VOLUME 12, NO3, SEPT 1990

SOME REACTIONS OF 6-CHLORO-2-METHYL 4H-1-BENZOPYRAN-4-ONE .1.

4H-1-Benzopyran-4-ones (Chromones are proved to be of special importance in medicine as stimulants of the central nervous system, spasmolytics, coronary dilators, inhibitors for the growth of human cancer cells, reductants for blood pressure, diuretics, antiallergic, antibiotics and cardiovascular agents. In the course of the present work several new derivatives containing the chromone moiety were prepared. Some of their reactions were investigated in the hope of obtaining new compounds having biological activities. The reactivities of chromone nucleus towards cycloaddition reactions under Diels- Alder conditions, nucleophilic and electrophilic reagents, photocyclodehydrogenation and thiation have been investigated.read more

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H M F MADKOUR ,A S BABAQUI ,A A HAMED ,A G EL SHEKEIL ,M A I SALEM ,

PREPARATION AND GAS-CHROMATOGRAPHIC SEPARATION OF COPPER(II), NICKEL(II), PALLADIUM(II) AND VANADIUM(IV) OXIDE CHELATES OF DL-BIS AND MESO-BIS (PIVALOYLACETONE) STILBENEDIIMINE

The copper(II), nickel(II) and palladium(II) chelates of bis-(pivaloylacetone)mesostilbenediimine(meso-H2PA2S) and copper(II), nickel(II), palladium(II) and vanadium(IV) oxide chelates of bis-(pivaloylacetone) dl-stilbenediimine(dl- H2PA2S) were prepared and characterised using IR, (H-NMR)-H-1 and mass spectroscopic techniques. Spectrophotometric studies, TGA and DTA of metal complexes were also carried out. The complexes are sufficiently volatile and thermally stable and elute easily on GLC columns with linear calibration range within 125-3760 ng and detection limits within 2.8-19 ng of metal ion. Separations between copper, nickel, palladium and vanadium oxide chelates have been achieved, but some overlapping between copper and nickel complexes is obtained. A mixture of metal complexes of meso-and dl-isomers could also be resolved.read more

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A I SOOMRO ,M Y KHUHAWAR ,A G M VASANDANI ,

EFFECT OF LIGHT AND HUMIDITY ON THE DOSIMETRIC PROPERTIES OF LOCALLY MANUFACTURED CLEAR PMMA

Effect of environmental conditions such as humidity during irradiation, or during post irradiation storage and different light conditions on the response of locally manufactured 3 mm thick clear PMMA dosimeter were investigated. The dosimeter showed a uniform response at almost all humidity conditions (12-92%) during irradiation. The response during post irradiation storage at different humidities also showed a stable response at least for two weeks after irradiation at almost all humidity conditions (12-92%); however at longer storage time fading takes place.read more

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G AHMAD ,H M KHAN ,A SATTAR ,

PREPARATION OF SOME 1,3,4,5-TETRAHYDRO-2H-1,5-BENZODIAZEPINES AND STUDY OF THEIR PHYSICAL AND SPECTRAL PROPERTIES

Preparation of 4-methyl-(1), 3-methyl-(2), 2,2- dimethyl-(3) and unsubstituted -(4), 1,3,4,5-tetrahydro-2H-1:5- benzodiazepines has been accomplished by LiAIH4 reduction of corresponding 1,3,4,5-tetrahydro-2H-1:5-benzadiazepin-2-ones (5- 8). Physical properties, mass and H-1 n.m.r. spectral properties of 1 - 4 have been described, whereas those of 5 - 8 are being published elsewhere. Carbon-13 n.m.r. spectral properties of 1 - 8 are included in this paper. All these compounds will be subjected to dynamic H-1 n.m.r. spectral studies in order to obtain information regarding the effect of methyl- and carbonyl - substitution on the solution conformation of medicinally important 1,3,4,5-tetrahydro-2H 1:5-benzodiazepine ring.read more

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Z MAQBOOL ,F MALIK ,M HASSAN ,M C G ALVAREZ ,

ADSORPTION OF COPPER FROM COPPER-SULFATE SOLUTION ON CARBON-BLACK SPHERON-9

Adsorption studies of copper from copper sulphate solution by carbon block ''Spheron 9'' were made under varying conditions of time and solution concentration. The results showed that adsorption equilibrium was established within two hours in case of copper solutions of 10-mu-g/ml concentration. In case of copper solutions of higher concentrations, however, equilibrium was attained after longer duration of time, which was thought to be due to high repulsive forces between copper ions adsorbed in large amounts from concentrated salt solutions, compared to that from dilute solutions.read more

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M A KHAN ,Y I KHATTAK ,

SYNTHESIS OF SILICON DERIVATIVES OF 1,3-DIOXABUTYLBENZENE AND 3'-(1,3-DIOXABUTYL)PYRIDINE

Silicon containing compounds, 1,3-dioxabutylbenzene and 3'-(1,3-dioxabutyl) pyridine have been investigated for pseudorotation on pentacoordinated silicon atom. H-1 and Si-29-NMR at ambient and different temperatures were recorded and no evidence was found for intramolecular O Si coordinate bond in these compounds.read more

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I A ZIA ,M MAZHAR ,SAQIB ALI ,

NEW COMPLEXES OF RUTHENIUM(II) WITH THIOSEMICARBAZIDE AND BETA-DIKETONE LIGANDS

The reaction of thiosemicarbazide (NH2.NH.CS.NH2) with [Rh(CO)2Cl2]n in THF gives an air stable, off white solid Ru(CO)2Cl2.NH2.NH.CS.NH2. The ligand acts as bidendate and its has been suggested that it coordinates to the metal through N(1) and S atom. Also the salt [Ru(CO)2Cl2]n reacts with an excess of sodium acetylacetonate in THF and gives very stable red solid Ru(CO)2(acac)2xH2O. Similar product is obtained when [Ru(CO)2Cl2]n is treated with acetylacetone in presence of a base such as triethylamine. The complexes were characterised by IR, NMR and elemental analyses.read more

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A A AL NAHDI ,M ISHAQ ,A O BAGHLAF ,F A ALI ,

A THERMODYNAMIC STUDY OF SUPERMOLECULAR ORDER IN AQUEOUS-SOLUTIONS OF POLY (VINYL ALCOHOL)

From the temperature viscosity data the various thermodynamic parameters were determined. It was observed that the free energy of viscous flow increase with the increase of concentration, but the effect with rise in temperature is uncertain. However, the value of DELTA-G(v) of PVA in aqueous propyl alcohol were found to be high than water. It means that associations are high in water than aqueous Propyl alcohol solutions. The values of heat and entropy of activation of viscous flow increases with concentration but no generalization can be made due to its irregular pattern at various temperature. The values of heat and entropy of activation show that solution of the polymer in aqueous propyl alcohol have a high order, whereas in water have low, but in no case there is complete order.read more

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A RASHID ,A K BHETTANI ,N HAMAD ,M S KHAN ,

COMPARATIVE THERMAL-STABILITY OF HOMOPOLYSILOXANES AND COPOLYSILOXANES OF DIMETHYL DIPHENYL SILANES

The thermal degradation study of homopolysiloxane and copolysiloxanes of dimethyl/diphenyl silanes have been carried out. The analysis of the degradation products by mass spectrometry, and infra-red spectroscopy show the presence of oligomers and benzene. The mechanism of degradation is discussed and it has been found that one copolysiloxane containing 75% methyl and 25% phenyl is the most stable among the series studies.read more

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S ALI ,M MAZHAR ,A AHMED ,M ZULFIQAR ,A PIRACHA ,

CYCLOADDITION REACTION ON NAPHTHOPYRAN-2-ONE DERIVATIVES

4-Methyl-2H-naphtho[1,2-b]pyran-2-one (I), 2-oxo-2H-naphtho[1,2-b]pyran-4-acetic acid (II), 1-methyl-3H-naphtho[2,1-b]pyran-3-one (III) and 3-oxo-3H-naphtho [2,1-b]pyran-1-acetic acid (IV), have been synthesized. Compound (I) and (II) condensed with aromatic aldehydes to give 2-naphthalene acrylic acid (Va- d), and 4-styryl pyranones (VIa-e) derivatives. Va and/or Vd reacted with maleic anhydride under Diels-Alder condition to give 2- naphthalenyl cyclohex-4-ene 1,2,3-tricarboxylic acid derivatives (VIIIa & b), decarboxylation of VIIa gave 2-naphthalenyl cyclohex-2-ene-1-carboxylic acid derivative (VIII). The 4-styryl pyranones derivatives (VId & e) reacted with maleic anhydride to give benzo[d]naphtho[1,2-b]pyranone derivatives (Xa & b). Compound (Xa) condensed with hydrazines, amines and thiourea to give naphthalenyl-N-substituted cyclohexene carboxamide derivatives (XIa-d), while (Xa) reacted with Grignard reagents to give naphthalenyl cyclohexenyl aryl ketone derivatives (XIIa-c), also (Xa) reacted with benzene under Friedel-Crafts condition to give (XIIa).read more

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H M BAKEER ,S EL NAGDY ,A Y SOLIMAN ,A M YOUSSEF ,