bluuebunny/crossref_metadata_2025 huggingface dataset:
A SIMPLIFIED PROCEDURE FOR THE ANALYSIS OF COMPLEX NUCLEAR MAGNETIC RESONANCE SPECTRA: II. THE ANALYSIS OF SYMMETRICAL TRIFLUOROBENZENE, THE AA′A″XX′X″ SYSTEM
Authors: Jones R. G. , Hirst R. C. , Bernstein H. J.
Published: May 2006

The analysis of the six spin AA′A″XX′X″ system consisting of two sets of three chemically equivalent nuclei with spin [Formula: see text] and four coupling constants JAA, JXX, JAX, and JAX′ has been developed with the use of group theory and the appropriate Hamiltonian. It is found that there will be differences in the A and X spectra if JAX ≠ JAX′ and simultaneously JAA ≠ JXX. If JAA = JHH the A and X spectra become identical. If JAX = JAX′ each spectrum of course becomes trivial.The complex n.m.r. spectrum of the AA′A″XX′X″ can be decomposed into subspectra, and the analysis of the nuclear magnetic resonance spectra of symmetrical trifluorobenzene has been carried out in this manner. The experimental proton and fluorine spectra of this molecule exhibit marked differences. Calculated spectra have been fitted to the experimental spectra and the following values of the coupling constants have been found:[Formula: see text]The sign of JHH is the same as the sign of JHF•JHF and JHF′ have opposite signs. It is not possible to relate the signs of JHH and JFF to the signs of JHF and JHF′ in this type of spectrum. However, comparison of the signs of couplings in related molecules suggest that JHF, JHH, and JFF have the same sign.
PYROLYSIS STUDIES. XIV. THE PYROLYSIS OF t-BUTYL BENZOATES
Authors: Smith Grant Gill , Yates Brian L.
Published: May 2006

not available
THE CHEMICAL SHIFT OF THE HYDROXYL PROTON OF PHENOLS IN DIMETHYL SULFOXIDE
Authors: Ouellette Robert J.
Published: May 2006

not available
BIOSYNTHESIS OF COLCHICINE. TRACER STUDIES WITH CINNAMATE-3-14C, METHANOL-14C, AND ORNITHINE-2-14C
Authors: Hill R. D. , Unrau A. M.
Published: May 2006

not available
SOME BASE-CATALYZED CONDENSATIONS OF SYSTEMS OF THE FORM R1R2C=C(CN)2
Authors: Weir Mary R. S. , Hyne J. B.
Published: May 2006

We have investigated the condensations of the systems [Formula: see text] and CH3HC=C(CN)2 in the presence of organic bases. Proton nuclear magnetic resonance (n.m.r.) spectral evidence is presented in support of the suggested structures of the condensation products, and an attempt has been made to present diagrammatically the interrelation between these condensations and other known reaction pathways for condensations of this type.
COORDINATION COMPLEXES OF GROUP (IV) HALIDES: PREPARATION OF THE COMPLEXES OF TITANIUM TETRACHLORIDE, TITANIUM TETRABROMIDE, AND TIN TETRACHLORIDE WITH SOME THIO-, ISOTHIO-, AND ISO-CYANATE LIGANDS
Authors: Jain Sumer Chand , Rivest Roland
Published: May 2006

Coordination complexes between ethyl thiocyanate, ethyl isothiocyanate, ethylene dithiocyanate, ethyl isocyanate, and tetrachlorides of titanium and tin and titanium tetrabromide have been prepared. The analytical results indicate that under different experimental conditions one can obtain compounds of the following type:[Formula: see text]where MX4 is a Lewis acid and L, L—L are mono- and bi-dentate ligands respectively. The complexes obtained are compared with the dinitrile complexes prepared by us previously (1).
CHASMANINE AND ITS STRUCTURE
Authors: Achmatowicz Jr. O. , Tsuda Y. , Marion Léo , Okamoto T. , Natsume Mitsutaka , Chang Hong-Hsi , Kajima K.
Published: May 2006

The alkaloid chasmanine, C25H41O6N, isolated from A. chasmanthum contains four methoxyl and two hydroxyl groups as well as an imino-ethyl. It undergoes the usual pyrolytic reaction and the unsaturated product, pyrochasmanine, C25H39O5N, gives rise to an acid-catalyzed allylic rearrangement product, isopyrochasmanine. Pyrochasmanine, on treatment with lithium aluminium hydride, is demethoxylated. It can be concluded that the base, like bikhaconine, contains the sequence [Formula: see text]. Chasmanine can be oxidized to a compound containing a cyclopentanone ring so that its second hydroxyl must be secondary and located on a five-membered ring. It is possible to benzoylate the secondary hydroxyl and acetylate the tertiary hydroxyl. The n.m.r. characteristics of the resulting double ester determine the location of these two groups and their stereochemistry. The relative position of two of the remaining methoxyl groups is established via a demethylation reaction resulting in the formation of a cyclic ether. All the chemical reactions studied are in agreement with structure IV (R = R′ = H) for chasmanine. There is, however, no positive proof for the location of the fourth methoxyl and it has been placed in ring A by analogy. An attempted correlation with bikhaconine is described.
REACTION MECHANISM STUDIES: 3. SOLVENT EFFECTS AND THE NATURE OF THE TRANSITION STATE IN THE DIAXIAL → DIEQUATORIAL REARRANGEMENT
Authors: King J. F. , Pews R. G.
Published: May 2006

The rates of the diaxial → diequatorial rearrangement of 2β,3α-dibromocholestane (Ia), and the analogous bromohydrin p-toluenesulfonates (Id and Ie) and anisates (If and Ig) have been measured in various solvents. The change in rate with variation in solvent was found to correlate with the change in the ionizing power of the solvents. The sensitivity of the rate of rearrangement to changes in solvent ionizing power, as measured by the ratio of the rate of rearrangement in nitromethane to that in decalin, was found to be smaller for the dibromide (Ia) than for the esters (Id to Ig). A detailed discussion of the mechanism of the reaction is presented. It is proposed that the following factors (either singly or simultaneously) could lead to the smaller sensitivity to solvent change shown by the dibromide (Ia) as compared with the esters (Id to Ig): (1) a difference in a postulated change of the axial: equatorial opening ratio with change in solvent, and (2) the development of a smaller charge in the transition state for the rearrangement of the dibromide (Ia) as compared with that in the rearrangement of the esters, when the reactions are carried out in the less polar solvents. It is argued that the operation of the latter factor would be most simply interpreted in terms of a merged ion-pair, cyclic-concerted mechanism, as initially suggested by Grob and Winstein.
SLIP FLOW IN LONG, SINGLE CAPILLARIES: PART II. STEADY-STATE FLOW AND SPECULAR REFLECTION
Authors: Barrer R. M. , Nicholson D.
Published: May 2006

The steady-state slip flow of the rare gases (He, Ne, Ar, Kr, and Xe) and of propane, CO2, and SO2 has been studied at different temperatures in long, single glass capillaries. The results give values of viscosity which are in agreement with literature values when Ar is used as a calibrating gas. The results can be expressed as a linear plot of the non-dimensional permeability ratio K/K0 against reciprocal Knudsen number; the intercept on the K/K0 axis is a. The value of this intercept depends on both gas and temperature being higher for light gases and high temperatures than for more condensable gases and low temperatures. The parameter a is therefore replaced by ((2 – β)/β)a1 where (1 – β) is the so-called specular reflection coefficient and a1 is a constant. The factors affecting (1 – β) have been discussed. It is suggested that contributions to (1 – β) will arise both from elastically and from inelastically scattered molecules, and the magnitude of these contributions is assessed in terms of the properties of the gas and the surface. The expression finally obtained is compared with experimental values of (1 – β).
THE STRUCTURE OF A SYNTHETIC ARABINAN
Authors: Dutton G. G. S. , Unrau A. M.
Published: May 2006

Hydrolysis of the fully methylated synthetic arabinan showed it to have a highly branched structure in which about 16% of the terminal units were furanose and 2,3-di-O-methyl-L-arabinose was the principal di-O-methyl ether. A method has been developed whereby mixtures of isomeric di- or mono-O-methyl arabinoses may be qualitatively analyzed by successive borohydride reduction, periodate oxidation, and borohydride reduction. The resulting fragments may be separated directly by vapor phase chromatography or by paper chromatography after demethylation.
AROMATIC SUBSTITUTION: PART IX. ON THE MECHANISM OF THE PSCHORR CYCLIZATION
Authors: Abramovitch R. A. , Tertzakian G.
Published: May 2006

The decomposition of the diazonium salt from 3-(o-aminobenzoyl)pyridine has been studied under various conditions. A competitive-type cyclization of an equimolar mixture of the diazonium salts of 2-aminobenzophenone and 2-amino-3′-nitrobenzophenone has also been carried out. The results are interpreted in terms of a radical process in the copper-catalyzed reactions. It is suggested that the uncatalyzed thermal decompositions in aqueous acid solution give rise to a diradical cation intermediate in equilibrium with the aryl cation.
THE REACTION OF GALACTOSE WITH HYDRAZINE AT ELEVATED TEMPERATURE
Authors: Jones J. K. N. , Reid P. , Turvey J. R.
Published: May 2006

not available
THE ALKALOIDS OF FUMARIACEOUS PLANTS. LII. A NEW ALKALOID, CULARICINE, AND ITS STRUCTURE
Authors: Manske Richard H. F.
Published: May 2006

not available
ERRATUM: EFFECTS OF pH IN THE γ-RADIOLYSIS OF AQUEOUS SOLUTIONS OF CYSTEINE AND METHYL MERCAPTAN
Authors: Armstrong D. A. , Wilkening V. G.
Published: May 2006

not available
LOCALIZATION OF THE C=Se VIBRATION IN THE INFRARED SPECTRA OF SELENOSEMICARBAZONES
Authors: Gingras B. A. , Suprunchuk T. , Bayley C. H.
Published: May 2006

Few organic compounds of selenium are known and, consequently, very little published data are available concerning the various vibrations around the selenium atom. The present paper discusses the C=Se vibration in selenosemicarbazones by comparing their infrared spectra with those of corresponding Se-benzyl derivatives in which the C=Se group has been replaced by a C—Se—Bz. On this basis, it can be seen that a band at 800–780 cm−1in the spectra of selenosemicarbazones is absent in the spectra of the benzyl derivatives. This band is assigned to the C=Se vibration.
SURFACE CHEMISTRY AND CATALYTIC PROPERTIES OF BORON PHOSPHATE: 1. SURFACE AREA AND ACIDITY
Authors: Moffat J. B. , Goltz H. L.
Published: May 2006

Surface properties of the dehydration catalyst, boron phosphate (BP), prepared by the reaction of triethyl borate and phosphoric acid, were investigated by the use of a microbalance system. During evacuation at elevated temperatures, weight changes of the BP were obtained. Nitrogen adsorption isotherms were measured after each treatment. Surface areas appear to increase, and reach a maximum in the range 200–300 °C. Weight changes are initially large but begin to level off as the temperature is increased. Ammonia isotherms were obtained at 25.00 °C on aliquots of the same BP sample after various pretreatments. Amounts of ammonia remaining adsorbed after evacuation overnight were taken as the quantity chemisorbed. An approximate value of 8.9 kcal/mole of ammonia was obtained for the heat of chemisorption of ammonia by measuring the pressure and weight change as the amount of chemisorbed ammonia is decreased on heating the BP to various temperatures in a closed system. Results are interpreted in terms of change of number of active sites with surface area and the deactivation of sites on loss of water.
TELLURATE COMPLEXES OF NICKEL, PALLADIUM, AND PLATINUM, AND A PERIODATE COMPOUND OF NICKEL
Authors: Lister M. W. , McLeod P.
Published: May 2006

The periodate or tellurate complexes of nickel, palladium, and platinum have been examined. The preparation of NaNi2IO6•2H2O, NaNi4(H3TeO6)3•6H2O, Na6Ni(H3TeO6)3•H2O, Na9H5Ni2 (TeO6)3, Na5H3Pd(TeO6)2•4H2O, and Na5H3Pt(TeO6)2•2H2O is described.
9,10-DIMETHYL- AND 9,10-DIPHENYL-9,10-DIHYDRO-9,10-ETHANO-ANTHRACENE BY FRIEDEL–CRAFTS CYCLIALKYLATIONS OF 1,4-DIARYLSUBSTITUTED-1,4-DIOLS
Authors: Barclay L. R. C. , Chapman Ralph A.
Published: May 2006

The 1,4-diols, 2,5-diphenylhexane-2,5-diol (Ia), and 1,1,4,4-tetraphenylbutane-1,4-diol (Ib) were found to undergo intramolecular cyclodehydrations and dehydration yielding 9,10-disubstituted-9,10-dihydro-9,10-ethanoanthracenes, 2,2,5,5-tetrasubstituted-tetrahydrofurans, and 1,1,4,4-tetrasubstituted-1,3-butadienes when treated with hydrogen fluoride or aluminium chloride. No evidence could be found for intermolecular cyclialkylations of added aromatics such as benzene, anisole, or veratrole. Nuclear magnetic resonance spectra of the products are discussed.
THEORETICAL STUDIES ON THE ELECTRONIC SPECTRA OF SUBSTITUTED AROMATIC MOLECULES: PART III. SEMIEMPIRICAL SCF CALCULATIONS FOR POLYCYCLIC ALTERNANT HYDROCARBONS
Authors: Bloor J. E. , Brearley N.
Published: May 2006

The effect of changing the method of calculating repulsion integrals within the framework of the semiempirical self-consistent field method is investigated with respect to the transition energies of the alternant hydrocarbons benzene, anthracene, phenanthrene, and pyrene. Of the methods investigated, the one originally suggested by Mataga gave the best agreement with experiment. By statistical analysis of the linear relationship between the internuclear distance rpqand the bond order ppq, the regression line[Formula: see text]was obtained.The success of the Hückel LCAO procedure in correlating observed p-band transition energies with the Hückel energy number[Formula: see text](NP = No. of atoms contributing π electrons) for the highest occupied MO was shown to be due to (1) the relative unimportance of configuration interaction for this transition, (2) the invariance of the electron interaction terms calculated by the SCF method for different hydrocarbons, and (3) the identity of the Hückel energy number [Formula: see text] with the corresponding term[Formula: see text]of SCF theory, the latter value being insensitive to the method of choosing repulsion integrals even though the individual AO coefficients [Formula: see text] were quite sensitive.
A PROTON MAGNETIC RESONANCE STUDY OF N-BIS(2-HALOETHYL)AMINES
Authors: Pettit George R. , Settepani Joseph A. , Hill Ralph A.
Published: May 2006

The proton magnetic resonance chemical shifts of N-bis(2-haloethyl)amine hydrohalide salts have been found useful for rapidly assessing organohalide composition. An important illustration of nitogen mustard reactivity was obtained by observing the p.m.r. response of N-bis(2-haloethyl)amine hydrohalide salts (in deuterium oxide) following neutralization. In general, the amines rapidly entered a complex series of intra- and inter-molecular reactions. Among the substances studied N-bis(2-fluoroethyl)amine was by far the most stable and remained essentially unchanged during a 7-day period. By contrast N-bis(2-iodoethyl)amine was completely transformed in less than 6 min. The self-condensation reactions of, for example, N-bis(2-chloroethyl)amine appear to be accompanied by transient formation of N-2-chloroethylaziridine (IIIb). The present investigation indicates that p.m.r. spectroscopy is a valuable technique for evaluating the course of nitrogen mustard self-condensation reactions.
STUDIES IN THE BIOCHEMISTRY OF MICROORGANISMS: PART 117. SEPEDONIN, A TROPOLONE METABOLITE OF SEPEDONIUM CHRYSOSPERMUM FRIES
Authors: Divekar P. V. , Raistrick H. , Dobson T. A. , Vining L. C.
Published: May 2006

Two yellow substances were isolated from culture filtrates of the fungus Sepedonium chrysospermum Fries. One of these, named sepedonin, predominates in growing cultures and is believed to be the direct product of metabolism. The second, an anhydro derivative of sepedonin, was probably formed spontaneously in the culture filtrate, and during the isolation process, by chemical dehydration. Sepedonin, C11H12O5with one C-methyl group, gave two dimethyl ethers with diazomethane and has the spectral characteristics of a substituted tropolone. Dehydration under mild conditions afforded anhydrosepedonin, from which a monomethyl ether and two dimethyl ethers were prepared. One of the latter was unstable and rearranged slowly to a third dimethyl ether. By fusion with alkali, anhydrosepedonin was converted to a mixture from which two substituted benzoic acids and a product formulated as 6-hydroxy-4-methyltropolone were separated. The bathochromic displacement of the peaks in the ultraviolet spectrum of anhydrosepedonin compared with those in sepedonin indicated an unsaturated group conjugated to the tropolone ring, confirmed by catalytic reduction to a dihydro derivative. By careful oxidation of one of the dimethyl ethers of anhydrosepedonin with permanganate a substance believed to be a tropolone containing ester and carboxyl substituents was obtained, together with a second product formulated as the 3,4-cyclic anhydride. From these results and supporting n.m.r. and spectral evidence anhydrosepedonin is considered to be a 6-hydroxytropolone with a 2′-methylpyran ring fused at the 4,5,4′,5′-positions. Sepedonin differs only by having a 2′-hydroxy-2′-methyldihydropyran ring as the heterocyclic moiety.
ON THE USE OF NUCLEAR MAGNETIC RESONANCE FOR THE DETECTION, ESTIMATION, AND CHARACTERIZATION OF N-METHYL GROUPS
Authors: Ma J. C. N. , Warnhoff E. W.
Published: May 2006

A useful n.m.r. technique for the detection, estimation, and characterization of N-methyl groups is described. The method depends on the decreased shielding of Nbasic-methyl protons when the solvent is changed from deuterochloroform to perdeuteroacetic (PDA) (or acetic) acid to trifluoroacetic acid (TFA). The decreased shielding results in a downfield shift of the N-methyl resonance of ca. 0.3–1.3 p.p.m. depending on the type of amine. Most N-methyl groups on neutral nitrogen atoms show little movement. For the majority of aliphatic amines in trifluoroacetic acid the NH exchange rate is slow enough at 38° to permit observation of coupling of H(N) with the N-methyl protons, and thus determination of whether the amine is secondary or tertiary. In some cases information can be obtained about methylene and methine groups attached to basic nitrogen. In acid solution compounds with basic nitrogen attached to, or part of, an aromatic ring show considerable shift of the aromatic proton resonance signals to lower magnetic field. Combination of the n.m.r. technique with the Herzig-Meyer analysis can also reveal the number of methyl groups attached to neutral nitrogen.
GLUCOPUTRANJIVIN
Authors: Benn M. H. , Meakin D.
Published: May 2006

not available
THE PHOTOLYSIS OF CARBON DISULFIDE AND CARBON DISULFIDE – OXYGEN MIXTURES
Authors: Sorgo M. De , Yarwood A. J. , Strausz O. P. , Gunning H. E.
Published: May 2006

not available
FULLY FLUORINATED ALKOXIDES: PART I. TRIFLUOROMETHOXIDES OF ALKALI METALS
Authors: Redwood M. E. , Willis C. J.
Published: May 2006

The preparation is described of the trifluoromethoxides of the heavier alkali metals, i.e. MOCF3 where M = K, Rb, or Cs. These are stable, crystalline, ionic solids made by the reversible reaction of carbonyl fluoride with the appropriate metal fluoride. No trifluoromethoxides could be prepared from lithium, sodium, barium, or thallium(I) fluorides. Factors affecting the relative stability of such compounds are discussed.
THE REACTION OF ACTIVE NITROGEN WITH MIXTURES OF ETHYLENE AND NITRIC OXIDE
Authors: Fersht E. , Back R. A.
Published: May 2006

The reaction of active nitrogen, produced in a condensed discharge at 1 mm pressure, with mixtures of ethylene and nitric oxide has been studied with mixtures ranging in composition from pure ethylene to pure nitric oxide. The sum of HCN + 14N16N produced from mixtures of C2H4 and 15NO remained constant and equal to the HCN produced from pure C2H4 for NO concentrations up to 50 mole %. As more NO was added, this sum rose towards the value of 14N15N produced from pure 15NO. These data appear to lend support to the HCN yield from ethylene as the true measure of nitrogen atom concentration. It is suggested that 15NO also undergoes a concerted reaction with excited 14N14N molecules, probably in the A3 Σu+ state, to produce 14N15N, and that these excited molecules can be quenched by collision with ethylene or methane without consuming nitrogen or forming HCN.
AN ADIABATIC SOLUTION CALORIMETER USED FOR MEASURING THE MOLAR EXCESS ENTHALPY OF THE SYSTEM CARBON TETRACHLORIDE – BENZENE AT 25 °C
Authors: Bennett J. E. , Benson G. C.
Published: May 2006

A new adiabatic calorimeter for measuring heats of mixing is described. The design of the mixing cell avoids the presence of a vapor space, and accommodates changes in volume by means of a flexible diaphragm. The apparatus is equipped with automatic adiabatic control and produces a continuous record of the temperature of the mixing cell. An extensive series of measurements was carried out for the system carbon tetrachloride – benzene at 25 °C. The maximum value of the molar excess enthalpy, 113.4 ± 0.5 J mole−1, occurred at a mole fraction of carbon tetrachloride equal to 0.4907. For most of the concentration range, the results are from 1 to 2 J mole−1 lower than data reported recently by other investigators.
THE SYSTEM: BISMUTH–CADMIUM–MERCURY
Authors: Campbell A. N. , Kartzmark E. M.
Published: May 2006

The liquidus surface of this ternary alloy has been determined, together with the nature of the solid phase separating from various melts. The densities and molar volumes of the binary system: Cd—Hg have been determined and it is shown that there is marked contraction when the α and β phases form from the components. X-ray powder photographs of various Cd—Hg alloys at room temperature have been made and the limits of homogeneity determined.
ELECTRON SPIN RESONANCE SPECTRA OF S2O2− IN IRRADIATED THIOSULFATE SINGLE CRYSTALS
Authors: Morton J. R.
Published: May 2006

Single crystals of Na2S2O3•5H2O were irradiated and examined, at room temperature, with an e.s.r. spectrometer. Two radicals are present: the species present in highest concentration is S2O2−; the other species has not yet been identified.
THE DISSOLUTION OF COPPER IN AMMONIACAL POTASSIUM BROMATE SOLUTIONS
Authors: Kulkarni M. , Wiles D. R.
Published: May 2006

The dissolution of copper in ammonia solutions was found earlier to be bimolecular in ammonia, involving a fast equilibrium adsorption of one molecule, followed by attack by a second molecule of ammonia (or an ammonium ion). The present work, differing in that potassium bromate is used as oxidizing agent rather than oxygen under pressure, shows that the dissolution process is essentially similar in many respects. The most striking difference is that the oxidation step can now be seen and proves to be quite complex. In particular two quite different oxidation mechanisms appear to operate: one is a simple adsorption of KBrO3 and the other is a higher order reaction interpreted as involving a multiple adsorption on the reaction site, for which ammonia and ammonium also compete.
BIOSYNTHESIS OF BERBERINE AND BERBERASTINE INCORPORATION OF CATECHOLAMINES
Authors: Monković Ivo , Spenser Ian D.
Published: May 2006

Dopamine serves as a precursor of berberastine, berberine, hydrastine, and canadine in Hydrastis canadensis L. Noradrenaline serves as a precursor of berberastine but is not incorporated into the other three bases. It is shown that the incorporation of labelled dopamine into berberine and of labelled noradrenaline into berberastine takes place without randomization of radioactivity.
TERPENOIDS: X. PRE-SENEGENIN, A QUITE NORMAL TRITERPENOID
Authors: Dugan J. J. , Mayo P. de
Published: May 2006

Pre-senegenin has been obtained by a combination of oxidative and hydrolytic cleavage of the saponin, and has been shown to be a member of the normal and unrearranged oleanolic acid series: 2β,27-dihydroxy-23-carboxyoleanolic acid (XXII). On treatment with ethanolic hydrochloric acid it is converted quantitatively to a mixture of polygalic acid (XXI) and senegenin.Previous work (1) has shown that senegenin is a triterpenoid of empirical formula C30H45O6Cl with a 2β,3β-glycol system and a 4α-carboxyl group. A second carboxyl group is also present. It has now been found to be a member of the β-amyrin-oleanolic acid series in which a carbon atom at C14has migrated to C12with concomitant movement of the double bond to the C13—C14position, and that it has the structure (XX).
INFRARED EMISSION SPECTRA OF FATTY ACIDS ON STEEL SURFACES
Authors: Low M. J. D. , Inoue H.
Published: May 2006

Infrared emission spectra of oleic, linoleic, linolenic, and stearic acids, and of methyl linolenate, on the surfaces of steel plates were measured at 100, 150 and 200° from 5 to 10 microns. Reactions occur to produce complex iron soaps.
TRIDENTATE COMPLEXES OF PERIODATE AND SOME FURANOSE DERIVATIVES
Authors: Perlin A. S. , Rudloff E. Von
Published: May 2006

1,2-O-Isopropylidene-α-D-glucofuranose (I) is highly resistant to glycol scission by periodate in alkaline solution. This atypical effect is caused by preferential formation of a stable periodate complex. Proton magnetic resonance spectroscopy shows that the 3-, 5-, and 6-protons of I (and the 3- and 5-protons of I-6,6′-d2) become strongly deshielded during this process, which, together with accompanying changes in proton–proton coupling, establishes that the complex (II) has a 3,5,6-tridentate structure. Variations in the stability of II with pH suggest that it can exist either as a monoanion or dianion. A complex analogous to II is formed by ethyl α-D-thioglucofuranoside, whereas methyl β-D-galactofuranoside forms a complex that probably has the 2,5,6-structure. The characteristics of these tridentate complexing reactions support the general concept that a five-membered cyclic complex is a transient intermediate of α-glycol oxidation by periodate.
THE PREPARATION OF ANHYDROUS ZIRCONIUM DICHLORIDE
Authors: Swaroop B. , Flengas S. N.
Published: May 2006

not available
A SYNTHESIS OF 2,2,4-TRIMETHYL-4-HYDROXYTETRAHYDROFURAN, A PRODUCT OF THE PHOTOLYSIS OF 4-METHYL-4-METHOXY-2-PENTANONE
Authors: Gianturco M. A. , Friedel P.
Published: May 2006

not available
THE EFFECT OF PHENOLS ON THE POLYMERIZATION OF VINYL ACETATE
Authors: Bird R. A. , Russell K. E.
Published: May 2006

not available
ERRATUM: NEW NITROCHALCONES. VII
Authors: Szell T. , Eastham A. M. , Sipos Gy.
Published: May 2006

not available
ELECTRON SPIN RESONANCE DETERMINATION OF THE RADIOLYTIC YIELDS OF TRAPPED ELECTRONS AND OTHER SPECIES IN AN ORGANIC GLASS
Authors: Smith D. R. , Pieroni J. J.
Published: May 2006

The radiolytic yields, at liquid nitrogen temperature, of trapped electrons and radicals or radical-ions in 2-methyltetrahydrofuran and the yields of these species plus the biphenyl anion in solutions containing biphenyl have been determined by e.s.r. These measurements were also carried out after photolysis of the trapped electrons. The combined results are interpreted in terms of the identity of the intermediates and the reactions which they undergo. "Dual e.s.r. cavity" techniques have enabled greater accuracy and precision than is normally obtained when concentrations of paramagnetic species are determined by e.s.r.
THE PREPARATION AND CONFIGURATIONS OF TRI-O-ACETYL-α-D-GLUCOPYRANOSE 1,2-(ORTHOESTERS)
Authors: Lemieux R. U. , Morgan A. R.
Published: May 2006

Reaction of tri-O-acetyl-2- O-acyl (acetyl, benzoyl, pivalyl, and methoxycarbonyl)-α-D-glucopyranosyl halides with a variety of alcohols in sym-collidine containing a tetraalkylammonium halide gave the 1,2-orthoesters in near quantitative yields. In each case one of the two diastereoisomeric orthoesters was obtained in high yield and was shown by application of n.m.r. spectroscopy to be that isomer which has the alkoxy group on the dioxolan ring trans to the pyranose ring (exo-configuration). Participation of a methoxycarbonyloxy group allowed the preparation of a 1,2-(dimethyl orthocarbonate). 1,2-(Phenyl orthoacetates) were prepared.
ÉTUDE DES EFFETS ÉLECTROSTATIQUES SUR LE MÉCANISME D'ACTION CATALYTIQUE DE LA PHOSPHATASE ALCALINE INTESTINALE DE VEAU
Authors: Lazdunski Michel , Brouillard Jacques , Ouellet Ludovic
Published: May 2006

The influence of dioxane and ethanol on the rate of hydrolysis of p-nitrophenyl phosphate in the presence of an intestinal alcaline phosphatase can be interpreted as a dielectric constant effect, at high substrate concentration. The dielectric constant effect is a function of the pH of the medium and is maximum around pH 9.4 at 25 °C and pH 9.0 at 15 °C. An interpretation suggesting that the change in diameter of the enzyme molecule becoming an activated complex is minimum at a pH of maximum activity is proposed. The same model can take into account the influence of the ionic strength on the same reaction.
KINETICS OF VAPOR-PHASE HYDROCARBON–OZONE REACTIONS
Authors: Bufalini J. J. , Altshuller A. P.
Published: May 2006

The reactions of nine olefinic and aromatic hydrocarbons with ozone in the vapor phase have been investigated in static and dynamic systems. Some of the rate constants for the olefin–ozone reactions are in good agreement with previously published data, whereas others are larger than values previously reported. Rate constants for trans-2-butene–, isobutene–, and ethylene–ozone reactions were measured between 30 and 100 °C. The activation energies for the reaction of ozone with trans-2-butene, isobutene, and ethylene are 0.2 ± 0.3, 2.8 ± 0.4, and 4.2 ± 0.4 kcal/mole. In general, the reactions of hydrocarbons with ozone are non-stoichiometric. However, these reactions do appear to be second order. The rates of reaction between alkylbenzenes and ozone are too low to be of importance in air pollution studies.
INFRARED SPECTRA AND STRUCTURE OF POLYALDEHYDES: VI. POLYFLUORAL
Authors: Busfield W. K. , Whalley E.
Published: May 2006

The infrared spectrum of oriented polyfluoral is reported. The number and polarization of the bands suggest that the chain is helicoidal.
THE ACID HYDROLYSIS OF GLYCOSIDES: II. EFFECT OF SUBSTITUENTS AT C-5
Authors: Timell T. E. , Enterman W. , Spencer F. , Soltes E. J.
Published: May 2006

First-order rate coefficients at three temperatures, and energies and entropies of activation, have been determined for the acid-catalyzed hydrolysis of methyl glucopyranosides containing various substituents at C-5 and for glycopyranosiduronic acids with different aglycones. Substitution at C-5 increased the stability towards acids of methyl α- and β-D-glucopyranosides, but there was no correlation between either the polarity or the size of the substituent and the rates of hydrolysis. The operation of either an inductive or a conformational effect alone was accordingly deemed unlikely.Methyl α- and β-D-glucopyranosiduronic acids and methyl α-D-galactopyranosiduronic acid were only slightly more stable towards acids than the glycoside analogs, while benzyl β-D-glucopyranosiduronic acid was three times more stable. The presence of a methyl ester group at the carboxyl function increased the stability of the glycuronide bond. Isopropyl, n-butyl, isobutyl, and neopentyl β-D-glucopyranosiduronic acids were hydrolyzed approximately twice and cyclohexy β-D-glucopyranosiduronic acid five times as fast as the corresponding glucosides. This appears to be the first time that glycuronides have been found to be hydrolyzed by dilute acid at a higher rate than their glycoside analogs.The energies and, especially, the entropies of activation were, throughout, lower for the glycuronides than for the glycosides. The difference in entropy suggests that the two classes of compounds are hydrolyzed by different mechanisms.
1,4-DIMETHYLBICYCLO[2.2.1]HEPTANE DERIVATIVES
Authors: Yates Peter , Lynch Thomas R.
Published: May 2006

The product from the action of methylmagnesium iodide on bicyclo[2.2.1]heptane-2,5-dione gave 2-exo-5-endo-diacetoxy-1,4-dimethylbicyclo[2.2.1]heptane on treatment with sulfuric acid in acetic acid. This has been converted to 1,4-dimethylbicyclo[2.2.1]heptane-2-exo-5-endo-diol, to 1,4-dimethylbicyclo[2.2.1]heptane-2,5-dione, and to 1,4-dimethylbicyclo[2.2.1]heptane-2-endo-5-endo-diol. The stereochemical assignments have been made on the basis of the interpretation of the nuclear magnetic resonance spectra of these compounds. The exo–endo diacetoxy compound is shown to be the expected product from a double Wagner–Meerwein rearrangement.
SUR LE SPECTRE INFRAROUGE DE SO2 À HAUTE TEMPÉRATURE
Authors: Giguère Paul A. , Savoie Rodrigue
Published: May 2006

The infrared spectra of SO2 have been recorded both in absorption and emission over the range 400 to 3 000 cm−1 at atmospheric pressure and at temperatures up to 700 °C. Two weak bands were found at 1075 and 1290 cm−1 which represent a downward shift of some 75–80 cm−1 from the fundamental stretching vibrations of the SO2 molecule. They cannot fit the hypothetical isomer SOO, suggested sometime to account for the perturbations in the ultraviolet spectrum at high temperature. Other possibilities, such as "hot" bands involving a low-lying, electronically excited state of SO2 are discussed. A third, very weak band at about 680 cm−1, detected in emission only, must be due to the formation of traces of disulfur monoxide S2O.
STUDIES IN THE CYCLIZATION OF THE PRODUCTS OF STOBBE CONDENSATION WITH PROPIOPHENONE
Authors: El-Abbady A. M. , Doss S. H.
Published: May 2006

The isomeric mixture of the half-esters resulting from the Stobbe condensation of propiophenone with diethyl succinate is cyclized with stannic chloride as well as with sodium acetate in acetic anhydride. Cyclization of the ethyl half-ester chlorides with stannic chloride gives the keto-ester "4-carbethoxy-2-methyl-3-phenylcyclopent-2-enone." This on acid hydrolysis and decarboxylation yields 2-methyl-3-phenylcyclopent-2-enone, from which 2-methyl-3-phenylcyclopentanone is prepared by catalytic reduction. The keto-ester on Clemmensen reduction gives the corresponding unsaturated ester from which 3-methyl-2-phenylcyclopentane-1-carboxylic acid is obtained by catalytic hydrogenation and hydrolysis. 2-Methyl-3-phenylcyclopentanone and 3-methyl-2-phenylcyclopentane-1-carboxylic acid are of interest as intermediates for analogues of steroid hormones. From the latter 3-methyl-2-phenylcyclopentyl hydroxymethyl ketone and its acetate are prepared.Cyclization of the isomeric mixture of the ethyl half-esters with sodium acetate in acetic anhydride gives methyl 4-acetoxy-1-ethyl-2-naphthoate which is converted into 1-ethyl-4-methoxy-2-naphthoic acid.
THE IDENTITY OF OXYJAVANICIN WITH FUSARUBIN
Authors: Arsenault G. P.
Published: May 2006

not available
THE PHOTOLYSIS OF MALEIC HYDRAZIDE: EVIDENCE FOR AN INTERMOLECULAR HYDROGEN TRANSFER
Authors: Stoessl A.
Published: May 2006

not available
CHEMICAL STRUCTURE AND ADSORPTION OF ORGANIC MOLECULES AT THE POLARIZED MERCURY–ELECTROLYTE INTERFACE
Authors: Barradas R. G. , Hamilton P. G.
Published: May 2006

Previous studies on electrochemical adsorption at mercury of a series of heterocyclic and aromatic nitrogen bases and their respective conjugate ions by electrocapillary measurements are extended to simple saturated heterocyclic compounds containing oxygen and to aliphatic alcohols with different degrees of unsaturation. Adsorption isotherms for various electrode potentials are derived, and standard electrochemical free energies of adsorption are calculated as before, to relate the influence of molecular and electronic structure of the adsorbates on the properties of the electrical double layer. Oxygen as the heteroatom in cyclic compounds and in the hydroxyl group of the alcohols plays a distinct role in the characteristics of metal–adsorbate and adsorbate–solvent interactions through its higher electronegativity as compared with nitrogen. Considerations of the different geometric areas of adsorbed molecules due to isomerism of the saturated heterocyclic compounds, and the varying unsaturation of the alcohols lead to more realistic interpretation of orientation effects, surface coverages, and degrees of adsorbability. Improvement in pressure control in the electrocapillarometer assembly gives better precision in surface tension measurements. Some preliminary results on the adsorption of furfurylamines and related analogues which constitute a newly available class of corrosion inhibitors are briefly discussed.
SYNTHESIS OF 2,2-DISUBSTITUTED-5-CYANOCYCLOPENTANONES
Authors: Kulp Stuart S. , Fish Velmer B. , Easton Nelson R.
Published: May 2006

The synthesis of a series of 2,2-disubstituted-5-cyanocyclopentanones by hydrolysis of the precursor 3,3-disubstituted-2-amino-1-cyanocyclopentenes (2,2-disubstituted-5-cyanocyclopentanoneimines) is described. The new compounds possess the following substituants: dimethyl, diethyl, phenyl hydrogen, and ethyl phenyl.
35Cl AND 37Cl MAGNETIC RESONANCE OF SIMPLE CHLORINE COMPOUNDS
Authors: Saito Yasukazu
Published: May 2006

The nuclear magnetic resonances of 35Cl and 37Cl in a number of simple chlorine compounds were measured. Since both the paramagnetic contribution for chemical shift and the quadrupole coupling constant of the atom are determined by the same radial distribution of the electron, a linear relationship between the chemical shifts and the quadrupole coupling constants may be expected for compounds for which the electronic excitation energies are comparable. This was demonstrated for the series of chloro-substituted methanes. By graphical extrapolation the absolute chemical shift of the reference compound, NaCl aqueous solution, was obtained. The chemical shift of Cl− aq. ion can be interpreted as the sum of the diamagnetic shift of Cl− spherical ion and a paramagnetic shift resulting from its hydration. The experimental and theoretical values of the paramagnetic chemical shift of the Cl2 molecule were −2.06 × 10−3 and −2.17 × 10−3, respectively. Paramagnetic chemical shifts and line widths of resonance spectra of simple chlorine compounds are discussed, as well as the feasibility of high-resolution chlorine resonances for structural applications.
LIGHT ABSORPTION STUDIES: PART XXI. THE ULTRAVIOLET AND INFRARED ABSORPTION OFo-ALKYL- ANDo,o′-DIALKYL-SUBSTITUTED ANISOLES
Authors: Balasubramanian A. , Dearden J. C. , Forbes W. F. , Cheetham N. F.
Published: May 2006

Steric effects, previously reported by other workers in o- and o,o′-alkyl-substituted anisoles, were reinvestigated using compounds carefully purified by vapor phase chromatography. The ultraviolet spectral data indicate that the o-alkyl-substituted anisoles exist in one conformation, whereas the investigated o,o′-dialkyl-substituted anisoles exist in a different conformation. The conformations appear to be almost independent of the size of the substituent groups. Infrared, dipole moment, and other data are consistent with this interpretation.
THE SYNTHESIS OF 2-AMINOBENZENETHIOL HYDROCHLORIDES
Authors: Dannley Ralph L. , Zazaris Dimitri A.
Published: May 2006

not available
CONCERNING THE PREPARATION OF p-ALLYLPHENOL FROM SAFROLE BY SODIUM – LIQUID AMMONIA REDUCTION
Authors: Baldwin M. J. , Brown R. K.
Published: May 2006

not available
STEREOCHEMISTRY OF THE REDUCTION OF CYCLIC KETONES WITH THE PYRIDINE-n-BUTYLHTHIUM ADDUCT: STERIC APPROACH AND PRODUCT DEVELOPMENT CONTROLS
Authors: Abramovitch R. A. , Marsh W. C. , Saha J. G.
Published: May 2006

not available
THE PHOTOLYSIS AND THE MERCURY-PHOTOSENSITIZED DECOMPOSITION OF HYDROXYLAMINE VAPOR
Authors: Betts J. , Back R. A.
Published: May 2006

The mercury-photosensitized decomposition (2 537 Å) and the direct photolysis of hydroxylamine vapor have been studied at a pressure of 0.27 Torr, at 25 °C. The mercury-sensitized decomposition followed closely the simple stoichiometry, 3NH2OH → N2 + NH3 + 3H2O, which strongly suggests an initial decomposition into NH2 and OH. The direct photolysis was more complex, with N2, H2, and H2O major products, and N2O and NH3 minor ones. The mechanism is uncertain, but it seems probable that the major primary process is NH2OH + hv → NH2O + H. The absorption spectrum of hydroxylamine vapor was examined, and extinction coefficients determined from 2 250 to 1 600 Å. Absorption was continuous, starting about 2 250 Å, with no structure evident except a broad maximum at about 1 825 Å.
PYRIDINE N-OXIDE COMPLEX OF TITANYL PERCHLORATE
Authors: Krishnan V. , Patel C. C.
Published: May 2006

Pentakispyridine N-oxide oxotitanium(IV) perchlorate, TiO•5C5H5NO•(ClO4)2, has been prepared and its physicochemical properties investigated. The infrared and electronic spectra show that pyridine N-oxide is bonded to the metal ion through oxygen of the N—O. The complex explodes at 215 °C, a temperature slightly above the starting decomposition temperature of titanyl perchlorate, TiO(ClO4)2•3H2O.
QUANTITATIVE PREPARATION OF CHLORO- AND BROMOPHTHALAZINES
Authors: Hirsch A. , Orphanos D.
Published: May 2006

A new improved synthesis of 1,4-dichloro- and 1,4-dibroniophthalazine has been effected by reaction of 1,4-dioxophthalazine with PX5 (X = Cl, Br) in a sealed reaction flask. Halogenation of the dioxophthalazine has also been accomplished at atmospheric pressure in a halogenated solvent. The synthesis of 1-bromophthalazine is reported.
PHOTO-ADDITION OF N-NITROSODIALKYLAMINES TO CYCLOHEXENE
Authors: Chow Y. L.
Published: May 2006

Under the simultaneous influence of light and an acid, the nitrosamines derived from four heterocyclic amines readily form 1:1 photo-adducts with cyclohexene giving excellent yields of 2-tert-aminocyclohexanone oximes. While N-nitrosodi-n-butylamine, under similar conditions, gives a fair yield of the 1:1 photo-adduct, N-nitrosodicyclohexylamine and N-nitrosodiisopropylamine do not. The conformations of these oximes are discussed in conjunction with the n.m.r. data.
THE MONO-OXALATO COMPLEXES OF IRON(III): PART II. KINETICS OF FORMATION
Authors: Bauer R. F. , Smith W. MacF.
Published: May 2006

The kinetics of the formation of the mono-oxalato complexes of iron (III) have been examined spectrophotometrically over the range of temperatures 5 to 25 °C in an aqueous medium of ionic strength 0.50 and the range of hydrogen ion concentrations 0.03 to 0.45 M. The kinetic-ally significant paths under the conditions studied involve reactions first order in iron (III) and in bioxalate but there appears to be some decrease in the second order rate constant with increase in hydrogen ion concentration at the highest acidities and at the highest temperatures. Although there is no significant contribution to the rate by an acid-independent path first order in free oxalate under the experimental conditions, the possibility of the rate constant for such a path being greater than that first order in bioxalate is not precluded.
ON A PLATINUM–RHODIUM – OXYGEN ELECTRODE IN SILICATE MELTS
Authors: Ranford R. E. , Flengas S. N.
Published: May 2006

The potential of the formation cell[Formula: see text]was studied in the temperature range 900 °C to 1 100 °C. The platinum–rhodium – oxygen electrode was found to behave reversibly in the pressure range 5 × 10−3 atm to 1 atm oxygen. The effects on the cell potential of oxygen pressure, nickelous oxide concentration, and temperature, were all found to follow an exact Nernst relationship.
1,2-O-ISOPROPYLIDENE-α-D-GLUCOFURANOSE-5-d AND -5,6,6′-d3
Authors: Mackie W. , Perlin A. S.
Published: May 2006

not available
ON THE RELATIONSHIP BETWEEN EQUILIBRIUM PRESSURES AND THE PHASE DIAGRAM OF A REACTIVE SYSTEM: THE SYSTEMS: NaCl–Na2ZrCl6, KCl–K2ZrCl6, NaCl–KCl–ZrCl4
Authors: Lister R. L. , Flengas S. N.
Published: May 2006

The binary equilibrium phase diagrams for the systems NaCl–Na2ZrCl6 and KCl–K2ZrCl were established from the combined results of cooling curve and vapor pressure measurements. A portion of the ternary NaCl–KCl–ZrCl4 has also been determined. Vapor pressure measurements on the two pure compounds, Na2ZrCl6 and K2ZrCl6, as well as on mixtures with the respective alkali metal chlorides, were taken. The vapor-producing reaction is given as[Formula: see text]where M represents, respectively, sodium and potassium.Thermodynamic relationships relating the phase diagram to the measured equilibrium pressures have been developed. The classical shape of the pressure–temperature curves, even for the pure compound, as well as mixtures of the two components, indicates a dependency on liquidus and eutectic melting. Vapor pressure measurements were also carried out over that composition of the ternary which could be of interest for the recovery of zirconium metal by fused salt electrolysis. From these data, the activities and the other partial molar properties of the components in solution were calculated for both the M2ZrCl6 and ZrCl4 species.
REACTIONS OF SUGAR CHLOROSULFATES: PART VI. THE STRUCTURE OF UNSATURATED CHLORODEOXY SUGARS
Authors: Jennings H. J. , Jones J. K. N.
Published: May 2006

Methyl α- and β-L-arabinopyranosides when treated with sulfuryl chloride yielded methyl 4-chloro-4-deoxy-α-D-xylopyranoside 2,3-dichlorosulfate and methyl 3,4-dichloro-3,4-dideoxy-β-D-ribopyranoside 2-chlorosulfate respectively. L-Arabinose gave, in addition to 4-chloro-4-deoxy-D-xylosyl chloride 2,3-dichlorosulfate, an unsaturated tetrachloro–tetradeoxy dimer. The structure and mode of formation of these compounds is discussed.
SEMIEMPIRICAL SCF CALCULATIONS ON AZULENE AND ITS SINGLY CHARGED IONS
Authors: Bloor J. E.
Published: May 2006

SCF MOs for azulene have been obtained by the semiempirical Pariser, Parr, Pople procedure using the Nishimoto–Mataga method of calculating repulsion integrals and the assumption that nearest neighbor resonance integrals are independent of interatomic distance. Excited states calculated from these MOs by a CI calculation are in very good agreement with experiment. Ground state charge densities, bond orders, and the dipole moment are similar to other SCFMO calculations and reveal no disadvantage in adopting a constant resonance integral for all bonds. It is shown that estimates of the π-electron charge density by n.m.r. methods are not compatible with direct dipole moment measurements and it is suggested that the interpretation of the n.m.r. measurements suffers from inaccuracies in estimating ring currents. Doubt is also thrown on the use of simple relationships between calculated π-bond orders and bond lengths obtained by X-ray crystallographic measurements on the solid state, particularly since all the bond lengths in azulene are predicted to be longer than in benzene whereas experiment shows some to be shorter. Calculations on spin densities and charge densities of the singly charged azulene anion and cation have been performed by a restricted Hartree–Fock perturbation method in which the matrix elements for the interaction between singly excited states and the ground state are calculated using the closed shell SCFMOs of azulene as the basis set. Agreement with experiment for the anion is fairly good. For the cation our results are in severe disagreement with recent VB calculations, but there are no experimental results available to decide between the two methods.
THE UNIMOLECULAR DECOMPOSITION OF METHYL CHLORIDE
Authors: Forst W. , Laurent P. St.
Published: May 2006

The second-order rate constant for the unimolecular decomposition of methyl chloride[Formula: see text]has been calculated on a computer by the quantum version of the Marcus–Rice theory assuming no active rotations and using the experimental activation energy. With a harmonic energy level density count the calculated rate constant is 32 times smaller than the experimental value. When correction for anharmonicity is applied, the agreement is somewhat improved but the calculated rate constant is still some 20 times too small. These results are discussed in the light of the assumptions made in the course of the calculations. It is concluded that the quantum statistical collision theory, to which the Marcus–Rice theory reduces at low pressure, is a good deal more successful than Slater's, which is in error by a factor of 105–106.
THE REACTION OF HEXAFLUOROACETONE WITH SOME SILANES
Authors: Janzen A. F. , Willis C. J.
Published: May 2006

The reaction of hexafluoroacetone with various methyl- and chloro-silanes has been studied. It has been found that ready addition occurs to give a variety of fluorinated alkoxy-silanes, containing the grouping Si—O—CH (CF3)2. Some properties of these new compounds are given.