bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of some organophosphorus compounds: a study of the electron spin resonance spectra of the free radical anions formed by the reactions of 4,4′-bis(diphenylphosphine)biphenyl with alkali metals
Authors: Hnoosh Mahdy H. , Zingaro Ralph A.
Published: May 2006

By the halogen–lithium interconversion method, 4,4′-bis(diphenylphosphine)biphenyl (1) was prepared. Under different reaction conditions, mono- and di-oxygenated products were obtained. An attempt to prepare 1 by the Grignard reagent method failed to give the expected product but[Formula: see text]was obtained. Bis(diphenylamine)phenylphosphine was also prepared. Tetraphenyldiphosphine monoxide resulted from an attempt to prepare N-diphenylaminodiphenylphosphine. The mechanism of this reaction is discussed. Infrared spectroscopy, elemental analysis, and activation analysis for the determination of oxygen content were performed for the identification of the above compounds.Reactions of 1 with sodium–potassium alloy in tetrahydrofuran (THF) and 1,2-dimethoxyethane (DME) gave a radical anion which was identified by its electron spin resonance spectra at different temperatures.
Methods of numerical differentiation in the analysis of thermodynamic data for the mercury–solution interface
Authors: Fawcett W. R. , Kent J. E.
Published: May 2006

Methods of numerical differentiation for the calculation of surface charge densities and relative surface excesses from electrocapillary data are considered. Estimates of the random error in calculated derivatives are made by testing eight different differentiation methods with artificial data containing known levels of random error. The relative merits of these techniques and the number and spacing of data points needed to perform numerical differentiation precisely are discussed.
Long-range spin–spin coupling constants between ring protons and aldehydic protons in some para-substituted benzaldehydes
Authors: Danyluk S. S. , Bell C. L. , Schaefer T.
Published: May 2006

not available
Phosphinohydrazines. Part IV. Coordination compounds of N,N-dimethyl,N′-diphenylphosphinohydrazine and N,N-dimethyl-N′-diphenylthiophosphinatohydrazine
Authors: Ainscough E. W. , Peterson L. K. , Sabourin D. E.
Published: May 2006

A study of complexes of (a) N,N-dimethyl,N′-diphenylphosphinohydrazine, DPH, viz., Pd(DPH)Cl2, Pd(DPH)2Cl2, [Pd(DPH)2Cl]ClO4, Pt(DPH)2Cl2, Pt(DPH)Cl4, Hg(DPH)Cl2; (b) N,N-dimethyl,N´-diphenylthiophosphinatohydrazine, DPS, viz., Pd(DPS)Cl2, Pt(DPS)Cl4, Ag(DPS)NO3, Zn(DPS)Cl2, Cd(DPS)Cl2, and Hg(DPS)Cl2, and (c) N,N-dimethylhydrazine, DMH, viz., Zn(DMH)2Cl2 and Cd(DMH)Cl2, has been carried out using conductivity, molecular weight, infrared, and nuclear magnetic resonance measurements. DPH functions mostly as a unidentate ligand, with the phosphorus atom as the preferred donor site. Thus Pd(DPH)Cl2 is a chlorobridged dimer in solution in weakly polar solvents, while the monomeric form in polar solvents is of uncertain structure. A trans, four-coordinate structure is consistent for Pd(DPH)2Cl2. For [Pd(DPH)2Cl]ClO4, however, one DPH ligand is chelating through the phosphorus and terminal nitrogen atoms, while the second ligand is unidentate; the compound is a monomeric uni–univalent electrolyte in nitrobenzene. The ligand DPS appears to chelate via the sulfur and central nitrogen atoms, giving four-membered ring structures; a cis configuration is suggested for Pd(DPS)Cl2. Zn(DMH)2Cl2 is monomeric in solution, with the Me2N group coordinated to the metal.
Etude par résonance paramagnétique électronique de la radiolyse en phase solide de composés cycliques perfluorés
Authors: Chachaty Claude , Forchioni Alain , Shiotani Masaru
Published: May 2006

Perfluorocyclohexane (PFCH) and perfluoromethylcyclohexane (PFMCH) have been irradiated in the solid state by γ rays of 60Co. The electron spin resonance (e.s.r.) spectrum of PFCH irradiated at 77 °K corresponds mainly towhich is tumbling in the matrix above 160 °K and disappears at the transition point (180 °K). When γ irradiation is carried out at 200 °K, C6F11• is also produced, but reacts with PFCH giving a radicalsupposed to be [Formula: see text]The e.s.r. spectrum of PFMCH γ irradiated at 77 °K has not been identified; it might be attributable in part to (•C6F11CF3)−. Above 160–170° K, the e.s.r. spectrum corresponds only toThe equal coupling of the four γ fluorines and also the relative intensity 1:4:1 of the three main groups of lines observed above 210 °K suggest that ring inversion occurs with a high rate.We have also studied the radicals [Formula: see text]produced by γ irradiation in the presence of oxygen. The variation of their spectra with temperature, particularly near the transition points, is very characteristic of the motion involved.
Radiolysis of cyclohexane with perfluorocyclohexane at very high dose rates
Authors: Sagert N. H.
Published: May 2006

The radiolysis of liquid cyclohexane using perfluorocyclohexane as an electron scavenger has been examined at very high dose rates. The dose rates, 1027 to 1028 eV/g s, were such that geminate recombination of ions is essentially unaffected by dose rate, but high concentrations of radicals are produced, leading to radical–radical reactions. Up to 0.7 G units of the mixed dimer, C6F11•C6H11, were produced indicating that large concentrations of C6F11 radicals are formed in the neutralization process. Thus, at conventional dose rates (1016 eV/g s), C6F11H is probably produced by reactions of C6F11 radicals rather than by proton transfer to a perfluorocyclohexane or perfluorocyclohexyl anion.
Halogenation with N-haloamines in strong acids. II. Kinetics and rate constants
Authors: Spanswick J. , Ingold K. U.
Published: May 2006

The kinetics of the radical chain chlorination of decanoic acid by N-chlorodimethylamine and N-chloropiperidine in 2 and 4 M H2SO4 in acetic acid have been examined at 30°. The rate of reaction is proportional to the decanoic acid concentration and to the square root of the rate of chain initiation. The rate controlling step for propagation involves the attack of an aminium radical on decanoic acid, and termination involves the self-reaction of two aminium radicals. The latter reaction may involve the prior, rapid deprotonation of one or both radicals. The propagation rate constant has been estimated to be in the range 7 × 102 to 1 × 104 M−1 s−1 and the termination rate constant to be in the range 6 × 106 to 5 × 107 M−1 s−1.
Selenium tetrafluoride adducts. II. Adducts with boron trifluoride and some pentafluorides
Authors: Gillespie R. J. , Whitla A.
Published: May 2006

Adducts of selenium tetrafluoride with SbF5, AsF5, NbF5, TaF5, and BF3 have been investigated by means of infrared, Raman, and nuclear magnetic resonance spectroscopy and conductimetric and cryoscopic measurements. It is concluded that in the solid state these compounds are best formulated as having ionic structures SeF3+MF6−(BF4−), although the ions interact rather strongly by fluorine bridging. This fluorine bridging apparently persists in the molten state and to some extent in solution in nitrobenzene.
Electrochemical studies of yttrium and yttrium–zinc alloys in fused LiCl–KCl eutectic
Authors: Hoshino Yoshio , Plambeck James A
Published: May 2006

The electromotive force of cells of the type Y(s)/YCl3 + LiCl–KCl (eutectic)/Y–Zn alloy (saturated liquid) has been measured over the temperature range 450–570 °C. Thermodynamic values for the limiting solid YZn12 existing in this region are: ΔGf0, −48.7 kcal/mole at 450 °C; ΔHf0, −74.9 kcal/mole; ΔSf0, −36 cal/deg mole. The standard molar potential of the Y(III)–Y(0) couple was determined to be −2.831 V against Pt(II)–Pt(0).
Conditions in solution during the formation of gibbsite in dilute Al salt solutions. 4. Effect of Cl concentration and temperature and a proposed mechanism for gibbsite formation
Authors: Turner R. C. , Ross G. J.
Published: May 2006

Experiments were made to determine the effect of conditions in chloride solution on the formation of gibbsite. It was found that the temperature of the systems and the chloride concentration in solution had a marked effect on the rate of all the reactions occurring. In all cases gibbsite was identified as the final product, except when the temperature was 10 °C and when the chloride concentration was about 0.6 N. When the temperature was 10 °C the reactions were very slow, and there was no reason to believe that gibbsite would not have been the final product if sufficient time had been allowed. In the system in which the chloride concentration was about 0.6 N, the final product was an aluminum hydroxychloride. In all systems the concentration of polynuclear hydroxyaluminum ions started at relatively low values, increased with time to a maximum, and then decreased, while with the solids the reverse was true. A mechanism for the formation of gibbsite is proposed.
Dehydration of alcohols derived from 1-t-butyl-3-dimethylaminopropan-1-one; a novel cleavage reaction involving 2,6-dichlorobenzylmagnesium bromide
Authors: Casy A. F. , Ison R. R.
Published: May 2006

The acid-catalyzed dehydration of 1-t-butyl-3-dimethylamino-1-phenylpropan-1-ol gives cis(t-Bu/H)1-t-butyl-3-dimethylamino-1-phenylprop-1-ene exclusively. Dehydration of the product of reaction between 1-t-butyl-3-dimetnylammopropari-1-one and 2,6-dichlorobenzylmagnesium bromide gives cis and trans 2-t-butyl-1-2,6-dichlorophenyl-4-dimethylaminobut-2-ene plus the cis aminopropene of the first reaction. The formation of the aminopropene, together with that of its precursor tertiary alcohol, represents a novel cleavage reaction of 2,6-dichlorobenzylmagnesium bromide. The configurations of the aminoalkenes were established from proton magnetic resonance spectroscopic data, the cis(t-Bu/H)but-2-ene providing a further example of a magnetically non-equivalent t-butyl group.
A refinement of the crystal structures of K2ReCl6, K2ReBr6, and K2PtBr6
Authors: Grundy H. D. , Brown I. D.
Published: May 2006

The crystal structures of K2ReCl6, K2ReBr6, and K2PtBr6 have been refined using data collected on a single-crystal X-ray diffractometer to give weighted agreement indices ranging from 0.026 to 0.054 for 75 to 90 nonequivalent reflections. The following bond lengths were obtained: Re—Cl = 235 pm, Re—Br = 248 pm, Pt—Br = 246 pm, K—Cl = 348 pm, and K—Br = 367 and 364 pm in the Re and Pt compounds, respectively. The differences in the root-mean-square angles of libration of the MX62− ions in these and a number of isomorphous crystals are discussed.
Pyrochlores. VI. Preparative chemistry of sodium and silver antimonates and related compounds
Authors: Stewart David J. , Knop Osvald
Published: May 2006

A number of pyrochlore-structure antimonates MSbyOz (M = Na, Ag, K) have been prepared by dry-firing methods. Each M forms a series of compounds which adopt the pyrochlore structure up to a maximum ratio of M:Sb; the ratio depends on M. Antimony in these compounds is usually present simultaneously in trivalent and pentavalent states.The preparation of the above antimonates by wet methods was also examined. The products obtained were found to depend on the pH of the solution. In acid solution a polyantimonate ion exists which on addition of M salts leads to compounds of formula MSb3Oz, while in alkaline solution the Sb(OH)6− ion exists and MSb(OH)6 antimonates are obtained.A previous literature claim that NaSbO3 occurs with the pyrochlore structure has been disproved. It has been shown that NaSbyOz pyrochlore phases exist only for Na:Sb less than 1:1.5.The preparation of antimonates in the presence of Cl− and from hydrated reactants was carried out. It was concluded that neither Cl− nor OH− or H2O play a significant part in causing an antimonate of Na, Ag, or K to adopt the pyrochlore structure.
Orientation in nitration and sulfonation of 2,5-dimethylbenzoic acid
Authors: Fujiwara Allan N. , Acton Edward M.
Published: May 2006

Nitration of 2,5-dimethylbenzoic acid was only 29% at the meta2 position vs. 41% at the ortho, in contrast to sulfonation which was 85% meta vs. 15% para. Identity of the products (and of their derived amino esters and phenolic esters) was determined from the nuclear magnetic resonance spectra and confirmed by chemical means.
Some reactions of 4,4′-dimercaptooctafluorobiphenyl
Authors: Langille K. , Peach M. E.
Published: May 2006

The reactions of 4,4′-dimercaptooctafluorobiphenyl, HSC6F4C6F4SH, have been studied and compared with those of other thiols. Various metallic and non-metallic derivatives have been prepared and characterized. Polymerization occurred on oxidation or reaction with a multifunctional group or multivalent atom.
Hexanor–cucurbitacin D, a degraded cucurbitacin from Begoniatuberhybrida var. alba
Authors: Doskotch Raymond W. , Hufford Charles D.
Published: May 2006

A compound isolated from Begoniatuberhybrida has been shown to have the structure of hexanor–cucurbitacin D (3). Its diacetate is identical to the neriodate cleavage product of cucurbitacin B diacetate.
A determination of W and G(H2) values for methyl fluoride and fluoroform
Authors: Saca Mario , Lee R. A.
Published: May 2006

Methyl fluoride and fluoroform have been irradiated with gamma rays from a 1200-Ci 60Co source. Ionization currents were measured using a Pyrex parallel-plate-type ionization chamber. W values of 27.2 and 28.0 eV were determined for the two gases, CH3F and CHF3, respectively. The method employed was a comparative one, making use of the Bragg–Gray theory of cavity ionization. G(H2) yields of 4.20 and 1.25 for CH3F and CHF3, respectively, were then calculated from the above W values and the measured ion-pair yields for hydrogen. The formation of hydrogen is probably due to the fact that the C—H bonds in these compounds are weaker than the C—F bonds.
Preparation of an aromatic hydroxylamine and some cyclic hydroxamic acids, and their reaction with hydrochloric acid
Authors: Coutts R. T. , Pound N. J.
Published: May 2006

The reduction of 2,3-dimethyl-4-(o-nitrophenylthio)-1-phenyl-3-pyrazolin-5-one by sodium borohydride and palladium–charcoal gave the corresponding hydroxylamine. The action of hydrochloric acid on this hydroxylamine gave the p-chloroamine. In a similar manner, treatment of some 2H-1,4-benzothiazine and -benzoxazine hydroxamic acids with hydrochloric acid resulted in the formation of 7-chloro-2H-1,4-benzothiazine and -benzoxazine lactams.
Reactions of pentachlorothiophenol. I. Preparation of some simple metallic and non-metallic derivatives
Authors: Lucas C. R. , Peach M. E.
Published: May 2006

The preparation and properties of simple metal derivatives of pentachlorothiophenol are described: MSC6Cl5 (M = Na, K, Rb, Cs, TI, Cu, Ag, Au, Ph3Sn, n-Bu3Sn, Ph3Pb, Ph4As), M(SC6Cl5)2 (M = Zn, Cd, Hg, Ni, Pd, Pb, n-Bu2Sn, Sn), Ge(SC6Cl5)4, and Pt(SC6Cl5)3Cl. Non-metallic derivatives of group V, M(SC6Cl5)3 (M = P, As, Sb) and PhP(SC6Cl5)2 have also been prepared from Pb(SC6Cl5)2 and the corresponding non-metallic chloride. The infrared spectra of these compounds and the mass spectra of C6Cl5SH and (C6Cl5S)2 have been examined.
Confirmation of the dielectric polarization theory of anodic film formation: a voltage pulse technique for investigating Faradaic-current-driven polarization processes
Authors: Dignam M. J. , Taylor D. F.
Published: May 2006

Potentiostatic voltage-pulse experiments, carried out on anodically formed tantalum oxide films, show directly the existence of a dielectric polarization process which is driven by the passage of ion-current. Furthermore, quantitative analysis of the data yields a value for the constant coupling the polarization rate to the ion-current density, of the same order as that obtained from galvanostatic field transients, a result expected if the dielectric polarization of the film makes a large contribution to the effective field causing film growth. This experiment provides, therefore, convincing evidence in support of the main tenet of the dielectric polarization theory for anodic film growth (the ion-current-driven polarization process) with some support for the effective-field postulate also provided.
On the ionization of isobutyryl chloride
Authors: Paul Ram Chand , Sharma R. D. , Malhotra K. C.
Published: May 2006

Conductance, freezing point, and infrared studies of the solutions of isobutyryl chloride in disulfuric acid and in Lewis acids and bases show that it is a feebly self-ionized solvent. This finds further support from solvolytic reactions.
The effect of electron scavengers on the γ-radiolysis of gaseous H2S
Authors: Huyton D. W. , Woodward T. W.
Published: May 2006

The effect of the electron scavengers SF6 and N2O on the γ-radiolysis of gaseous H2S has been studied. Neither scavenger lowered the radiation yield of H2, G(H2). With added N2O, nitrogen was produced, though not in the amount Ge, the ion pair yield in H2S. Possible explanations of the findings are discussed.
Synthesis of methyl 4-O-methyl-α-DL-arabinopyranoside from 3-methoxy-3,4-dihydro-2H-pyran
Authors: Srivastava R. M. , Brown R. K.
Published: May 2006

3-Bromo-2,5-dimethoxytetrahydropyran (2), obtained by bromomethoxylation of 3-methoxy-3,4-dihydro-2H-pyran (1), was dehydrohalogenated to cis-2,5-dimethoxy-5,6-dihydro-2H-pyran (3). The epoxide 5, derived from 3, was converted to methyl 4-O-methyl-α-DL-arabinopyranoside (7) by treatment with aqueous potassium hydroxide. The structure and conformation of 7 and of its diacetate 8 were proven by analysis of their 100 MHz proton magnetic resonance spectra. Subsequent comparison with an authentic sample of methyl 4-O-methyl-α-L-arabinopyranoside corroborated the structural assignment.
Spectrométrie de masse des peroxydes organiques. III. Ozonides des styrènes substitués dans le noyau
Authors: Carles J. , Rousseau Y. , Fliszár S.
Published: May 2006

The mass spectrometry of the ozonides of ring substituted styrenes has been studied, with R = p-CH3O, p-CH3, H, p-Cl, m-Cl, and p-NO2. Electron withdrawing substituents favor, in general, the appearance of molecular ions. The intensities of the carbonyl fragments [Formula: see text] from the fragmentation of the molecular ions follow the Hammett relationship (ρ = −0.44), as does the formation of [RC6H4CH2]+ from [M-32]+ (ρ = −1.36) The relative abundance of [M-32]+ to that of the molecular ion is independent of R (ρ ≈ 0). The possible participation of electronically excited states in the primary fragmentation process of the m-chlorostyrene ozonide has been invoked to explain its particular behaviour.
Addition of nitromethane to L-idose. Stereochemistry of the Fischer–Sowden reaction
Authors: Kovář Jan , Baer Hans H.
Published: May 2006

The addition of nitromethane to aldoses giving 1-deoxy-1-nitroalditols (the Fischer–Sowden reaction) was extended to L-idose. Both epimeric products, 1-deoxy-1-nitro-L-glycero-D-ido-heptitol (1) and 1-deoxy-1-nitro-L-glycero-D-gulo-heptitol (2), were isolated in crystalline form, and 2 was shown to preponderate. The stereoselectivity is evaluated by a comparison of literature data on the Fischer–Sowden reaction of other hexoses, and attention is drawn to the importance of the C-3 configuration in the hexose, which appears to be the main factor influencing the ratio of epimers produced. An explanation in conformational terms is offered.
Kinetics of the oxidation of acetophenone by manganese(III) sulfate.
Authors: Nath P. , Banerji K. K.
Published: May 2006

The oxidation of acetophenone with Mn(III) is first order with respect to each of the oxidant and the ketone. The rate is independent of acidity and solvent composition. The thermodynamic parameters have been evaluated. A mechanism consistent with the observed data is proposed.
An inexpensive noise source for broad-band heteronuclear decoupling experiments
Authors: Burton R. , Hall L. D.
Published: May 2006

Experiments performed with trimethylphosphite demonstrate that music can be used as a source of "noise" for certain broad-band heteronuclear decoupling experiments.
Molar excess enthalpies, volumes, and Gibbs free energies of methanol – isomeric butanol systems at 25 °C
Authors: Polák Jiří , Murakami Sachio , Lam V. T. , Pflug H. D. , Benson G. C.
Published: May 2006

The vapor–liquid equilibria of the 4 binary systems formed by mixing methanol with n-butanol, isobutanol, sec-butanol, and tert-butanol were investigated at 25 °C in a dynamic still with circulation. The results were used to calculate the molar excess Gibbs free energies. For the three systems containing isobutanol, sec-butanol, or tert-butanol, molar excess enthalpies and volumes were also determined (mainly at 25 °C) by direct calorimetric and dilatometric techniques. The behavior of the excess properties is discussed with reference to differences in the hydrogen bonding and in the shapes of the component molecules.
Some pyrrolidone derivatives
Authors: Bailey K. , Rees A. H.
Published: May 2006

4-Cyano-3-hydroxy-2-oxo-3-pyrrolines are strongly acidic and form salts rather than enamines with strongly basic amines. We have revised the structures proposed for some of their derivatives and report the first synthesis of the parent compound 1 (R = H) and other new related pyrrolines.
Synthesis and properties of some α-D-alkyl glucosides and mannosides: apparent molal volumes and solubilization of nitrobenzene in water at 25 °C
Authors: Brown G. M. , Dubreuil P. , Ichhaporia F. M. , Desnoyers J. E.
Published: May 2006

Normal and cyclic α-D-alkyl glucosides and mannosides have been synthesized in a one-step procedure from the corresponding sugar. The apparent molal volume and the influence on the solubility of nitrobenzene of some of these glycosides have been measured in water at 25 °C. Evidence for micelle formation is presented for α-D-n-hexyl glucoside, -n-octyl glucoside, and -cyclohexyl mannoside. Comparison of the physical properties of the aqueous solutions shows that the stereochemistry of the sugar unit plays an important role in the hydrophobic hydration and hydrophobic interactions of the glycosides.
The equilibration of ortho- and para-hydrogen on alumina at 77 °K and its influence on the determination of small amounts of excess para H2, D2, and HD in the presence of large amounts of normal H2
Authors: Quickert K. A. , Roy D. J. Le
Published: May 2006

When alumina is activated sufficiently to separate excess para H2, D2, and HD in a gas–solid chromatographic column at 77 °K using normal H2 as the carrier gas, appreciable ortho-para equilibration takes place on the alumina. A kinetic study of the equilibration process was made, as the result of which procedures were established which made it possible to determine small concentrations of excess para H2 in the presence of normal H2. If D2 and/or HD are also present in the sample, the observed peak area for excess para H2 is subject to correction terms which are directly proportional to the concentrations of D2 and/or HD.
Stability constants of three iron(III) salicylates
Authors: McBryde W. A. E. , Rohr Janet L. , Penciner J. S. , Page J. A.
Published: May 2006

Stability constants of the iron(III) complexes of salicylic acid, sulfosalicylic acid, and 4-aminosalicylic acid, together with several of the acidity constants of these, have been determined at 25 °C and in solutions with 0.5 M background electrolyte. For the spectrophotometric measurement of the stability constants improved methods for determining the extinction coefficients of the first and second complexes are described. Protonated species appear only with the aminosalicylate complexes, and the site of this protonation is discussed. Previous values of these equilibrium constants have been collected and critically assessed.
Hydrogenolysis of steroid 3β-acetoxy-5-ene systems
Authors: Pettit George R. , Green Brian
Published: May 2006

Palladium catalyzed hydrogenation of 3β-acetoxy (or hydroxy)-5-ene-type steroids was shown to afford small amounts (5–10%) of the corresponding 3-deoxy derivatives. The hydrogenolysis reaction appeared general in scope and offers a one-step method for converting, e.g., cholesteryl acetate to 5α-cholestane.
New nitrochalcones. IX
Authors: Széll T. , Sohàr I.
Published: May 2006

not available
Spin–lattice relaxation in liquid ethylene chloride
Authors: Bock E. , Wollner G. , Tomchuk E.
Published: May 2006

The proton spin – lattice relaxation time of ethylene chloride in deuterated ethylene chloride was determined as a function of concentration and temperature over the temperature range 230 to 390 °K. It was found that the activation energy for the total spin–lattice relaxation as well as for the intra-molecular contribution to the total spin–lattice relaxation was 2.0 kcal/mole and was nearly equal to the activation energy for viscous flow, viz. 2.3 kcal/mole.
Thermogravimetric analysis of Ontario limestones and dolomites I. Calcination, surface area, and porosity
Authors: Chan R. K. , Murthi K. S. , Harrison D.
Published: May 2006

The calcination of natural Ontario limestones and dolomites in a flow of 100 cm3/min of nitrogen at 745 °C required from 0.43 ± 0.03 to 0.35 ± 0.05 min/mg of 100 mesh samples, respectively. The nitrogen adsorption isotherm at 77 °K for all the calcined samples belonged to the type II isotherm of the B.D.D.T. classification. There was hardly any hysteresis between the adsorption and desorption branches which implied that most of the pores were relatively large in agreement with independent measurements of the most probable pore diameter by an Aminco mercury intrusion porosimeter (~ 0.1 μ). The B.E.T. surface areas ranged from 13.6 to 34.2 m2/g of oxide calcined at 745 °C. The surface area decreased rapidly with increasing calcination temperature. At 1090 °C the surface area was less than 1 m2/g. The surface area was also related to percentage calcination, percentage calcium oxide in the sample, and size of the sample. A sample of pure magnesium carbonate calcined at 565 °C had an inordinately large surface area of 174 m2/g; pure calcium carbonate calcined at 745 °C, 15.2 m2/g. Using a model of non-intersecting cylindrical or square capillaries for the pore configurations, one could calculate the surface area, porosity, and bulk density of the calcined samples with satisfactory agreement.
Cobalt(II) and nickel(II) complexes of some bidentate imidazoline ligands. Stereochemically dependent derealization in the imidazoline rings
Authors: Lever A. B. P. , Ramaswamy B. S. , Simonsen S. H. , Thompson L. K.
Published: May 2006

Tetrahedral and octahedral cobalt(II), and square and octahedral nickel(II) complexes of 1,2-bis(2′-imidazolin-2′-yl)benzene, 1,2-bis(2′-imidazolin-2′-yl)ethane, and some imidazoline ring methyl substituted ligands are reported. The structures are confirmed by three X-ray structural analyses, magnetism, and electronic and vibrational (conventional and far i.r.) spectroscopy. Both cis and trans octahedral complexes of the type M(ligand)2(NCS)2 [M = Co(II), Ni(II)] have been characterized, and none of these exhibit splitting of the v(CN)(NCS) absorption in the i.r. spectrum at room temperature. Low temperature studies reveal splitting of the v(CN) band in the cis isomers. Both 13C and 15N satellite absorption is identified. The delocalization of the double bond in the imidazoline rings in these complexes is discussed in terms of the i.r. and X-ray data.
Lignans of western red cedar (Thujaplicata Donn). X. γ-Thujaplicatene
Authors: MacDonald Bruce F. , Barton G. M.
Published: May 2006

The structure of the tenth in the series of novel lignans from the heartwood of western red cedar (Thujaplicata Donn) has been determined as 2-(3″,4″-dihydroxy-5″-methoxybenzylidene)-3-(4′-hydroxy-3′-methoxybenzyl)-butyrolactone (γ-thujaplicatene) (1) by spectrometric methods and comparison with synthetic derivative reactions. The discovery of this lignan with a double bond conjugated with an aromatic ring confirms previously suggested biosynthetic routes to the cedar lignans.
Radicals derived from heteroaromatic systems. II. Thiazolyl radicals
Authors: Lee Mrs. A. L. , Mackay Donald , Manery E. L.
Published: May 2006

2-Thiazolylhydrazine and all three thiazole carbonyl peroxides have been synthesized and examined as radical precursors in solution in benzene, bromobenzene, and cumene. Silver oxide oxidation of the hydrazine or thermal decomposition of the 2-peroxide gives good yields of 2-arylthiazoles but negligible amounts of esters; in cumene a trace of bicumyl is formed. The isomer ratios in bromobenzene and cumene fully support the involvement of 2-thiazolyl radicals (1).The 4-carbonyl peroxide gives fair yields of 4-arylthiazoles but the phenyl ester is also a major product in benzene, indicative of reactions of both 4-thiazolyl radicals (2) and thiazole-4-carbonyloxy radicals. The 5-peroxide gives no products clearly diagnostic of 5-thiazolyl radicals (3) or thiazole-5-carbonyloxy radicals. Bicumyl is a major product of the reactions of the 4- and the 5-peroxides in cumene.
Synthesis of pyrazol-4-ols
Authors: Nye M. J. , Tang W. P.
Published: May 2006

3,5-Diphenylpyrazol-4-ol (4) has been prepared by four convenient routes starting with the following compounds: diphenylpropanetrione (1), 2-acetoxyl-1,3-diphenyl-1,3-propanedione (5), chalcone oxide (7), and 1,3-diphenyl-2-propanone (10).
Identification of 1-(4-methoxyphenyl)-1-methoxy-2-aminopropane diastereoisomers
Authors: Bailey K.
Published: May 2006

A method for the assignment of erythro and threo configurations to the diastereoisomeric 1-(4-methoxy-phenyl)-1-methoxy-2-aminopropanes and related compounds based on p.m.r. data is presented and discussed.
Chemical reactions in a Toepler pump
Authors: Johnson J. H. , Knipe R. H. , Gordon A. S.
Published: May 2006

Products have been generated in a Toepler pump from a variety of hydrocarbons and ketones. From the nature of the products, it is deduced that the mechanism must involve more processes than just mercury 3P0 sensitization. These observations suggest that trace products from samples taken with a Toepler pump may be at least partly artifactual.
Structural and conformational studies on tetrahydroprotoberberine alkaloids
Authors: Yu C. K. , MacLean D. B. , Rodrigo R. G. A. , Manske R. H. F.
Published: May 2006

Two new tetrahydroprotoberberine alkaloids are reported, one from Corydalisthalictrifolia and the other from Corydalistuberosa. The former is apparently identical with a previously described synthetic compound. The latter is a des-methyl derivative of the first. Both compounds are 13-methyltetrahydroprotoberberines in which the hydrogens at C-13 and -14 are cis to one another. An examination has been made of the p.m.r. spectra of the two new bases and of several 13-methyltetrahydroprotoberberines of established structure and stereochemistry. The spectra can be used to assign the relative stereochemistry of these 13-methyl compounds.
Deoxidation studies with cyclopropylcarbinol
Authors: Cessna A. J. , Lee C. C.
Published: May 2006

The liquid products from the deoxidation with cyclopropylcarbinol in KOH–CHBr3 were identified as cyclopropylcarbinyl, cyclobutyl, and allylcarbinyl alcohols, bromides, and the various ethers, with dicyclopropylcarbinyl ether as the most abundant product. In addition, small amounts of methylene bromide, cyclopropanecarboxaldehyde, and cyclobutanone were also found. The deoxidation with cyclopropylcarbinol-α-14C gave rise to isotopically scrambled cyclopropylcarbinol-x-14C, with about 22% of the 14C-label rearranged from C-α to the cyclopropyl group.
Bromination and chlorination of exo,exo-5,6- and endo,endo-5,6- dideuterionorbornene; on the mechanism of nortricyclyl bromide and chloride formation
Authors: Werstiuk Nick H. , Vancas Ivan
Published: May 2006

Proton (deuteron) loss from C-6 to form tricyclic product occurs with exo and endo stereoselectivity when bromine and chlorine, respectively, are added to exo,exo-5,6- and endo,endo-5,6-dideuterio-norbornene. These data strongly suggest that elimination occurs predominately from 6 in bromination and from 4 in chlorination or alternatively from the unsymmetrically bridged ions 2 and 3, respectively.
Total Synthesis of ( ± )-α-Cubebene and ( ± )-β-Cubebene
Authors: Piers Edward , Britton Ronald W. , Waal William De
Published: May 2006

An efficient total synthesis of the racemic forms of the novel tricyclic sesquiterpenes α-cubebene (1) and β-cubebene (2) is described. The key step of this synthesis involved the cupric sulfate catalyzed intramolecular cyclization of the olefinic diazoketone 3, which produced, in high yield, ( ± )-β-cubebene norketone (24) and ( ± )-1,6-epi-β-cubebene norketone (25), in a ratio of approximately 3:5, respectively.
A New Tetrahydroprotoberberine Alkaloid from Corydalis caseana A. Gray
Authors: Yu C. K. , Maclean D. B. , Rodrigo R. G. A. , Manske R. H. F.
Published: May 2006

The isolation and structure of a new tetrahydroprotoberberine alkaloid from C. caseana is reported. This alkaloid, named caseanadine, has a phenolic hydroxyl at C-1 and methoxyls at C-2, -9, and -10. Its structure has been deduced from an analysis of its p.m.r. mass, and i.r. spectra. The alkaloid has a substitution pattern different from other members of this group of alkaloids of established structure.
Studies on the Decomposition of Tetra-alkylammonium Salts in Solution. IV. The α-Deuterium Secondary Isotope Effect
Authors: Ko E. C. F. , Leffek K. T.
Published: May 2006

The secondary deuterium isotope effect is reported for the decomposition of benzyl-α-d2-phenyldimethylammonium bromide in both chloroform and acetone solvent, over a temperature range of 25 to 30°. The magnitudes of the rate ratios are compared to literature values for SN1 reactions, from which it is concluded that the mechanism of the decomposition involves a carbonium ion or ion-pair. The variation of the isotope effect with solvent is rationalized in terms of specific solvent interaction with the benzyl group.
Dipole moments, charge-transfer parameters, and ionization potentials of the methyl-substituted benzene–tetracyanoethylene complexes
Authors: Chan R. K. , Liao S. C.
Published: May 2006

not available
Biosynthesis of Lobinaline
Authors: Gupta R. N. , Spenser Ian D.
Published: May 2006

The biosynthesis of lobinaline (1) in intact plants of Lobelia cardinalis L. was studied by tracer methods. The incorporation data are consistent with the view that the alkaloid is formed by dimerization of α-phenacylpiperidine (3), whose piperidine nucleus is derived from lysine via a nonsymmetrical intermediate, and whose sidechain originates, as an intact C6–C2 unit, from phenylalanine via cinnamic acid.
Effect of an External Heavy Atom on the Photochemistry of Monofluorobenzene Vapor. II
Authors: Macbeath M. E. , Unger I.
Published: May 2006

The effect of added Xe on the singlet and triplet yields of monofluorobenzene vapor excited at 2670, 2520, and 2470 Å has been reinvestigated. The fluorescent yields, and hence the singlet yields, were monitored directly while triplet yields were determined by both the sensitized emission of biacetyl technique and the isomerization of olefins technique. The data obtained confirm that Xe enhances intersystem crossing in monofluorobenzene (1). However, contrary to results previously published from this laboratory (1), Xe does not quench the triplet state of biacetyl.
Activities and Ionic Distributions in Cobalt Silicate Melts
Authors: Smith I. B. , Masson C. R.
Published: May 2006

Activities of CoO in CoO–SiO2 melts were measured at 1450–1500 °C by equilibrating the melts, held in Pt–Rh containers, with atmospheres of known oxygen potential. Activities were calculated by the relationship[Formula: see text]where aCo, the activity of cobalt in the container, was determined in separate experiments.The results were compared with theoretical activity–composition curves based on the application of polymer theory to silicate melts. The results were in good agreement with theoretical curves calculated on the assumption of linear chains. In contrast, for all other binary silicate melts so far investigated the results are best represented in terms of theory in which all chain configurations are allowed. Ionic distributions and number average and weight average molecular weights were calculated as functions of the silica content from the experimental data. The calculated proportions of monomeric ion, SiO44−, dimer Si2O76−, and trimer Si3O108− were in reasonable agreement with experimental values based on trimethylsilylation and gas-chromatographic separation of the ionic constituents in quenched melts.
Thermal and Photochemical Ring Expansion of Some Phosphole Derivatives
Authors: Hughes A. N. , Srivanavit Chit
Published: May 2006

Pyrolysis and photolysis of 3,4,5-triphenyl-4-phosphabicyclo[3.1.0]hex-2-ene-4-oxide and the 1:1 adduct of diazomethane with 1,2,5-triphenylphosphole oxide lead to the formation of compounds of formula C46H36O2P2, andC46H34O2P2, respectively. These compounds are shown to be derivatives of the 4,4′-diphosphabi(cyclohexa-1,5-dienyl) and 4,4′-diphosphabi(cyclohexa-2,5-dienylidene) systems, respectively, and possible mechanisms for the formation of these systems are briefly discussed.
Alkaline Hydrolysis of 1-Iodomethyl-1,2,5-triphenylphospholium Iodide, a New Route to the 4-Phosphabicyclo[3.1.0]hex-2-ene System
Authors: Hughes A. N. , Srivanavit Chit
Published: May 2006

Alkaline hydrolysis of 1-iodomethyl-1,2,5-triphenylphospholium iodide gives 3,4,5-triphenyl-4-phosphabicyclo[3.1.0]hex-2-ene-4-oxide in very high yield. Three possible mechanisms are discussed and isolation of a key intermediate allows one of these mechanisms to be discarded. Alkaline hydrolysis of 1-allyl-1,2,5-triphenylphospholium bromide in methanol gives 1,2,5-triphenylphosphole and small quantities of a compound C26H27O2P which is an adduct of the original phospholium ion, hydroxide ion, and methanol.
2-Arylimino-1,3-thiaazacycloalkanes
Authors: Garmaise D. L. , Paris G. Y. , Efthymiadis G.
Published: May 2006

The reaction of ω-bromoalkyl isothiocyanates with aromatic amines served as a general preparative method for homologous 2-arylimino-1,3-thiaazacycloalkanes. Rings containing seven to thirteen members were prepared in this way. The isothiocyanates and some of the thiaazacycloalkanes had anthelmintic activity.
Radiation and Radiationless Processes in 2,3-Pentanedione; Phosphorescence Lifetime in the Gas Phase
Authors: Jackson A. W. , Yarwood A. J.
Published: May 2006

Fluorescence and phosphorescence are observed when 2,3-pentanedione in the gaseous state is excited at 365, 405, and 436°nm. The phosphorescence lifetime has been investigated as a function of temperature (298 to 363 °K) and concentration of the diketone (0.5 to 90 × 10−4 M). A mechanism that explains the experimental data is proposed. Apart from the radiative process and an intersystem crossing to the ground state, the triplet state 2,3-pentanedione molecules are removed by two other processes. One is a unimolecular reaction with a rate constant of 1 × 1011 exp (−11.0/RT) s−1 (consistent with an intramolecular hydrogen atom abstraction), and the other is an interaction with ground state molecules. The photochemistry of the triplet state of 2,3-pentanedione is compared with that of biacetyl to consider the effect of substitution of a hydrogen atom by the methyl group on the radiationless processes in diketones.
Polysaccharides of Soybeans. VI. Neutral Polysaccharides from Cotyledon Meal
Authors: Aspinall G. O. , Cottrell I. W.
Published: May 2006

An arabinan and the previously characterized arabinogalactan and acidic polysaccharide complex have been isolated by extraction of defatted and deproteinized soybean cotyledon meal with water. Methylation analysis involving gas chromatography – mass spectrometry of methylated alditol acetates formed from the methylated arabinan has shown that the parent polysaccharide is highly branched and of the same structural type as other arabinans associated with pectins. Methylated derivatives of mustard seed and lemon-peel arabinans and of soybean arabinogalactan have been similarly analyzed.
Comment: On the Decomposition of Aqueous Sodium Dithionite
Authors: Burlamacchi L. , Guarini G. , Tiezzi E.
Published: May 2006

The mechanism proposed by M. Wayman and W. J. Lem for the decomposition of dithionite ion in aqueous solution is reconsidered in the light of previous work done by the authors.
Electrophilic Additions to Ethylidenenorbornene and Vinylnorbornene
Authors: Shields T. C.
Published: May 2006

Electrophilic and free radical additions to 5-ethylidenebicyclo[2.2.1]hept-2-ene and 5-vinylbicyclo-[2.2.1]hept-2-ene have been carried out with peracetic acid, hydrogen chloride, and methanol. In contrast to chlorosulfonyl isocyanate, peracetic acid primarily attacks the exocyclic double bond in 5-ethylidenebicyclo[2.2.1]hept-2-ene. Several other electrophilic additions are discussed which demonstrate the unpredictable reactivity of the norbornyl system.
New Synthesis of Columbianetin and Related Coumarins
Authors: Steck Warren
Published: May 2006

2,4-Dihydroxy-3-(3-methyl-2-butenyl)benzaldehyde was obtained from 2,4-dihydroxybenzaldehyde with either 3-hydroxy-3-methyl-1-butene or 1-bromo-3-methyl-2-butene. Oxidation of the product in neutral medium with m-chloroperoxybenzoic acid gave (±)-2,3-dihydro-2-(1-hydroxy-1-methylethyl)-4-hydroxybenzofuran-5-aldehyde, whose condensation product with malonic acid was (±)-3-carboxy-columbianetin. Oxidation in acidic medium gave (±)-2,2-dimethyl-3,5-dihydroxybenzopyran-6-aldehyde, whose condensation product with malonic acid was (±)-3-carboxylomatin. (±)-Columbianetin and (±)-lomatin were obtained by decarboxylation.
Pyrolysis of Oxime Carbonates: Novel Conversion of Aldehydes into Nitriles under Mild Conditions
Authors: Prokipcak J. M. , Forte P. A.
Published: May 2006

A new synthesis of nitriles is reported based on the pyrolysis of oxime carbonates.
Total Synthesis of 4-O-Methyl-DL-lyxose and 4-Deoxy-DL-ribose. Further Evidence of the Stereoselective Hydroxylation of Double Bonds by Osmic Acid
Authors: Srivastava R. M. , Brown R. K.
Published: May 2006

Methyl 4-O-methyl-α-DL-lyxopyranoside (6) and methyl 4-deoxy-β-DL-erythro-pentopyranoside (3) were obtained in excellent yield as the sole isolable products of the reaction of osmic acid in pyridine on cis-2,5-dimethoxy-5,6-dihydro-2H-pyran (2) and 2-methoxy-5,6-dihydro-2H-pyran (1), respectively. Hydrolysis of 6 and 3 gave respectively 4-O-methyl-DL-lyxose (9) and 4-deoxy- DL-ribose (8).The attack on the double bond of 1 and 2 occurs nearly completely if not exclusively from the unhindered side, remote from the substituent. These results indicate that 1 must be predominantly in the conformation in which the C-2 alkoxy group is quasi axial.
Synthesis of 2,3,6,7,8,9-Hexahydro-1H-cyclohepta[gh]phenalene
Authors: Fischer A. , Leonard D. R. A. , Happer D. A. R.
Published: May 2006

2,3,6,7,8,9-Hexahydro-1H-cyclohepta[gh]phenalene (7) has been prepared via the tricyclic ketone 3-oxo-1,2,3,7,8,9,10,10a-octahydrocyclohepta[de]naphthalene (1) and the tetracyclic ketone 1-oxo-2,3,6,7,8,9-hexahydro-1H-cyclohepta[gh]phenalene (6). Conversion of the tricyclic ketone 1 into 1-oxo-1,2,3,3a,5,5a,6,7,8,9-decahydro-4H-cyclohepta[cd]phenalene (8) and reduction of this tetracyclic ketone to 1,2,3,3a,5,5a,6,7,8,9-decahydro-4H-cyclohepta[cd]phenalene (9), followed by aromatization, gave 5,5a,6,7,8,9-hexahydro-4H-cyclohepta[cd]phenalene (10) (73 %) together with the desired isomeric 2,3,6,7,8,9-hexahydro-1H-cyclohepta[gh]phenalene (7) (23%).
Sulfonyl Chloride Kinetics. Part II. Solvolysis of a Series of Benzenesulfonyl Chlorides: An Unexpected Heat Capacity Variation
Authors: Robertson R. E. , Rossal B.
Published: May 2006

First order rate constants for the solvolysis of a series of 4-X-benzenesulfonyl chlorides (where X = MeO, Me, Br, and NO2) were measured by the conductance method in H2O over the approximate temperature range of 0 to 25°. Pseudothermodynamic parameters, ΔG≠, ΔH≠ ΔS≠, and ΔCp≠ were derived and the high accuracy of the rate constants enabled an estimation of dΔCp≠/dT.A trigonal bipyramidal transition state is favored for the nucleophilic attack which is probably by an SN2 type mechanism. A novel explanation for the effect of 4-methoxy on ΔCp≠ involves a temperature dependent water–solute interaction, which has general applicability to the behavior of 4-methoxy substituents.
Semicarbazide Complexes with Metal Chlorides
Authors: Boldrini P.
Published: May 2006

Complexes of semicarbazide with bivalent metal chlorides were characterized. Crystal data are reported, together with some optical properties and general relations among their crystal structures.
The Effect of Pressure on the Aquation of Chromium(III) Complexes
Authors: Gay David L. , Nalepa Robert
Published: May 2006

The effect of pressure on the rates of aquation of Cr(NCS)63− and Cr(NH3)2(NCS)4− has been studied over the pressure range 1 to 2043 atm, at 50 ˆC. The activation volumes for these reactions are found to be 16 ± 2 and −2.4 ± 0.8 ml/mol, respectively. The pressure dependence of the activation volumes, (∂ΔV*/∂P)T, are 15 ± 5 and 0 ± 1 ml/katm mol, respectively. These results are consistent with a dissociative interchange (Id) process for the aquation of Cr(NCS)63− and an SN2 front-side process for the aquation of Cr(NH3)2(NCS)4−.
A 19F Nuclear Magnetic Resonance and Raman Spectroscopic Study of Complex Formation between Antimony Pentafluoride and the Pentafluorides of Niobium and Tantalum
Authors: Dean P. A. W. , Gillespie R. J.
Published: May 2006

The low temperature 19F nuclear magnetic resonance (n.m.r.) spectra of NbF5–SbF5–SO2ClF and TaF5–SbF5–SO2ClF systems appear to indicate ionization of the pentafluorides to form niobium (tantalum) fluorocations and antimony polyfluoroanions, but the solutions show an unusual distribution of species and have very low conductivities. It is concluded that neutral "fluxional" MF4–SbnF5n+1 molecules are formed. The 19F n.m.r. spectra and conductivities of the liquid systems NbF5–SbF5 and TaF5–SbF5 are consistent with the formation of neutral fluorine-bridged polymers with mixed transition metal and antimony units. These polymers may be "fluxional" on the n.m.r. time scale. The Raman spectra of the liquid systems and the crystalline pentafluoride mixtures show that both contain mixed cis fluorine-bridged units. The Raman spectrum of crystalline SbF5 and the 19F n.m.r. spectrum of the NbSbF11− ion are reported.
Dehydrogenation of 7,12-Dihydropleiadene Compounds with High Potential Quinones
Authors: Lown J. W. , Aidoo A. S. K.
Published: May 2006

Dehydrogenation with high potential quinones has been extended to dihydro derivatives of non-aromatic hydrocarbons using 7,12-dihydropleiadenes as models. Reaction of 7-phenyl-7,12-dihydropleiadene with high potential quinones resulted in dehydrogenative cyclization whereas preparative scale and rate studies in 9-aryl-9,10-dihydroanthracenes gave no evidence of aryl participation during quinone dehydrogenation due to geometrical restrictions on this system.
Infrared Combination Frequencies in Coordination Complexes containing Nitrate Groups in various Coordination Environments. A Probe for the Metal–Nitrate Interaction
Authors: Lever A. B. P. , Mantovani E. , Ramaswamy B. S.
Published: May 2006

The number and relative energies of nitrate combination frequencies in the 1700–1800 cm−1 region of the infrared spectrum may be used as an aid to distinguish the various coordination modes of the nitrate group. The data also provide an excellent probe for the strength of the metal–nitrate interaction.
A Possible Relationship Between Oxidation Rates of Alcohols and Their Carbon-13 Chemical Shifts
Authors: Perlin A. S.
Published: May 2006

Variations in the oxidation rates of alicyclic alcohols with chromate and of aldopyranoses with bromine, parallel variations in 13C chemical shifts for the carbinols. Accepting that these shifts closely reflect electron densities, mechanisms for these oxidations are depicted in terms of the minimal change in electron configuration required on passage from the ground to the transition state. A net flow of electrons from H-1 to C-1 is visualized for the chromate reaction, and hence relief of strain is associated in the transition state, as well as in the ground state, with a relatively high electron density on carbon. In the bromine oxidations, a net flow of electrons from C-1 to H-1 is visualized, which thereby allows for a sterically-dependent contribution by the ring oxygen atom to resonance stabilization of the transition state. These patterns are consistent with chromate and bromine oxidation mechanisms that now find wide acceptance.