Search results for "ALK"

Studies on the metabolism of mitragynine, the main alkaloid of the herbal drug Kratom, in rat and human urine using liquid chromatography-linear ion …

2009

Mitragynine (MG) is an indole alkaloid of the Thai medicinal plant Mitragyna speciosa (Kratom in Thai) and reported to have opioid agonistic properties. Because of its stimulant and euphoric effects, Kratom is used as a herbal drug of abuse. The aim of the presented study is to identify the phase I and II metabolites of MG in rat and human urine after solid-phase extraction (SPE) using liquid chromatography-linear ion trap mass spectrometry providing detailed structure information in the MSn mode particularly with high resolution. The seven identified phase I metabolites indicated that MG was metabolized by hydrolysis of the methylester in position 16, O-demethylation of the 9-methoxy group…

A clean analytical method for the spectrophotometric determination of formetanate incorporating an on-line microwave assisted hydrolysis step

1999

Abstract A fast and completely automated procedure is proposed for the spectrophotometric determination of formetanate in waters by means of its reaction with p-aminophenol (PAP). The method involves the on-line alkaline hydrolysis of formetanate to m-aminophenol (MAP) and its reaction, in the presence of KIO 4 as oxidant agent, with the quinoneimine form of PAP, to form a blue indophenol dye which absorbs at 576 nm. The on-line hydrolysis can be carried out in a 6 m reaction coil located inside the cavity of a domestic microwave oven operated at 650 W, or in a 4 m reaction coil located inside the cavity of a Microdigest 301 microwave system operated at 60 W and allows us, in both cases, a …

Classification of vegetable oils according to their botanical origin using n-alkane profiles established by GC-MS.

2013

n-Alkane profiles established by gas chromatography-mass spectrometry (GC-MS) were used to classify vegetable oils according to their botanical origin. The n-alkanes present in corn, grapeseed, hazelnut, olive, peanut and sunflower oils were isolated by means of alkaline hydrolysis followed by silica gel column chromatography of the unsaponifiable fractions. The n-alkane fraction was constituted mainly of n-alkanes in the range C8-C35, although only those most abundant (15 n-alkanes, from 21 to 35 carbon No.) were used as original variables to construct linear discriminant analysis (LDA) models. Ratios of the peak areas selected by pairs were used as predictors. All the oils were correctly …

Improved detection of alkaloids in crude extracts applying capillary electrophoresis with field amplified sample injection

1997

Abstract A simple and effective method for the sensitive detection of alkaloids in crude plant extracts applying capillary electrophoresis with field amplified sample injection (FASI) is described. This method was compared with normal pressure injection for the determination of alkaloids in methanolic extracts from roots of Berberis vulgaris L. (Berberidaceae) and Hydrastis canadensis L. (Ranunculaceae) using a 1:1 mixture of 200 mM ammonium acetate at pH 3.1 and methanol. By introducing a short plug of 70% methanol (v/v) before electrokinetic injection with 16 kV for 8 s the concentration sensitivity was 1000-times higher compared to hydrodynamic injection for 1 s. No difference between bo…

Gas—liquid chromatographic analyses

1985

Abstract The gas chromatographic retention behaviour of methylethyl, 1-methylpropyl, 2-methylpropyl, 1,2-dimethylpropyl, 1-methylbutyl and 3-methylbutyl esters of benzoic and o-, m- and p-chlorobenzoic acids on low-polarity (SE-30) and polar (OV-351) capillary columns under several temperature-programmed and isothermal conditions is reported. The retention data and the Kovats retention indices for all 24 components are given and the separation of a complex mixture is discussed. The retention index increments have been used to examine the effects of chain branching and chlorine substitution. The results are compared with those for n-alkyl benzoates and monochlorobenzoates.

ChemInform Abstract: Synthesis of Areno-Condensed [24]Annulenes.

2010

[24]Annulenes condensed with three phenanthrene units (11a−d) or with three chrysene ring systems (22) were prepared by multi-step syntheses. The cyclic condensation reaction in the final step led to highly symmetrical compounds. Long flexible alkoxy groups attached to the periphery enhance the solubility and give rise to a strong aggregation of the molecules which was observed in solution by NMR and fluorescence excitation spectroscopy, and in the pure state by the detection of liquid crystalline phases in differential scanning calorimetry and polarization microscopy.

Pauson-Khand reaction of internal dissymmetric trifluoromethyl alkynes. Influence of the alkene on the regioselectivity.

2014

Abstract: The scope of the Pauson-Khand reaction (PKR) of internal trifluoromethyl alkynes, previously described with norbornadiene, is expanded to norbornene and ethylene. A thorough structural analysis of the resulting PK adducts has been carried out to unveil that α-trifluoromethylcyclopentenones are preferred in all cases, independently of the electronic properties of the alkyne. The regioselectivity observed with norbornadiene and ethylene is higher than in the case of norbornene.

Diastereoselective Insertion of Isocyanide into the Alkyl−Metal Bond of Methylbenz[ e ]indenyl ansa ‐Zirconocene Complexes

2004

Alkylation of ansa-zirconocene [Zr{(η5-C5H5)SiMe2(MBI)}Cl2] (MBI = η5-2-Me−C13H7) with MgRCl gave the dimethyl complex [Zr{(η5-C5H5)SiMe2(MBI)}Me2], but unresolvable mixtures containing mono-alkylated compounds were obtained when bulkier alkyls were used. However pure dialkyl complexes [Zr{(η5-C5H5)SiMe2(MBI)}R2] (R = CH2Ph, CH2SiMe3) were easily obtained using K(CH2Ph) and Li(CH2SiMe3) as alkylating agents. Diastereoselective insertion into the MBI-unprotected Zr−R bond was observed when all of these dialkyl complexes were treated with 2,6-xylyl isocyanide to give the iminoacyl compounds [Zr{(η5-C5H5)SiMe2(MBI)}R{CR[η2-N-(2,6-xylyl)]}] (R = Me, CH2Ph, CH2SiMe3). All of the new complexes we…

Синтез и оптические свойства монокристаллических слоев окислов щелочноземельных металлов

1980

Isopropanolic Cimicifuga racemosa is favorable on bone markers but neutral on an osteoblastic cell line

2009

Postmenopausal women treated with an isopropanolic extract of Cimicifuga racemosa underwent a decrease in the urinary concentration of N-telopeptides, a marker of bone resorption, and an increase in alkaline phosphatase, a marker of bone formation, at the third month of therapy. Serum from treated women did not modify the activity of alkaline phosphatase or the expression of three genes, runt-related transcription factor-2 (Runx-2), alkaline phosphatase, and osteocalcin, when added to the MC3T3-E1 osteoblastic cell line.