- Tuesday, May 1, 2007
- Published at:ASIAN JOURNAL OF CHEMISTRY Volume: 19 Issue: 3 Pages: 1658-1666 Published: MAY-JUN 2007
- Aromatic and heteroaromatic N-methyl-N-(2-pyridyl)-hydrazones 3a-f were synthesized and characterized by elemental analyses, and spectral data. H-1, C-13 NMR and mass spectra supported the formation. of the E-isomer. N-Methyl-N-(2-pyridyl)hydrazone carboxaldehydes can be readily characterized by mass spectrometry. The new hydrazones 3a-h have been screened for antimicrobial activity.
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- Thursday, January 1, 2004
- Published at:Journal of Applied Sciences 4 (2): 193.1 96,2004
- The rates of cleavage of p-chlorotrimethylsilane were measured in various ROH-DMSO meda (R: Me, Et, i-Pr, t-By CF,CH,-HOCH,CH,-) and the results were reported. These results have shown that the rates of cleavage decrease as the mole ratio of ROH increases.
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- Wednesday, January 1, 2003
- Published at:Pakistan Journal of Applied Sciences 3(2): 125-128, 2003
- The nucleophilic cleavage of substituted benzyltrimethyl-silanes in DMSO-Hz0 media using tetraalkylammonium fluoride, TAAF, has been studied. The observed rate constants, pseudo first order rate constants, activation, and thermodynamic parameters have been reported. A mechanism for such cleavage has been proposed. The results fit well Hammett equation. The reaction constant, p! value of (6.7) has been reported. The p value is consistent with a substantial negative charge developing in the transition state.
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- Wednesday, November 1, 1989
- Published at:Not Found
- A method for simultaneous spectrophotometric determination of total iron, iron(II) and iron(III) in mixtures containing other metal ions has been described. The method is based on the complexation of iron with di-2-pyridyl ketone benzoylhydrazone (DPKBH) in 50% (v/v) ethanolic solution. Iron(II) complex with DPKBH exhibits two absorption maxima at 360 and 650 nm. meanwhile iron(II1) complex with DPKBH exhibits only one maximum at 360nm. Iron(II) and iron(III) complexes with DPKBH have similar behaviour at 360nm. Iron forms 1:2 complexes with the reagent. Beer's laws are obeyed over the ranges 0.1-2 μgml-1 and 0.4-5 μgrn1-l for iron(II) complexes at 360 and 650nm respectively. Iron(III) showed results similar to those obtained for iron(II) at 360nm. The effect of pH, effect of excess reagent. the stability of complexes. and the tolerance limit of many metal ions have been reported. The method is applied to the determination of total iron, iron(I1). and iron(II1) in synthetic solutions.
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- Saturday, April 1, 1989
- Published at:Not Found
- The hydrolysis of furfurylidene benzoylhydrazone,FBH, in hydrochloric acid medium has been found to follow specific acid catalysis, whereas the hydrolysis in universal buffer medium has been found to follow general acid-base catalysis. Mechanisms for the hydrolysis in different acidic media have been postulated. The observed rate constants, secondary rate constants, activation and thermodynamic parameters for the hydrolysis of furfurylidene benzoylhydrazone have been reported. The effect of change in percentage of ethanol in the ethanol-buffer mixture on the rate of hydrolysis has been discussed.
Monatshefte für Chemie / Chemical Monthly, Volume 120, Number 4 / April, 1989
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