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Now showing items 21-28 of 28
Constituents Of Cymbopogon Species
(
Qatar University
, 1986 , Article)
A comprehensive review of the Cymbopogon species including the essential oils and their constituents is given. An account of the other components viz. non volatile terpenoids and phenolic compounds is also given. The ...
A New Tetrafluoroborate Liquid Membrane Electrode For Selective Determination Of Boron
(
Qatar University
, 1986 , Article)
The construction and performance characteristics of a new liquid membrane electrode selective for BF^ion are herein described. The electrode incorporates nitron-tetrafluoroborate ion pair complex in nitrobenzene as a liquid ...
Spectroscopic Studies On Some Methylphosphonothioic Diamides And Related Compounds
(
Qatar University
, 1987 , Article)
A series of methylphosphonothioic diamides MrP (S) (NHR)., ( R = Mr, pr' and Bu') and some related compounds viz, PhP(S)(NHBu)a ,P1^P(S) ( NHCHJ'h ) arc preparpd and their infrared, n.m.r. and mass spectra arc- recorded. ...
Constituents of catha edulis (alkaloids, triterpenoids and related substances and saponins)
(
Qatar University
, 1989 , Article)
The study of the alkaloids of khat samples from Egypt and Yemen revealed qualitative and quantitative differences. Cathine and the dimer of cathinone occured in both samples, while norephedine was detected only in Yemen ...
Pyrrolizidine Alkaloids From Senecio Aegyptius L.
(
Qatar University
, 1988 , Article)
Investigation of the alkaloidal constituents of Senecio aegyptius L. resulted in the isolation and identification of senecionine, dehydrosenkirkine and probably an isomer of seneciphylline. TLC, HPLC and GLC showed the ...
Copper Complexes Of Di-, Tri-, And Tetra-Peptides Containing Tryptophan, Histidine And Arginine
(
Qatar University
, 1983 , Article)
Fifty Seven copper complexes of di-, tri-. and tetra-peptides containing tryptophan, histidine and arginine are studied spectrophotometrically. The ^a, and colour of the complexes are dependent on the sequence of the amino ...
Aminoacid derivative? With psychotogenic activity by
(
Qatar University
, 1989 , Article)
As a part of an extensive programme concerned with the syntheses and investigation of a group of benzilyl-aminoacid and diphenylacetylaminoacid, piperidine esters possessing psychotogenic properties, attention has been ...
The electrical and optical properties of poly (4-ethylidene-l, 3-cyclopentylene vinylene)
(
Qatar University
, 1989 , Article)
The intrinsic viscosity, electrical conductivity and IR absorbance were measured for the sample of poly (4—ethylidene—1, 3—cyclopentylene vinylene). The sample is strongly oxidized in air. Under vacuum the activation energy ...