bluuebunny/crossref_metadata_2025 huggingface dataset:
EXCESS VOLUMES, VAPOR PRESSURES, AND RELATED THERMODYNAMIC PROPERTIES OF THE SYSTEM ACETONE–CHLOROFORM–BENZENE, AND ITS COMPONENT BINARY SYSTEMS
Authors: Campbell A. N. , Kartzmark E. M. , Chatterjee R. M.
Published: May 2006

The volume changes on mixing of the three binary mixtures, acetone–chloroform, benzene–chloroform, acetone–benzene, and the ternary mixture, acetone–chloroform–benzene, and their molar refractivities and viscosities, were determined.Determinations of total and partial vapor pressures were made. The systems acetone–chloroform and benzene–chloroform show negative deviations from Raoult's law. The system acetone–benzene shows positive deviations.The excess Gibbs free energies of mixing have been calculated for all systems. By combining these data with previously measured heats of mixing (1), the excess entropy has also been calculated. The curves representing zero excess volume, zero heat of mixing, zero excess free energy of mixing, and zero excess viscosity as functions of composition in the ternary system do not coincide. It, therefore, must be concluded that they result from compensating effects and do not represent ideality.
AUTOMATIC DIRECT ANALYSIS OF A2B2NUCLEAR MAGNETICRESONANCE SPECTRA
Authors: Lim T. K. , Taurins A. , Whitehead M. A.
Published: May 2006

A method for complete direct analysis of A2Ba n.m.r. spectra is described. The number of possible combinations of spectral lines is reduced from 1 663 200 to 128 by classifying the lines into six pairs. The method is equally effective in analyzing both overlapping and non-overlapping line systems. The n.m.r. spectra of phenazine, 2,3-dimethylquinoxaline, thianthrene, naphthalene, and o-dichlorobenzene are analyzed; they give theoretical spectra which agree well with the observed spectra.
THE COPPER/SELENIUM SYSTEM
Authors: Heyding R. D.
Published: May 2006

not available
CONFIGURATION OF DIELS–ALDER ADDUCT OF FURAN AND ACETYLENE DICARBOXYLIC ACID
Authors: Kallos J. , Deslongchamps P.
Published: May 2006

The configuration of the Diels–Alder adduct (I) of furan and acetylene dicarboxylic acid was established by chemical and spectroscopic methods and found to be exo–exo (IIa).
CYANOESTERS AND DINITRILES:I. SYNTHESIS OF MALONONITRILES FROM METHYLENE ETHERS
Authors: Latif N. , Mishriky N.
Published: May 2006

α-(9-Fluorenylidene) malononitrile (V) is obtained by the interaction of malononitrile and 9,9-(tetrachloro-o-phenylenedioxy) fluorene (II) in boiling n-butanol. Whereas fluorenone phenyl- or benzoyl-hydrazone is similarly obtained by the action of the corresponding hydrazine on II, the latter also undergoes reductive cleavage by hydrazine hydrate to give fluorene and tetrachlorocatechol. The heteropolar structures of methylene ethers are stressed.Methyl-, ethyl-, isopropyl-, and benzyl-magnesium halides react readily with V to give the 9-dicyanomethyl-9-alkylfluorenes (VIIb–VIIe), respectively, which give, upon oxidation with alkaline potassium permanganate, the corresponding 9-alkylfluorene-9-carboxylic acids.α-(9-Xanthenylidene) malononitrile (VIa) reacts similarly with alkylmagnesium halides to give the corresponding 9-xanthenylmalononitriles (VIIIb–VIIId). However, V and VI are reduced by isobutylmagnesium iodide to give 9-fluorenyl- (VIIa) and 9-xanthenyl-malononitrile (VIIIa), respectively.Whereas the infrared spectra of unsaturated malononitriles and cyanoesters show strong absorption in the 4.5 μ region, the spectra of the saturated analogues lack this absorption.
STRUCTURE OF A GALACTURONAN FROM SUNFLOWER PECTIC ACID
Authors: Zitko V. , Bishop C. T.
Published: May 2006

Fractions of sunflower pectic acid containing 89.8%, 94.2%, and 91.4% of D-galacturonic acid were carboxyl reduced as their methyl or ethylene glycol esters by potassium borohydride. Critical assessment of the effects of three different solvents (water, 80% aqueous dimethyl sulfoxide, and 80% aqueous methanol) on the efficiency of reduction showed that the latter solvent was best. The reductions caused a decrease in the degree of polymerization from 270 to 21. Measurement of the rates of hydrolysis of partially reduced pectic acids containing 90%, 41.6%, 19.9%, 11.0%, and 0.65% of D-galacturonic acid showed that the rate of hydrolysis was directly related to the proportion of galacturonosidic linkages present. Methylation and hydrolysis of the carboxyl-reduced pectic acid fractions yielded 2,3,4,6-tetra-O-methyl-D-galactose and 2,3,6-tri-O-methyl-D-galactose in an approximate molar ratio of 1:20. Results of the periodate oxidation of the carboxyl-reduced pectic acid supported the conclusion inferred from the methylation results that the pectic acid was a linear polymer of 1 → 4 linked α-D-galacturonic acid units.
CONCERNING cis- AND trans-3-THIOCYANOPROPENAL AND THE SYNTHESIS OF ISOTHIAZOLE
Authors: Raap R.
Published: May 2006

not available
SOME NEW ROUTES FOR THE SYNTHESIS OF AROMATIC FLUORINE COMPOUNDS
Authors: Sharma H. L. , Sharma V. N. , Mital R. L.
Published: May 2006

not available
A PARAMAGNETIC RESONANCE STUDY OF HINDERED DIARYLMETHYL RADICALS AND RELATED COMPOUNDS: I. ANALYSIS OF THE SPECTRA
Authors: Falle H. R. , Adam F. C.
Published: May 2006

Several ortho-substituted radicals of the benzhydryl type and a variety of diaryl ketyls have been studied through the nuclear hyperfine structure of their electron spin resonance spectra. A strong similarity is found between the spectra of a given ketyl and its hydrocarbon analogue. This suggests that when ketones are reduced, a very tight ion pair is formed between the ketyl anion and its cation. Although the coupling constants of the protons vary with different reducing agents, larger variations are observed when bulky groups are substituted into ortho positions. These larger changes are attributed to a forced internal rotation of the phenyl rings. The distortion results from the steric repulsion between the ortho groups. The effect of 'buttressing' of ortho methyl groups is also studied. Deuterium and13C substitutions have been effected in some of the compounds.
HYDROGENOLYSIS BY LITHIUM ALUMINIUM HYDRIDE – ALUMINIUM CHLORIDE OF ETHER SOLUTIONS OF CAMPHOR ETHYLENE KETAL AND NORCAMPHOR ETHYLENE KETAL
Authors: Zajac Jr. W. W. , Rhee B. , Brown R. K.
Published: May 2006

The lithium aluminium hydride – aluminium chloride reductive cleavage of norcamphor ethylene ketal yields 2-(2-endo-norbornyloxy)ethanol in ≥98% yield, whereas the similar reduction of camphor ethylene ketal gives 2-(2-isobornyloxy)ethanol in 78% yield and 2-(2-bornyloxy)ethanol in 22% yield. These are the products arising from steric approach control.
A CONVENIENT METHYLATION PROCEDURE
Authors: Diner U. E. , Sweet F. , Brown R. K.
Published: May 2006

not available
THE DESCRIPTION AND USE OF A SPIN-ECHO SPECTROMETER TO STUDY CHEMICAL EXCHANGE
Authors: Abramson K. H. , Inglefield P. T. , Krakower E. , Reeves L. W.
Published: May 2006

A spin-echo spectrometer, suitable for studies of chemical exchange, is described. The performance of the apparatus is described and illustrated. From a Carr–Purcell sequence of pulses T2 measurements have been made using two alternative schemes for the correction of cumulative error in the width of π pulses. Agreement is satisfactory and the standard errors in each method are ± 5% of the average T2. The Meiboom and Gill method of phase-shifting the r.f. in the first pulse has the advantage of more flexibility in the choice of pulse intervals.A theory developed by Bloom, Reeves, and Wells for the dependence of T2 measured in a Carr–Purcell experiment on pulse intervals in the presence of a suitable exchange process has been tested experimentally for two molecules. The rate constants for the hindered internal rotation about the N=N bond in N,N -dimethylnitrosamine agree for the following sets of data: (a) a previous high-resolution study by Phillips, (b) a repeated high-resolution study made in this work, (c) spin-echo studies using the complete closed expression for a two site exchange process, and (d) the approximate expression derived for the limit of fast pulse repetition rates.A similar study by the spin-echo method of the rates of internal rotation about the C=N bond in N,N-dimethyltrifluoroacetamide does not agree with a previous high-resolution study. Since the chemical shift between the inequivalent methyl groups is so small, it is suggested that the rates of rotation in this molecule are much better evaluated by the spin-echo method.The spin-echo method can more easily take account of variations with temperature of the natural relaxation time and the chemical shift. The non-selective nature of an experiment with such a large H1 field remains a disadvantage at this time. The selective deuteration of sites unaffected by exchange is in general difficult enough to limit the scope of the spin-echo method when protons are observed.
HEATS OF ASSOCIATION OF AQUEOUS COPPER, NICKEL, AND COBALT IONS WITH HALIDE IONS
Authors: Kennedy M. B. , Lister M. W.
Published: May 2006

Calorimetric measurements are reported for the heats of formation of CoCl+, NiCl+, CuCl+, CoBr+, NiBr+, and CuBr+ from simple aqueous ions. Values of ΔF, ΔH, and ΔS for these reactions at 25 and 40 °C, and an ionic strength of 2.0 were found. It was noted that ΔH and ΔS seem to be related by the equation: ΔH = 254ΔS + 201, for values at both temperatures.
THE SYNTHESIS OF SOME 6,7-METHYLENEDIOXY- AND 6,7-DIMETHOXY-1,4-BENZOXAZIN-2-ONES
Authors: Orphanos D. G. , Taurins A.
Published: May 2006

3,4-Methylenedioxy-6-aminophenoil(I) and 3,4-dimethoxy-6-aminophenol (IV) were condensed with various α-ketoesters to give the corresponding 6,7-methylenedioxy- and 6,7-dimethoxy-1,4-benzoxazin-2-ones.
LIQUID-PHASE OXIDATION OF CYCLOHEXENE IN THE PRESENCE OF BENZALDEHYDE
Authors: Ikawa Tsuneo , Fukushima Toshiyuki , Muto Minoru , Yanagihara Tadahisa
Published: May 2006

The kinetics, at room temperature, of the oxidation of cyclohexene in the presence of benzaldehyde have been measured, and the nature of the products when this oxidation was performed at 70 and 110 °C has been studied. The results indicate that the attack of benzoyl peroxy radical on the double bond of cyclohexene retards the rate of oxygen absorption and also causes epoxidation of cyclohexene. The epoxidation of cyclohexene by peroxybenzoic acid (produced from aldehyde) seems to proceed simultaneously with the epoxidation by peroxy radicals during the oxidation of cyclohexene in the presence of benzaldehyde.
REACTIONS OF 2-ACETOXY-4,6-DI-O-ACETYL-3-O-(2,6-DICHLOROBENZOYL)-D-GLUCAL, TRI-O-ACETYL-3-DEOXY-α-D-erythro-HEX-2-ENOPYRANOSYL CHLORIDE, AND RELATED COMPOUNDS
Authors: Lemieux R. U. , Bose R. J.
Published: May 2006

Attempts to dehydrobrominate tri-O-acetyl-3-O-tosyl-α-D-glucopyranosyl bromide with diethylamine led directly to products resulting from the replacement of the tosyloxy group by the diethylamine. It was readily possible to prepare 2-acetoxy-di-O-acetyl-3-(2,6-dichlorobenzoyl)-D-glucal (V). Acetolysis of this compound gave an equimolar mixture of the α- and β-anomers (II and VI, respectively) of 2-acetoxy-di-O-acetyl-pseudo-D-glucal as the first products of the reaction. Compound V reacted only reluctantly with methanol in pyridine to give a mixture of the anomeric methyl di-O-acetyl-3-deoxy-D-erythro-hex-2-enopyranosides. These glycosides were readily prepared by reaction of tri-O-acetyl-3-deoxy-α-D-erythro-hex-2-eno-pyranosyl chloride with methanol in the presence of pyridine. 2-Acetoxy-di-O-acetyl-3-O-mesitoyl-D-glucal was prepared from 3-O-mesitoyl-β-D-glucose. The anomerizations of compounds II and VI were examined with both sulfuric acid in 1:1 acetic acid – acetic anhydride and potassium acetate in acetic acid. The conformations of II and VI are discussed, as are a number of the mechanistic features of the reactions studied.
DECOMPOSITION PRODUCTS OF 5-OXO-3,5-SECO-A-NORCHOLESTAN-3-OIC ACID p-TOLUENESULFONYLHYDRAZONE
Authors: Edward J. T. , L'Anglais Daphne , Meyerson Seymour
Published: May 2006

not available
ALKALINE PERMANGANATE DECARBOXYLATION OF β-AMINO-AND β-HYDROXY-PROPIONIC ACID
Authors: Unrau A. M. , Fan May-Lay
Published: May 2006

not available
HALIDE ALKOXIDES OF SAMARIUM: III. REACTIONS OF SAMARIUM ALKOXIDES WITH ACETYL CHLORIDE AND ACETYL BROMIDE
Authors: Sankhla B. S. , Kapoor R. N.
Published: May 2006

The reactions of samarium n-butoxide, isopropoxide, and tert-butoxide with acyl halides in different stoichiometric ratios have been studied and products of the type Sm(OR)2X, Sm(OR)X2•0.5CH3COOR and SmX3•CH3COOR (where R = C4H9n, C3H7i, or C4H9t and X = Cl or Br) have been isolated in quantitative yields. All these reactions are exothermic and the amount of heat liberated also increases with the increase in the concentration of acyl halide. These reactions have been further confirmed by the reactions with anhydrous samarium trichloride and the corresponding esters, which are also exothermic reactions. Attempts to sublime the dialkoxy monohalide derivatives of samarium were unsuccessful. The reaction of a dry current of hydrogen chloride gas on samarium isopropoxide has also been investigated.
THE CORRELATION OF ABSORPTION SPECTRA AND STRUCTURE OF PSEUDO-OCTAHEDRAL AND TRIGONAL BIPYRAMIDAL COPPER(II)–1,10-PHENANTHROLINE COMPLEXES IN ACETONE SOLUTIONS
Authors: Faye G. H.
Published: May 2006

By the use of elementary ligand field theory to interpret the absorption spectra of complexes formed in the copper(II)–1,10-phenanthrolene (Phen) system in an acetone medium, it has been shown that the mono-Phen complex is of approximately octahedral symmetry and the bis-Phen complex probably has a trigonal bipyramidal structure. At high Phen concentration, a tris-complex is formed that is probably trigonally distorted from octahedral symmetry. The results of the present work suggest that the "pentammine effect" observed in spectra of the copper(II)–ammonia complex is due to the formation of a trigonal bipyramidal complex.
THE IMPORTANCE OF INDUCTIVE EFFECTS IN α-SILYL AND α-GERMYL KETONES
Authors: Yates Keith , Agolini Franco
Published: May 2006

not available
ELECTROPHILIC REACTIONS OF STEROIDAL AND OTHER α-PHENYL DIENES
Authors: Douek Maurice , Just George
Published: May 2006

3-Phenylcholesta-3,5-diene (I) is shown to undergo electrophilic substitution reactions exclusively at the 6 position with formaldehyde – perchloric acid, acetic anhydride – aluminium chloride, and the Vilsmeier reagent.In the case of formaldehyde, the final product is "dimmer" II. The reaction is specific for formaldehyde and can be used to detect trace amounts of formaldehyde in, for example, commercial acetic acid and acetic anhydride.
THE REACTIONS OF THE DISODIUM ADDUCT OF BENZOPHENONE ANIL
Authors: Smith James G. , Veach C. Doreen
Published: May 2006

The disodium adduct of benzophenone anil has been treated with a variety of reagents, and the products have been isolated and identified. With alkyl halides, ethylene oxide, and diethyl sulfate, alkylation occurs at the carbon atom. With tri- and tetra-methylene dibromide, nitrogen alkylation also occurs, thereby producing substituted pyrrolidine and piperidine derivatives. Benzaldehyde abstracts the alkali metal from the adduct whereas esters react to form the N-acyl derivatives.
THE THERMAL DECOMPOSITION OF ETHANE: PART III. SECONDARY REACTIONS
Authors: Lin M. C. , Back M. H.
Published: May 2006

The kinetics of the secondary reactions producing methane, butane, and butene-1 in the pyrolysis of ethane have been investigated over the temperature range 550–726 °C and at pressures from 600–10 mm. The rate of secondary methane production was second order in ethylene at high pressures but was first order in ethylene at low pressures and high temperatures. In the latter region it is concluded that isomerization of the n-butyl radical to sec-butyl with subsequent decomposition to CH3 + C3H6 was the main source of methane. The rate of butane formation increased with time at low temperatures and decreased with time at high temperatures. It is shown that the decrease in rate was mainly due to the thermal dissociation of butane. The main source of butene-1 was probably decomposition of the n-butyl radical.
ELECTROPHILIC CATALYSIS IN SOLVOLYTIC REACTIONS: IX. INDUCTOMERIC EFFECT
Authors: Anantaraman R. , Nair M. R.
Published: May 2006

The rates of solvolysis of 1-(p-alkylphenyl)ethyl chlorides (Alk = Me, Et, i-Pr, and t-Bu) in the presence and absence of mercuric chloride have been measured in aqueous acetone and ethanol solvents. In all cases, the Baker–Nathan order is followed. For all normal reactions and for the catalyzed reactions in 90% aqueous acetone and 90% aqueous ethanol there is an increase in the heats and entropies of activation as the series is ascended, while for the catalyzed reaction in 75% and 80% aqueous acetone, there is a decrease. It is suggested that in the more aqueous acetone solvents the catalyst calls into play an inductomeric effect. The effect of added chloride ions on the rate of hydrolysis has been studied and the results are discussed.
AZAINDOLES: I. PREPARATION OF 7-AZAINDOLES BY THERMAL INDOLIZATION OF 2-PYRIDYLHYDRAZONES
Authors: Kelly A. H. , Parrick J.
Published: May 2006

The preparation of 2-pyridylhydrazones and their thermal indolization to 2- and 3-monosubstituted and 2,3-disubstituted 7-azaindoles, and to 3,3-disubstituted and 2,3,3-trisubstituted 7-azaindolenhies are described. Attempts to cause thermal indolization of two 2-(5-nitropyridyI)hydrazones were unsuccessful.
THIAZOLOISOQUINOLINES: I. THE SYNTHESIS OF THIAZOLO[4,5-c]ISOOUINOLINE
Authors: Hall Catherine E. , Taurins Alfred
Published: May 2006

Thiazolo[4,5-c]isoquinoline (I), a new heterocyclic ring system, has been synthesized from 3-aminoisoquinoline (II) in four steps by reaction with potassium thiocyanate and bromine to give 3-amino-4-thiocyanoisoquinoline (VII), cyclization with hydrochloric acid to yield 2-aminothiazolo[4,5-c]isoquinoline (VIII), Sandmeyer reaction to give 2-chlorothiazolo-[4,5-c]isoquinoline (IX), and finally reduction with hydrogen iodide and red phosphorus to yield I. The attempted preparation of I via 3-amino-4-bromoisoquinoline was unsuccessful. Various 2-substituted derivatives of I were prepared by nucleophilic displacement of the chlorine atom in 2-chIorothiazolo[4,5-c]isoquinoline. The nuclear magnetic resonance and ultraviolet spectra of I and some of its derivatives were studied.
THE REDUCTIVE DIMERIZATION OFN-BENZYLIDENE ANILINE
Authors: Smith James G. , Veach C. Doreen
Published: May 2006

The formation of alkali metal adducts of N-benzylidene aniline in several inert solvents is studied by protonolysis of the adducts and analysis of the reaction products, the diastereomeric N,N′,1,2-tetraphenylethylenediamines. With sodium and potassium metal in polar solvents, the product is predominantly the dd,ll diamine. With lithium metal or with solvents of low polarity, the product contains approximately equal quantities of the two diastereomers.It is demonstrated that the initially formed diastereomeric mixture generally contains appreciable amounts of the meso isomer. In polar solvents with sodium, isomerization to the stable dd,ll diastereomer occurs. However, with lithium or with sodium in nonpolar solvents, the isomerization does not occur. The reasons for the preponderance of the dd,ll-disodio compound in the equilibrating systems are discussed.
DEUTERIUM ISOTOPE EFFECTS ON HYDROGEN BONDING
Authors: Singh Surjit , Rao C. N. R.
Published: May 2006

The interaction of phenol and phenol-d with a number of donors of varying basicity has been studied in terms of the equilibrium constants, ΔS0, ΔH0, ΔvOH, and ΔvOD and various aspects of deuterium isotope effects on hydrogen bonding have been discussed. The deuterium isotope effects are found to vary markedly with the basicity of the donor and the results are discussed in terms of the zero point contributions to the KH/KD.
KIHARA POTENTIAL AND LENNARD-JONES AND DEVONSHIRE EQUATION OF STATE OF LIQUIDS AND DENSE GASES
Authors: Nagata Isamu
Published: May 2006

The Kihara potential has been applied to the Lennard-Jones and Devonshire cell theory in place of the Lennard-Jones potential. The expressions for the internal energy, heat capacity, and entropy, as well as the compressibility, are given in excess over those of a perfect gas. A comparison between experimental data and the present theory is made.
CYCLOBUTADIENE–METAL COMPLEXES: PART VIII. SYNTHESIS OF TETRAPHENYLCYCLOBUTADIENE NICKEL HALIDES BY LIGAND-EXCHANGE REACTIONS
Authors: Pollock D. F. , Maitlis P. M.
Published: May 2006

The preparation of cyclobutadiene nickel halide complexes (R4C4NiX2)2, where R is phenyl or substituted phenyl, by reaction of the palladium complexes, [R4C4PdX2]2, with a tert-phosphine metal complex, e.g. (n-Bu3P)2NiX2, is described. The reaction proceeds according to the equation[Formula: see text]Possible mechanisms are suggested.
RADICALS DERIVED FROM HETEROAROMATIG SYSTEMS: I. THIENYL RADICALS
Authors: MacKay Donald
Published: May 2006

The decomposition of 3-thenoyl and 5-nitro-2-thenoyl peroxides in aromatic solvents leads to 3-thenoyloxy and 5-nitro-2-thenoyloxy radicals, which decarboxylate to some extent to 3-thienyl (I) and 5-nitro-2-thienyl (IIa) radicals, respectively. Attack of these radicals on the solvent leads to the corresponding aryl thenoates and arylthiophenes. The Gomberg reaction of 5-carbomethoxy-2-thienylamine or the silver oxide oxidation of the related thienylhydrazine leads to 5-carbomethoxy-2-thienyl radicals (IIb). A mechanism for the formation of biphenyl, formed in small quantities in the decomposition of 5-nitro-2-thenoyl peroxide in benzene, is proposed.
SOME STEAM-VOLATILE COMPONENTS OF THE EXTRACTIVES FROM POPULUS TREMULOÏDES HEARTWOOD
Authors: Abramovitch R. A. , Koleoso O. A.
Published: May 2006

not available
A COMPARISON OF OPTIMIZATION METHODS FOR FITTING CURVES TO INFRARED BAND ENVELOPES
Authors: Pitha J. , Jones R. Norman
Published: May 2006

A comparison has been made of seven numerical methods of fitting infrared absorption band envelopes with analytical functions using nonlinear least squares approximations. Gauss and Cauchy (Lorentz) band shape functions are used, and also sum and product combinations of the two. The methods have been compared with respect to both the degree of convergence and to the computation time needed to achieve an acceptable fit.The most effective method has matched the overlap envelope of a steroid spectrum containing 16 bands; this necessitated the optimization of 65 variables. More complex spectra can be dealt with by a "moving subspace" modification in which only the parameters of a group of adjacent bands are adjusted at one time. Automatic computer programs have been written for five of the methods, and for the moving subspace modification. These will be published elsewhere.If the computed curve is convoluted with the spectral slit function before making the least squares calculations, the distortion of the observed spectrum caused by the finite spectral slit width can be corrected. In some cases this method of diminishing the slit distortion is better than direct methods, particularly when dealing with strongly overlapped bands.
MASS SPECTROMETRIC STUDY OF SUBLIMING SELENIUM
Authors: Fujisaki H. , Westmore J. B. , Tickner A. W.
Published: May 2006

In the mass spectrum of the vapor from grey selenium subliming in the temperature range 102 to 187 °C all possible Sen+ ions between n = 1 and n = 8 were detected in measurable quantities. The ions Se5+, Se6+, Se7+, and Se8+ arise mainly from ionization of the corresponding parent molecules, which are believed to be cyclic. At 175 °C the composition of the vapor is Se5 ≤ 29.0%, Se6 ≥ 57.5%, Se7 ≥ 11.4%, and Se8 ≥ 2.0%. Thermodynamic data are reported for the sublimation of these molecules. Small amounts of Se9+ and Se10+ were also detected.
Photochemistry of nitroso compounds in solution. V. Photolysis of N-nitrosodialkylamines
Authors: Chow Y. L.
Published: May 2006

N-Nitrosodialkylamines underwent photolysis in the presence of an acid. From the analysis of the end products, the primary photolysis products were shown to be [NOH] and the corresponding alkylideneimine, which underwent further reaction, e.g. (i) recombination of the two species to give amidoximes, (ii) hyponitrous acid formation, and (iii) hydrolysis or polymerization. A pathway is proposed for the reaction. Evidence is presented to show that the formation of the parent amines was not the result of hydrolysis of nitrosamines.
Substituted 1,2,3,4-tetrahydro-β-carbolines
Authors: DeGraw J. I. , Skinner W. A.
Published: May 2006

A series of 6-substituted 3- or 4-methyl- and 4,4-dimethyl-1,2,3,4-tetrahydro-β-carbolines was prepared by reduction of the appropriate 1,2,3,4-tetrahydro-1-oxo-β-carbolines. Lithium aluminium hydride was employed for all but the 3-methyl compounds, which required either sodium–butanol or diborane to effect the reduction. A simple preparation is also described for 5-halo-β-methyl- and 5-halo-β,β-dimethyl-tryptamines.
Sulfite complexes of 1,3,5-trinitrobenzene and related compounds
Authors: Norris A. R.
Published: May 2006

The interaction between 1,3,5-trinitrobenzene and sulfite ion has been studied by spectrophotometry. A new absorption band which cannot be ascribed to either of the components was observed at 462 mμ. From quantitative measurements of this band at various concentrations and temperatures, it was found that sulfite ion and 1,3,5-trinitrobenzene form a stable 1:1 complex with ΔH0 of − 4.00 ± 0.14 kcal mole−1 and ΔS0 of − 2.26 ± 0.50 e.u. (entropy units). At 25.3°C, the formation constant (K) for complex formation and the molar extinction coefficient (ϵ) of the complex are 2.67 × 102 l mole−1 and 2.35 × 104 l mole−1 cm−1 respectively. Values of K and ϵ for the complex formation reactions of sulfite ion with 2,4,6-trinitrotoluene and 2,4,6-trinitrobenzaldehyde are also reported.
Sulfur isotope effects in the hydrogen ion decomposition of polythionates
Authors: Agarwala U. , Rees C. E. , Thode H. G.
Published: May 2006

The sulfur isotope effects in the decomposition of tri-, tetra-, and penta-thionate have been studied. There are three distinct intermolecular and three distinct intramolecular isotope effects. The experimental results show that the decomposition of these polythionates may be described in terms of a model where the rate-controlling step is the cleavage of a sulfur–sulfur bond, and that the appropriate cleavage forms are (S2O32−) (SO3), (S3O3) (SO32−), and (S4O3) (SO32−) for tri-, tetra-, and penta-thionate, respectively.
High temperature solution calorimetry. Part 1. Development of a spherical solution calorimeter
Authors: Baboian R. , Laing D. , Flengas S. N.
Published: May 2006

A high temperature solution calorimeter of a novel design has been developed whereby the separated components are brought together and mixed within a completely enclosed, vacuum-sealed cell. The instrument consists of an inner spherical compartment containing the reaction cell, surrounded by a number of concentric spherical shells made of Inconel alloy. The calorimeter may be operated at temperatures up to 1 200 °C. The temperature-sensing circuit includes a differential thermopile, a d-c. microvolt amplifier, and a recording millivoltmeter. With this instrument calorific effects of the order of 0.1 cal could be detected.
L'effet de la concentration sur les propriétés thermodynamiques du polyméthacrylate de méthyle en solution
Authors: Léonard Jacques , Daoust Hubert
Published: May 2006

Osmotic pressures of polymethylmethacrylate in solution in ethylene dichloride and in dioxane have been measured at 25 °C for concentrations up to 24%. In both cases, the apparent second virial coefficient, S, increases rapidly with concentration to reach a plateau at approximately 8% in polymer, and then increases monotonically as predicted by the well-known Flory–Huggins theory. The theoretical treatments of Fixman and Yamakawa on moderately concentrated polymer solutions give very good correlations with the experimental data up to the plateau region.However, both theories cannot use the same set of molecular dimension parameters in order to obtain the best fit.
The alkaloids of Lycopodium cernuum L. II. The stereochemistry of cernuine and lycocernuine
Authors: Ayer W. A. , Jenkins J. K. , Piers K. , Valverde-Lopez S.
Published: May 2006

The relative stereochemistries of cernuine (I) and lycocernuine (II) have been derived by a combination of chemical and physical methods. Evidence is presented which indicates that I and II also represent the absolute stereochemistry of these alkaloids. The stereochemistry of allocernuine is discussed, and the isomerization of allocernuine into epiallocernuine is described.
Kinetics of α-chymotrypsin action. I. pH, solvent, and temperature effects
Authors: Kaplan Harvey , Laidler K. J.
Published: May 2006

An investigation has been made of the influence of pH on the kinetics of the α-chymotrypsin-catalyzed hydrolysis of N-acetyl-l-tyrosine ethyl ester, p-nitrophenyl acetate, and N-benzoyl-d- and -l-alanine methyl esters. From the pH variations of

[Formula: see text], and

[Formula: see text], it is deduced that in the free enzyme there are ionizing groups of pK 6.9 and 9.2. From the variation of these pK values with dielectric constant, it is concluded that, when protonated, one group is cationic and the other neutral. A temperature-dependence study was carried out on N–benzoyl-d- and -l-alanine methyl esters. The sharp break in the plot of log

[Formula: see text] against 1/T is attributed to a rapid reversible denaturation of the enzyme at the higher temperatures. In the low-temperature region, the activation energies are ΔEL = 16.2 ± 0.3 kcal/mole and ΔED = 16.5 ± 0.6 kcal/mole.
Kinetics of the recombination of methyl radicals with benzyl radicals
Authors: Kominar R. J. , Jacko M. G. , Price S. J.
Published: May 2006

The recombination of methyl and benzyl radicals has been studied over the temperature range 529 to 799 °K. The Arrhenius parameters for the recombination reaction are log A (cc mole−1 s−1) = 11.20, E = 0.20 kcal mole−1. The frequency factor at 1 000 °K for the reverse reaction, the dissociation of ethyl benzene, is calculated to be log A (s−1) = 14.9. A value of 70.5 kcal mole−1 has been estimated for D(C6H5CH2—CH3).
The radiolysis of ethanol. VI. Hydrogen precursors at −196°C
Authors: Fletcher J. W. , Freeman G. R.
Published: May 2006

Reactions of trapped (or solvated) electrons in solid ethanol have been studied. The following reactions occur at − 196 °C.

[Formula: see text]

[Formula: see text]

[Formula: see text]The activation energy of reaction [6] is roughly 5 kcal/mole. Reaction [7] occurs with electrons that have not yet been trapped by the medium.Hydrogen atoms appear to be able to abstract from ethanol and to add to propylene at − 196 °C.
Electron-impact study of some binary metal carbonyls
Authors: Bidinosti D. R. , McIntyre N. S.
Published: May 2006

The mass spectra and appearance potentials for the major ions from Ni(CO)4, Fe(CO)5, Cr(CO)6, Mo(CO)6, W(CO)6, and V(CO)6 have been measured. Heats of formation have been calculated for 39 ions of the type M(CO)n+, where M = Ni, Fe, Cr, Mo, W, and V. The mean metal–carbon bond dissociation energies have been calculated for both the neutral molecules and the parent ions. From a comparison with the available thermochemical data for the neutral molecules it is concluded that the mean vanadium–carbon bond dissociation energy is 28 kcal/mole and the heat of formation of V(CO)6 vapor is − 204 kcal/mole.
Stabilité des complexes hydroxo et produits de solubilité des hydroxydes de métaux. I. Argent et zinc
Authors: Gubeli A. O. , Ste-Marie J.
Published: May 2006

The hydroxo-complexes of silver and zinc are determined from a plot of their hydroxide solubility curves vs. pH, at 25 °C and unit ionic strength (NaClO4). The hydroxide solubility products and the formation constants of AgOH, Ag(OH)2−, ZnOH+, Zn(OH)2, Zn(OH)3−, and Zn(OH)42− are calculated.
Spectrometric studies of γ-irradiated sulfuric acid glasses
Authors: Russell J. C.
Published: May 2006

γ-Irradiated sulfuric acid glasses have been studied at low temperatures by optical spectrophotometry and electron spin resonance (e.s.r.) spectrometry. The effects of nitrous oxide and ferrous ion on the spectra were observed. Optical absorptions were found with maxima at 22 000 and 32 000 cm−1in the pure glass and at 41 000 cm−1in the presence of ferrous ion, as well as two e.s.r. absorptions. These were a poorly resolved triplet and a narrow singlet. The spectra, and the changes observed on warming, suggest the presence of three species in the glass: a free radical similar to the radical ion SO4−, a ferric ion precursor, and a third unidentified species formed with a small yield.
Structure et configuration absolue du cédrélanol (( − )-δ-cadinol), alcool sesquiterpénique C15H26O de l'huile essentielle Cedrela odorata brasiliensis
Authors: Smolders R. R.
Published: May 2006

not available
Addition reactions of acetylenic esters with substituted thioureas
Authors: Lown J. W. , Ma J. C. N.
Published: May 2006

Thiourea and monosubstituted and sym-disubstituted alkyl and aryl thioureas react with dimethyl acetylenedicarboxylate to give, in a good yield, 2,3-dihydro-1,3-thiazin-4-ones, and not thiazolidinones as has been claimed previously. Monosubstituted thioureas react to give 2-alkylimino compounds exclusively. The adducts can be hydrogenated to give the perhydro-thiazinones. High-resolution mass spectrometry of the dihydro- and perhydro-thiazinones shows many common fragmentations typical of the ring system and often characteristic of the type and position of substituents, which may be used to identify such compounds readily.
Synthesis and chemical reactions of some conjugated heteroenoid compounds
Authors: Silver R. F. , Kerr K. Ann , Frandsen Peggy D. , Kelley Sheila J. , Holmes H. L.
Published: May 2006

A series of 326 3-benzal-2,4-pentanediones, 2-benzal-1,3-indanediones, ethyl benzalaceto-acetates, diethyl benzalmalonates, ethyl benzalcyanoacetates, benzalmalononitriles, benzalcyanoacetamides, benzalcyanoacetanilides, benzalmalonamides, β-nitrostyrenes, β-nitropropenylbenzenes, β-nitrobutenylbenzenes, and derivatives of a number of cinnamic acids have been synthesized and their geometric configuration discussed. Aniline, p-toluidine, and n-butanethiol have been added to some of these compounds. The aniline adducts have also been prepared from benzylideneaniline and the active methylene compounds. The aniline adducts of those containing a cyano group are not stable and lose aniline at room temperature. The structure of the compound prepared from benzylideneaniline and ethyl cyanoacetate and melting at 140 °C has been established.
Catalytic Hydrogenation of Methylacetylene
Authors: Mann R. S. , Naik S. C.
Published: May 2006

The reaction between methylacetylene and hydrogen over supported and unsupported nickel catalysts has been investigated in a static constant volume system for a wide range of temperature and reactant ratios. The pressure–time curves consist of two linear portions of different slopes. The reaction over nickel is largely simple hydrogenation, the early stages being principally a selective production of propylene with small yields of reduced polymers of methylacetylene. The orders of the hydrogenation reaction are first and zero with respect to hydrogen and methylacetylene respectively. The overall apparent activation energies for nickel–pumice and nickel–kieselguhr are 16.8 and 14.0 kcal/mole and for unsupported nickel catalysts vary between 17.2 and 20.0 kcal/mole. A satisfactory "compensation effect" exists between the activation energies and logarithmic values of the pre-exponential factors. The unsupported catalysts were not poisoned when methylacetylene was added first to the reaction vessel.
Oxygen exchange between carbonate and bicarbonate ions and water. I. Exchange in the absence of added catalysts
Authors: Poulton D. J. , Baldwin H. W.
Published: May 2006

The reaction of carbon dioxide with water and hydroxide ions has been studied by measuring the rate of oxygen exchange between sodium carbonate and bicarbonate and oxygen-18 enriched water as a function of pH, ionic strength, and carbonate–bicarbonate concentration. It has been shown that these reactions are catalyzed by carbonate and bicarbonate ions. Rate constants for the uncatalyzed and catalyzed reactions have been evaluated.
Solution properties of polyvinylacetate by thermoelectric measurements
Authors: Sharma R. K. , Sirianni A. F.
Published: May 2006

An unmodified model 301 Mechrolab osmometer is used to determine the molecular weight of a series of polyvinylacetate polymers of relatively low degrees of polymerization in acetone, benzene, carbon tetrachloride, chloroform, and methanol. Anomalous results were obtained with chloroform. The solute–solvent parameter μ1 and molecular weight are calculated with the Flory–Huggins theoretical equation.
Application of the Fuoss–Onsager theory to conductance data for sodium and potassium iodide solutions in various solvents
Authors: Janz George J. , Tait Malcolm J.
Published: May 2006

The 1957 Fuoss–Onsager conductance equation has been used to analyze data for sodium iodide and potassium iodide solutions in 13 one-component solvents, ranging from water (dielectric constant 78) to pyridine (dielectric constant 12). Values of the unknowns Λ0, åJ, an ion size parameter, and, where appropriate, Ka, the ion association constant, are calculated. In solvents of high dielectric constant it is found that the salts are completely dissociated (Ka = 0) and the mean value of åJis 4.5 Å for each salt. However, the ion size parameters from the conductance equation do not seem to have any physical significance in solvents of lower dielectric constant, where there is evidence of ionic association. An analysis of these data is considered in which the Fuoss–Onsager equation reduces to a one-parameter equation, with Kaas the unknown. The conductance data for sodium and potassium iodide can then be understood if the closest distance of approach of the ions is 4.5 Å in all 13 solvents.
Pulse radiolysis studies XI. Protonation reactions of aromatic anions in some aliphatic alcohols
Authors: Arai Shigeyoshi , Tremba E. L. , Brandon J. R. , Dorfman Leon M.
Published: May 2006

The protonation reaction of aromatic anion radicals in the aliphatic alcohols,

[Formula: see text]has been investigated by the pulse radiolysis method. Activation energies for this reaction have been determined for the anthracenide anion and diphenylide anion in methanol, ethanol, and isopropanol, and for the naphthalenide anion in isopropanol. Absolute rate constants have been determined as well for the phenanthrenide, o-terphenylide, and m-terphenylide anions in isopropanol at 25 °C. The values for the rate constants, activation energies, and the pre-exponential factors are given. Those properties of the system which determine the kinetics are briefly discussed.
Pressure–temperature–composition relations in the system anthracene–phenanthrene
Authors: Brady M. Xavier , Smith Norman O.
Published: May 2006

A melting point and cooling curve study of the solid–liquid equilibria in the system anthracene–phenanthrene indicated the existence of a complete series of solid solutions. Investigation of the system anthracene–phenanthrene–Cellosolve at 40 °C revealed that the series is incomplete at this temperature. X-ray studies showed an upper consolute temperature at about 80 °C. The sublimation pressures and vapor pressures of the pure components were measured at temperatures not heretofore studied. Sublimation pressure data for solid solutions at 95 °C gave activity coefficients and indicated positive deviations from Raoult's law. Liquid–vapor isobars were obtained at pressures of 25, 50, and 100 mm, and vapor pressures of dilute liquid solutions of anthracene in phenanthrene found at temperatures near 100 °C. The data point to the existence of an azeotrope of short range. The univariant three-phase line was determined in respect to the pressure, temperature, and composition of the coexisting phases.All the above results were synthesized to give a fairly complete picture of the pressure–temperature–composition phase model, excluding critical phenomena.
Liquid diffusivities for the system methanol–toluene
Authors: Shemilt L. W. , Nagarajan R.
Published: May 2006

Measurements of the liquid diffusivities over the complete range of compositions of the methanol–toluene system at atmospheric pressure and 25°C have been carried out using the magnetically stirred porous diaphragm cell technique. Diffusivities calculated on the usual basis of concentration as driving force have a minimum of 0.80 × 10−5 cm2 s−1 at 0.4 mole fraction methanol. There is a threefold variation of diffusivity over the entire composition range, and the general behavior is similar to analogous nonideal systems. At infinite dilution none of the semi-empirical correlations, based on various models of the liquid state, give values in agreement with experiment.
Substituent effects on the chemical shifts of the bridge protons of benzonorbornenes
Authors: Inamoto Naoki , Masuda Shozo , Tori Kazuo , Aono Katsutoshi , Tanida Hiroshi
Published: May 2006

The substituent effects on the chemical shifts of the C9 bridge protons in a series of 6-substituted benzonorbornenes and benzonorbornadienes, and on those of the C2 protons in 5-substituted 2-indanols, were investigated. They were linearly correlated with the modified Hammett relationship τR − τH = ρ (σm + σp)/2. The ρ values obtained from the anti-C9 protons in the bornenes and bornadienes were slightly but significantly larger than those from the corresponding syn protons, whereas no significant difference was observed between the ρ values obtained from syn-9-benzonorbornenols and the indanols. The larger ρanti values were explained in terms of a stereospecific electronic interaction between the π-electron system of the benzene ring and the orbital system of the bridge carbon. In addition, it was shown that the above modified Hammett relationship gives generally a good agreement with the substituent effects on the aliphatic constituents of benzocyclenes and analogous compounds.
The dimethyl formamide – acyl halide complex and its application to the synthesis of acyl azides
Authors: Horning Donald E. , Muchowski Joseph M.
Published: May 2006

A description of the conditions which favor the formation of the acid chloride – dimethyl formamide complex is given. The utility of the complex is illustrated by its application to the synthesis of acyl azides and, in particular, by the selective formation of 3-bromopropionyl azide from the corresponding acid chloride. The complex also results from a carboxylic acid salt and N,N-dimethyl chloroformiminium chloride, and thus provides an alternative method of effecting the direct conversion of a carboxylic acid into the corresponding acid azide.
Alkylation by secondary alcohols. I. The reaction of xanthydrol with someN1-monosubstituted sulfanilamides and related compounds
Authors: Moskalyk R. E. , Chatten L. G.
Published: May 2006

Sulfanilamides were found to undergo alkylation with xanthydrol, yielding either mono- or di-xanthenyl derivatives. The site of substitution, common to all sulfanilamides having a free p-amino group, was shown to be the N4-position in the sulfanilamide molecule. Three additional unique reactive sites were observed. Sulfanilamides carrying a thiazole, thiadiazole, or pyridazine substituent in the N1-position were also alkylated on the annular nitrogen atom of the heterocyclic ring, the reaction having occurred from the imido tautomeric form. Sulfisoxazole (IK), on the other hand, reacted from the amido form to give the N1,N4-dixanthenyl derivative. Sulfadimethoxine (Ih) was substituted at carbon, as well as at nitrogen, to yield N4-xanthenyl-N1-(2,6-dimethoxy-5-(9-xanthenyl)-4-pyrimidyl)sulfanilamide.Sulfanilamides possessing pKavalues of about 5.5 were found to be sufficiently acidic to catalyze their own reaction with xanthydrol, and no external catalyst was necessary. The exceptional ease of formation of the xanthylium ion was postulated to be associated with the resulting stability of this carbonium ion by virtue of its acquired aromatic character.
Egonol. Spectrometric properties and derivatives
Authors: Hopkins C. Y. , Ewing D. F. , Chisholm M. J.
Published: May 2006

Egonol, a 2-phenylbenzofuranoid compound of known structure, was obtained from the seed oil of Styrax americana Lam. The nuclear magnetic resonance spectra of egonol and 3-nitroegonol were examined, and all of the proton signals were assigned. Egonoic acid and egonyl chloroacetate were prepared; their ultraviolet, infrared, and nuclear magnetic resonance spectra confirmed the structure of egonol. The content of egonol in oils may be estimated from the intensity of specified bands in the spectra.
Non-equivalence of vicinal proton–fluorine coupling constants in a CF3—CH2 group
Authors: Fraser Robert R. , Hanbury Paul
Published: May 2006

The proton magnetic resonance spectrum of the tetrahydropyranyl ether of 2,2,2-trifluoroethanol has been measured in several solvents and at different temperatures. Analysis of the ABX3 pattern produced by the trifluoroethyl group revealed a unique feature. Under all conditions, it was found that the vicinal coupling constants JAX and JBX had different magnitudes. This non-equivalence is interpreted as evidence that the C—HA and C—HB bonds of the trifluoroethyl group differ electronically. A possible relation between this finding and the anomeric effect is discussed. In contrast to the above results, the tetrahydropyranyl ether of ethanol showed equal vicinal proton–proton coupling constants in the ethyl group.
A stable, blue free radical from the oxidation of methyl tri-O-methylplicatate
Authors: Swan Eric P. , Landgraf William C.
Published: May 2006

An intensely blue compound was isolated from the reaction of 3-methoxycarbonyl-3-hydroxy-4-(3′,4′,5′-trimethoxyphenyl)-6,7-dimethoxy-2-tetralone with sodium periodate – sodium thiosulfate. It was shown to be a stable free radical, the probable structure of which was that of the ‘plicatoxy’ dimer III. Evidence for this structure is discussed. The reaction of the oxidant with several model compounds gave dimers formed by phenolic coupling.
An improved synthesis of β-hydroxysulfones via α-sulfonylcarbanions in liquid ammonia. The direct metalation of dialkyl and aryl alkyl sulfones
Authors: Tavares D. F. , Vogt P. F.
Published: May 2006

Dimethyl sulfone, methyl p-tolyl sulfone, ethyl p-tolyl sulfone, benzyl p-tolyl sulfone, and tetrahydrothiophene 1,1-dioxide were rapidly and quantitatively metalated by lithium amide (or potassium amide) in liquid ammonia, and the resulting organometallic compounds were added to a variety of carbonyl compounds to form the corresponding β-hydroxysulfones in good to excellent yields. The advantages of this method are speed, convenience, and versatility. Possible reasons for the failure of 1-phenyl-1-(p-tolylsulfonyl)methyllithium (XVIII) to form β-hydroxysulfones are discussed.
Antineoplastic agents. XIX. N-Bis(2-haloethyl)glycine amides
Authors: Pettit George R. , Chamberland Maurice R. , Green Brian
Published: May 2006

A number of routes to N-bis(2-fluoroethyl)glycine (IIIa) were explored. Of these, condensation between N-bis(2-fluoroethyl)amine and bromoacetic acid in tetrahydrofuran proved to be the most satisfactory. Reaction between a carbonic anhydride derivative of, for example, glycine IIIa and the appropriate aromatic amine provided the glycine amides summarized by structures IVb-IVi. Treatment of N-bis(2-chloroethyl)glycine hydrochloride with oxalyl chloride at steam-bath temperature yielded N-bis(2-chloroethyl)amine hydrochloride as the major product.