Browsing Chemistry & Earth Sciences by Publication Date
Now showing items 1-20 of 609
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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 ... -
Constituents of plants growing in Qatar
( Elsevier , 1986 , Article)N/A. -
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 ... -
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. -
Far-infrared and Raman spectroscopic studies of polyiodides
( American Chemical Society , 1986 , Article)The far-infrared and Raman spectra of (CH3)4NI5, (TMA.H2O)10HI5 (TMA = trimesic acid), (phen)2HI5 (phen = phenacetin), (CH3)4NBrI4, (C2H5)4NI7, and (CH3)4NI9 have been recorded and analyzed. The first three compounds contain ... -
Resonance Raman studies of the peroxotitanate(IV) complexes K2(Ti(O2)(SO4)2).5H2O and K2(Ti(O2)(C2O4)2).3H2O
( Elsevier , 1986 , Article)The resonance Raman spectra of K2(Ti(O2)(SO4)2)·5H2O and K2(Ti(O2)(C2O4)2)·3H2O are recorded. The results are consistent with the triangular structure of the peroxotitanium unit, Ti(O2), with C2ν symmetry. The ν(OO), ... -
Resonance Raman and far-infrared studies of charge-transfer complexes of iodine
( John Wiley and Sons Inc , 1986 , Article)The reactions of I2 with phenazine (PH), acridine (AC) and hexamethylenetetramine (HMTA) have been investigated by resonance Raman and far-infrared spectroscopy. The results indicate that the species (PH)2I+I3−, (AC)2I+I3− ... -
Vibrational analysis of the trigonal bipyramidal NbCl5 and NbBr5 molecules
( Elsevier , 1986 , Article)Vibrational normal coordinate analysis has been made for NbCl5 and NbBr5 molecules with D3h symmetry and using Wilson's GF matrix method. The observed frequencies are quantitatively assigned on the basis of the calculated ... -
Spectroscopic studies of nickel and iron clusters at 12 K
( AIP Publishing , 1987 , Article)The electronic and far‐infrared spectra of nickel and iron clusters trapped in argon matrices at 12 K are reported. The ν3 antisymmetric stretching frequencies for Ni3 and Fe3 were observed for the first time at 198 and ... -
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 ... -
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: ... -
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 ... -
Infrared and Raman studies of [UO2(salen)(L)] (L=H2O and CH3OH)
( Elsevier , 1988 , Article)The infrared and Raman spectra of [UO2(salen)(H2O)] and [UO2(salen)(CH3OH)] (salen=N,N′-ethylenebis(salicylideneimine) have been recorded. Assignments for the fundamental vibrations are proposed on the basis of C2v symmetry ...