VOLUME 8, NO1, MAR 1986

ANALYSIS OF ENERGY TERMS AFFECTING THE GEOMETRY OF THE BEH2 AND WATER-MOLECULES - A CLASSICAL INTERPRETATION - OF THE FLOATING SPHERICAL GAUSSIAN ORBITAL MODEL OF MOLECULAR-STRUCTURES

The energy terms arising in the calculations of BeH2 and H20 mole­cules by the FSGO method are analysed as a function of the bond angle in order to gain insight into the reasons for the particular equilibrium con­figurations. The analysis is made in terms of symmetrically orthogonalized orbitals so as to exclude three and four-orbital electron repulsion terms.read more

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M AFZAL ,

PHOSPHORYLATED DERIVATIVES OF CYCLOHEXANEDIOLS AND SULFANILYL CHLORIDE

l,3,- and 1,4-Cyclohexanediols (I,IV) react with phosphorus oxychlo­ride to form the cyclic phosphorochloridate (II) and the tetrachloridate' (V). These were characterized by reaction with amines to give the ami dates (IlIa, b, IVa-d). (V) with diethylamine and aniline gave the amidic chlori­des (Vlla,b), which with hydrazine hydrate and methanol form the amidic acid (IX) and the methoxyamidate (VIII). Sulphanilic acid (IX) with .phos­phorus pentachloride - phosphorus oxychloride gave the trichloride (XII), characterized as the sulphanilamides (Xllla-d). The spectral characteristics of the various products are briefly discussed.read more

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R J CREMLYN ,L W U ,C BOGGIS ,

STUDIES OF THE SYNTHESIS OF 2-HYDROXY-6-METHYL-1 AND 2-ACETOXY-6-METHYL-1,4-OXATHIANE S-OXIDES AND RELATED-COMPOUNDS

The 4B.-and 4-oxides of (2B., 6) and (2, 6) -2-acetoxy-6-methyl-l, 4-oxathiane have been prepared by routes involving oxidation of the res­pective 1,4-oxathianes with periodate. In these compounds, an equatorial acetoxy group at C-2 leads to preponderant axial oxygenation by periodate, whereas an axial acetoxyl group at C-2 favours equatorial -oxygenation. Basic hydrolysis of (2B., 4, 6)-2-acetoxy-6-methyl-l,4-oxahiane -oxide provides a convenient route to (4, 6)-2-hydroxy-6-methyl-l,4-oxathiane ­oxide. The allyl ( and prop-l-enyl) and .e--nitrophenyl groups were shown to be unsuitable for the protection of HO-2 during the synthesis of 2-hydroxy­1,4-oxathiane derivatives.read more

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J W WEBBER ,M H QADIR ,

SYNTHESIS OF 1-DEOXY-D-GLUCITOL SULFIDE AND DISULFIDE

Bis(l-deoxy-Q-glucitol) l,l'-disulfide .!.Q and the corresponding l,l'-sulfide Q have been prepared. Nucleophilic displacement reaction of the l-tosylate ~ with potassium thioacetate afforded the l-S-acetate ~ which on deesterification gave the l-thiol-Q-glucitol ~. Oxidation of ~ followed by removal of the protecting groups gave the target compound lQ. The l,l'-sulfide Q has been obtained from ~ by condensation with the l-tosylate 6 followed by cleavage of the acetal groups.read more

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A U RAHMAN ,J R DANIEL ,R L WHISTLER ,

PREPARATION AND INFRARED SPECTRAL STUDIES OF BINUCLEAR MOLYBDENUM (VI) AND TUNGSTEN (VI) COMPLEXES OF NICOTINAMIDE

Binuclear Mo(VI) and W(VI) complexes of nicotinamide, [M204L(OH)4] (where M = Mo (vI) or W(VI) and L = nicotinamide) have been synthesized in acidic medium and characterized. The i.r. studies indicate that the coordi­nation occurs through the pyridine ring Nand N of the primary amide group. But since the complexes are binuclear, the ligand is possibly bridging in nature. Bridging also occurs through the M-O-M groups, and the complexes, have a binuclear octahedral structure.read more

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R SINGH ,A K SEXENA ,M N SRIVASTAVA ,

LIQUID-PHASE OXIDATION OF CUMENE OVER HETEROGENEOUS CATALYSTS

Liquid phase selective oxidations are normally catalysed homo­geneously. Significant interest has recently arisen in the use of solid cata­lysts for liquid-phase oxidations. Unlike similar studies[1-8] carried out on silver and gold, the present work is aimed at understanding the oxidation of copper and silver rather than the nature of adsorbed oxygen species. An inhibition technique was used to measure the radical initiation rate during liquid-phase cumene oxidation over copper and silver. The radical initiation rate was only slightly reduced by changing from an oxygen to an argon atmos

S M ISMAIL ,

DETERMINATION OF TRACE-METALS IN DRINKING WATERS BY A DIRECT NATURAL GAS-ACETYLENE MIXED FUEL ATOMIC-ABSORPTION METHOD

Using natural gas-acetylene mixed fuel system an atomic absorption spectrophotometric methoa is developed for the determination of trace metals in drinking waters. Optimum operating conditions are established in terms of fuel and air flow rates for the determination of sodium, potassium, zinc, nickel, cobalt, strontium and magnesium in drinking waters. Compared with the conventional acetylene-air method the proposed method provides an overall 25-40 percent increase in the absorption sensitivity with about 50 percent economy in acetylene consumpt ion. The concentra t ion data a re reported at 25 confidence level for replicate measurements, together with lower detection limit for each trace metal estimated.read more

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M JAFFAR ,M ASHRAF ,

SYNTHESIS AND REACTIONS OF PHTHALAZINE DERIVATIVES

O-aroylbenzoic acids (Ia and b) on treatment with hydrazine hydrate and hydrazine derivatives give the corresponding 2-substituted-4-aryl-l­(2H)-phthalazinones (2a-i). (2a) Reacts with POC13 to yield l-chlorophthala­zine (3) which reacts with hydrazine hydrate to give l-hydrazino-4-(2,5-di' methyl )-phenylphthalazine (4). Phthalazinone (2a) undergoes alkylation to give l-alkyl-4-arylphthalazine (5a and b) and also reacts with P2S5 to give the correspondi ng thi one (7). Phtha 1 azi nones (2a and b) undergo Manni ch reaction to give (8a and b). read more

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A A AFIFY ,M A SAYED ,A EL FARARGY ,G H TAMAM ,

EFFECT OF COATING WITH STARCH AND NORDIHYDROGUAIARETIC ACID ON THE STABILITY OF CAROTENOIDS OF DEHYDRATED CARROT

The effect of coating carrot with starch and nordihydroguaiaretic acid (NOGA) on the stabi·lity of dehydrated carrot was investigated. The effectiveness of these coatings was evaluated by following changes in caro­tenoid content of dehydrated carrot during 420 days of storage at 37°C. Starch coating reduced carotenoid breakdown considerably and increased the storage 1 i fe of dehydrated carrot to 123 days compared to 30 days for samples given a water treatment alone. The sotrage life was further enhanced to 237 and 420 days when coated with starch containing 0.03% and 0.3% NOGA respectively. However, high concentrations of NOG

R A EDWARDS ,A K BALOCH ,K A BUCKLE ,

REGIOSELECTIVE ELECTROPHILIC SUBSTITUTION ON 2,5-BIS(TRIMETHYLSILYL) 1-METHYLIMIDAZOLE AND 2,5-BIS(TRIMETHYLSILYL)THIAZOLE

2-as well as 3-positions of 2,5-bis(trimethylsilyl) I-methylimida­zole have been substituted selectively by reactions with aromatic aldehydes. The substitution reactions with 2,5-bis(trimethylsilyl)thiazole were not very selective.read more

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R AHMAD ,