ORIGINAL_ARTICLE
Synthesis, Spectroscopic and Thermal Behaviour of Salicylaldimine Complexes
THE COMPLEXES of N-salicylaldimine 2-urea (L 1) and N-salicylaldimine-2-thiourea (L2) with Fe(III), Co(II), Ni(II) and Cu(II) are formed in the molar ratios (1:1) as well as (1:2) (M:L) and characterized by elemental analysis, IR, electronic spectra, thermogravimetric analysis and magnetic measurements. The stoichiometry, proton-reagent stability constant, conditional formation constant of the complexes and the conductance are determined by using potentiometric and conductometric measurements. The study revealed that the ligands behave as monobasic bidentates, electronic spectra and magnetic measurements indicate that the metal chelates have octahedral or square-planar arrangements. Also, the TG analysis indicates the presence of hydrated and coordinated water molecules. The electrolytic and nonelectrolytic nature of the complexes were assigned based on molar conductance measurements.
https://ejchem.journals.ekb.eg/article_1224_cab5f6b03535346b70084f33afd18d97.pdf
2010-06-30
329
339
10.21608/ejchem.2010.1224
ORIGINAL_ARTICLE
Enhanced One-Pot Microwave Efficient Synthesis of Some Pyrrolidine-2, 5-Diones, Butenamides and their Sulfonamide Derivatives Versus Conventional Thermal Heating Technique
DUE TO the highly important medical applications and wide biological activities of pyrrolidines, butenamides, and their sulfonamide derivatives, such as bacteriocides, fungicides, and insecticides, compounds (4-42) were synthesized from condensation of α, β-unsaturated anhydrides (1-3), with the corresponding amines, using either enhancing microwave irradiation heating or the conventional thermal heating technique in order to compare between their efficiency.
https://ejchem.journals.ekb.eg/article_1225_b50b2b3164869eb6d5f29433c3cc1d14.pdf
2010-06-30
341
357
10.21608/ejchem.2010.1225
microwave
Synthesis
Condensation
Butenamides
Pyrrolidines and Sulfonamides
ORIGINAL_ARTICLE
Synthesis of Some New Thieno [2, 3-d] pyrimidines
4IMINO-3N- (substituted) -5-(thiophen-2-yl) -3,4,dihydro-thieno [2,3-d] pyrimidine-2(1H) (2) was used as precursor for the preparation of some novel 1-(2,3-dihydro-3-methyl-5-(thiophen-2-yl)-2-thioxothieno[2,3-d] pyrimidine – 4 (1H)-ylidene) -3-methyl or phenylthiourea (3a,b) and also for the preparation of 2-Hydrazinyl -3-methyl-5- (thiophen-2-yl)- thieno [2,3-d] pyrimidin-4(3H-imine) (5) which was reacted with methyl and phenylisothiocyanat at room temp. to give compounds 6a,b. Also, 5 was reacted with methylisothiocyanate, and / or formic acid to give the triazolopyrimidines 7 and 8. Also, 5 was reacted with nitrous acid to give the 2-azido thienopyrimidine 9.
https://ejchem.journals.ekb.eg/article_1226_1b59fab64e2d05bc1867b78e08718da0.pdf
2010-06-30
359
366
10.21608/ejchem.2010.1226
THIENOPYRIMIDINE
Triazolopyrimidines and Azido thienopyrimidine
ORIGINAL_ARTICLE
Effect of Water Content Chemical Composition and Antioxidant Activity from Volatile Generated from Beef Fat in Maillard Reaction
THE PRESENT work was aimed to examine the chemical composition and antioxidant activity of the reaction between beef fat and cysteine with and without water model systems. Fifty two and thirty three volatile compounds were isolated and identified with the predominance of esters and sulfur-containing compounds. Sensory evaluation was also performed for the model systems according to (ISO) and the results revealed that the presence of volatiles having roasted meat –like aroma might be due to certain components such as pyrazine and thiazoles derivatives as the main compounds. The radical scavenging activity of the model systems was quantified spectrophotometrically, using DPPH radical and β-carotene bleaching assays.
https://ejchem.journals.ekb.eg/article_1227_6b7a50b496e1ca2615c655da1be65bce.pdf
2010-06-30
367
383
10.21608/ejchem.2010.1227
Maillard reaction
water content
Beal fat
meat
Like aroma –antioxidant activity
ORIGINAL_ARTICLE
Synthesis of New Bithiophene and Thieno [2,3-d] Pyrimidine Derivatives with Potent Antimicrobial Activity
THE VERSATILE synthon 2-Amino-4-(thiophene-2-yl) thiophene-3-carbonitrile (1) was used as precursor for the synthesis of a series of bithiophene (2) and thieno [2, 3-d] pyrimidine (3) derivatives. The antimicrobial evaluations of the newly synthesized compounds were carried out in vitro assays for antifungal and antibacterial activities. Amongst the tested compounds, 1-(4\-cyano-2,3\-bithiophen-5\-yl)3-phenylthiourea (2b), 4-imino-3-phenyl-5-(thiophenyl-2-yl)-3,4-dihydrothieno[2,3-d] pyrimidine-2(1H)-thione (3b) and 1-phenyl-3-(5-(thiophenyl-2-yl)thieno[2,3-d]pyrimidin-4-yl) thiourea (5c) exhibit significant antibacterial activities against Pseudomonas sp, Escherichia coli, Streptococcus lactis, Bacillus subtilis and exhibit significant antifungal activities against Aspergillus niger, Penicillium sp, Candida albicans and Rhodotorula ingeniosa. From structure-activity relationship (SAR) point of view, the attachment of phenyl thioureido moiety to bithiophenes can be considered as a breakthrough in developing a new therapeutic antimicrobial agents related to bithiophene system.
https://ejchem.journals.ekb.eg/article_1229_fd95763e254c506b49f43a1d0da21a74.pdf
2010-06-30
385
401
10.21608/ejchem.2010.1229
Phenylthiourea
Bithiophen
Heterocycles
Antimicrobial agents
Structure elucidation and Thieno [2
3-d] pyrimidine
ORIGINAL_ARTICLE
Corrosion Inhibition of Copper and Its Alloys Using Benzotriazole
THIS paper investigates the effect of benzotriazole (BTAH) on the corrosion of copper and two of its alloys namely; Cu-10Ni and Cu-37Zn brass alloys in 3.5 % NaCl solution. Potentiodynamic polarization, potentiostatic polarization and electrochemical impedance spectroscopy (EIS) techniques were used in this investigation. Surface morphology was examined by using scanning electron microscopy (SEM). At lower concentration of BTAH (0.001 M) copper and brass showed slightly better behavior than CuNi while at high concentration (≥ 0.005 M) the Cu-10Ni alloy showed excellent inhibition efficiency compared to copper and brass. EIS showed that the polarization resistance, Rp, and hence the corrosion resistance is increased with the addition of BTAH. Results are supported by surface investigations.
https://ejchem.journals.ekb.eg/article_1231_f0e66574202ec178076ad42e975ab659.pdf
2010-06-30
403
415
10.21608/ejchem.2010.1231
copper
brass
Cu-Ni
Polarization
Corrosion
inhibition
Benzotriazole and SEM
ORIGINAL_ARTICLE
Synthesis and Structural Characterization of Lithiated and Delithiated LiCoO2 Using Different Chelating Agents
LAYERED LiCoO2 was synthesized by sol-gel method using ……succinic, malic and tartaric acid as chelating agent. The delithiated LixCoO2 oxide was obtained by chemically extracting lithium from the corresponding LiCoO2 with the oxidizer K2S2O8. X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electronic Microscope (TEM), Fourier Transform Infra-Red (FTIR), and Raman Scattering (RS) were used for characterization of the lithiated and delithiated phase. It shows that the samples obtained are layered LiCoO2 with the α-NaFeO2 structure. All the samples are homogenous and the particle size can be easily controlled by the preparation temperature. Upon lithium deintercalation from the host material, two different phases can be found.
https://ejchem.journals.ekb.eg/article_1232_60adb0612499f36eb1b9ab0f22418be9.pdf
2010-06-30
417
434
10.21608/ejchem.2010.1232
Transition-metal oxides
Layered structure
Spinel structure
Intercalation compounds. Cathode materials
Vibration spectroscopy and Li-ion batteries
ORIGINAL_ARTICLE
Synthesis and Conformational Analysis of Some Erythropoietin Mimetic Peptides Using Microwave Energy
THE CURRENT study describes the synthesis of Erythropoietin- ......which is a prohibited hormone by WADA-mimetic peptides [(AFIII54(chain I), (Ser)12AFIII54(chain II), AFIII54 with addition of Gly and Tyr in position 4 and 5, respectively (chain VI), AFIII54 devoid (Thr)9 and )Trp)10 (chain VII), (EMP3(chain III),(Ser)15EMP3 (chain IV), (Ala)15EMP3(chain V), EMP3 with addition of Gly and Tyr in position 7 and 8, respectively (chain VIII) and EMP3 devoid (Thr)12and (Trp)13(chain IX) ] by SPPS using microwave energy which accelerated reaction rate and improved the purities and yield.
Conformational analysis using FT-IR spectroscopy showed that most the synthesised peptides existed in α-helix structure
. Also, biological activity for one of these sequences was studied.
https://ejchem.journals.ekb.eg/article_1233_9dcca5414b805ddf0f6d33f58eca24ea.pdf
2010-06-30
435
448
10.21608/ejchem.2010.1233
erythropoietin
Mimetic peptides
Synthesis and Microwave conformational analysis
ORIGINAL_ARTICLE
Utilization of Synthetic Zeolite for Removal of Anionic Dyes
THE REMOVAL performance of highly colored soluble organic pollutpollutants in water has been investigated. Comparative adsorption studies of some anionic dyes on commercially zeolite X and zeolite X powder prepared from Egyptian kaolin have been studied. Brilliant blue FCF (BL), brilliant black PN (BB), eriochrome black T (EBT) and ponceau 3R (P3R) were introduced as models for organic pollutants of different structures. For comparison, the properties of the synthetic zeolite and commercial grade zeolite, such as crystallinity, thermal stability and cation exchange capacity using XRD, DSC and atomic absorption spectroscopy, respectively were conducted. UV/visible spectroscopic measurements have been used to determine the amount of adsorbed dyes by zeolites. The adsorption capacities for batch method were recorded. The influential parameters, such as initial pH value of the solution, temperature, adsorbate concentration and ion exchange on the adsorption process were studied. The suitability of Langmuir and Freundlich isotherms to the equilibrium data was investigated in the solid-liquid system. In all the adsorption experiments, the variation of adsorption capacities were recorded and explained in terms of both zeolite behaviour and dyes structures. Attempts to regenerate the adsorbents physically (at high temperature) were also made and the adsorptive properties of the recovered zeolite have been provided.
https://ejchem.journals.ekb.eg/article_1234_8282c491c312d3932f415db90c4ffc3d.pdf
2010-06-30
449
464
10.21608/ejchem.2010.1234
Adsorption
Anionic dyes
Zeolite and Egyptian kaolin
ORIGINAL_ARTICLE
Synthesis and Characterization of Carbon Nanotubes Using Amorphous Alloy Catalysts
ARC DISCHARGE method was utilized to synthesize carbon nanotubes ….. (CNTs). The arcing was carried out in air atmosphere in presence of amorphous alloy as catalyst. The current density was maintained constant during the experiment. The amorphous alloys used were CoFeB amorphous alloy and ZrCuNiAl amorphous alloy. Characterization of the samples produced indicates that the presence of CoFeB amorphous alloy much enhanced the yield of multiwall carbon nanotubes (MWNTs). In contrast, the use of ZrCuNiAl amorphous alloy exerted an opposite effect. The produced MWNTs were tested for hydrogen sorption at 20 bar.
https://ejchem.journals.ekb.eg/article_1242_3fc217b69dae77028f8a37808be22c95.pdf
2010-06-30
465
475
10.21608/ejchem.2010.1242
carbon nanotubes
Amorphous alloy
Hydrogen sorption