http://blogs.najah.edu/author/emp_2078 An-Najah Blogs :: en-us Sat, 27 Jul 2024 14:22:20 IDT Sat, 27 Jul 2024 14:22:20 IDT [email protected] [email protected] http://blogs.najah.edu/staff/emp_2078/article/Short-Communication-Synthesis-and-Dethiation-of-5--Phenyl--3--thioxo-23-dihydro-1H-24-lrmbenzodiazepine--1--onelrmPublished Articles An-Najah University Journal for Research - Natural Sciences A ISSN: 1727-2114 Volume 20 2006 Pages: 207-212 http://blogs.najah.edu/staff/emp_2078/article/OsmiumVIII-Catalyzed-Oxidation-of-Some-Cyclic-Amines-by-Potassium-HexacyanoferrateIII-in-Alkaline-Media-a-Kinetics-and-Mechanistic-StudyPublished ArticlesReactions of morpholine piperidine and piperazine with OsVIII-catalyzed hexacyanoferrateIII in alkaline media to produce the corresponding lactam have been studied at constant temperature and ionic strength The reactions followed first-order kinetics with respect to [amine] and [OsVIII] but were independent of [FeCN6 3-] and [OH-] The effects of introduced electrolytes potassium hexacyanoferrateII relative permitivity and temperature have also been studied A mechanism accounting for these results has been proposed Chemistry of Heterocyclic Compounds Volume 39 Number 4 April 2003 http:wwwspringerlinkcomcontentj06688m34677p8w0http://blogs.najah.edu/staff/emp_2078/article/Dethiation-of-alpha-Methyl-and-alpha-Phenylmercaptopropionic-Acid-DerivativesPublished ArticlesDethiation of -3benzoylphenyl--methyl and -phenylmercaptopropi-onic acid I II with Raney nickel is described An-Najah University Journal for Research - Natural Sciences A ISSN: 1727-2114 Volume 16 Issue 1 2002 Pages: 057-061http://blogs.najah.edu/staff/emp_2078/article/Oxidation-of-some-Alicyclic-Amines-by-Potassium-Hexacyanoferrate-III-in-Alkaline-Medium-A-Kinetic-and-Mechanistic-StudyPublished ArticlesOxidation of some alicyclic amines morpholine piperazine and piperidine by potassium hexacyanoferrate??? in basic medium has been investigated at 35C Stoichiometric results showed that four moles of hexacyanoferrateIII were consumed per mole of piperidine or morpholine whereas piperazine consumed eight moles of the oxidant to produce the corresponding lactams Kinetic studies indicated that piperidine and morpholine also followed different kinetics from that of piperazine being first order in the amine concentration and independent of the concentrations of hexacyanoferrate??? and hydroxide ion while in the case of piperazine the reaction was first order in both oxidant and substrate concentrations and zero order with respect to the concentration of hydroxide ion The changes in reaction rate due to changing ionic strength of the medium as well as other factors has also been investigated The activation parameters of the oxidation process have been evaluated and a mechanism consistent with the observed kinetics has been proposed Keywords: Hexacyanoferrate??? morpholine piperazine piperidine oxidation lactam An-Najah University Journal for Research - Natural Sciences A ISSN: 1727-2114 Volume 15 2001 Pages: 029-039http://blogs.najah.edu/staff/emp_2078/article/Spectrophotometric-Determination-of-Tiopronin-in-Pharmaceutical-PreparationsPublished ArticlesTwo spectrophotometric methods are described for the determination of tiopronin in pharmaceuticals They are based on the oxidation-reduction reaction between tiopronin and iron III then forming a complex between iron II and ferrozine or di-2-pyridyl ketone-2-thiophenoylhydrazone The produced colored iron II-ferrozine complex [system I] absorbs at 562 nm while the iron II-di-2-pyridyl ketone-2-thiophenoylhydrazone complex [system II] absorbs at 656 nm The effect of different factors such as: pH reagent concentration time of reaction temperature and the tolerance amount of the common excipients have been studied Applying the optimum working conditions tiopronin can be determined over the range 02-86 and 05-170 ppm and with molar absorptivities of 20x104 and 10x104 l mol-1cm-1 for systems I and II respectively Both methods offer high selectivity sensitivity and accuracy with a relative standard deviation RSD of less than 11 for five measurements The proposed methods were applied successfully for the determination of tiopronin in Captimer tablets Key Words: Spectrophotometry Tiopronin Ferrozine Di-2-pyridyl ketone-2-Thiophenoylhydrazone DPKTH Pharmaceutical analysis An-Najah University Journal for Research - Natural Sciences A ISSN: 1727-2114 Volume 15 2001 Pages: 145-157http://blogs.najah.edu/staff/emp_2078/article/Adsorptive-Cathodic-Stripping-Voltammetric-Studies-of-EmodinPublished ArticlesA differential pulse cathodic stripping voltammetric DP-CSV method for determination of emodin in Britton- Robinson buffer pH2 at a hanging mercury drop electrode HMIDE is described The method is based on measuring the reductive peak height at 025V vs AgAgCl reference electrode The linear relationship between the peak current and emodin concentration allowed the voltarnmetric determination of emodin over a wide concentration range 10 X 10-2 25 X10-6 M with a relative standard deviation of 33 10 determinations at 1 X 10-2 M Adsorption of emodin at HMDE enabled a detection limit of 2X10-1M after 3 min accumulation at 00V The applicability of the suggested method was found to be suitable for the determination of emodin in roots stems and leaves of Rumex cyprius planthttp://blogs.najah.edu/staff/emp_2078/article/Emodin-A-Naturally-Occuring-Anthraquinone-Its-Isolation-and-Spectrophotometric-Determination-in-Rumex-Cyprius-PlantPublished ArticlesA new method for isolation and specrophotometric determination of emodin is presented Emodin was isolated by thin layer chromatography tlc and column chromatography cc techniques as an orange long crystalline substance Emodin exhibits two absorption maxima at 420 and 520 nm Stability of the color and the effect of pH were studied Beers law is obeyed in the range 2-30 ppm The method is applied to the determination of emodin in roots stems and leaves of Rumex cyprius plant Spectroscopy Letters Volume 29 Issue 8 December 1996 pages 1539 - 1543http://blogs.najah.edu/staff/emp_2078/article/Plumbagin-a-Naturally-Occurring-Naphthoquinone-Its-Isolation-Spectrophotometric-Determination-in-Roots-Stems-and-Leaves-in-Plumbago-Europaea-LPublished ArticlesA new method for isolation and spectrophotometric determination of plumbagin is presented Plumbagin was isolated by thin layer chromatography TLC and column chromatography CC techniques as an orange tinged yellow long crystalline substances Plumbagin exhibits two absrop-tion maxima at 410 and 510 nm Stability of the color pKa value and the effect of pH were studied Beers law is obeyed over the range 09-45 ppm The method is applied to the determination of plumbagin in roots stems and leaves of Plumbago europaea L plant Spectroscopy Letters Volume 27 Issue 4 May 1994 pages 409 - 416http://blogs.najah.edu/staff/emp_2078/article/Spectrophotometric-Determination-of-Uranium-with-Di-2-pyridyl-Ketone-BenzoylhydrazonePublished ArticlesA method for the spectrophotometric determination of uranium VI by complexation with Di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution is described Uranium VI forms a 1:2 complex with DPKBH The complex has a maximum absorbance at 377 um Beers law is obeyed over the range 0 2 - 12 ugm1 1 The effect of pH excess reagent percentage of ethanol vv stability of the complex and the tolerance limit of many metal ions and common anions have been reported The method has been applied to the determination of uranium in Egyptian monazite sandhttp://blogs.najah.edu/staff/emp_2078/article/Spectrophotometric-and-Polarographic-Studies-of-Di-2-Pyridyl-Ketone-2-ThienoylhydrazonePublished ArticlesThe spectral and differential pulse polarographic DPP behaviour of di-2-pyridyl ketone 2-thienoylhydrazone DPKTH has been investigated in 30 vv ethanol-buffer mixtures over a wide range of pH 20-120 The spectral bands located at 325 276 230 and 208 nm of the DPKTH in ethanol are assigned to the possible electronic transitions of the molecule The spectral data at various pH values indicates that the molecule characterized by the keto = enol tautomerization and the pKa value for the enolic form of the compound is determined in aqueous ethanol and was found to be 106 The effect of various operational parameters on the reduction current and the mechanism of the electrode reaction of DPKTH at the DME are discussed The main reduction peaks are attributed to the reduction of C=N centre of both the keto and enol forms This behaviour is compared with the DPP behaviour of the other related acid hydrazone compounds The applicability of DPP technique for the trace determination of DPKTH was tested under the optimum experimental conditions and the detection limit is found to be 009 mu mhttp://blogs.najah.edu/staff/emp_2078/article/Spectrophotometric-Determination-of-Trace-Amounts-of-Cobalt-and-Copper-with-3--2-Thiazolylazo--26--DiaminopyridinePublished ArticlesSensitive methods for the determination of trace amounts of cobalt and copper by complexation with 3-2-Thiazolylazo-26- diaminopyridine 26-TADAP are described Copper forms a 1:2 violet complex with the reagent having a molar absorptivity of 100 104 L mol-1cm-1 Baers law is obeyed over the range 0 -5084 g in the total volume of 10ml Cobalt also forms a 1:1 green complex with a molar absorptivity of 107 104L mol-1cm-1 and obeying Beers law over the range 0 -2357 g in the total volume of 10 ml The procedure is simple and rapid without any tedious extraction steps for copper and without oxidation of cobalt II to cobalt III Spectroscopy Letters Volume 25 Issue 7 November 1992 pages 1049 - 1055http://blogs.najah.edu/staff/emp_2078/article/Differential-pulse-polarography-and-voltammetry-of-di-2-pyridyl-ketone-benzoylhydrazonePublished ArticlesThe differential pulse polarographic DPP and voltammetric DPV behaviour of di-2-pyridyl ketone benzoylhydrazone DPKBH has been investigated over a wide pH range 21115 The effect of various operational parameters on the reduction current are discussed and the mechanism of the electrode reaction is also included Both methods DPP and DPV are applied for the analytical determination of this reagent and the detection limits are found to be 124 moll and 086 moll respectively The DPP behaviour of DPKBH in the presence of PbII CdII and CuII is studied and the behaviour of the CuII-DPKBH complex is fully investigated The voltammetric determination of CuII based on the accumulation of its complex at the hanging mercury drop electrode is described Statistical analysis of the calibration curve data is included Fresenius Journal of Analytical Chemistry Volume 344 Number 6 June 1992 http://blogs.najah.edu/staff/emp_2078/article/Spectrophotemetric-determination-of-cobalt-in-aqueous-solution-using-di-2-pyridyl-ketone-derivativesPublished ArticlesA method for the spectrophotometric determination of cobaltII is presented with a comparison of the binary complexes formed by cobaltII with di-2-pyridyl ketone nicotinoylhydrazone DPKNH di-2-pyridyl ketone 2-thiophenoylhydrazone DPKTH and di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution CobaltII forms 1:2 complexes with the three reagents Maximum absorbance is at 372 nm for CoII-DPKNH at 389 nm for CoII-DPKTH and at 370 nm for CoII-DPKBH Ranges of linearity effects of pH and excess reagent sensitivity stability of the complexes and tolerance limits of ions are reported It was concluded that the system with DPKTH is the best followed by DPKNH and then DPKBH The method was applied to the determination of cobalt in different alloys http://blogs.najah.edu/staff/emp_2078/article/Polarographic-Study-of-Some-Arylidene-2-PyridylhydrazonesPublished ArticlesThe polarographic behaviors of some arylidene-2-pyridyl hydrazones have been studied in aqueous Britton - Robinson buffer solution containing 40 ethanol using DC polarographic technique In the pH range 19 - 64 the observed single irreversible 4 - electron reduction wave is attributed to the splitting of the N - N bond and saturation of C = N centre All compounds studied are polarographically inactive in alkaline medium The effect of pH on the limiting current and E 112 as well as the reduction mechanism and the effect of substituents are discussed and compared with similar compounds The kinetic parameters of the electrode reaction have been calculatedhttp://blogs.najah.edu/staff/emp_2078/article/Spectrophotometric-Determination-of-Cobalt-with-Di-2-Pyridyl-Ketone-BenzoylhydrazonePublished ArticlesA method for the spectrophotometric determination of cobalt II by complexation with di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution is described Cobalt II forms a 1:2 complex with DPKBH The complex has maximum absorbance at 370 nm Beers law is obeyed over the range 01 - 28 gml-1 The effect of pH effect of excess reagent stability of the complex and the tolerance limit of many metal ions have been reported The method is applied to the determination of cobalt in different alloys containing other metals ions Spectroscopy Letters Volume 24 Issue 9 November 1991 pages 1145 - 1152http://blogs.najah.edu/staff/emp_2078/article/Polarographic-assay-of-Ranitidine-Drugs-in-Pharmaceutical-FormulationsPublished ArticlesA simple accurate and rapid method for the quantitative determination of five ranitidine drugs in pharmaceutical formulations Tablets and Ampoules is proposed The supporting electrolyte was acetic acid-sodium acetate buffer solution pH 52 An excellent linear relationship was obtained between the concentration and current with correlation coefficient 09996 Good agreement was obtained between the results with the dc polarograhic method and those by the manufacturers method of assay Analytical Letters Volume 21 Issue 10 October 1988 pages 1845 - 1853http://blogs.najah.edu/staff/emp_2078/article/Spectrophotometric-Studies-and-Analytical-Application-of-Cerium-III-and-Thorium-IV-Chelates-with-Pyridine-2-Aldehyde-2-Pyridylhydrazone-PAPHPublished ArticlesCe III and Th IV reacts with pyridine-2aldehyde-2pyridylhydrazone in aqueous solutions containing 50 ethanol at pHs 775 and 845 respectively Beers law is obeyed over the range 00-15pg and 00-18 ktg of cerium and thorium respectively The proposed procedure is sensitive since molar absortivity is 256 x 10 4 and 360 X 10 4 1mol -1 cm-1 for Ce III and Th IV respectively The composition and stability of these complexes have been determined The limitation of this procedure and the effect of other ions have been studiedhttp://blogs.najah.edu/staff/emp_2078/article/Spectrophotometric-Determination-of-Trace-Amounts-of-Mercury-with-3-2-Thiazolylazo-2-6-Diaminopyridine-and-GelatinePublished ArticlesA sensitive method for the determination of trace amounts of mercury by complexation with 3-2-Thiazolylazo-2 6-diaminopyridine 2 6-TADAP is described HgII forms a 1:2 complex with the reagent Beers law is obeyed over the range 5-40 g in the total volume of 10 ml The molar absorptivity was found to be 14 104 L mol-1 cm-1 This method is simple rapid and involves no extraction steps whereby the use of gelatine as a solubilizing agent is described Spectroscopy Letters Volume 19 Issue 8 October 1986 pages 929 - 937http://blogs.najah.edu/staff/emp_2078/article/Alpha-Phenylpropionic-Acid-Derivatives---Synthesis-and-Dethiation-Of-5-BenzoylbenzoBThiophene-3-Carboxylic-AcidPublished ArticlesJournal of Heterocyclic Chemistry Volume: 19 Issue: 5 Pages: 1131-1136 Published: 1982http://blogs.najah.edu/staff/emp_2078/article/Synthesis-of-Some-New-Alpha-Phenylpropionic-Acid-DerivativesPublished ArticlesActa Pharmaceutica Jugoslavica Volume: 31 Issue: 2 Pages: 59-66 Published: 1981http://blogs.najah.edu/staff/emp_2078/article/Synthesis-of-Imidazolidin-4-Ones-and-their-Conversion-into-14-Benzodiazepin-2-OnesPublished ArticlesJournal of Heterocyclic Chemistry Volume: 18 Issue: 5 Pages: 963-965 Published: 1981http://blogs.najah.edu/staff/emp_2078/article/Friedel-Crafts-Acylation-Of-3-CarboxymethylbenzoBThiophenes-Lis-Nmr-and-Homo-Study-of-RegioselectivityPublished ArticlesJournal of Heterocyclic Chemistry Volume: 16 Issue: 5 Pages: 1029-1033 Published: 1979http://blogs.najah.edu/staff/emp_2078/article/Synthesis-and-Desulfuration-of-Thianaphthen-3-Carboxylic-Acid-DerivativesPublished ArticlesPhosphorus Sulfur and Silicon and the Related Elements Volume: 6 Issue: 1-2 Pages: 125-126 Published: 1979http://blogs.najah.edu/staff/emp_2078/article/Stereoselective-Invitro-Aromatic-Ring-Oxygenations-of-Chiral-14-Benzodiazepin-2-OnesPublished ArticlesHelvetica Chimica Acta Volume: 60 Issue: 1 Pages: 265-283 Published: 1977