Search results for "Furan"

Comparative Study of Different Column Types for the Separation of Polar Basic Hallucinogenic Alkaloids

2016

The number of hallucinogenic compounds that have been separated simultaneously by liquid chromatography is limited. This research aimed to identify a column(s) that can allow for separation of several hallucinogens. The extent of separation of seven polar hallucinogenic tryptamine and phenethylamine derived alkaloids containing a basic N atom that becomes protonated at low pH values were investigated on five reverse-based columns and one hydrophilic interaction liquid chromatography (HILIC) column. An RP-phenyl and a negatively charged fused core HILIC were identified and recommended as effective columns in this regard. This research is the first to introduce a HILIC column in separation of…

Reduction of tris(benzene-1,2-dithiolate)molybdenum(VI) by hydroxide ions in dry tetrahydrofuran solution.

2001

Tris(benzene-1,2-dithiolate)molybdenum(VI) reacts rapidly and quantitatively with tetrabutylammonium hydroxide to yield the corresponding Mo(V) and Mo(IV) complexes and hydrogen peroxide; the reaction has been executed in dry tetrahydrofuran where the reaction rate shows a fair dependence on complex and OH2 concentrations. Cervilla Avalos, Antonio, Antonio.Cervilla@uv.es ; Perez Pla, Francisco, Francisco.Perez@uv.es ; Llopis Jover, Elisa, Elisa.Llopis@uv.es

UV photoexcitation of a dissolved metalloid Ge9 cluster compound and its extensive ultrafast response.

2015

Femtosecond pump-probe absorption spectroscopy in tetrahydrofuran solution has been used to investigate the dynamics of a metalloid cluster compound {Ge9[Si(SiMe3)3]3}(-). Upon UV photoexcitation, the transients in the near-infrared spectral region showed signatures reminiscent of excess electrons in THF (bound or quasi-free) whereas in the visible part excited state dynamics of the cluster complex dominates.

Novel inhibitors of mitochondrial respiratory chain: endoperoxides from the marine tunicate Stolonica socialis.

2001

The Mediterranean tunicate Stolonica socialis contains a new class of powerful cytotoxic acetogenins, generically named stolonoxides. In this paper, which also details the isolation and chemical characterization of a minor component (3a) of the tunicate extract, we report the potent inhibitory activity (IC(50) < 1 microM) of stolonoxides (1a and 3a) on mitochondrial electron transfer. The compounds affect specifically the functionality of complex II (succinate:ubiquinone oxidoreductase) and complex III (ubiquinol:cytochrome C oxidoreductase) in mammalian cells, thereby causing a rapid collapse of the whole energetic metabolism. This result, which differs from the properties of similar known…

Kinetic characterization of mitochondrial complex I inhibitors using annonaceous acetogenins

1999

The NADH:ubiquinone oxidoreductase (complex I) of the mitochondrial respiratory chain is by far the largest and most complicated of the proton-translocating enzymes involved in the oxidative phosphorylation. Many clues regarding the electron pathways from matrix NADH to membrane ubiquinone and the links of this process with the translocation of protons are highly controversial. Different types of inhibitors become valuable tools to dissect the electron and proton pathways of this complex enzyme. Therefore, further knowledge of the mode of action of complex I inhibitors is needed to understand the underlying mechanism of energy conservation. This study presents for the first time a detailed …

Hypoxia Positively Regulates the Expression of pH-Sensing G-Protein–Coupled Receptor OGR1 (GPR68)

2016

Background & Aims: A novel family of proton-sensing G-proteinâcoupled receptors, including ovarian cancer G-proteinâcoupled receptor 1 (OGR1) (GPR68) has been identified to play a role in pH homeostasis. Hypoxia is known to change tissue pH as a result of anaerobic glucose metabolism through the stabilization of hypoxia-inducible factor-1α. We investigated how hypoxia regulates the expression of OGR1 in the intestinal mucosa and associated cells. Methods: OGR1 expression in murine tumors, human colonic tissue, and myeloid cells was determined by quantitative reverse-transcription polymerase chain reaction. The influence of hypoxia on OGR1 expression was studied in monocytes/macrophages and…

Determination of 5-nitrofurylacrylic acid in wines by high-performance liquid chromatography

1988

1-(3′,6′-Dihydroxy-3-oxo-3H-spiro[isobenzofuran-1,9′-xanthen]-5-yl)-3-[4-({4-[1-(4-fluorophenyl)-1H-imidazol-5-yl]pyridin-2-yl}amino)phenyl]thiourea …

2016

The title compound, which crystallized as a methanol monosolvate, C41H27FN6O5S·CH3OH, was synthesized as a probe for a fluorescence polarization-based competition binding assay. The isobenzofuran fused-ring system is close to planar and orientated almost perpendicular to the central ring of the xanthene system. The dihedral angle between the benzene rings of the xanthene system is 10.0 (2)°, indicating a butterfly-like orientation. A short intramolecular C—F...π contact [F...π = 3.100 (4) Å and C—F...π = 139.9 (3)°] to the six-membered ring of the isobenzofuran system may influence the molecular conformation. The methanol solvent molecule is disordered over two orientations in a 0.6:0.4 rat…

Sigma-1 Receptor Activation Induces Autophagy and Increases Proteostasis Capacity In Vitro and In Vivo

2019

Dysfunction of autophagy and disturbed protein homeostasis are linked to the pathogenesis of human neurodegenerative diseases and the modulation of autophagy as the protein clearance process has become one key pharmacological target. Due to the role of sigma-1 receptors (Sig-1R) in learning and memory, and the described pleiotropic neuroprotective effects in various experimental paradigms, Sig-1R activation is recognized as one potential approach for prevention and therapy of neurodegeneration and, interestingly, in amyotrophic lateral sclerosis associated with mutated Sig-1R, autophagy is disturbed. Here we analyzed the effects of tetrahydro-N,N-dimethyl-2,2-diphenyl-3-furanmethanamine hyd…

ChemInform Abstract: Diastereoselective Synthesis of Spongian Diterpenes. Total Synthesis of the Furanoditerpene (-)-Spongia-13(16),14-diene.

2010

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.