Browsing Chemistry & Earth Sciences by Publication Date
Now showing items 1-20 of 557
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Synthesis and biological activity of some new 3-and 6-substituted coumarin amino acid derivatives. Part I
( Wiley-Blackwell , 1981 , Article)The synthesis of 6-nitrocouarrain-3-CO-amino acids and their corresponding methyl esters (II-XVII) and some dipeptide methyl esters (XVIII-XXVI) are described. 6-(N-Tosyl- or N-phthalylaminoacyl)aminocoumarin-3-carboxylic ... -
Constituents of plant growing in Qatar. II. Investigation of Euphorbia granulata
(1982 , Article)N/A. -
Synthesis and biological activity of some new aminoacylcarbazole derivatives. Part I
( Wiley-Blackwell , 1982 , Article)The syntheses of different 9-(N-phthalyl- or N-tosyl- or free aminoacyl)carbazoles and the corresponding derivatives of 3,6-dinitrocarbazoles and some derivatives of 3,6-diamino-9-(N-phthalylaminoacyl)carbazoles (II-XXXII) ... -
Constituents of plants growing in Qatar III - Nutritive constituents of Garawah (Glossonema edule)
( Junk Publishers , 1983 , Article)Both the pericarp and the unripe seeds of the unripe fruits of Glossonema edule were separately analysed. The crude protein content of the unripe seeds is double that of the pericarp. Investigation of the amino acids of ... -
Constituents of plants growing in qatar V. Constituents of the volatile oil of cymbopogon parkeri
( Elsevier , 1983 , Article)Analysis of the volatile oil of Cymbopogon parkeri has been carried out by capillary gas chromatography-mass spectrometry. To facilitate identification, prefractionation of the oil by adsorption high-performance liquid ... -
Constituents of plants growing in Qatar VII an examination of certain plants for anti-inflammatory activity
( Taylor & Francis , 1985 , Article)Six desert plants native to the State of Qatar were successively extracted with hexane, chloroform and ethanol. These extracts were examined for their ability to inhibit aggregation of rabbit blood platelets induced by ... -
Iridoids and flavonoids of Teucrium polium herb
( Thieme , 1986 , Article)The iridoid glycoside teucardoside and the flavonoids salvigenin and cirsiliol have been isolated from Teucrium polium var. pilosum and T. polium var. alba. The medicinal significance of these findings is discussed. -
Constituents of plants growing in Qatar IX. The antispasmodic components of cymbopogon parkeri stapf. Parkeri stapf
( Taylor & Francis , 1986 , Article)Investigation of the lipid fraction of Cymbopogon parkeri revealed the presence of several active constituents, one of which possesses an antispasmodic activity and was identified as cryptomeridiol. Study of the other ... -
Constituents of plants growing in Qatar
( Elsevier , 1986 , Article)N/A. -
Polarization Resistance Study on Copper Corrosion in Aqueous Potassium Hydrogen Phthalate Solution
( WILEY-VCH Verlag , 1987 , Article)The effect of temperature on corrosion of copper in 0.1 M aqueous solution of potassium hydrogen phthalate (KHPh) has been investigated using polarization resistance technique. it was found that that the corrosion rate in ... -
Sesquiterpene lactones from Pulicaria sicula
( Elsevier , 1988 , Article)The aerial parts of Pulicaria sicula afforded the known xanthanolides 1-6, the guaianolides 7 and 8 as well as two new ones, the lactone 9 and the corresponding epoxide 10. Furthermore nerylisobutyrate and the thymol ... -
Inhibitory effect of sodium nitrite on corrosion of lead in 0.1 M sodium hydroxide solution
( Council of Scientific and Industrial Research , 1988 , Article)The effect of NaNO2 as an inhibitor for corrosion of lead in 0.1 M NaOH solution has been investigated at different temperatures using the Tafel plot technique. The concentrations of NaNO2 employed are in the range 1-5×10-5. ... -
Constituents of plants growing in Qatar part XV. Chemical investigation and pharmacotoxicity of pyrrolizidine alkaloids of moltikiopsis ciliata
( Taylor & Francis , 1988 , Article)Chemical study of the alkaloidal constituents of Moltikiopsis ciliata resulted in the isolation and identification of heliotrine and echinatine, in addition to other minor alkaloids. Pharmacological experiments revealed: ... -
Evidence for some prostaglandins in Allium sativum extracts
( John Wiley & Sons, Ltd. , 1988 , Article)Homogenized garlic (Allium sativum Linn.) was extracted successively with organic solvents and the prostaglandin-rich fraction separated. Fractionation of the extract with column chromatography was performed. TLC of the ... -
Substituted phenols as corrosion inhibitors for copper in nitric acid
( WILEY-VCH Verlag GmbH , 1988 , Article)The dissolution of copper in nitric acid solution in the presence of resorcinol, o, p-aminophenols, catechol, o-cresol and salicylaldehyde as corrosion inhibitors has been studied by galvanostatic polarization and weight ... -
Chemical survey of some plants Growing in Qatar
(1989 , Other)Fifty one plants growing in Qatar, belonging to thirty families, were surveyed for alkaloids, anthraquinones, coumarins, flavonoids, tannins and saponins. The medicinal uses of these plants arereported. -
Selective determination of thiamine (vitamin B1) in pharmaceutical preparations by direct potentiometric argentometric titration with use of the silver-silver sulphide ion-selective electrode
( Elsevier , 1989 , Article)A simple and selective argentometric titration method is described for determination of thiamine (vitamin B1), based on direct potentiometric titration in alkaline media (⩾0.5M) in which a chemical transformation takes ... -
Thiamine-reineckate liquid membrane electrode for the selective determination of thiamine (vitamin B1) in pharmaceutical preparations
( The Royal Society of Chemistry , 1989 , Article)The construction and electrochemical response characteristics of a liquid membrane electrode for thiamine (vitamin B1) based on the formation of an ion pair between the thiamine cation and the reineckate anion in nitrobenzene ... -
Amphetamine Selective Electrodes Based on Dibenzo-18-crown-6 and Dibenzo-24-crown-8 Liquid Membranes
( American Chemical Society , 1989 , Article)Two novel membrane electrodes highly sensitive and selective for amphetaminium cation are developed and electrochemically evaluated according to IUPAC recommendations. These electrodes Incorporate amphetamine-dibenzo-18-crown-6 ...