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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
M AFZAL ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 1
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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
R J CREMLYN ,L W U ,C BOGGIS ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 11
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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
J W WEBBER ,M H QADIR ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 19
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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
A U RAHMAN ,J R DANIEL ,R L WHISTLER ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 31
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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
R SINGH ,A K SEXENA ,M N SRIVASTAVA ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 39
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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 ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 43
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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
M JAFFAR ,M ASHRAF ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 49
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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
A A AFIFY ,M A SAYED ,A EL FARARGY ,G H TAMAM ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 53
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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 ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 59
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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
R AHMAD ,
- 01 Aug 2011
- Volume Detail: VOLUME 8, NO1, MAR 1986
- Pages: 63
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