VOLUME 7, NO4, DEC 1985

An Automatic Differential Potentiometric Estimation Technique

A new differential potentiometric technique bas~d on a simple, inexpensive RC filter circuit, capable of producing primary derivative signals, is presented for quantitative differential poten­tiometric work. The relevant experimental set-up to carry out automa­tic potentiometric titrations is designed and its performance is demonstrated for various weak/strong acid-base combinations. The technique has the potential of application to other areas of poten­tiometric estimation such as compleximetry and redox titrimetry. The overa 11 average accuracy of the method when app 1 i ed to a set of 16 acid-base combinations turns out to be about 1.5% with a precision of ± 1% in duplicate runs.read more

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M JAFFAR ,S N HUSAINI ,

SYNTHESIS AND REACTIONS OF SOME BETA-AROYL-ALPHA-(INDOL-3-YL)-PROPIONIC ACIDS

a -Aroyl- a. -(indol-3-yl)propionic acids 2 were prepared by the reaction of a -aroylacrylic acid 1 with indoles in dry benzene. Condensation of 2 with anisaldehyde afforded the a -arylidene derivatives 3. Dehydration of 2 yielded the butenolides 4 which underwent ring opening by reaction with amines to give 5. Reaction of 2 with hydrazine hydrate and phenylhydrazine afforded the corresponding dihydropyridazinones 6a-d and7a-d. Dihydropyrida­zinones 6 reacted with dimethyl sulfate. diethylsulfate. ethyl bromoacetate. POC13 and P2S5 and yielded the corresponding N-alkylated. Chloropyridazine and thione derivatives 8a-c. 13a. 13b, 17a and 17b. Reactions of pyridazi­nones 6 with anisaldehyde, Grignard reagents and bromine-acetic acid mixture are described. The behaviour of 3-chloropyridazine 13 towards hydrazine hydrate. sodi um azi de and anthranil i c aci d was i nvesti gated. Carboethoxy­methylation and the action of p-anisidine and Grignard reagents on the thione 17 were investigated.read more

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M HAMDY ,G H SAYED ,I A ELMAWGOUD ,M Y EL KADY ,

RADIATION-CHEMISTRY OF BROMATE ANION IN AQUEOUS-SOLUTIONS

Steady state radiolytic studies were carried out and G{-Br03-), G{Br02-), G{BrO-), G(02) and G{H2) were determined. The va~ues obtained are 4.46 .:!:. 0.08, 3.05 .:!:. 0.1, 0.51 .:!:. 0.08, 3.48 .:!:. 0.08 and 0.4 .:!:. 0.08 respec­tively. A mechanism for the radiolytic decomposition of bromate anions in solution is suggested.read more

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M S SUBHANI ,

Isolierung und Lymphozytenstimulation von Kalbsthymuspetiden

A gel chromatographically uniform extract of soluble peptides of thymus (thymus fraction A) of molecular weight about 10,000 is separated into further six subfractions with a HPLC system developed in our laboratory for preparation of peptides. Thymus fraction A induces a modjrate proliferation of human lymphocytes as assessed by the incorporation of H thymidine into the DNA yielding a maximal stimulation index of 15.4 at the 4th day at a concentration of 50 ug/ml. Except factor I which causes a slight but significant lymphocyte prolifera­tion,the factors II to VI do not show any stimulating activity. Therefore, besides the well known differentiation-inducing capacity, thymus fraction A has also a cell division-inducing activity.read more

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O LEHAR ,H BAUER ,W VOELTER ,D BARON ,

COMPARATIVE-STUDY OF ONION AND GARLIC ON SERUM-CHOLESTEROL, LIVER CHOLESTEROL, PROTHROMBIN TIME AND FECAL STEROLS EXCRETION IN MALE ALBINO-RATS

COMPARATIVE-STUDY OF ONION AND GARLIC ON SERUM-CHOLESTEROL, LIVER CHOLESTEROL, PROTHROMBIN TIME AND FECAL STEROLS EXCRETION IN MALE ALBINO-RATSread more

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R BAKSH ,M I D CHUGHTAI ,

POLAROGRAPHIC-REDUCTION OF NICKEL IN METHYLENE BIS THIOACETIC ACID-MEDIA

The reduction of nickel in presence of methylene bis thio acetic acid (referred to herein as MBTAA) has been studied polarographically in the pH range 1-7. The discharge of nickel at the d.m.e. has been found to be irreversible and diffusion controlled at constant ionic strength (1M KN03). Hence kinetics of the electrode reaction has been investigated and the values of k i net i cs parameters ( trans fer co-effi ci ent and formal rate constant kOf h) have been calculated at 25°, 30°, 35°, 40°, 45° and 50°C by Koutecky's theoretical treatment as extended by Meites and Israel. The values of thermodynamlc parameters - f" H,f" G and f"S for the system have also been evaluated at 30°C.read more

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R D PARIKH ,R S SAXENA ,

CHELATING BEHAVIOR OF SUBSTITUTED 3-ARYLHYDRAZOPENTANE-2,4-DIONE .7. STABILITY-CONSTANTS OF CHELATES OF DIVALENT TRANSITION-METALS WITH 2(4-METHYL), 3(4-METHYL), 4(4-METHYL) AND 2-SULFONIC-(4-METHYL) PHENYLHYDRAZO-PENTANE-2,4-DIONE

The dissociation constants for 2-, 3-, 4-and 2-sulphonic (4-methyl) phenyl hydrazo acetyl acetone 1igands, as well as the stabi1ity constants for chelates of these ligands with divalent metal ions Cu(ll), N;(II), Co(ll), Mn(I1) , Zn(Ilt} and Cd(I I) , have been calculated pH-metrically. The first dissociation constant for 503 H group was foudn to be strong. The difference between the values of both pKI and pK2 for the vari ous 1 i gands were found to be small. The stability constants for chelates containing 1:1 and 2:1 ratio have been calculated and compared with the stability constants of acetyl acetone itself. These differences may be attributed to the lower basicity of the sulfonated ligands and to the different nature of the ligands. The relation between 1/2 log B (overall stability constant) of the chelate compounds and both electronegativity (Xm) and second ionization potential (2nd 1p) was discussed.read more

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A A TAHA ,G EL INANY ,B EL SHETARY ,S A ALI ,

SYNTHESIS, CHARACTERIZATION AND PHARMACOLOGICAL PROPERTIES OF A COBALT (II) COMPLEX OF ANTIBIOTIC AMPICILLIN

A new complex [Co(amplicillin)2(OH2)2] C12.3H20 has been synthesised and characterized by elemental analysis, magnetic and spectral studies. The pharmacological assay show that the complex is 2-3 times more active than ampicillin itself, against bacteria such as Salmonela arizona, Proteus vulgaris, Staphylococcus pyogeneus and Klebsiella pneumonie while inactive against Enterobector agrogenus.read more

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C MUNIR ,N AHMAD ,S M YOUSAF ,

REACTIONS OF SOME UNSATURATED CARBOXYLIC-ACIDS WITH ORTHO-PHENYLENEDIAMINE IN ACID-MEDIUM .1.

Vinyl acetic acid and crotonic acid when separately condensed with orthophenyl enedi ami ne in the presence of 4N hydroch 1 ori c aci d gave 2, 3-pro­pene-2 benzimidazole 1 and 7-methyl, 2,3-benzo, 1:4-diazocyclo-heptene-5-one ~ respectively. These results indicate that the migration of double bond to adjacent carbon in the formation of 1 occurs after the formation of benzimida­zole ring.read more

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M HASAN ,M C G ALVAREZ ,F LATIF ,

SYNTHESIS OF 6-(P-HALO-BENZYL)-1,2,4-TRIAZINE-3,5(2H,4H) DITHIONES HAVING POTENTIAL ANTIMICROBIAL ACTIVITY

Starting from p-halo-benzaldehyde, five-step syntheses of 6-(p-halo­benzyl) 1,2,4 triazine-3,5 (2H,4H) dithiones VI(a-c) have been described according to scheme 1. The spectroscopic data and antimicrobial activity of these compounds have also been reported.read more

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R AHMAD ,S AJAZ ,