bluuebunny/crossref_metadata_2025 huggingface dataset:
Polarography and coulometry of Rh(III) in a pyridine – pyridinium chloride electrolyte
Authors: Johnston Leslie E. , Page John A.
Published: May 2006

The polarography and coulometry of Rh(III) has been studied in an aqueous pyridine–pyridinium chloride–sodium chloride electrolyte at pH 5.30 and ionic strength 0.30 M at 25.0 °C. Two distinct types of polarographic behavior were noted as the total Py concentration was varied between 0.05 and 0.45 M, a "normal" wave with E1/2 of −0.43 V vs. a standard calomel electrode, and a second catalytic wave which under some conditions masked the normal wave.For both types of behavior, controlled potential electrolysis gave a well-defined two electron reduction but there was a definite H+ consumption in the electrolyses. It is postulated that hydride species are involved in the reduction according to the scheme[Formula: see text]surface reaction at dropping mercury electrode[Formula: see text]slow, bulk solution in controlled potential electrolysis
Background scattering of a supersonic free jet: source temperature dependence
Authors: LeRoy Rodney L. , Govers Thomas R. , Deckers Jacques M.
Published: May 2006

The attenuation of nozzle beams by scattering on background gas in the expansion chamber is examined experimentally. It is found that, due to the velocity dependence of the collision cross section, this attenuation is significantly reduced as the source temperature is increased.
Optical rotatory dispersion studies of 2H-naphtho(1,8-bc)- and naphtho(2,3-b)furan derivatives
Authors: Joseph-Nathan P. , González Ma. P.
Published: May 2006

The study of the optical rotatory dispersion (o.r.d.) curves of some derivatives of the title systems, possessing various degrees of oxidation which contain asymmetrical centers near the chromophores, permits correlations between Cotton effects and stereochemistry. The configurations of those asymmetrical centers not known earlier, have been determined with the aid of the o.r.d. curves.
Nuclear magnetic resonance studies of hydrogen bonding in acetylenes containing oxygen functions
Authors: Bentz W. E. , Colebrook L. D.
Published: May 2006

Dilution shifts in carbon tetrachloride and cyclohexane solution have been obtained for the terminal acetylenic proton signals in the nuclear magnetic resonance (n.m.r.) spectra of some acetylenes. The presence of an oxygen atom results in a significant increase in the magnitude of the dilution shift, suggesting that oxygen is an important proton acceptor site in these compounds. Steric influences on the dilution shift and differences between the infinite dilution chemical shifts in the two solvents used, have been observed.
Anodic addition of hydroxy and benzoyloxy groups to stilbenes
Authors: Koyama Kikuhiko , Ebara Tatsuyoshi , Tani Tadahiko , Tsutsumi Shigeru
Published: May 2006

The anodic reaction of benzoic acid in acetonitrile has been carried out in the presence of trans- and cis-stilbenes using platinum electrodes. The reaction with added trans-stilbene gave meso-hydrobenzoin dibenzoate together with threo-2-benzoyloxy-1,2-diphenylethanol. Under similar conditions, cis-stilbene also gave these products. No evidence for the isomerization of cis-stilbene to the trans-isomer during the electrolysis was found. Stereoisomeric dl-hydrobenzoin dibenzoate and erythro-2-benzoyloxy-1,2-diphenylethanol were not obtained from either stilbene. For comparison, the "wet" Prévost reaction of cis-stilbene with silver acetate and iodine was studied. These results are discussed on the basis of a stepwise oxidation mechanism which involves a cyclic 1,2-benzoxonium ion intermediate.
Total synthesis of (±)ochotensine
Authors: Kelly R. B. , Beckett B. A.
Published: May 2006

A total synthesis of (±)ochotensine is described.
Kinetic study of the reduction of cobalt(II) by carbon monoxide in an aqueous system
Authors: Halvorson H. N. , Peters E.
Published: May 2006

A study of the catalyzed reduction of cobalt(II) to metal by carbon monoxide from aqueous, ammoniacal solutions between 180 and 230 °C and from 0 to 50 atm CO is reported.The reaction proceeds through the intermediate formation of a cobalt carbonyl anion. Under the conditions of this study this intermediate is produced homogeneously and also heterogeneously in the presence of cobalt sulfide. Metal formation occurs only in the presence of cobalt sulfide.The stoichiometry of the production of cobalt carbonyl anion is consistent with the equation[Formula: see text]Metal formation follows the stoichiometry of the equation[Formula: see text]A mechanism that is consistent with the kinetic observations is presented.
Molecular complexes: effects of multiple equilibria on calculated absorptivities and association constants
Authors: Thompson Jr. C. C.
Published: May 2006

Simulated absorbance data have been used to demonstrate the effects of 2:1 molecular complexes on formation constants and absorptivities calculated for 1:1 donor–acceptor interactions. By systematic variation of associated spectral, thermodynamic, and concentration parameters for these systems, it is found that previous attempts to describe effects produced by the presence of more than one stoichiometric complex species are inadequate. Formation constants and absorptivities calculated with the assumption of a simple 1:1 interaction may be increased or decreased by the occurrence of higher order complexes. These variations depend largely on the ratios of complex absorptivities, relative formation constants, and the range of donor concentrations. Equations incorporating 5 of the experimental variables permit the prediction of formation constants and absorptivities to a high degree of accuracy.
Activities from vapor pressure measurements of lithium and of sodium chlorates in water and water–dioxane solvents
Authors: Campbell A. N. , Oliver B. G.
Published: May 2006

The vapor pressures of solutions of sodium chlorate and of lithium chlorate in water and in solvents consisting of 44.5% dioxane–55.5% water and of 64.5% dioxane–35.5% water, at 25 °C, were determined using a differential manometer. The vapor compositions of the dioxane–water solutions were found by the air-saturation method.The mean molal activity coefficients were calculated from the vapor pressures and compositions. The activity coefficients of the solute were fitted to the theoretical equations of Stokes and Robinson and of Glueckauf, yielding hydration numbers for the cations of the salts.The minimum dioxanation numbers of sodium and of lithium chlorates in the dioxane–water mixtures were calculated from the experimental activity coefficients by the method of Grunwald. The results show that lithium chlorate is more highly solvated than sodium chlorate and that dioxane plays a major role in the solvation of both electrolytes in the dioxane–water mixtures.
Activity coefficients of aqueous thiocyanic acid solutions from electromotive force, transference number, and freezing-point depression measurements
Authors: Bartlett H. E. , Jurriaanse A. , Haas K. De
Published: May 2006

Accurate values of the activity coefficients of thiocyanic acid in aqueous solution have been obtained for concentrations of up to 0.1 molal at 25 °C by combining results for transference-number experiments with those for cells with transport. The transference-number experiments were done with the moving-boundary method, the transference-number at infinite dilution being calculated from measured conductivities of the thiocyanic acid. For the electromotive force (e.m.f.) measurements, conventional glass electrodes were used in conjunction with a high input-impedance electrometer.The results obtained electrochemically were checked by determining activity coefficients from freezing-point depression measurements which also extended the range of concentrations to 1 molal.The results of the two types of measurement are in good agreement.
Absolute rate constants for hydrocarbon autoxidation. XIII. Aldehydes: photo-oxidation, co-oxidation, and inhibition
Authors: Zaikov G. E. , Howard J. A. , Ingold K. U.
Published: May 2006

The oxidations of acetaldehyde, heptanal, octanal, cyclohexanecarboxaldehyde, pivaldehyde, and benzaldehyde in chlorobenzene at 0 °C have been studied. These aldehydes oxidize at similar rates under similar conditions because there are compensating changes in the rate constants for chain propagation (kp) and chain termination (2kt). The termination rate constants increase from ∼7 × 106 M−1 s−1 for pivaldehyde and cyclohexanecarboxaldehyde to ∼2 × 109 M−1 s−1 for benzaldehyde. The propagation rate constants increase from ∼1 × 103 M−1 s−1 for pivaldehyde to ∼1 × 104 M−1 s−1 for benzaldehyde.The rate of oxidation of the aldehydes was decreased by the addition of 1,4-cyclohexadiene, tetralin, tetralin hydroperoxide, cumene, cumene hydroperoxide, t-butyl hydroperoxide, and 2,6-di-t-butyl-4-methylphenol. As a result of product analysis and absolute rate constant measurements, it is concluded that the peroxy radicals derived from aldehydes are considerably more reactive in hydrogen atom abstraction from hydrocarbons than are the peroxy radicals derived from the hydrocarbons. In the abstraction from cyclohexadiene, the acylperoxy radicals appear to be from 15 to 70 times as reactive, and the benzoylperoxy radicals about 800–900 times as reactive, as the hydroperoxy radical. The differences in reactivity are very much less pronounced in the abstraction from 2,6-di-t-butyl-4-methylphenol.The great ease of oxidation of all aldehydes, and particularly benzaldehyde, is due at least in part to the high reactivity of the peroxy radicals formed in these reactions.
Solubility of some iodides in non-polar solvents
Authors: Suri S. K. , Ramakrishna V.
Published: May 2006

The solubilities of SnI4, AsI3, SbI3, and BiI3 in carbon tetrachloride, cyclohexane, benzene, and dioxane have been determined at different temperatures (30–55 °C). The entropy of solution of these iodides at 25 °C has been calculated from the data, and compared with the calculated entropy of fusion. The solubility parameters of these iodides have been computed and their spectral behavior in the solvents studied in the near ultraviolet region. On the basis of these data, the nature of the solutions of the iodides in the non-polar solvents has been compared.
Some reactions of 2,4-dimethoxytetrahydropyrans
Authors: Baldwin M. J. , Brown R. K.
Published: May 2006

Acid-catalyzed elimination of methanol from 2,4-dimethoxytetrahydropyran (1) produces 2-methoxy-5,6-dihydro-2H-pyran (3) rather than the expected olefin 4-methoxy-3,4-dihydro-2H-pyran (2).The reaction of 1,3-dibromo-5,5-dimethylhydantoin with 3 in ether – methanol gives a 2:1 mixture of the isomers 3β-bromo-2α,4α-dimethoxytetrahydropyran (5a) and 3α-bromo-2α,4β-dimethoxytetrahydropyran (5b) respectively. A rationale is given to explain the preponderance of 5a over 5b and the highly selective attack of the bromine of the hydantoin and the methanol on C-3 and C-4 respectively of the double bond of 3. Reduction of 5ab with zinc in ethanol provides only compound 3.The room temperature reaction of 1 in a mixture of water and 1,2-dimethoxyethane containing Amberlite IR-120, produces 2-hydroxy-4-methoxytetrahydropyran (6) as an equilibrium mixture of cis and trans isomers in the ratio 1:1. This gave a value of 0.9 kcal/mole for the anomeric effect in 6. Pyrolysis of the derivative, 2-acetoxy-4-methoxytetrahydropyran failed to produce the olefin 2 and resulted only in extensive decomposition.
Les acétates énoliques des tert-butyl-6α et 7α décalones-2 cis
Authors: Favre H. , Liston A. J.
Published: May 2006

not available
Azaindoles. Part II. The proton magnetic resonance spectra of 5-azaindoles
Authors: Riley P. G. , Robinson B.
Published: May 2006

The proton magnetic resonance (p.m.r.) spectra of 5-azaindole and 5-aza-1- and 3-methylindoles have been recorded and analyzed. It has been shown that in the spectrum of 5-azaindole, 3,7- coupling occurs but 1,3- coupling is not observed. In none of the spectra were any 2,6- or 4,6- couplings observed.
Sur la stéréochimie de la réduction des alkyl-2 cyclohexanones par les organomagnésiens
Authors: Chauvière Gérard , Welvart Zoltan , Eugène Denis , Richer Jean-Claude
Published: May 2006

not available
Etude des bandes fondamentale ν1 et première harmonique 2 ν1 des haloformes CHF3, CHCl3 et CHBr3 à l'état gazeux
Authors: Rossi Inga , Nguyen-Van-Thanh Mm. , Haeusler Claude
Published: May 2006

Some rotational and vibrational constants in the ν1(CH) and 2ν1(CH) bands of gaseous CHF3, CHCl3, and CHBr3 have been determined. Intensity measurements of these bands are obtained and perturbations in some bands of haloforms are pointed out.
The formation of alkanes in the pyrolysis of n-hexadecane: effect of an inert gas on the decomposition of alkyl radicals
Authors: Doue François , Guiochon Georges
Published: May 2006

The rate of formation of alkanes in the pyrolysis of n-hexadecane is shown to be drastically reduced in the presence of an inert gas.The experimental results are in good quantitative agreement with the predictions of a theoretical model, which assumes that the decomposition of alkyl radicals is not monomolecular, because the Maxwell–Boltzmann activation process would be perturbed by a bimolecular reaction having a lower activation energy.
Nuclear magnetic resonance studies. XVIII.The proton parameters of some bicyclo[2•2•2]octane derivatives
Authors: Gurudata Gurudata , Stothers J. B.
Published: May 2006

The high resolution proton spectra of ten substituted bicyclo[2•2•2]octenes and octanes have been analyzed. The proton shieldings and coupling constants are discussed with particular emphasis on the stereochemical dependence of these parameters. Evidence bearing on the anisotropic effect of carbonyl bonds is presented to substantiate other recent findings on these shielding effects. Certain long-range couplings permit stereochemical assignments.
The structure of ochrobirine
Authors: Manske R. H. F. , Rodrigo R. G. A. , MacLean D. B. , Gracey D. E. F. , Saunders J. K.
Published: May 2006

Structure 1 is proposed for ochrobirine from an analysis of the proton magnetic resonance spectra of ochrobirine and its di-O-acetate.
Ring openings of γ- and δ-lactones to form γ- and δ-hydroxyamides. Cyclodehydration. Mass spectra of δ-hydroxyamides
Authors: Levi Earl M. , Mao Chung-Ling , Hauser Charles R.
Published: May 2006

Ring openings of γ- and δ-lactones were effected with potassium amide or hydrazine to form γ- and δ-hydroxyamides, which were cyclodehydrated with sulfuric acid to give γ- and δ-lactams, respectively. These products are, respectively, phthalimidines and 3,4-dihydroisocarbostyrils having no substituent on nitrogen or having the N—NH2 group. The possible linear dehydration of the δ-hydroxyamides was not observed. The δ-hydroxyamides exhibited, on mass spectrometry, a type of carbon–carbon cleavage that has apparently not been reported for ordinary alcohols. An example of the "ortho effect" in mass spectra of o-disubstituted benzene derivatives is also discussed.
Hydrogen transfer reactions. I. Reduction of carbonyl compounds by alcohols catalyzed by alumina
Authors: Ramana D. V. , Pillai C. N.
Published: May 2006

Alumina containing about 2.2% by weight of Na+ has been found to be an effective catalyst for the vapor phase reduction of carbonyl compounds by alcohols and for the reverse reaction, the oxidation of the alcohols by carbonyl compounds. The reduction of a number of aliphatic and aromatic aldehydes and ketones by isopropyl alcohol and the oxidation of a number of primary and secondary alcohols by ketones like acetone and cyclohexanone are reported.
Oxidations involving silver. V. The oxidation of primary aliphatic amines
Authors: Hampson N. A. , Lee J. B. , Morley J. R. , Scanlon B.
Published: May 2006

Primary aliphatic amines are rapidly oxidized using a silver electrode at potentials more positive than 0.6 V normal hydrogen electrode (n.h.e.) in aqueous alkali. Primary aliphatic amines with a mono-substituted α-carbon atom give the corresponding nitrile and aldehyde, α,α-disubstituted ones give the corresponding ketone, and α,α,α-trisubstituted ones give the corresponding alcohol, nitro-compound, and unsaturated hydrocarbons. Some evidence for the reaction pathway is presented. The effect of amine on the kinetic parameters for Ag2O formation is reported.
Preparation of ferrimagnetic barium- and strontium-iron oxides, BaFe12O19 and SrFe12O19
Authors: Routil R. J. , Barham D.
Published: May 2006

Ferrimagnetic BaFe12O19 and SrFe12O19 were prepared from BaSO4 and from SrSO4 by heating the sulfates in mixtures with Fe2O3 and Na2CO3 to 900–1400 °C. The highest yields were obtained from mixtures containing 6 moles of Fe2O3 and 1 mole of Na2CO3 per mole of sulfate. Similar results were observed when Na2CO3 was substituted with compounds yielding oxides of sodium, potassium, or calcium but not with analogous lithium compounds.
Quantitative investigation of the ozonolysis reaction. IX. On the mechanism of ozonide formation
Authors: Fliszár Sándor , Carles Jacques
Published: May 2006

The ozonide cis–trans ratios, for both normal and cross-ozonides, have been examined, in a number of cases, in pentane and in benzene solutions. In benzene, at 25 °C, almost invariant cis–trans ratios are observed, regardless of the geometry and initial concentration of olefin. In pentane, these ratios have been found to depend, both at −78 and 25 °C, on the geometry and the initial concentration of the olefin when 1,2-disubstituted ethylenes with bulky substituents are ozonized. However, the cross-ozonide cis–trans ratios obtained from trisubstituted ethylenes do not depend on the initial olefin concentration. A tentative mechanistic proposal is suggested in terms of transitory zwitterion–olefin adducts.
Kinetics of sulfonation of 4-hydroxyazobenzene
Authors: Strachan W. M. J. , Buncel E.
Published: May 2006

Spectral changes exhibited by 4-hydroxyazobenzene in the 90–100% H2SO4 region are shown to be the result of a sulfonation process, superimposed (above 98% H2SO4) on a second equilibrium protonation. The reaction product is 4-hydroxyazobenzene-4′-sulfonic acid. The rate of this sulfonation reaction increases by a factor of 500 over 91.7–100.0% H2SO4. The increase in rate is more gradual in acid media in which diprotonation of reactant is effective.In 100% H2SO4 and above, a second, much slower, rate process is discerned from the spectral changes in this system and is probably the result of a further sulfonation of 4-hydroxyazobenzene-4′-sulfonic acid. Kinetic data for this reaction are reported for 99.99–100.76% H2SO4.The results are in agreement with previous qualitative reports on the formation of sulfonation products from 4-hydroxyazobenzene or from azoxybenzene, its precursor in the Wallach rearrangement. The mechanism of the consecutive sulfonation reactions is discussed.
Selenium tetrafluoride adducts. I. Trifluoroselenium fluorosulfate
Authors: Gillespie R. J. , Whitla W. A.
Published: May 2006

The structure of the adduct between selenium tetrafluoride and sulfur trioxide in the solid state, in the molten state, and in solution has been investigated using infrared, Raman, nuclear magnetic resonance spectroscopy, conductivity measurements in fluorosulfuric acid and nitrobenzene, and cryoscopic measurements in nitrobenzene. The data can be best interpreted in terms of a polymeric bridged fluorosulfate structure for the solid and the melt, which is broken down in solution to form mainly a dimeric species.
Effect of temperature on the spectrum of sulfur dioxide
Authors: Brown J. , Burns George
Published: May 2006

The effect of temperature on the ultraviolet spectrum of sulfur dioxide has been studied over the temperature range 20 to 1000 °C. The equilibrium constant for the reaction[Formula: see text]where (SO2) is an isomeric form or an excited state of sulfur dioxide, has been obtained at several temperatures. The enthalpy change for the transition was found to be 4.1 ± 0.4 kcal mole−1.
ortho-Diquaternary aromatic compounds. II. Synthesis and spectral properties of β,β′-dihydroxy-2,3-di-t-butylnaphthalene and related crowded aromatics
Authors: Barclay L. R. C. , Nixon G. R. , Foote H. M. , Barclay S. L.
Published: May 2006

Cyclialkylation of naphthalene with 2,2,5,5-tetramethyltetrahydrofuranone yielded 2-keto-1,1,4,4-tetramethyl-1,2,3,4-tetrahydroanthracene (1). Selenium dioxide oxidation of 1 yielded the corresponding diketone (3) and periodate cleavage of 3 yielded 2,3-naphthalene-diisobutyric acid (4). Hydride reduction of the dimethyl ester (6) of 4 yielded the diol, β,β′-dihydroxy-2,3-di-t-butylnaphthalene (7). The relative chemical shifts of aromatic protons of 1,2,4,5-tetraalkylbenzenes containing gem dimethyls are rationalized in terms of compression effects exerted by the bulky ortho groups. Nuclear magnetic resonance and ultraviolet spectral results for the ortho di-t-butyl aromatic derivatives 4, 6, and 7 are compared to the model cyclic compounds 1 and anhydride (5) of 4 in terms of the strain caused by bond angle deformations in the side chains.
Reaction of methyl azidoformate with norbornene
Authors: Oehlschlager A. C. , McDaniel R. S. , Thakore A. , Tillman P. , Zalkow L. H.
Published: May 2006

The thermal reaction of methyl azidoformate and norbornene has been found to proceed via 1,3-dipolar-cycloaddition yielding exo triazoline adduct, 15a. Thermal decomposition of the triazoline results in the loss of nitrogen and the formation of at least 5 products. The major products of the thermal decomposition in decalin were 3-carbomethoxy-3-azatricyclo(3.2.1.02,4 exo)octane, 18a, and N-carbomethoxy-2-norbornimine, 20. In addition, syn-2-norbornene-7-methyl carbamate, 21, and 3-carbomethoxy-3-azatricyclo(3.2.1.02,3 endo)octane, 19a, were isolated. The thermal decomposition of the triazoline adduct is considered to proceed by a multi-step mechanism. The first step is considered to involve heterolytic cleavage of the N3—N4 bond togive a zwitterion which may lead to products or rearrange via carbon–carbon bond cleavage to give a diazoalkyl imine.
Preparation and properties of the hydroxyindole-3-carboxylic acids
Authors: Marchelli Rosangela , Hutzinger O. , Heacock R. A.
Published: May 2006

A procedure for the synthesis of the 4-, 5-, 6-, and 7-hydroxyindole-3-carboxylic acids starting from the corresponding 4-, 5-, 6-, and 7-benzyloxyindoles respectively has been devised. The benzyloxyindoles are converted to mixtures of their 1- and 3-carbethoxy derivatives by the action of ethyl chloroformate on their Grignard reagents. The hydroxyindole-3-carboxylic acids are then obtained by the alkaline hydrolysis and debenzylation of the benzyloxy-3-carbethoxyindoles.
Photochemistry of imines: concerning the formation of dihydrophotodimers from N-diphenylmethylenebenzylamine
Authors: Fraser-Reid Bert , McLean Angus , Usherwood E. W.
Published: May 2006

When alcohol solutions of N-diphenylmethylenebenzylamine (1d) are irradiated in the presence of benzophenone with light of intensity ∼200 W there is predominant formation of the unsymmetrical dihydrophotodimer (4) and no symmetrical dimers are detected. The dihydromonomer (2d) is also produced. However, when a more intense light source (450 W) is used nodimerofanysort is formed although the dihydromonomer is still produced. The formation of the unsymmetrical dihydrodimer (4) cannot be attributed entirely to secondary reactions of the dihydromonomer (2d) since irradiation of the latter produces both symmetrical (7) and unsymmetrical (4) dihydrodimers in the ratio 1:2.
Radiolysls In the adsorbed state. III. Methyl iodide adsorbed on silica gel
Authors: Sagert N. H. , Reid J. A. , Robinson R. W.
Published: May 2006

The 60Co γ-radiolysis of methyl iodide adsorbed on silica gel has been studied by examining the hydrocarbon products, which are mainly methane and ethane. These products are formed in large yields, indicating that a large fraction of the energy absorbed in the silica gel is able to cause decomposition of the methyl iodide. The “energy transfer” is thought to occur by electron or excitation transfer to the methyl iodide, leading to the production of methyl radicals.Evidence has been obtained that the silica gel takes part in the system as a chemical reactant as well as being an energy transfer medium, and that changing the nature of the surface changes the course of the reaction. This is most clearly shown in two ways. The ratio of methane to ethane decreases as the surface hydroxyl concentration decreases, and it is concluded that excited methyl radicals form methane by abstraction of hydrogen from surface hydroxyls. Experiments using methyl iodide-d3 adsorbed on protiated silica gel confirm the participation of hydrogen from the silica gel, as the methane is over 85% CD3H, while the ethane is over 95% C2D6.The effect of additives such as N2O and SF6, which are known to be electron scavengers, was also studied. It was shown that methyl iodide is a much better electron scavenger than N2O and is as good an electron scavenger as SF6 in this system.
Preparation and characterization of some methyl cyanide complexes of Cu(I), Cu(II), and Zn(II) fluorosulfates
Authors: Milne J. B.
Published: May 2006

Tetrakis(methyl cyanide) complexes of Cu(I), Cu(II), and Zn(II) fluorosulfates have been prepared by reactions of anhydrous Cu(II) and Zn(II) fluorosulfates in methyl cyanide. The infrared spectra indicate a strong interaction between the fluorosulfate anion and the complex Cu(II) and Zn(II) cations. Conductivity measurements in methyl cyanide show strong association between the fluorosulfate anion and the dipositive cations. The Cu(I) compound is completely dissociated in methyl cyanide and, according to the infrared spectrum, shows no strong interaction with fluorosulfate anion.
Reductive C-alkylation. II
Authors: Roomi M. W. , MacDonald S. F.
Published: May 2006

Methylpyrrole carboxylic esters generally are reductively methylated at 25–45°. Some are also reductively alkylated by aliphatic aldehydes generally to give, for example, 2,3(or 2,4)-dimethyl-4(or 3)-alkyl-5-carbethoxypyrroles, using hydriodic acid or HCl/AcOH–Zn/Hg respectively. An analogous alkylation by glyoxylic acid gave 5-carbethoxyhemopyrrole-dicarboxylic ester. Using HI, paraldehyde at 100° gave diethyl derivatives of dimethylpyrroles, and aminoacetal at 35° converted 2,4-dimethyl-3-acetylpyrrole into its 5-(2-amino-ethyl)-derivative. Reductive alkylations have been most useful with pyrroles but HI converted 2-biphenylcarbaldehyde into fluorene.
Photoreaction of nitroso compounds in solution. XI. Secondary reactions in the photoaddition of N-nitrosopiperidine to olefins
Authors: Chow Y. L. , Chen S. C. , Chang D. W. L.
Published: May 2006

Irradiation of N-nitrosopiperidine and 3,3-dimethyl-1-butene in a Pyrex apparatus gave 3,3-dimethyl-1-piperidino-2-(N-nitrosohydroxylamino)butane as the major product, in contrast to similar additions to 1-hexene and other olefins. Depending on the conditions, minor amounts of 3,3-dimethyl-1-piperidino-2-(N-hydroxylformamido)butane and 3,3-dimethyl-1-piperidino-2-butanone oxime were also isolated. It was proposed that the butane derivatives were formed by the reactions of the C-nitroso monomer with HNO and formaldehyde respectively which were photolytically generated from N-nitrosopiperidine and methanol. In agreement with this proposal, irradiation of a mixture of trans-dimer of 1-piperidino-2-nitrosohexane and N-nitrosopiperidine gave 1-piperidino-2-(N-nitrosohydroxylamino)hexane. By adjusting the irradiation conditions, this nitrosohydroxylamine could be obtained as the major product from addition of the nitrosamine to 1-hexene.
Chelating polymers. I. The synthesis and acid dissociation behavior of several N-(p-vinylbenzenesulfonyl)-substituted diaminopolyacetic acid monomers, monomeric analogues, and related intermediates
Authors: Genik-Sas-Berezowsky R. M. , Spinner I. H.
Published: May 2006

Two new chelating monomers, N-(p-vinylbenzenesulfonyl)1,2-diaminoethane-N′,N′-diacetic (SS-EDDA) and -N,N′,N′-triacetic (SS-ED3A) acids, as well as several monomeric analogues and related intermediates have been prepared. In addition, 2-oxo-1-piperazine acetic (S-KP), 3-oxo-1-piperazine acetic (U-KP), and 2-oxo-1,4-piperazine diacetic (3-KP) acids have been synthesized and the interconvertibility between these cyclic amides and their unsubstituted linear amino acid analogues, ethylene-diamine-N,N′-diacetic (S-EDDA), -N,N-diacetic (U-EDDA), and -N,N,N′-triacetic (ED3A) acids respectively, was demonstrated.The acid dissociation constants of the various amino acids were determined potentiometrically at 25° and μ = 0.1 M(KNO3) and the results were compared with the hydrogen ion affinities of related compounds. Dissociation schemes were proposed for all the compounds based on these results. Rationalizations of the linear amino acid and the cyclic amide dissociation constants were made in terms of the effects of cyclization and the inductive effects of neighboring groups. These rationalizations were found to be helpful in clarifying the dissociation schemes previously proposed for several of the linear amino acids.
Self-association of alcohols and phenols in nonpolar solvents
Authors: Murty T. S. S. R.
Published: May 2006

A number of alcohols (primary, secondary, and tertiary) and phenols, covering a pKa range from 9.4 to 19.0, gave on association a peak about 125 ± 5 cm−1 lower than the monomeric hydroxyl peak in the fundamental stretching region. Taken together with the extensive literature available on the association of alcohols and phenols in nonpolar solvents, this seems to indicate the presence of dimers.
The proton relaxation and Overhauser effect in the nuclear magnetic resonance spectra of some amides
Authors: Brownstein S. , Bystrov V.
Published: May 2006

The relaxation behavior of some amides was investigated in their high resolution spectra by the direct saturation–recovery and Overhauser effect methods. The recovery curves and steady-state Overhauser effects were obtained for solutions of dimethylformamide with double- and triple-resonance irradiations. The results were analyzed for 3- and 4-spin systems and the values of relaxation parameters were calculated. It was shown that for dimethylformamide the one-exponential recovery curve approximation gives the T1 values with a precision better than experimental error (±2%). The observed difference in relaxation times for methyl group protons was explained by different correlation times and more restricted rotation of 1 of the groups. The correlation times for dipole–dipole interactions of methyl groups with the formyl proton were also evaluated with some reasonable assumptions.The change of the relaxation rate of N-methyl protons in C6H6 and C6D6 solutions was explained by formation of the collision complex with amide molecules and specific intermolecular dipole–dipole proton interaction. This effect could be useful for determination of the cis- and trans-conformations in N-methyl substituted amides and peptides as an absolute method because it does not require measurements on both isomers.
Crystal and molecular structure of the m-bromobenzoate derivative of bisnorquassin
Authors: Lynton H.
Published: May 2006

The molecular structure of the m-bromobenzoate derivative of bisnorquassin, C27H27O7Br, has been determined by the heavy atom method. The compound crystallizes in the orthorhombic system, space group P212121, with unit cell dimensions a = 20.09 ± 0.02 Å, b = 14.63 ± 0.02 Å, c = 8.06 + 0.01 Å and 4 molecules in the unit cell. Final atomic parameters have been obtained from a blockdiagonal least-squares refinement using anisotropic temperature parameters. The final agreement residual for 1665 observed reflections is R = 0.107.The structure of bisnorquassin previously proposed by Findlay and Cropp, on the basis of spectroscopic and chemical evidence, is shown to be essentially correct.
Kinetics of the pyrolysis of propylene. Part I
Authors: Simon M. , Back M. H.
Published: May 2006

The kinetics of the pyrolysis of propylene have been studied over the temperature range 743–873 °K and the pressure range 200–600 Torr. At the lower temperatures initial rates of formation of methane, propane, and C6 products were measured and shown to be formed by a radical process of very short chain length. The orders and activation energies of the rates were consistent with the occurrence of the bimolecular initiation step[Formula: see text]Measurement of the pressure change showed that products of molecular weight higher than C7 and not measured by the analysis were formed in the initial stages of the reaction at the lower temperatures. As these higher molecular weight compounds, which are more unstable than propylene, accumulated in the system their dissociation increased the concentration of radicals and caused a sharp increase in the rates of formation of the lower molecular weight stable products.
The crystal and molecular structure of NaBF3OH
Authors: Clark M. J. R. , Lynton H.
Published: May 2006

The crystal and molecular structure of sodium hydroxytrifluoborate, NaBF3OH, has been established by X-ray analysis. This compound crystallizes in the hexagonal system, space group P63 with cell parameters a = 8.084 Å and c = 7.958 Å. There are 6 molecules in the unit cell. Atomic parameters have been obtained from a block-diagonal least-squares refinement using anisotropic temperature parameters for boron and fluorine, and isotropic temperature parameters for sodium. The final agreement residual for 195 observed reflections is R = 0.090.The [BF3OH]− anions are distorted tetrahedra. It was not possible to distinguish between the positions of the fluorine atoms and the isoelectronic hydroxyl group.
Lignin and related compounds. II. Studies using ruthenium and Raney nickel as catalysts for lignin hydrogenolysis
Authors: Pepper J. M. , Lee Y. W.
Published: May 2006

Five cyclohexyl compounds, derived from lignin, have been isolated and identified from the products of the catalytic hydrogenolysis of spruce wood over ruthenium and Raney nickel catalysts. One of these, 3-(4-hydroxy-3-methoxycyclohexyl)-1-propanol, a previously unreported compound, has been synthesized and characterized.
Photoreaction of nitroso compounds in solution. XIII. Photo-oxidation of alkyl nitrites
Authors: Chow Y. L. , Hayasaka T. , Tam J. N. S.
Published: May 2006

Photolysis of 1-pentyl and menthyl nitrites in the presence of oxygen were shown to give mainly the oxidized rearrangement products 4-nitratopentyl and 10-nitratomenthyl derivatives in disagreement with the published report (2). Under the photo-oxidation conditions, menthyl nitrite also gave 10-nitrosomenthyl derivatives which were also shown to be photo-oxidized to 10-nitratomenthyl derivatives. The photo-oxidation products were conveniently reduced to the corresponding diols and were, in turn, identified as bisbenzoate.
Halogenation with N-haloamines in strong acids. I. The nature of the chain propagating radical
Authors: Spanswick J. , Ingold K. U.
Published: May 2006

The N-haloamine halogenation of 1-chlorobutane in 4 M sulfuric acid in acetic acid as solvent is a radical chain process in which aminium radicals are the principal hydrogen atom abstracting species. With N-chloroamines, a concurrent chlorine atom chain is promoted by impurities such as molecular chlorine, hydrogen chloride, and chloride ion.
Condensation of some substituted phenols and anilines with formaldehyde. Formation of 2-phenyl-1,3-benzoxazines and N-(2-hydroxybenzyl)-anilines
Authors: Horswill E. C. , Lindsay D. A. , Ingold K. U.
Published: May 2006

The formalin condensation of 2,4-di-t-butylphenol and 2,4-di-t-butylaniline yields the benzoxazine 2 which, on hydrolysis, gives the hydroxybenzylaniline 3a. In contrast to a report by Kuliev etal. (2, 3) the condensation of equimolar quantities of 4-t-butylphenol, o-toluidine, and formaldehyde yields N-(2-hydroxy-5-t-butylbenzyl)-o-toluidine (4), rather than 2-amino-3-methyl-2′-hydroxy-5′-t-butyldiphenylmethane (5).
Perhaloketones. XX. A monoenophilic perchlorinated cage ketone
Authors: Gilbert Everett E.
Published: May 2006

Ketone 4 reacted thermally with a series of terminal alkenes, forming unsaturated alcohols of type-1. The failure of 4 to react with internal or cyclic alkenes, with some alkenes at multiple ratios, or to more than a limited extent with the pendant vinyl groups of polybutadiene, suggests a high degree of steric inhibition in this reaction compared with hexafluoroacetone. Several allyl ethers formed tetrahydrofuran derivatives (type-2). 4-Allylanisole uniquely formed a type-1 product thermally convertible to type-2. Type-2 derivatives could also be obtained from sym-tetrafluorodichloroacetone, but not from diethyl oxomalonate.
Reductions with sulfurated borohydrides. IV. Reduction of oximes
Authors: Lalancette J. M. , Brindle J. R.
Published: May 2006

Sulfurated sodium borohydride can reduce oximes to the corresponding amine with yields depending on the steric requirement of the oxime. Intermediate hydroxylamine can be obtained predominantly under appropriate experimental conditions. A reaction mechanism taking into account the availability of only one hydrogen for reduction on the hydride and the production of intermediate hydroxylamine is proposed.
An analytical solution of the Gibbs–Dehem equation in multicomponent systems
Authors: Pelton A. D.
Published: May 2006

A general analytical power-series solution of the Gibbs–Duhem equation in multicomponent systems of any number of components has been developed. The simplicity and usefulness of the solution is made possible through the choice of a special set of composition variables.
Synthesis of DL-chalcose from acrolein dimer
Authors: Srivastava R. M. , Brown R. K.
Published: May 2006

1,6:2,3-Dianhydro-4-deoxy-β-DL-ribo-hexopyranose (1), a product obtained from acrolein dimer (3,4-dihydro-2H-pyran-2-carboxaldehyde), has been converted to 1,6-anhydro-4-deoxy-3-O-methyl-β-DL-xylo-hexopyranose (2) by reaction with acidic methanol or sodium methoxide in methanol. The structure and conformation of 2 have been confirmed by nuclear magnetic resonance spectroscopy. The reaction of 2 with methanol in the presence of Amberlite IR-120 (H+) gave a 2:1 mixture of the α and β isomers of methyl 4-deoxy-3-O-methyl-DL-xylo-hexopyranoside (3) from which the individual α and β isomers of the di-p-nitrobenzoates could be obtained as crystalline solids. Conversion of 3 to the corresponding di-O-p-toluenesulfonates 4, followed by selective reduction of these diesters with LiAlH4 gave a mixture of the α and β isomers of methyl 4,6-dideoxy-3-O-methyl-2-O-p-toluenesulfonyl-DL-xylo-hexopyranoside (5). Reaction of 5 with sodium methoxide in methanol gave a 2:1 mixture of the α and β isomers of methyl 4,6-dideoxy-3-O-methyl-DL-xylo-hexopyranoside (6) (methyl DL-chalcoside) from which only the α isomer could be separated in pure form by column chromatography or gas–liquid chromatography. The α isomer, 6-α, upon acid-catalyzed hydrolysis in aqueous dioxane, gave a mixture of the α and β isomers of 4,6-dideoxy-3-O-methyl-DL-xylo-hexopy-ranose (DL-chalcose) which gave the same nuclear magnetic resonance spectrum in D2O as did authentic D-chalcose. Yields are good to excellent in the various steps from 1 on.
Friedel–Crafts alkylation of benzene with 1,1-d2-1-chloropropane
Authors: Lee C. C. , Woodcock D. J.
Published: May 2006

The AlCl3 catalyzed reaction of 1,1-d2-1-chloropropane with benzene was carried out in excess benzene at about 5° or in 1,2,4-trichlorobenzene as solvent at 0°. The products, n-propylbenzene and isopropylbenzene, were examined by nuclear magnetic resonance and mass spectrometry. The results indicated only very minor amounts of isotope position scrambling in the propyl side chain, suggesting no major involvement of protonated cyclopropane intermediates in the reaction. The mass spectral data, however, demonstrated that the products are quite labile in the reaction medium, with extensive intermolecular hydride and deuteride transfers taking place.
Properties relating to critical phenomena in the acetic anhydride – acetone – carbon disulfide system
Authors: Campbell A. N. , Kartzmark E. M.
Published: May 2006

The following physical properties of the acetic anhydride – acetone – carbon disulfide system have been investigated: congruent compositions, excess volumes, dielectric constants. For the system acetone – carbon disulfide, the excess volumes and the molar polarizations are much greater than those required by the mixture rule. From this we deduced that this system is very non-ideal and might, at a suitable temperature, form two layers; two liquid layers did indeed form at −73 °C, the upper critical solution temperature occurring somewhere between this temperature and 0 °C. We offer it as a general rule that, if the deviation from additivity of molar polarization is large and positive, two layers will form at a sufficiently low temperature, provided that solid phases do not intervene. This deduction becomes almost a certainty if large positive deviations from additivity of molar volume and large positive heats of mixing are also present.
Long-range spin–spin coupling in N-methyl 2-carbomethoxy-4,6-dinitroaniline
Authors: McCubbin J. A. , Moir R. Y. , Neville G. A.
Published: May 2006

Long-range coupling [Formula: see text] between the amino proton and the C-5 ring proton of N-methyl 2-carbomethoxy-4,6-dinitroaniline (1) was established unequivocally by comparison of the proton magnetic resonance spectra of the 3-d and 5-d analogs of 1 together with the N-deutero derivatives of the above compounds. Deuterium decoupling experiments indicated that meta-deuterium coupling was of the order of band resolution (< 0.2 Hz). Elucidation of the source of long-range coupling with the amino proton enabled the chemical shifts of the aromatic protons to be assigned. The relative magnitude of these chemical shifts is discussed in terms of the shielding effects operative in the predominant conformer in which the amino hydrogen is intramolecularly hydrogen bonded to the oxygen of the ester carbonyl group.
Diels–Alder reaction between cyclopentadiene and 3-O-acetyl-5,6-dideoxy-1,2-O-isopropylidene-6-nitro-α-D-xylo-hex-5-enose
Authors: Szarek W. A. , Jewell J. S.
Published: May 2006

A Diels–Alder reaction between cyclopentadiene and 3-O-acetyl-5,6-dideoxy-1,2-O-isopropylidene-6-nitro-α-D-xylo-hex-5-enose (3) gave a crystalline adduct, whose structure has been established to be that of 5-endo-nitro-6-exo-(3′-O-acetyl-1′,2′-O-isopropylidene-α-D-xylo-tetrofuranos-4′-yl)-2-norbornene (4) by nuclear magnetic resonance spectroscopy.
Synthesis of polymer intermediates containing the bicyclo[3.2.2]nonane ring
Authors: Taimr Ludek , Smith James G.
Published: May 2006

The preparation of 1,5-biscarbethoxybicyclo[3.2.2]nonane and 1,5-bis(hydroxymethyl)bicyclo[3.2.2]nonane is described. The procedure generally followed that reported for the analogous bicyclo[2.2.2]octanes. However, certain differences in chemical behavior were observed and are reported.The alkylation of the sodium salt of diethyl succinylsuccinate produced the expected 1,5-biscarbethoxybicyclo[3.2.2]nonane-6,8-dione along with a by-product which was shown to be 1,5-biscarbethoxybicyclo[4.2.1]nonane-7,9-dione. It was also shown that this compound arose by isomerization of the bicyclo[3.2.2]nonane analogue after the alkylation occurred.Conversion of these compounds to thioketals with 1,3-propanedithiol was also examined in detail. The reaction between 1,3-propanedithiol and 1,5-biscarbethoxybicyclo[3.2.2]nonane-6,8-dione generated an equilibrating system of 4 compounds. Three of these are shown to be the monothioketal, the bisthioketal, and a mixed thioketal–vinylthioether.
Lemon-peel pectin. III. Fractionation of pectic acids from lemon-peel and lucerne
Authors: Aspinall G. O. , Cottrell I. W. , Molloy J. A. , Uddin M.
Published: May 2006

The pectic acids formed on saponification of lemon-peel pectins C and L have been fractionated by graded precipitation with sodium acetate. The results of analytical and electrophoretic studies on the pectic acid fractions have been interpreted as being typical of those of the fractionation of chemically homogeneous polydisperse systems. Similar fractionations of lucerne polysaccharides have indicated the presence of a single component in pectic acid A and of two components in pectic acid B. The nature of polysaccharide heterogeneity in pectic acid preparations is discussed.
Reaction of azide ion with 9-[2,3-anhydro-5-O-(p-tolylsulfonyl)-β-D-lyxofuranosyl]adenine
Authors: Hubert–Habart Michel , Goodman Leon
Published: May 2006

The reaction of 9-[2,3-anhydro-5-O-(p-tolylsulfonyl)-β-D-lyxofuranosyl]adenine (7) with sodium azide afforded 9-(2,5-anhydro-3-azido-3-deoxy-β-D-arabinofuranosyl)adenine (11) rather than the anticipated 5′-azido-2′,3′-anhydrolyxoside (8). Treatment of the azide 11 with sodium benzyl mercaptide resulted in formation of the Schiff base 15 via the 3′-amino-2′,5′-anhydroarabinoside (12). Compound 12 was also formed directly by hydrogenation of the azide 11.
Preparation of antidotes for anticholinesterase poisoning. IV. Synthesis and protective effectiveness of 2′-(cis- and trans-2″-hydroxycyclohexyl)aminoethyl 1-phenylcyclopentanecarboxylate hydrochlorides
Authors: Bannard R. A. B. , Parkkari J. H.
Published: May 2006

The syntheses of cis- and trans-2-aminocyclohexanols and of cis- and trans-2-ethylaminocyclohexanols are described. The cis isomers were prepared by treatment of the corresponding trans-2-acetamidocyclohexanols with thionyl chloride followed by hydrolysis of the resulting intermediate oxazolines. The 2-aminocyclohexanols were converted to 2′-(cis- and trans-2″-hydroxycyclohexyl)aminoethyl 1-phenyl-cyclopentanecarboxylate hydrochlorides (1 and 2, R = H) by treatment with 2′-bromoethyl 1-phenyl-cyclopentanecarboxylate, but attempts to convert the 2-ethylaminocyclohexanols to 1 and 2 (R = C2H5) by a similar reaction were unsuccessful. The anticholinesterase activities of several of the compounds are discussed, as are the potencies of 1 and 2 (R = H) in protecting mice and rats from sarin poisoning.
Novel electrophilic reaction of dichlorodicyanobenzoquinone
Authors: Reimann Hans , Jaret Robert S.
Published: May 2006

The reaction of some steroid 1,3,5-trien-3-ol benzoates with dichlorodicyanobenzoquinone affords 6β-(4′-benzoyloxy-2′,3′-dichloro-5′,6′-dicyanophenoxy)-1,4-dien-3-ones in addition to the expected 1,4,6-trien-3-ones.
Nuclear magnetic resonance study of proton exchange in the water – 2-propanol system
Authors: Tewari K. C. , Li N. C.
Published: May 2006

The specific rate constants for the reaction[Formula: see text]where ROH is 2-propanol, have been determined at four different temperatures. The activation energy has been calculated to be 10.4 kcal/mole. In addition, the effect of the presence of several electron donors on the kinetics of the reaction has been noted.
Some further reactions of pyrrylthiol esters
Authors: Bullock E. , Chen T.-S. , Loader C. E. , Wells A. E.
Published: May 2006

Reduction of pyrrylthiol esters with Raney nickel will yield, under specified conditions, the corresponding hydroxymethyl- or methylpyrroles. Evidence for at least two reduction mechanisms is presented. A convenient synthesis of a previously difficultly accessible pyrrole (1f) related to the coproporphyrins is described.
"Ideal" intensities of supersonic molecular beams
Authors: LeRoy Rodney L. , Govers Thomas R.
Published: May 2006

A general equation is derived to predict ideal supersonic beam intensities, allowing for an ellipsoidal local speed distribution at the skimmer. With suitable approximations this is found to reduce to all of the previously derived results. A new approximate equation is presented. This can accurately reproduce the intensities predicted by the general equation, provided only that the speed ratio in the radial direction at the skimmer is much greater than 3/2. It is found that a relatively broad speed distribution in the radial direction can result in an increase in the centerline beam intensity. This increase is only weakly dependent on the nozzle–skimmer separation, and it decreases as the skimmer radius is increased.
Reaction of nitrogen atoms with sulfur monoxide
Authors: Jacob A. , Winkler C. A.
Published: May 2006

The reaction sequence of N atoms with SO appears to be SO + N → NO + S, followed by NO + N → N2 + O, with a rate constant at 27 °C of about 0.8 × 10−12 cc molecule−1 s−1.