Search results for "DISCOVERY"

Functionality transfer from C8 to C9 in sesquiterpenes. Synthesis of the named Herbolide E from artemisin.

1992

Abstract The key intermediate 6 was obtained in five steps from artemisin (1). The spectroscopic characteristics of the synthetic product 7a reveal that the proposed structure for the natural herbolide E must be revised.

The Peroxisomal 3-keto-acyl-CoA thiolase B Gene Expression Is under the Dual Control of PPARα and HNF4α in the Liver

2011

PPARα and HNF4α are nuclear receptors that control gene transcription by direct binding to specific nucleotide sequences. Using transgenic mice deficient for either PPARα or HNF4α, we show that the expression of the peroxisomal3-keto-acyl-CoA thiolase B(Thb) is under the dependence of these two transcription factors. Transactivation and gel shift experiments identified a novel PPAR response element within intron 3 of theThbgene, by which PPARα but not HNF4α transactivates. Intriguingly, we found that HNF4α enhanced PPARα/RXRα transactivation from TB PPRE3 in a DNA-binding independent manner. Coimmunoprecipitation assays supported the hypothesis that HNF4α was physically interacting with RXR…

A facile microsynthesis of 14C-labelled picene

1984

Microscale Wittig olefination of commercially available [7-14C]-benzal dehyde of high specific radioactivity with aryl bromomethyl phosphonium salt and subsequent oxidative photocyclisation affords pure 14C-labelled picene in efficient yield.

Deprotonation of Thiophenes Using Lithium Magnesates.

2005

Abstract Thiophene was regioselectively deprotonated at C2 on treatment with 1/3 equiv of Bu3MgLi in THF at room temperature. The lithium arylmagnesate formed was either trapped with electrophiles or cross-coupled in a ‘one-pot’ procedure with aryl halides under palladium catalysis. 2-Chlorothiophene and 2-methoxythiophene were similarly deprotonated at C5 under the same reaction conditions. The enhancement of the reactivity of the base using TMEDA was evidenced using 1H NMR spectroscopy.

Trienediolates of hexadienoic acids in synthesis. Addition to unsaturated ketones. A convergent approach to the synthesis of retinoic acids

1995

Abstract The regioselectivity of the addition of the lithium trienediolates generated from hexa-2,4dienoic acids 1 and 2 or the dihydropyran-2ones 4 and 5 to unsaturated ketones 6 is studied. Equilibration conditions favour reaction of the trienediolates through their ω carbon, and the ketones according to 1,2- and 1,4-additions. β-Ionone 6a and the aryl-butenone 6b lead to the 1,2-ω-adducts 8 , which undergo a facile acid catalyzed dehydration to retmoic acids 11 . On reaction with the unsaturated ketone 6b or with the aryl ketones 21 , the trimethyldihydropyran-2one S leads to γ-adducts derived from deprotonation of the chain methyl mbstituent along with the 1,4-ω-adducts.

Regio-specific synthesis of new 1-(tert-butyl)-1H-pyrazolecarboxamide derivatives

2017

Regio-specific and non-regiospecific condensation reactions on 1,3-dicarbonyl compounds rendered 1,3,5-trisubstituted pyrazoles. Herein, the control of regio-specificity was a significant improvement in pyrazole research. A high yield acylation of poorly nucleophilic aryl amines, which resulted in mono- or diacylated products depending on the reaction conditions, is described. As a result, a library of potentially bioactive compounds was obtained. Fil: Ruatta Merke, Santiago Matías. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina Fil: Murguia, Marcelo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Co…

Über das Vorkommen von Atropin in Sclerotinia minor Jagger und Corticium rolfsii Curzi

1960

Discovering representative models in large time series databases

2004

The discovery of frequently occurring patterns in a time series could be important in several application contexts. As an example, the analysis of frequent patterns in biomedical observations could allow to perform diagnosis and/or prognosis. Moreover, the efficient discovery of frequent patterns may play an important role in several data mining tasks such as association rule discovery, clustering and classification. However, in order to identify interesting repetitions, it is necessary to allow errors in the matching patterns; in this context, it is difficult to select one pattern particularly suited to represent the set of similar ones, whereas modelling this set with a single model could…

Über die pharmakologische Prüfung von 2-Skatyl-alkylpyridinen

1968

2-Skatyl-alkylpyridine wurden an verschiedenen isolierten Organen untersucht. Die Substanzen zeigten am isolierten Rattendarm eine kompetitiv-nichtkompetitive anticholinerge Wirkung, am isolierten Meerschweinchendarm eine kompetitiv-nichtkompetitive Antihistaminwirkung. An isolierten Meerschweinchenvorhofen trat nach Gabe der tertiaren 2-Skatyl-alkylpyridine eine durch Atropin aufzuhebende negativ inotrope Wirkung auf, die quartaren Substanzen waren dagegen positiv inotrop wirksam. Die tertiaren Stoffe wirkten blutdrucksenkend, die quartaren bei kleinen Dosen blutdrucksteigernd, bei hoheren Dosen blutdrucksenkend. 2-Skatyl-alkyl-pyridines have been studied on different isolated organs. The …

Supernormal conduction in the right bundle branch: lack of influence of autonomic blockade.

1984

A programmed atrial stimulation at a driving rate of 100/min was performed in a 47-year-old woman with left bundle branch block. Supernormal conduction lasting 40 ms was revealed within the right bundle branch. After autonomic blockade (0.2 mg propranolol/kg body weight and 0.04 mg atropine/kg body weight) the position and duration of the supernormal conduction did not change. This suggests that the autonomic nervous system has no influence on the supernormal phase of conduction in the human intraventricular conduction system.