bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of derivatives of 4-acetamido-4-deoxy-D- and L-arabinose
Authors: Dick A. J. , Jones J. K. N.
Published: May 2006

4-Acetamido-4-deoxy-D- and L-arabinose have been synthesized from methyl 4-azido-4-deoxy-D- and L-arabinopyranoside, respectively. In contrast to other 4-acetamido-4-deoxypentoses, the arabinose derivatives in aqueous solution at tautomeric equilibrium exist both in the pyranose and in the furanose forms. The presence of the furanose form (containing nitrogen as the hetero atom in the ring) has been demonstrated by paper chromatography and infrared and nuclear magnetic resonance (n.m.r.) spectroscopy. Acetolysis of methyl 4-amino-4-deoxy-α-D-arabinopyranoside hydrochloride and of the N-acetyl derivative gave 4-acetamido-4-deoxy-D-arabinofuranose tetraacetates whose anomeric configurations were assigned by n.m.r. spectroscopy. Treatment of the 4-acetamido-4-deoxy-D-arabinofuranose tetraacetates with a cation exchange resin in methanol solution and subsequent de-O-acetylation, gave the anomeric methyl 4-acetamido-4-deoxy-D-arabinofuranosides, whose n.m.r. spectra in D2O exhibited the phenomenon of hindered internal rotation.
Crystal and molecular structure of the pyridine solvate of bis(8-hydroxyquinoline)silver(I)
Authors: Fleming J. E. , Lynton H.
Published: May 2006

Crystals of the pyridine solvate of bis(8-hydroxyquinoline)silver(I), Ag(C9H9NO)C9H6NOHO•C5H5N, are monoclinic, space group P21/a, with cell dimensions a = 10.87 ± 0.01 Å, b = 10.65 ± 0.01 Å, c = 16.70 ± 0.01 Å, β = 92.6 ± 0.2°, Z = 4. Atomic parameters have been determined from a three-dimensional analysis using 2163 independent intensities to which no absorption corrections were applied. Refinement was by observed and calculated differential syntheses using isotropic temperature factors. The final discrepancy index is R = 0.116.The coordination of the silver atom is distorted tetrahedral, with bonds to the phenolic oxygen and ring nitrogen atoms of both 8-hydroxyquinoline molecules. Adjacent bis(8-hydroxyquinoline)silver molecules are linked by a hydrogen bond between two oxygen atoms. The pyridine molecules are held in the lattice by van der Waals' forces.
Elementary processes in the acetaldehyde pyrolysis
Authors: Liu Michael T. H. , Laidler K. J.
Published: May 2006

The acetaldehyde pyrolysis has been studied over the 480–540 °C temperature range, and at pressures from 1 to 560 mm Hg. Measurements were made of the rates of production of the major product methane and of the minor products hydrogen, ethane, acetone, and propionaldehyde. The kinetic effects of adding carbon dioxide, of changing the surface:volume ratio, and of coating the vessel have been determined. The elementary processes are found to occur largely in the gas phase. The dissociation of CH3CHO into CH3 + CHO is deduced from the rates of hydrogen and ethane formation; there is significant falling off of the rate constants at lower pressures. The kinetic parameters for the reaction CH3 + CH3CHO → CH4 + CH3CO are obtained, and it is suggested that quantum-mechanical tunnelling plays a role. Acetone production has an activation energy of 12.4 kcal/mole and it is concluded that its formation involves the participation of the isopropoxy radical, the activation energies being as indicated:[Formula: see text]
Study of phase changes in some iodides by the Hahn emanation technique
Authors: Narang V. P. , Yaffe L.
Published: May 2006

135I was incorporated into TlI, AgI, HgI2, CuI, and PbI2 and phase changes in the solid were studied by the Hahn emanation technique of following the emanation of the 135Xe daughter. Good agreement was obtained with results previously obtained by conventional techniques.
Nuclear magnetic resonance study of arene metal tricarbonyl complexes
Authors: Price J. T. , Sorensen T. S.
Published: May 2006

The n.m.r. spectra of all the methyl-substituted benzene complexes of chromium tricarbonyl, molybdenum tricarbonyl, and tungsten tricarbonyl have been obtained. The unusual features include a large upfield shift of alkene proton chemical shifts on complex formation, but within the metals the order of increasing shift is Cr > W > Mo, a non-periodic trend. It has also been observed that the individual alkene proton chemical shifts in an unsymmetrical methyl benzene become markedly different on complex formation, in contrast to the behavior found in the free arene. Symmetrical methyl-substituted benzene metal complexes, on the other hand, show the same symmetry characteristics as the free arenes, and hence, on an n.m.r. time scale, there is no permanent distortion of the ring. A theory is presented, invoking partial three-point bonding of the M(CO)3 moiety to the arene ring. This bonding is postulated to occur most strongly at arene carbon atoms bearing methyl groups and, as a consequence, results in an abnormally strong electron withdrawal from carbon positions meta to this carbon, even though this meta position may be unsubstituted.
Effect of changing pH upon the kinetic 13C-isotope effect in the decarboxylation of 4-methoxyanthranilic acid
Authors: Dunn G. E. , Buccini John
Published: May 2006

The 13C-carboxyl kinetic isotope effect on decarboxylation of 4-methoxyanthranilic acid has been determined in aqueous solutions of ionic strength 0.50 at 60 °C. The isotope effect, 100(k12/k13 −1), is found to be 4.2% at pH −0.3, 1.4% at pH 1.3, and zero at pH 4.0. This information makes it possible to decide between two mechanisms previously proposed in favor of the one in which both anion and neutral acid are protonated at carbon-1 of the aromatic ring but only the protonated anion decarboxylates.
Hameka theory of optical rotation
Authors: Hutchinson D. A.
Published: May 2006

sRosenfeld's formula, for off-resonance optical rotation, is derived by an alternative approach. The scattering amplitudes are determined for the scattering of right circularly polarized light and left circularly polarized light by a molecule. The calculation is carried out to the order of approximation which includes electric quadrupole and magnetic dipole terms. From the real parts of the forward scattering amplitudes the corresponding indices of refraction are determined for left and right circularly polarized light. Rosenfeld's formula then follows from the difference between the two refractive indices.
Gas-liquid chromatography of terpenes. Part XVI. The volatile oil of the leaves of Juniperus ashei Buchholz
Authors: Rudloff E. Von
Published: May 2006

The major components of the leaf oil of the Ashe juniper were found to be d-camphor (42.1 %), d-bornyl acetate (22.5%), d-limonene (8.4%), tricyclene (4.8%), d-camphene (4.4%), d-borneol (2.9%), p-cymene (2.8%), d-α-myrcene (1.8%), d-α-pinene (1.7%), and d-camphene hydrate (1.5%). This appears to be the first time that the latter alcohol has been isolated from a natural source. Smaller amounts of linalool, carvone, elemol, and traces of trans-2-methyl-6-methylene-3,7-octadien-2-ol were also identified. Several alcohols having terminal methylene groups were isolated in trace amounts.The monoterpenes found in this oil are not typical for the genus Juniperus and this result offers a unique chemical approach to the study of introgression of the Ashe juniper with other juniper species.
Ranunculin
Authors: Benn M. H. , Yelland Lois Jean
Published: May 2006

A reinvestigation of the structure of ranunculin, the glucosidic precursor of the vesicant principle of many Ranunculus species, protoanemonin, supported the gross structure proposed by Hill and van Heyningen and led to the stereochemistry at the asymmetric center of the aglucone.
Concerning the mechanism of the reaction of methyllithium with methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside to form 4,6-O-benzylidene- 1,2-didehydro-1,2-dideoxy-2-methyl-D-ribo-hexopyranose
Authors: Sharma M. , Brown R. K.
Published: May 2006

Evidence supports the view that methyllithium, which contains no iodide or bromide ions as competitors, reacts with methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside to form, first, methyl 4,6-O-benzylidene-2-deoxy-2-methyl-α-D-altropyranoside. The latter compound then reacts with excess methyllithium to form 4,6-O-benzylidene-1,2-didehydro-1,2-dideoxy-2-methyl-D-ribo-hexopyranose by loss of methyl alcohol.A synthesis of methyl 4,6-O-benzylidene-2-deoxy-2-methyl-α-D-altropyranoside is given.The reactions of excess lithium iodide, bromide, and chloride with both methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside and methyl 2,3-anhydro-4,6-O-benzylidene-α-D-mannopyranoside are described.
Equilibrium reactions of n-butanethiol with some conjugated heteroenoid compounds
Authors: Pritchard R. B. , Lough C. E. , Currie D. J. , Holmes H. L.
Published: May 2006

The reactions of 2-benzal-1,3-indanediones and the cyano-containing benzalmalononitriles, ethyl benzalcyanoacetates, benzalcyanoacetamides, and benzalcyanoacetanilides with n-butanethiol at 25 °C in 20% ethanol – 80% pH 7 buffer attain equlibrium at a rate too fast to measure by standard methods. The equilibrium constants have been calculated and these in turn related to Hammett σ and Taft σ* constants. The differences in the reactions of these and other gem difunctional systems which react virtually completely with n-butanethiol under the same experimental conditions and at a measurable rate, are attributed to participation of the functional group cis to the phenyl group in the reverse reaction. It is shown that n-butanethiol adds to cinnamalacetophenone by a 1,4-mechanism and the reactions of this nucleophile with similar compounds having extended conjugated systems are discussed.
2-Deoxy-D-glacto-heptose
Authors: Perry M. B. , Webb Ann C.
Published: May 2006

Catalytic reduction of 3,4,5,6,7-pentaacetoxy-D-glacto-1-nitro-1-heptene afforded 3,4,5,6,7-penta-O-acetyl-1,2-dideoxy-1-nitro-D-glacto-heptitol which on treatment with acid gave 2-deoxy-D-glacto-heptose. The properties of 2-deoxy-D-glacto-heptose and the preparation of its derivatives 1,3,4,5,6,7-hexa-O-acetyl-2-deoxy-D-glacto-heptitol, 2-deoxy-D-glacto-heptose 2,5-dichlorophenylhydrazone and 2-deoxy-D-glacto-heptose methylphenylhydrazone are recorded.
N-alkyne-N-bis(2-chloroethyl)amines
Authors: Pettit George R. , Danley B. J.
Published: May 2006

A reaction employing copper(II) chloride has been developed for condensing propargyl alcohol with formaldehyde and bis(2-chloroethyl)amine. The modified Mannich reaction was extended to include condensation of several other α-hydroxyacetylenes of the terminal alkyne class with bis(2-chloroethyl)-amine.
Pyrrole chemistry. VIII. By-products in the synthesis of 2-pyrrolecarbonitrile
Authors: Anderson Hugh J.
Published: May 2006

Two by-products are formed when 2-pyrrolecarbonitrile is prepared by the acetic anhydride dehydration of 2-pyrrolecarbaldoxime. These have been proved to be 2-acetamidocarbonylpyrrole and 1-acetyl-2-pyrrolecarbonitrile. The latter acts as an acetylating agent.
Addition of C-phenyl-N-methyl nitrone to norbornene and norbornadiene
Authors: Fraser Robert R. , Lin Y. S.
Published: May 2006

The reaction of C-phenyl-N-methyl nitrone with norbornene gave two 1:1 cycloadducts in a ratio of 9:1. Both adducts have been shown to possess an exo-cis isoxazolidine ring by nuclear magnetic resonance and to be diastereomeric at the benzylic carbon of the isoxazolidine ring by chemical degradation of both adducts to 3-exo-benzyl-2-exo-hydroxybicyclo [2•2•1] heptane. The reaction of the same nitrone with norbornadiene gave a 1:1 and a 2:1 adduct. The stereochemistry of the 1:1 adduct was shown to be the same as that of the major norbornene adduct which it gave on hydrogenation of the double bond. The structure of the 2:1 adduct was not investigated.
Reductive elimination of 1,2-dibromides with sodium borohydrides
Authors: King J. F. , Allbutt A. D. , Pews R. G.
Published: May 2006

Sodium trimethoxyborohydride or a 1:3 mixture of sodium borohydride and sodium tetramethylborate reacts with a number of vicinal dibromides to form the corresponding olefin. Variable (sometimes good) yields were obtained when the bromine atoms were on secondary or tertiary carbons, but little or no olefin was detected when one bromine was primary.
Nuclear magnetic resonance spectra of 2-pyrazolines
Authors: Brey Jr. Wallace S. , Valencia Carmen M.
Published: May 2006

The nuclear magnetic resonance spectral parameters for a series of 3-carbomethoxy-2-pyrazolines are presented and discussed. Substitution of a phenyl group at position-5 has a large effect on the relative chemical shift of the two protons at position-4, although a carbomethoxy group at position-5 has little effect. The cis and trans vicinal coupling constants in compounds with two protons in position-4 are nearly equal and differ from the values found when there is a substituent in position-4. The presence of three groups in positions-4 and -5 appears to hold the ring in a rigid conformation. The line width for the hydrogen attached to nitrogen depends upon the number of phenyl groups in position-5.
Erratum: Carbonyl-bridged and related compounds. Structural assignments by nuclear magnetic resonance spectroscopy
Authors: Allen C. F. H.
Published: May 2006

not available
Dielectric studies. Part XVII. Relaxation processes and corresponding enthalpies of activation of some mono-substituted benzenes
Authors: Crossley J. , Walker S.
Published: May 2006

The dielectric absorption at several microwave frequencies of liquid ethylbenzene, isopropylbenzene, and phenyltrimethylsilane at 15, 37.5, and 50 °C and cyclohexane solutions of t-butylbenzene and benzotrichloride at 15, 37.5, 45, and 50 °C has been examined. Benzotrichloride has also been studied in cyclohexane and p-xylene solution at 25 °C. Only molecular reorientation can be detected for benzotrichloride, whereas the remainder are all characterized by an absorption that may be analyzed into two relaxation times, one associated with molecular reorientation (τ1) and a shorter relaxation time (τ2) which appears to be attributable to an intermolecular process. The enthalpies of activation of the τ1 process show the expected increase with increasing molecular size, while no temperature dependence is detectable for the shorter relaxation process.
Effets ioniques spécifiques sur le taux de formation du ClO2 par la réaction chlorure–chlorate
Authors: Lenzi F. , Rapson W. H.
Published: May 2006

Rate enhancing specific ion effects have been detected in 2.3 M and 5.0 M H2SO4 for the reaction [Formula: see text]. These effects can be related to the hydration numbers of the added ions. This suggests a Bascombe and Bell type of interpretation for the overall twelfth power rate dependence of the above reaction on the sulfuric acid concentration in the reaction medium; the chloride–chlorate reaction acts as a "chemical amplifier" for hydration effects.
Application of temperature-programmed desorption to surfaces with physically adsorbed species
Authors: Schreiber H. P. , MacKinnon A. G.
Published: May 2006

Temperature-programmed desorption has been applied to physisorbed aliphatic alcohols and acids on a rutile pigment surface. Reproducible desorption chromatograms for a series of alcohol adsorbates indicate that the same sites are involved in adsorbing the series and that the adsorbate orientation from the surface deviates progressively from normal as the chain length increases. The data also infer a reduction in the activation energy of desorption with increasing chain length. Acid adsorbates also generate reproducible chromatograms, those for formic and acetic acid showing characteristic peaks near 300 °C. The reason for the very high stability of these adsorbates has not yet been resolved.
1,2-Alkylidene and 1,2-ortholactone derivatives of 3,4,6-tri-O-acetyl-α-D-glucose
Authors: Lemieux R. U. , Detert D. H.
Published: May 2006

Reaction of 3,4,6-tri-O-acetyl-1,2-O-(1′-exo-ethoxyethylidene)-α-D-glucopyranose with ketones in the presence of toluenesulfonic acid provides 3,4,6-tri-O-acetyl-1,2-O-alkylidene-α-D-glucoses. With butyrolactone the interchange yielded the 1,2-ortholactone.
A stereoselective synthesis of α-D-glucopyranosides
Authors: Lemieux R. U. , Suemitsu R. , Gunner S. W.
Published: May 2006

Deoximation of 3,4,6-tri-O-acetyl-2-oximino-α-D-arabino-hexopyranosides to the corresponding 2-ulosides followed by borohydride reduction affords the α-D-glucopyranosides in excellent yields.
Réduction de cétones conjuguées dans la série acétyl méthyl cyclohexène
Authors: Dufort Normand , Flamand Eddy
Published: May 2006

not available
Synthetic studies of hydrazine and guanidine: derivatives of 5-pyrazoles
Authors: Zauhar Joseph , Ladouceur Benoit F.
Published: May 2006

The reactions of several substituted 5-chloropyrazoles with hydrazine hydrate and guanidine, respectively, were investigated in ethanol and dimethyl formamide media. In certain cases, only SN2 reactions occurred, while in others the 5-hydrazino- and 5-guanidopyrazoles reacted still further to yield related compounds with two pyrazole rings. On the basis of the intermediates and the different condensation products isolated, reaction schemes are proposed for the reactions discussed.
Synthesis of anisomycin. Part I. The stereospecific synthesis of N-benzoyl-2-(p-methoxybenzyl)-3-hydroxy-4-carboxamido pyrrolidine and the absolute configuration of anisomycin
Authors: Wong C. M.
Published: May 2006

L-Tyrosine was converted stereospecifically to N-benzoyl-2-(p-methoxybenzyl)-3-hydroxy-4-cyanopyrrolidine (10) which had a specific optical rotation [Formula: see text]. Anisomycin was converted also to N-benzoyl-2-(p-methoxybenzyl)-3-hydroxy-4-cyanopyrrolidine (16) which had a specific rotation [Formula: see text]. The infrared spectra of the synthetic compound and the derivative of anisomycin were superimposable with each other. This result showed that the absolute configuration of the three asymmetric centers in (10) of synthetic origin were 2S, 3S, 4S, and those in (16) were 2R, 3R, 4R. Thus, anisomycin should have the absolute stereochemistry 2R, 3S, 4S as depicted in the structure (2). Hydrolysis of the hydroxy nitriles (8) and (10) gave an identical amide (3) which should have the absolute stereochemistry 2S, 3S, 4R as shown in structure (3).
The synthesis and saponification kinetics of some 4′-substituted 4-phenoxyphenyl acetates
Authors: Mattano L. A. , Falk J. C.
Published: May 2006

Phenoxyphenyl acetate and several 4′-substituted derivatives were synthesized and their rates of saponification determined. The nature of the 4′-substituent was correlated with the rate of saponification by means of the Hammett equation.
Etard reactions. I. Nature of complexes and their reactions with some oxygen and nitrogen donor molecules
Authors: Makhija R. C. , Stairs R. A.
Published: May 2006

Dilute carbon tetrachloride solutions of chromyl chloride and toluene react to form a product of empirical composition, C6H5CH3•2CrO2Cl2 (1). On refluxing 1 with carbon tetrachloride solutions of pyridine, α-picoline, acetonitrile, dioxan, tetrahydrofuran, and triethylamine, adducts of approximate compositions C6H5CH3•2CrO2Cl2•2D (D = donor molecule) are obtained.Results of magnetic susceptibility, infrared, and preliminary X-ray observations are discussed. Possible structures for 1 and for the ternary adducts are described.
Réactions dans le sulfolane. II. Etude électrochimique de systèmes oxydo-réducteurs des halogènes
Authors: Benoit R. L. , Guay M. , Desbarres J.
Published: May 2006

The electrochemical oxidation of halides and reduction of halogens have been studied in sulfolane, an aprotic solvent. Stable trihalide ions X3− are formed. The formation constants K of these X3− ions have been determined by potentiometry as 107.4 (X = I), 106.8 (X = Br), and 1031(X = Cl) in a 0.1 M LiClO4 medium. The values of the constants K have also been obtained in methanol, a hydroxylic solvent, 104.2 (X = I), 102.3 (X = Br), and in mixtures of both solvents (X = I). The variations of solvation energies of X3− and X− ions from one solvent to the other were estimated by means of a ferrocene electrode.
Studies on the thermodynamics and conductances of molten salts and their mixtures. Part VI. Calorimetric studies of sodium chlorate and its mixtures with sodium nitrate
Authors: Campbell A. N. , Kouwe E. T. van der
Published: May 2006

The following properties have been determined by direct experiment for pure sodium chlorate and its mixtures with sodium nitrate: heat capacity (both solid and liquid) and heat of fusion. From these experimental quantities, the following properties have been derived: entropy of fusion, heat of mixing, and free energy and entropy of mixing. The results have been compared with our previous results for the corresponding lithium chlorate – lithium nitrate system. On the whole, the conclusion is justified that the structure of melts containing lithium chlorate is more complex than that of melts involving sodium chlorate.
Studies on the thermodynamics and conductances of molten salts and their mixtures. Part VII. The electrical conductance of sodium chlorate and its mixtures with sodium nitrate
Authors: Campbell A. N. , Kouwe E. T. van der
Published: May 2006

The specific and equivalent conductances of molten sodium chlorate and of its mixtures with sodium nitrate have been determined over the temperature range 240–280 °C. The results are treated as temperature functions at constant composition and as composition functions at constant temperature. From these data, the activation energies of conductance have been derived. The results have been compared with various theoretical equations and the conclusion is made that, while melts containing lithium chlorate may be associated or complexed in some way, the sodium chlorate melts show less of such a structure and are more ionic.
Adsorption and coprecipitation of silver on hydrous ferric oxide
Authors: Dyck Willy
Published: May 2006

With silver-110 m as a tracer, detailed investigations were carried out on the adsorption of silver on freshly prepared hydrous ferric oxide in the pH region 4–8, and silver equilibrium concentration range 10−4–102 p.p.m. The results fit Freundlich adsorption isotherms, and may be explained in terms of hydrogen–silver ion exchange. They also show that adsorption is essentially complete in less than 5 min and is strongly dependent on pH and the manner in which the precipitate was prepared, but is independent of temperature in the 0–50 °C range, of moderate concentrations of sodium nitrate (~10 g/l), and of trace concentrations of sodium chloride [Formula: see text] during test periods ranging from 1 to 3 days.Tests also showed that under equilibrium conditions and similar chemical environments the amounts of silver coprecipitated or adsorbed were identical.
Solvent effects on the boron–fluorine coupling constant and on fluorine exchange in the tetrafluoroborate anion
Authors: Gillespie R. J. , Hartman J. S. , Parekh M.
Published: May 2006

The 11B—19F spin–spin coupling constant in AgBF4 is shown to have an opposite sign in water from that found in a number of organic solvents. Application of the hypothesis of Bell and Danyluk indicates that it has a positive sign in water. Evidence is presented for association, probably in the form of solvent-separated ion pairs, in aqueous LiBF4 and NaBF4 solutions, and for the formation of more tightly bound ion pairs in solvents of lower dielectric constant. In contrast, there apparently is no solute association in AgBF4 solutions in water, DMSO, DMF, or acetonitrile. The pronounced changes observed in the 11B—19F coupling constant support the postulate that its small size is a result of near cancellation of large opposing terms.The collapse of the 10B—11B isotope shift at high temperatures in the 19F spectra of solutions of AgBF4 in acetonitrile and in acetone provides evidence for exchange of fluorine among boron atoms; a mechanism is proposed for this process.
Behavior of a sulfur vapor electrode in sulfide melts
Authors: Thompson W. T. , Flengas S. N.
Published: May 2006

The reversible potentials for the formation cell[Formula: see text]have been measured for concentrations of silver sulfide in silver chloride up to 12 mole %, in the temperature range 490 to 860 °C. Nernst behavior with respect to the partial pressures of the various sulfur species present in the vapor phase over the electrode is observed in the range 10−3 to 1.0 atm. Calculations of partial pressures are based on existing mass spectrometric data. The concentration dependence of the cell voltage follows the Nernst law only in very dilute silver sulfide solutions. The data are used to calculate the thermodynamic properties of silver sulfide in solution with silver chloride.
Radiolysis of ethyl iodide and carbon tetrachloride mixtures at 77°K
Authors: Leblanc R. M. , Thyrion F. C. , Herman J. A.
Published: May 2006

The radical yields of C2H5• and CCl3• observed by electron spin resonance of CCl4 + C2H5I mixtures irradiated by γ rays at 77°K are compared with yields of HCl, I2, and HI measured after thawing. The dissociative capture of thermalized electrons by CCl4 is extremely effective and accounts for most of the observed radicals. The difference between yields of HCl and CCl3• results from charge transfer from C2H5I+ to CCl3•. The formation of iodine proceeds both from neutralization processes of Cl− ions with positive ions formed from C2H5I, and from ion–molecule reactions.
Phosphine-substituted carbonyl halide complexes of chromium and molybdenum
Authors: Allen. A. D. , Barrett P. F.
Published: May 2006

A number of phosphine tetracarbonyl halide salts of the Group VI metals have been prepared of the type: cis-[Et4N][PR3M(CO)4X] where PR3 = (p-FC6H4)3P or (p-ClC6H4)3P, M = Cr or Mo for X = Cl, and M = Mo for X = Br, by the reaction of phosphines with the pentacarbonyl halides [Et4N][M(CO)5X]. A new method for the preparation of cis-[Formula: see text] complexes from the phosphine tetracarbonyl halides is described.Assignments are made for the bands in the carbonyl stretching region of the infrared spectra of these complexes.
Dielectric properties of the hydrates of argon and nitrogen
Authors: Gough S. R. , Whalley E. , Davidson D. W.
Published: May 2006

The dielectric relaxation of water in the structure I clathrate hydrates of argon and nitrogen was studied over a range of temperature and pressure. Hydrates were slowly grown at pressures of 1 to 2 kbar in a coaxial cell enclosed in a pressure vessel. The complex permittivity loci resemble circular arcs with static dielectric constants of ~56 at 0 °C and high-frequency dielectric constants of 2.85 ± 0.05. Relaxation near 0 °C is about as slow as in ice I, but activation energies and entropies are much smaller. Formation of Bjerrum defects probably takes place preferentially near the occasional sites at which argon and nitrogen molecules have replaced water molecules in the lattice. The much faster relaxations found previously in the isostructural hydrates of ethers arise from orientational defects induced in the water lattice by the encaged molecules, a small proportion of which may form hydrogen bonds with water. The effect of small gaps in series with samples showing circular-arc dispersion behavior was evaluated.
Preparation and infrared spectra of alkali and alkaline earth metal chlorosulfates
Authors: Ciruna J. A. , Robinson E. A.
Published: May 2006

A new method for the preparation of alkali and alkaline earth metal chlorosulfates is described which involves the precipitation of the salts from saturated solutions in chlorosulfuric acid using thionyl chloride. The infrared spectra of all the chlorosulfates in the region 400–1500 cm−1 have been measured and the assignment of the frequencies is discussed.
Electron spin resonance detection of radicals and electrons condensed from water vapor after irradiation with 1 MeV helium ions
Authors: Seddon W. A. , Smith D. R. , Bindner P. E.
Published: May 2006

A stream of water vapor was irradiated in a "crossed-beam" experiment by 1 MeV He+ ions. After traversing the He+ ion beam, the vapor was condensed on a quartz tube at 77°K. The deposit so formed was then isolated under vacuum and transferred to an electron spin resonance (e.s.r.) spectrometer. E.s.r. spectra were observed that arise from species formed as a consequence of radiolysis in the vapor phase. Species trapped in the deposit were identified as HO2 radicals and electrons. Addition of CH3I and N2O gives results which indicate that hydrogen atoms were also formed although they do not become trapped in the deposit.The physical parameters of the experiment have been measured or calculated. These include the pressure and velocity of molecules in the vapor stream, and the time between irradiation and deposition on the cold finger.
Ion–molecule reactions in acetylene and acetylene–methane mixtures
Authors: Myher J. J. , Harrison A. G.
Published: May 2006

The ion–molecule reactions in acetylene have been studied. The reaction of C2H2+ with C2H2 yields C4H2+ and C4H3+ in the ratio 0.40:1. C2H+ ions also react to form C4H2+. Excited states of C2H2+ and possibly C2H+ are shown to be important in the ion–molecule reactions in acetylene.In acetylene–methane mixtures the following reactions have been identified and their rates measured.[Formula: see text]By studying the reactions in CH4–C2D2 mixtures the condensation reactions have been shown to involve extensive isotopic scrambling while the hydrogen-transfer reactions occur without isotopic scrambling.
Reactions of iron carbonyls with various ligands in the presence of chloroform. A new method for the preparation of iron halide complexes
Authors: Singh. P. P. , Rivest R.
Published: May 2006

Iron halide complexes of the type FeCl2•2L (L = CH3CONH2, HCONH2, HCONHCH3) and FeCl3•L (L = (C6H5)3P, (C6H5)3As, C6H5NH2, C6H5CONH2) have been prepared by the reaction of iron carbonyls with various ligands in chloroform as solvent. The mechanism of the reaction and the effect of other solvents have also been studied. The magnetic susceptibility measurements and infrared spectral study (4000–200 cm−1) suggest that these complexes have tetrahedral configuration. The possible site of bonding in ligands and infrared assignments for Fe—O, Fe—Cl, Fe—N, Fe—P, Fe—As bands have been given. The relative Fe—O bond strengths in various amide complexes have been determined on the basis of metal–oxygen stretching frequency and of shifts in carbonyl stretching frequency.
Carbon-13 kinetic isotope effects. IV. The effect of temperature on k12/k13 for benzyl halides in bimolecular reactions
Authors: Bron Jan , Stothers J. B.
Published: May 2006

The temperature dependence of the 13C kinetic isotope of the α-carbon in benzyl bromide (1) and in 1-bromo-1-phenylethane (2) has been measured for reaction with alkoxide ion. For these bimolecular displacements, a relatively large temperature effect was found, comparable to that reported for other SN2 processes. A reexamination of the reaction of 2 with EtO− has shown an earlier value for k12/k13 to be in error.
Reformatsky reactions with o- and p-substituted benzophenones
Authors: Charlesworth E. H. , Charleson Peter
Published: May 2006

Nine new β,β-diarylhydracrylic acids are reported from the condensation of monosubstituted benzophenones with ethyl bromoacetate in Reformatsky reactions. The reaction of 4-nitrobenzophenone which fails to go into classical Reformatsky reactions can be accomplished in excellent yield by the two-step process; however, 2-nitrobenzophenone fails to react under any conditions.In the case of 2-chlorobenzophenone in benzene–toluene, the hydracrylic acid is not isolated, but rather the unsaturated β-chlorophenyl-β-phenyacrylic acid. Diethyl ether appeared in general to be superior to benzene–toluene as a solvent for the reactions. Anisole under reduced pressure has also been used successfully in two cases.
Synthesis of some 1,4-naphthoquinones and reactions relating to their use in the study of bacterial growth inhibition
Authors: Silver R. F. , Holmes H. L.
Published: May 2006

A series of 107 1,4-naphthoquinones and related products has been synthesized to study their mode of action in bacterial growth inhibition. The in vitro reactions of a number of these with aniline, n-butylamine, sodium methoxide, and an n-buthanethiol–triethylamine mixture have been examined. A series of epoxides of C-2 monosubstituted and C-2,C-3 disubstituted 1,4-naphthoquinones has been synthesized and their reactions with amines, thiols, and halogen acids have been studied. The ultraviolet absorption maxima of many of these quinones are also tabulated.
Steroids and steroidases. VII. A unique long-range directing effect exerted by the cholestane C8H17 group on the formation of A-homosteroid ketones
Authors: Jones J. Bryan , Zander J. Malcolm
Published: May 2006

The diazomethane homologation of a broad spectrum of variously C-17-substituted steroid-3-ketones has shown that the C8H17 cholestane side chain exerts a unique influence on the direction of the ring enlargement reaction. This long-range effect is not explicable in terms of polar or conformational transmission.
Some silicon-containing phenyl and benzyl isoquinoline derivatives, 2-aralkyl imidazolines, and N-substituted phenethylamines
Authors: Belsky Igal , Gertner David , Zilkha Albert
Published: May 2006

Several trimethylsilyl substituted 1-phenyl or 1-benzyl isoquinoline derivatives were synthesized by the Bishler–Napieralsky reaction starting from the corresponding homoveratrylamides, which were cyclized in toluene in the presence of phosphorus pentoxide or phosphorus oxychloride. These conditions were suitable for the homoveratrylamides of p- or o-trimethylsilylbenzoic acid and p-trimethylsilylmethylphenylacetic acid but not for that of p-trimethylsilylphenylacetic acid, due to the greater sensitivity of the silicon–aryl bond in the latter to cleavage under acid conditions.Some 2-aralkyl imidazolines containing a trialkylsilyl group in the para-position were synthesized by condensation of silicon-containing aromatic acids and ethylenediamine.Several N-substituted p-trialkylsilyl phenethylamines were prepared by lithium aluminium hydride reduction of the corresponding amides.
Préparation de quelques nouveaux dérivés de la morpholone-2
Authors: Jankowski Krzysztof , Berse Casimir
Published: May 2006

not available
Synthesis of new chalcone analogues and derivatives
Authors: Laliberté Réal , Manson Jane , Warwick Hilda , Medawar George
Published: May 2006

The synthesis of new derivatives of 2′-hydroxychalcone, such as esters, sulfonates, and thiocarbamates, prepared for evaluation as antiparasitic agents as well as new heterocyclic chalcone analogues prepared for the same purpose, is described.
Electrical conductivities of quaternary ammonium salts in acetone.: Part I. Pressure and temperature effects
Authors: Adams W. A. , Laidler K. J.
Published: May 2006

The equivalent conductivities of tetramethylammonium iodide, tetraethylammonium iodide, and tetra-n-propylammonium iodide in acetone solution were determined at concentrations from 1 to 10 × 10−4 mole/liter and at temperatures of 25 to 55 °C and pressures from atmospheric to 1.1 kbar. The concentration dependence of the equivalent conductivities was analyzed by the Shedlovsky method. Limiting equivalent conductivities and ion-pair dissociation constants are tabulated.
Electrical conductivities of quaternary ammonium salts in acetone.: Part III. Ion-pair formation
Authors: Adams W. A. , Laidler K. J.
Published: May 2006

The ion-pair dissociation constants determined from a Shedlovsky analysis of conductivity (see Part I) were used to calculate the enthalpy, the internal energy at constant volume, the entropy, and the volume of dissociation of tetramethylammonium iodide, tetraethylammonium iodide, and tetra-n-propylammonium iodide ion pairs in acetone solution. The sign and magnitude of these parameters over the range of conditions investigated, temperature 25 to 55 °C and atmospheric to 1.1 kbar pressure, indicated that the free ions in acetone solution are extensively solvated and that, depending on the conditions, solvent-shared or solvent-separated ion pairs are formed.
Analyses of chlorine dioxide, chlorous acid, chlorite, chlorate, and chloride in composite mixtures
Authors: Hong C. C. , Rapson W. H.
Published: May 2006

An analytical procedure was devised to determine chlorine dioxide, chlorous acid, and chlorite, chlorate, and chloride ions in composite mixtures. Chlorine dioxide was determined spectrophotometrically at 360 mµ. After the removal of chlorine dioxide by passing air through the solution, the total concentration of chlorous acid and chlorite ion in the solution was determined spectrophotometrically at 250 mµ where the two species have the same molar absorptivity. The total concentration of chlorous acid, chlorite ion, and chlorate ion was determined by iodimetric titration. Chloride ion was determined by the Mohr titration in neutral solution.
Nuclear magnetic resonance studies of tertiary phosphine hydrobromides
Authors: Grim Samuel O. , McFarlane William
Published: May 2006

Phosphorus and proton magnetic resonance data are presented for hydrobromides of 15 tertiary phosphines, of which 5 are trialkylphosphines, 5 are dialkylphenylphosphines, and 5 are diphenylalkylphosphines. The 31P chemical shifts of each of these series of phosphonium compounds are linearly related to the sum of the group contributions (g.c.) of the organic groups on the respective phosphines.
Radiolysis in the adsorbed state. II. N2O adsorbed on silica gel and zirconia
Authors: Sagert N. H. , Robinson R. W.
Published: May 2006

The 60Co γ-radiolysis of N2O adsorbed on silica gel and zirconia has been studied. In both systems a large fraction of the energy absorbed in the solid is able to cause decomposition of the N2O. For the silica gel – N2O system, studies with electron scavengers have shown that on gels degassed at low temperatures, electrons are precursors for a large fraction of the yield and about 1 G unit of nitrogen is produced by other processes. The total nitrogen yield is smaller for gels degassed at high temperatures, but the yield of nitrogen produced by direct excitation stays constant at 1 G unit.Experiments using electron scavengers with the zirconia–N2O system have shown that direct excitation of the solid is responsible for most of the nitrogen yield at 7 G units on high surface zirconia. Studies of nitrogen yields on a number of zirconias showed that the range over which energy is transferred is about 50 Å.
Bis(metalloidal)ketones
Authors: Brook A. G. , Jones Peter F. , Peddle G. J. D.
Published: May 2006

A number of bis(silyl)- and bis(germyl)-ketones have been prepared by the oxidation of the corresponding carbinol or by the hydrolysis of the dithiane precursor. The ketones are all highly colored and their spectral properties are consistent with inductive interaction of both metalloid atoms with the carbonyl group. The reactions of bis(triphenylgermyl)ketone under various conditions have been studied and the results obtained are consistent with the intermediacy of triphenylgermyl radicals.
Group vibrations and the vibrational analysis of molecules containing methylene groups. Part II. Ethylene oxide, d4-ethylene oxide, and ethylene sulfide
Authors: Freeman J. M. , Henshall T.
Published: May 2006

Vibrational analyses, based on the group frequency factorization procedure of King and Crawford, are reported for ethylene oxide, d4-ethylene oxide, and ethylene sulfide in an attempt to decide between two possible vibrational assignments for these molecules.The results, whilst not providing an unequivocal decision between the assignments, nevertheless do suggest that the higher frequencies in the A2 and B2 species may be preferentially assigned to the methylene rocking modes.
Strongly hindered rotation in α,α,2,6-terrachlorotoluene. Stereospecific five-bond coupling. Hyperconjugative contributions to long-range sidechain-ring proton coupling constants
Authors: Schaefer T. , Schwenk R. , Macdonald C. J. , Reynolds W. F.
Published: May 2006

At −40 °C the C—H bond of the dichloromethyl group of α,α,2,6-tetrachlorotoluene lies in the plane of the ring. The proton resonance spectrum demonstrates a stereospecific five-bond coupling between the C—H proton and the ring proton in the meta position. The coupling to the para proton is essentially zero as expected from a hyperconjugative mechanism. The free energy of activation of rotation of the dichloromethyl group is about 15 kcal/mole at 25 °C.
Synthesis of 5-methyl-8-hydroxy-1-tetralone
Authors: John Joseph P. , Natarajan R. K. , Swaminathan S. , Venkataramani P. S.
Published: May 2006

The tetralone 2a has been obtained in 45% overall conversion from the dione 3 by the sequence 3 → 4a → 4b → 5b → 5a → 2a.
Methods of preparation of sulfanes
Authors: Muller E. , Hyne J. B.
Published: May 2006

Sulfane crude oils obtained by acidification of aqueous sodium polysulfide solutions vary little in composition with varying sulfur content of the solution. Evidence presented suggests that the distribution of the sulfanes in such crude oils reflects the equilibrated distribution of the various polysulfide anions in the aqueous solution before acidification. The sulfane distribution in mixtures obtained by reaction of liquid H2S with Br2, SCl2, and S2Cl2 respectively varies over a wide range, depending on the molar ratio of the reactants. Liquid H2S reacts with Br2 or SCl2 to yield essentially the same products. These reactions, however, differ in the nature of their intermediates. By using a large excess of liquid H2S, H2S3 was directly synthesized in over 90% purity. Liquid H2S reacts with S2Cl2 to yield H2S4 in over 90% purity. Gaseous HCl catalyzes the reaction of H2S with the chlorosulfanes and a mechanism is suggested involving HCl as a proton transfer agent in the formation of the reactive intermediates.
Infrared and electronic spectral studies of 2-thiazolidinethione complexes of Co(II) halides
Authors: Singh P. P. , Rivest R.
Published: May 2006

Cobalt(II) halide complexes [CoX2•2L] (X = Cl, Br, I and L = 2-thiazolidinethione) and [CoL4] (ClO4)2 have been prepared. The infrared spectral study suggests that the probable site of bonding in the ligand is nitrogen. The results of electronic spectral study and magnetic susceptibility measurements indicate that the complexes are tetrahedral in structure. The various ligand field parameters Dq, B′, and β show about 80% covalency in the complexes and suggest a weak ligand field.
Reactions of thiyl radicals. V. The gas phase photolysis of methyl disulfide and ethyl disulfide mixtures in the presence of ethylene
Authors: Rao P. M. , Knight A. R.
Published: May 2006

The gas phase photolysis of methyl disulfide and ethyl disulfide and their mixtures, in the presence and absence of ethylene, has been studied at 25 °C and λ = 2300–2800 Å. The pure substrates give predominantly the corresponding thiol, whereas co-photolysis yields methyl ethyl disulfide in appreciably larger yields.When ethylene is added, the substrates individually show a reduction in RSH rate and the formation of relatively small amounts of sulfides. In their co-photolysis, added C2H4 does not appreciably alter the rate of methyl ethyl disulfide formation, indicating a low efficiency of RS scavenging by the olefin in this system.Isopropanol and 2,3-dimethyl butane do not increase the thiol yield from the pure substrates.
Synthesis of substituted quinazolone hydrazides: the relationship between chemical structure and monoamine oxidase inhibitory activity
Authors: Parmar Surendra S. , Arora R. C.
Published: May 2006

Several substituted quinazolone hydrazides were synthesized to investigate their ability to inhibit rat liver mitochondrial monoamine oxidase. The monoamine oxidase activity was measured manometrically as oxygen uptake during oxidative deamination of tyramine. All quinazolone hydrazides, except 2-methyl-3-(3′-benzhydrazide)-4-quinazolone and 2-methyl-6,8-diiodo-3-(4′-phenylacetylhydrazide)-4-quinazolone, inhibited monoamine oxidase activity when used at a final concentration of 3 × 10−4 M. Substitution at position-6 or positions-6 and -8 of the quinazolone nucleus increased enzyme inhibitory power of quinazolone hydrazides. Monosubstituted quinazolone hydrazides exhibited maximum inhibitory effects while disubstitution resulted in a decrease in their ability to inhibit monoamine oxidase.
Selective deshielding of aromatic protons in some ortho-substituted acetanilides
Authors: Bartels-Keith James R. , Cieciuch Ronald F. W.
Published: May 2006

Certain ortho-substituted acetanilides exhibit proton magnetic resonance signals at unusually low field for the amido proton and the aromatic proton adjacent to the acetamido group. This effect, explicable in terms of intramolecular hydrogen-bonding, has been observed for nitro, carbonyl, sulfamoyl, and sulfonyl substituents. Solvent effects are discussed.
Investigations on steroids. XL. 14,19-Dihydroxy-14β,17α-cortexone and other compounds derived from 17α-strophanthidol
Authors: Gupta Virendra N. , Ehrenstein Maximilian
Published: May 2006

As continuation of our early research on the synthesis of steroid hormone analogues of the 14β,17α-pregnane series (1–5,7), the conversion of 17α-strophanthidol (5) into 14,19-dihydroxy-14β,17α-cortexone (19) has been achieved.—In basic investigations the 3,19-diacetate (6), the 3-monoacetate (7), and the 19-monoacetate (8) of 5 were studied. Using independent routes 5 and 8 were converted into 3-oxo-14,19-dihydroxy-Δ4,2O(22)-14β,17α-cardadienolide(11).—In preparing 19,5 was first subjected to ozono-lysis yielding 3β,5,14,19,21-pentahydroxy-5β,14β,17α-pregnan-20-one (13) which was characterized as the 3,19,21-triacetate (14). Selective oxidation of 13 with N-bromoacetamide gave 5,14,19,21-tetrahydroxy-5β,14β,17α-pregnane-3,20-dione (18) which by treatment with Girard′s reagent T underwent dehydration yielding 19.—In degradation studies, oxidation of 13 with sodium periodate gave 3β,5,14,19-tetrahydroxy-5β,14β,17α-etianic acid (15) which was characterized as the methyl ester (16) and the corresponding 3,19-diacetate (17). In a similar fashion, oxidation of 19 with sodium periodate gave 3-oxo-14,19-dihydroxy-Δ 4-14β,17α-etienic acid (21) which was characterized as the methyl ester (22).—Regarding compounds 13 and 14 there are discrepancies with findings reported in the literature earlier. A discussion of this matter is included in this paper.14,19-Dihydroxy-14β,17α-cortexone (19) appears to exhibit sodium excreting activity in the adrenal-ectomized rat.
Imidazo(1,2-a)indole and s-triazolo(2,3-a)indole derivatives by intramolecular cyclization of 1-(o-acetylphenytyl)azoles
Authors: Khan Misbahul Ain , Polya J. B. , Lynch Brian M.
Published: May 2006

9-Hydroxy-9-methyl derivatives of the ring systems named in the title are formed along with the expected 1-(o-acetylphenyl)azoles in the Ullmann condensations of o-bromoacetophenone with imidazole and with 1,2,4-triazole. The structures of these compounds follow from their characteristic proton magnetic resonance spectra.
Electronic absorption spectra and photodecomposition of some substituted ferrocenes
Authors: Tarr A. M. , Wiles D. M.
Published: May 2006

The photostabilities of various ferrocene derivatives in solution have been studied as a function of solvent and, to a lesser extent, of incident wavelength. Some substituted ferrocenes, like ferrocene itself, did not decompose in methanol solution on exposure to near-ultraviolet light or sunlight; the remainder decomposed rapidly. Solutions of some derivatives in a number of other solvents also proved susceptible to photolysis. Qualitative evidence suggests that solute–solvent interaction leads to photo-chemically unstable species. Ferric ions do not appear to be formed in significant quantities during the degradative processes.Of the substituted ferrocenes investigated in this work, p-acetophenylferrocene appears to have considerable merit as a relatively stable and therefore protective light absorber. None of the derivatives, however, is as stable as ferrocene, which is prohibitively volatile for most practical applications.