Dibenzofuran ab, sind also brukkensubstituierte Oligophenylene. Ihre Darstellung erfolgte mit Hilfe der ULLMANN-Reaktion unter Verwendung von Jodderivaten des Dibenzofurans; zu deren Darstellung dienten entsprechende Aminoverbindungen. Einige Oxydo-p-oligophenylene wurden auf der Grundlage der Kupplungs-Reaktion von o-Chlorphenyl-diazoniumverbindungen mit p-Benzochinon und nachfolgendem Oxydoringschlus an daraus hervorgehenden 2-Chlor-2′-hydroxybiarylen erhalten. Als weitere Ringschlus-Reaktion wurde die dehydratisierende Atherspaltung von 2,2′-Dimethoxybiarylen angewandt. Damit konnte die Synthese eines Trioxydo-p-quaterphenyls, eines dur…
CCDC 955315: Experimental Crystal Structure Determination
2013
Related Article: Brian D. Rekken , Thomas M. Brown , James C. Fettinger , Felicitas Lips , Heikki M. Tuononen , Rolfe H. Herber , and Philip P. Power|2013|J.Am.Chem.Soc.|135|10134|doi:10.1021/ja403802a
Diastereoselective synthesis of spongian diterpenes. Total synthesis of the furanoditerpene (−)-spongia-13(16),14-diene
1999
Abstract An effective diastereoselective synthesis of the marine-sponge metabolite (−)-spongia-13(16),14-diene 1 is achieved starting from S-(+)-carvone via a homochiral phenanthrenone as the key intermediate for the construction of the furan ring system. S-(+)-Carvone was transformed into the phenanthrenone 2a in six steps (53% overall yield), using an intramolecular Diels-Alder reaction as the key step. Conversion of the enone function in 2a into an epoxyaldehyde function followed by cyclisation and aromatisation in acid conditions completed the construction of ring D.