bluuebunny/crossref_metadata_2025 huggingface dataset:
A STUDY OF THE PECTIN PRESENT IN THE BARK OF AMABILIS FIR (ABIES AMABILIS)
Authors: Bhattacharjee S. S. , Timell T. E.
Published: May 2006

A pectic material has been isolated from the bark of Abies amabilis (Dougl.) Forbes in a yield of 2%. On hydrolysis it yielded D-galacturonic acid, D-galactose, and L-arabinose in a ratio of 85:4:11, and also traces of rhamnose. The product, when submitted to several conventional fractionation methods, appeared homogeneous. Further resolution could be effected by acidification of an aqueous solution of the pectin, followed by ultracentrifugation. The insoluble portion (50%) was an electrophoretically homogeneous galacturonan with [α]D + 246°. The material remaining in solution (30%), here referred to as a pectic acid, had [α]D + 225° and on hydrolysis gave D-galacturonic acid, D-galactose, and L-arbabinose in a ratio of 74:7:19, as well as traces of rhamnose.The structure of the galacturonan was established by partial hydrolysis and methylation. It consisted of α-D-galacturonic acid residues linked together by (1 → 4)-glycosidic bonds to a linear macromolecule. The same techniques were applied to the pectic acid. While a unique structural formula could not be assigned in this case, one probable alternative involved a framework of (1 → 4)-linked α-D-galacturonic acid residues together with a few residues of 1,2,4-linked L-rhamnose. Some of the galacturonic acid units carried at C-2 and C-3 side chains which were terminated by D-galactopyranose and L-arabinofuranose residues. A few of the latter also occurred as inner units, probably in the side chains. This appears to be the first time a pectic material has been resolved into a galacturonan and a pectic acid containing the four sugar residues usually found in pectins. It is probable that the pectin occurring to a limited extent in wood has a similar composition.
CHARGE TRANSFER IN THE RADIOLYSIS OF DILUTE SOLUTIONS OF HYDROCARBONS IN KRYPTON MATRICES AT 77 °K
Authors: Stone J. A.
Published: May 2006

The radiolysis of dilute solutions (0.3 to 10 electron %) of saturated hydrocarbons in krypton matrices at 77 °K results in the production of much more hydrogen than that obtained in the absence of krypton. This enhanced hydrogen yield is independent of hydrocarbon concentration over the range studied. The cyclohexane–krypton system wds studied in detail: The energy transferred from the krypton to the cyclohexane results in a large first-order yield of hydrogen with a corresponding large yield of cyclohexene. Cyclohexane-d12 are irradiated at the same concentration in a krypton matrix has the same product yields. However, when mixtures of cyclohexane and cyclohexane-d12 are irradiated in a krypton matrix the hydrogen evolved has a high H2 content which must be the result of an isotope effect in the energy transfer process. This isotope effect and the enhancement of product yields is consistent with a charge transfer mechanism.
INTRAMOLECULAR HYDROGEN TRANSFER IN MERCURY PHOTOSENSITIZATION OF PENTENE-1
Authors: Placzek D. W. , Rabinovitch B. S.
Published: May 2006

Upon photosensitization with Hg 6 (3P1), pentene-1 undergoes several reactions: the well-known C—C and C—H ruptures and the recently found isomerization consisting of an H-atom transfer and subsequent bond formation. We report two additional products formed by an H-transfer mechanism, 1,2-dimethylcyclopropane and cyclopentane, the former being a major product.
A NOVEL SYNTHESIS FOR AMINODIDEOXY SUGARS: 3-AMINO-2,3-DIDEOXY-D-ARABINO-HEXOSE
Authors: Baer Hans Helmut , Neilson Thomas
Published: May 2006

The 4,6-O-benzylidene derivative II of methyl 3-nitro-3-deoxy-β-D-glucopyranoside (I) was prepared. Its 2-O-acetate (III) was converted by a Schmidt–Rutz reaction into methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-β-D-erythro-hexos-2-enide (IV). Selective hydrogenation of the olefinic double bond in IV afforded methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-β-D-, arabino-hexopyranoside (V). The debenzylidenated derivative of V (VI) was reduced to methyl 3-amino-2,3-dideoxy-β-D-arabino-hexopyranoside hydrochloride (VII), from which the free reducing sugar (VIII), the N-acetyl glycoside (IX), the N-acetyl glycoside 4,6-di-O-acetate (X), and the N-acetyl glycoside 4,6-di-O-mesylate (XI) were obtained. The solvolysis of XI proceeded with neighboring group participation to give a product of either aziridine (XII) or pyrrolidine (XIII) structure.
AN ELECTRON SPIN RESONANCE STUDY OF TRAPPED ELECTRONS FORMED AT 77.5 °K BY GAMMA IRRADIATION OF AN ORGANIC GLASS
Authors: Smith D. R. , Pieroni J. J.
Published: May 2006

2-Methyltetrahydrofuran (MTHF) traps electrons and free radicals or radical-ions when irradiated with 60Co gamma rays at 77.5 °K. The e.s.r. difference spectrum technique has been used to determine the microwave saturation properties and line shape parameters of the absorption due to "trapped" electrons. These measurements support the postulate that physically trapped electrons are present and indicate that trapped electrons and free radicals or radical-ions exist in local concentrations which are considerably greater than their average concentration in the sample. It is concluded that they are trapped in clusters. A study of the thermal decay of the trapped electrons supports the cluster model.
INFRARED SPECTRA OF TRIS-ETHYLENEDIAMINE COMPLEXES OF RUTHENIUM (II)
Authors: Allen A. D. , Senoff C. V.
Published: May 2006

A number of complexes [Ru(en)3]X2, where X = I−, Br−, PtCl42−, ClO4−, and PF6−, have been prepared and their infrared spectra measured in the solid state between 4 000–600 cm−1. The effect of the various anions on the spectra and assignments for the observed fundamental vibrations are discussed.
STUDIES ON STOBBE CONDENSATION: REACTIONS OF ALDEHYDES AND KETONES WITH DIMETHYL METHYLSUCCINATE
Authors: El-Abbady A. M. , Mousa H. H.
Published: May 2006

Benzaldehyde, o-methoxybenzaldehyde, p-chlorobenzaldehyde, benzophenone, and acetophenone are condensed with dimethyl methylsuccinate in the presence of potassium tert-butoxide to give the corresponding β-half-esters. In the case of o-methoxybenzaldehyde the lactonic acid (IX) is also obtained. The β-half-esters are cyclized by sodium acetate and acetic anhydride to the corresponding acetoxynaphthoates which are converted into their methoxynaphthoates. Alkaline hydrolysis of the β-half-esters yields the corresponding itaconic acids, the anhydrides of which are converted to their α-half-esters.
THE REACTION OF ACTIVE NITROGEN WITH ETHANOL
Authors: Gartaganis P. A.
Published: May 2006

The reaction of active nitrogen with ethanol has been investigated in the range 300 to 593 °K using a modified condensed-discharge Wood–Bonhoeffer fast-flow system. The only condensable products found in appreciable amounts were hydrogen cyanide and water. Hydrogen was the main noncondensable product. A very small amount of acetaldehyde was also formed along with traces of ethane, ethylene, methane, acetonitrile, cyanogen, and probably carbon monoxide. The overall activation energy is 3.4 kcal/mole. It is postulated that the mechanism consists of the formation of two fragments NC2H5 and OH, from which the condensable products result as follows:[Formula: see text]A number of products found in trace quantities are produced by concomitant reactions of the hydrogen atoms with methyl radicals, and with ethanol as well as by disproportionation of ethyl radicals to produce ethane and ethylene. A preliminary study of the reaction of active nitrogen with isopropanol indicated that the energy of activation is in line with the energies of activation of methanol and ethanol.
REARRANGEMENT REACTIONS FOLLOWING ELECTRON IMPACT ON ETHYL AND ISOPROPYL ESTERS
Authors: Harrison A. G. , Jones E. G.
Published: May 2006

The mass spectra of ethyl and isopropyl propionate and butyrate show rearrangement ions R1COOH+ and R1C(OH)2+ formed by reactions [a] and [b]:[Formula: see text]The mass spectra of ethyl-d2 propionate and butyrate show that both [a] and [b] occur with essentially complete scrambling of the alkoxy hydrogens. For the isopropyl esters the mass spectra of the isopropyl-d6 molecules show that reaction [a] occurs by transfer of one of the methyl hydrogens to the acid moiety while reaction [b] occurs predominately by transfer of two methyl hydrogens.
SYNTHESIS OF 4-ACETAMIDO-4-DEOXY-SUGARS
Authors: Dick A. J. , Jones J. K. N.
Published: May 2006

The tri-O-methanesulfonate derivative (I) of methyl α-D-xylopyranoside has been prepared. This compound when heated with sodium azide in N,N-dimethylformamide yielded a 4-azido derivative with inversion at C4. It (I) was thus converted to a methyl 4-azido-4-deoxy-β-L-arabinopyranoside (II) and thence by removal of methanesulfonate residues to a 2,3-anhydro-L-ribopyranoside derivative and further to methyl 4-amino-4-deoxy-β-L-xylopyranoside (V); 4-acetamido-4-deoxy-1,2;3,5-di-O-isopropylidene-L-xylose (IX), a sugar with nitrogen in the ring, was prepared from 4-acetamido-4-deoxy-L-xylose. Acetolysis of methyl 4-acetamido-4-deoxy-L-xylopyranoside yielded a pentacetate of unknown ring size (X or XI).
THE DIHYDROXYSTRYCHNINES
Authors: Wheeler D. M. S. , Smith Mary C. , Kneece Abbie M. , McMaster Jan B.
Published: May 2006

not available
11α,12α-EPOXY-3,20-DIOXOPREGNANE
Authors: Ziegler P.
Published: May 2006

not available
NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY OF SOME SELENIUM COMPOUNDS
Authors: Birchall T. , Gillespie R. J. , Vekris S. L.
Published: May 2006

Selenium nuclear magnetic resonance spectra have been observed for a number of selenium compounds. Chemical shifts and coupling constants with hydrogen and fluorine have been obtained. Various systems involving selenium compounds have been studied. It was found that a mixture of SeOF2and SeOCl2contains SeOClF and that rapid selenium exchange occurs between SeOCl2and SeOBr2presumably via the intermediate SeOClBr. The reactions of selenium tetrahalides with sulfur and selenium trioxides and with boron trifluoride were studied. It was observed that antimony pentachloride, tin tetrachloride, arsenic trichloride, quinoline, and potassium chloride produce considerable shifts in the resonance of selenium oxychloride. These shifts can be interpreted in terms of the acid–base behavior of the solutes.
CONDITIONS FOR THE PHOTOCHEMICAL NITRATION OF BENZENE
Authors: Bunbury David L.
Published: May 2006

The reaction of benzene and nitrogen dioxide to produce nitrobenzene has been studied in the liquid and gas phases, in the dark, and with irradiation by light of 439 mμ and of 366 mμ. The concentration of NO2 in the liquid was varied from 0.08 to 1.6 moles/1 and in the gas from 0.0035 to 0.053 moles/1. No nitrobenzene was produced under any conditions in the liquid phase. Nitrobenzene is produced in the gas phase at high NO2 concentrations with irradiation by 366 mμ light. The quantum yield is 0.2. At 439 mμ the quantum yield is not more than 0.02. There is a very small dark reaction. As the concentration of NO2 in the gas is reduced the yield of nitrobenzene falls off very rapidly and is zero at the lowest concentration used, both in dark and light.
APPLICATION OF DIFFERENTIAL THERMAL ANALYSIS TO THE DISSOCIATION OF MnO2 AND Mn2O3
Authors: Matsushima T. , Thoburn W. J.
Published: May 2006

The method of differential thermal analysis was employed to determine the oxygen pressures produced by the reactions[Formula: see text]and[Formula: see text]in the temperature range 250–1000 °C. The heats of reaction calculated from the slope of the van't Hoff curves are: ΔH835°K0 = 25.8 ± 1.5 and ΔH1200°K0 = 25.3 ± 4.2 kcal per mole of oxygen. These are in agreement with previously reported values based on equilibrium measurements, but are lower than those determined by calorimetry.
PERMANGANATE–PERIODATE OXIDATION: VI. THE OXIDATION OF VARIOUS ALIPHATIC COMPOUNDS
Authors: Rudloff E. Von
Published: May 2006

A study was made of the reaction of the permanganate–periodate reagent with a wide variety of aliphatic alcohols, polyols, aldehydes, acids, oxy-acids, ketones, ethers, and esters. Saturated monols, ketones, and ethers, as well as acetic, pelargonic, pyruvic, lactic, and oxalic acids reacted only very slowly. Glycols, olefinic alcohols, and unsaturated acids were cleaved to give predictable end products. Activated alcohols and ethyl acetoacetate reacted at relatively high rates. Formic, glyoxylic, lactic, and malonic acids as well as 1,3-propanediol and 2,5-hexane dione reacted extensively and diethyl tartrate consumed as much oxidant as did tartaric acid. The oxidation of tetrahydrofurfuryl alcohol gave succinic acid instead of the expected tetrahydro-2-furoic acid. Saturated mono- and di-carboxylic acids, 3-hydroxy propionic acid, γ-valero lactone, and saturated esters were stable towards the reagent.
THE SULFUR–CHLORINE STRETCHING BAND IN SULFONYL CHLORIDES
Authors: King J. F. , Smith David J. H.
Published: May 2006

not available
THE HEAT OF FORMATION OF BORON TRIBROMIDE–ACETONITRILE
Authors: Miller J. M. , Onyszchuk M.
Published: May 2006

not available
COORDINATION COMPLEXES OF NIOBIUM PENTACHLORIDE WITH TRIPHENYL DERIVATIVES OF GROUP V ELEMENTS
Authors: Desnoyers Jean , Rivest Roland
Published: May 2006

not available
SYNTHESIS AND REACTIVITY OF SOME ORTHO-SUBSTITUTED DIPHENYL SULFONES
Authors: Bennett O. Francis
Published: May 2006

not available
SYNTHESIS OF β-D-MANNOSE 1,2-ORTHOACETATES
Authors: Mazurek M. , Perlin A. S.
Published: May 2006

Synthesis of 3,4,6-tri-O-acetyl-β-D-mannopyranose 1,2-orthoacetates (I) from 2,3,4,6-tetra-O-acetyl-α-D-mannopyranosyl bromide (II) and various alcohols in the presence of pyridine and substituted pyridines is described. 2,6-Lutidine is a particularly effective acid acceptor in these condensations, and the use of chloroform as a diluent is advantageous. The lutidine-buffered system has afforded a good yield of orthoacetate (I) with several alcohols that barely react with II in the presence of silver ion; this difference is attributed to the dominance of side reactions under the latter conditions. The N-bases also promote a more highly stereoselective orthoester synthesis than does the silver-catalyzed reaction, leading to formation of the OR-exo-diastereoisomer almost exclusively.
THE PHOTOLYSIS OF CYCLOPENTANONE AND CYCLOBUTANONE
Authors: Klemm R. F. , Morrison D. N. , Gilderson P. , Blades A. T.
Published: May 2006

The vapor phase photolysis of cyclopentanone, cyclopentanone-d8, and cyclobutanone have been investigated at 3 130 Å and 2 537 Å under a variety of conditions. In cyclopentanone photolysis a pressure- and wavelength-dependent "falloff" has been observed in the product ratio cyclobutane:ethylene, while a similarly dependent effect in the ratio cyclopropane: propylene exists in cyclobutanone photolysis. In the light of this data a reappraisal has been made of existing concepts regarding the photodecomposition of these ketones.
THE RELATIVE SIGNS OF THE PROTON COUPLING CONSTANTS IN DIKETENE AND VINYL FORMATE
Authors: Hruska F. , Hutton H. M. , Schaefer T.
Published: May 2006

The relative signs of the proton coupling constants in diketene and vinyl formate have been determined by the field-sweep selective decoupling method. In both compounds, the couplings between protons separated by an even number of bonds are of the same sign, but of opposite sign to the couplings between protons separated by an odd number of bonds. The coupling mechanisms, especially in vinyl formate, are discussed briefly.
THE REACTION OF UNSATURATED CARBOHYDRATES WITH CARBON MONOXIDE AND HYDROGEN: IV. STRUCTURE AND STEREOCHEMISTRY OF ANHYDRODEOXYHEPTITOLS FROM 3,4,6-TRI-O-ACETYL-D-GALACTAL
Authors: Rosenthal Alex , Abson Derek
Published: May 2006

3,4,6-Tri-O-acetyl-D-galactal reacted with carbon monoxide and hydrogen in the presence of dicobalt octacarbonyl to yield 2,6-anhydro-3-deoxy-D-galacto-heptitol (I) and 2,6-anhydro-3-deoxy-D-talo-heptitol (II). The stereochemistry of (I) and (II) has been established by correlation with 2,6-anhydro-3-deoxy-D-gluco-heptitol (VI) of known configuration. Evidence that both (I) and (II) are formed by the addition of a hydroxmethyl group to C-1 of the glycal is also furnished by the proton n.m.r. spectra of the normal and deuterated anhydrodeoxyheptitols.
LA RÉACTION DU PENTACHLORURE DE PHOSPHORE SUR LES ACYLOXY-3β-Δ4-CETO-6 STÉROIDES: I. SÉRIE DU PREGNANE
Authors: Lefebvre Yvon , Gaudry Roger
Published: May 2006

not available
THE ALCOHOLYSIS OF TRIALKYLALKOXYSILANES: PART II. THE PREPARATION AND CHEMISTRY OF METHYL 2,3,4-TRI-O-TRI-METHYLSILYL-α-D-GLUCOPYRANOSIDE
Authors: Hurst D. T , McInnes A. G.
Published: May 2006

The trimethylsilyl group on the 6-position of methyl 2,3,4,6-tetra-O-trimethylsilyl-α-D-glucopyranoside is preferentially removed by methanolysis, using basic or acidic catalysts, giving methyl 2,3,4-tri-O-trimethylsilyl-α-D-glucopyranoside in high yield (>80%). Reaction of the latter with acetic anhydride, benzoyl chloride, or phenyl isocyanate produces the corresponding 6-substituted derivatives in quantitative yield. The trimethylsilyl residues from the latter compounds are hydrolyzed by 50% aqueous methanol with the concomitant formation of 6-O-acetyl, 6-O-benzoyl, or 6-carbanilate derivatives of methyl α-D-glucopyranoside in excellent yield. Chemical and proton magnetic resonance (p.m.r.) studies established the structure of methyl 2,3,4-tri-O-trimethylsilyl-α-D-glucopyranoside, and of subsequent derivatives prepared from this compound. Infrared and p.m.r. evidence is offered to support conclusions regarding the conformation of the groups or atoms attached to C6 and C5 of the glucoside residue in some of these compounds.
SYNTHESIS IN AQUEOUS SOLUTIONS OF BINARY COMPOUNDS OF THE TRANSITION METALS WITH GROUP VA AND VIA ELEMENTS
Authors: Cranton G. E. , Heyding R. D.
Published: May 2006

Some of the compounds in the systems Cu/Se, Cu/As, Cu/Sb, Ni/Se, Ni/As, Ni/Sb, and Ni/Bi have been synthesized by precipitation from aqueous solutions, following procedures similar to those described by Kulifay. The precipitates were finely divided and of relatively low purity. No new compounds were observed. None of the compounds in the Fe/As and Co/As systems were obtained, nor were any intermediate phases formed in the systems Fe/Bi, Co/Bi, and Cu/Bi.
CHEMISTRY OF THE COMPLEXES OF URANYL AND PLUTONYL IONS WITH ORGANIC LIGANDS
Authors: Balakrishnan P. V. , Patil S. K. , Sharma H. D. , Venkatasetty H. V.
Published: May 2006

A series of complexes of uranyl and plutonyl ions with different organic ligands have been prepared and investigated by infrared spectra and magnetic susceptibility measurements. The uranyl complexes were found to be weakly diamagnetic and the plutonyl complex was found to be paramagnetic. Two ligand series are defined on the basis of the infrared asymmetric stretching frequency of the uranyl and plutonyl groups.
SUBSTITUTIONAL AND CONFIGURATIONAL EFFECTS ON CHEMICAL SHIFT IN PYRANOID CARBOHYDRATE DERIVATIVES
Authors: Lemieux R. U. , Stevens J. D.
Published: May 2006

The effects of long-range and virtual long-range coupling on the observed spectra of acetylated hexopyranoses and pentopyranoses are examined. Use is made of both spin decoupling and specific deuteration for the assignment of signals. It is seen that specific solvent effects on chemical shift can be superior to increasing the applied magnetic field for the resolution of the signals of closely related protons. The alteration of virtual long-range coupling effects in these ways can be useful in the diagnosis of spectra. Empirical rules are derived for estimating the long-range shielding effects which occur on changing configurations. It is seen that the inversion of a center can lead to deshielding of axial protons and to shielding of equatorial protons at other centers relative to the chemical shifts observed in reference compounds wherein all the acetoxy groups are in equatorial orientation. The effects in several cases result in equatorial protons giving their signal to higher field than chemically similar but axial protons. The conformational properties of pentopyranose tetraacetates as estimated from chemical shifts and coupling constants are seen to be in good agreement with expectations based on non-bonding interaction free energies. As expected, 2-deoxy-β-D-ribopyranose triacetate has the 1C-conformation when dissolved in chloroform.
SURFACE EFFECTS IN THE UNINHIBITED AND THE INHIBITED PYROLYSES OF ISOMERIC HEXANES: PARTS I-III.n-HEXANE, 2-METHYL PENTANE, 3-METHYL PENTANE
Authors: Chrysochoos J. , Bryce W. A.
Published: May 2006

The rates of pyrolysis of n-hexane, 2-methyl pentane, and 3-methyl pentane decrease with increasing S/V ratio in the pressure range of 15 to 90 mm at temperatures around 520 °C. The partial pressure of nitric oxide required for maximum inhibition which appears to be independent of the hydrocarbon pressure and is approximately constant for all isomers, namely 12–14 mm, for hydrocarbon ranging from 50 to 100 mm, increases slightly with increasing S/V ratio. Nitric oxide affects the product distribution markedly. The simultaneous increase in the yield of C2H4and decrease in the yield of C2H6with increasing NO pressure can be attributed to the set of competitive reactions[Formula: see text][Formula: see text]Similarly, the slight decrease in the yield of C3H8with increasing NO pressure can be accounted for by the competition[Formula: see text][Formula: see text]Increased S/V ratios favor the formation of C2H6in both the uninhibited and the inhibited pyrolyses, but has no effect on the yields of such products as C3H6, 1-C4H8, and i-C4H8. The analytical balance becomes less complete at higher NO pressures for the inhibited decomposition, which can be attributed to the formation of some nitrogen-containing compounds undetectable by the analytical methods used. Mechanisms are proposed accounting qualitatively for the products of the uninhibited and the inhibited pyrolyses.
THE IONIZATION OF SOME TYPICAL WEAK BASES IN CONCENTRATED PERCHLORIC ACID
Authors: Yates Keith , Wai Henry
Published: May 2006

not available
THE DETERMINATION OF THE SATURATION VAPOR PRESSURE OF SOLID HYDROXYLAMINE USING A PISTON PRESSURE GAUGE
Authors: Back R. A. , Betts J.
Published: May 2006

The saturation vapor pressure of solid hydroxylamine has been determined at temperatures from −12 to 7° C and found to fit the equation[Formula: see text]From this have been calculated several thermochemical quantities, including a heat of sublimation of 15.34 kcal/mole, and a dissociation energy of 61.3 kcal/mole for the NH2—OH bond. Vapor density measurements showed that hydroxylamine vapor consisted of single molecules of NH2OH at 0.27 Torr and 25 °C.A novel pressure gauge used in the measurements is described. Pressures were determined with an accuracy of ±0.001 Torr by measuring the force acting on a piston, moving freely in a glass cylinder, suspended on the arm of a torsion balance.
SYNTHÈSES DE PEPTIDES CONTENANT DES THIOACIDES
Authors: Berse Casimir , Dupuis Gilles
Published: May 2006

not available
THE ALKALOIDS OF PAPAVERACEOUS PLANTS: LIV. THE STRUCTURE OF ESCHSCHOLTZINE
Authors: Manske Richard H. F. , Shin Kju Hi , Battersby A. R. , Shaw D. F.
Published: May 2006

Eschscholtzine, a new alkaloid from Eschscholtzia californica, has been shown to be the bismethylenedioxy analogue of N-methylpavine (argemonine). The mass spectrometric fragmentation of alkaloids of the pavine type is discussed.
THE ABNORMAL CONFORMATIONS OF PYRIDINIUM α-GLYCOPYRANOSIDES
Authors: Lemieux R. U. , Morgan A. R.
Published: May 2006

The nuclear magnetic resonance spectra for N-(tetra-O-acetyl-α-D-glucopyranosyl)-pyridinium and 4-methylpyridinium bromides and N-(tri-O-acetyl-2-deoxy-2-iodo-α-D-mannopyranosyl)-pyridinium perchlorate (V) require these compounds to exist in the 1C-conformation wherein the pyridinium group is in equatorial orientation. The highly strained condition of V was evidenced by its high reactivity as compared to the β-D-gluco diastereoisomer (IV). It is suggested that the instability of the C1-conformation is partly attributable to the reverse of the anomeric effect, and the probable importance of this phenomenon is discussed. The optical rotatory dispersion properties of these and a number of other pyridinium glycosides are presented.
α-DEUTERIUM KINETIC ISOTOPE EFFECTS IN SOLVOLYSES OF endo-NORBORNYL p-BROMOBENZENESULFONATE
Authors: Lee C. C. , Wong Edward W. C.
Published: May 2006

endo-Norbornyl-2-d p-bromobenzenesulfonate was synthesized and the isotope effects, as measured by kH/kD, were determined over a range of temperatures for solvolyses in 30% water – 70% dioxane, acetic acid, and formic acid. Values of kH/kD are of the order of 1.20. The data appear to indicate slightly higher isotope effects as the solvents are changed from aqueous dioxane to acetic acid to formic acid, as well as somewhat higher isotope effects at lower temperatures. Possible mechanistic implications of these results are presented. Relative titrimetric acetolysis rates, kexo/kendo, at different temperatures, and enthalpies and entropies of activation for these acetolyses are evaluated and discussed.
THE ROLE OF Hg 63P0 ATOMS IN MERCURY PHOTOSENSITIZATION: III. REACTIONS WITH Hg 61S0 ATOMS
Authors: McAlduff J. E. , Roy D. J. Le
Published: May 2006

Metastable Hg 63P0 atoms were produced in a flow system by reaction of Hg 63P1 atoms with nitrogen. Concentrations of the metastable atoms were studied as a function of Hg 61S0 and N2 concentration by absorption spectrometry. Rate constants have been obtained for the deactivation of Hg 63P0 to the ground state and for its activation to the 63P1 state by collisions with nitrogen, as well as for its reaction with Hg 61S0 atoms to form a relatively long-lived diatomic species, presumably in the A(3Ou−) state. The last process involves stabilization by collision with nitrogen.
NUMERICAL SOLUTIONS OF SMOLUCHOWSKI'S EQUATIONS FOR THE COAGULATION OF UNCHARGED AEROSOLS
Authors: Beeckmans J. M.
Published: May 2006

Smoluchowski's equations for the coagulation of uncharged aerosol particles were programmed for solution by electronic computer. Terms representing differential sedimentation, turbulence, and mean aggregate density in solid aerosols were included. The effect of heterogeneity in the particle-size distribution of the aerosols on their rate of coagulation was illustrated by means of a slip-corrected coagulation factor Fc, which assumes a value of unity in all non-turbulent homogeneous aerosols. Curves of Fc vs. σg, the geometrical standard deviation, were calculated for aerosols of various mean particle-size. The effects due to turbulence, and to differential sedimentation, were illustrated in a similar manner. It was also found that the process of coagulation gives rise to a degree of dispersion which is independent of the original dispersion parameter, and depends only slightly on the mean particle-size of the aerosol over a wide range of particle-sizes. In the particle-size range in which differential sedimentation is inappreciable, the relatively constant value of the dispersion parameter implies that heterogeneous aerosols must obey the simplified integrated form of Smoluchowski's equation, which is applicable to homogeneous aerosols. The coagulation constant exceeds that predicted by the simple theory by about 10% for liquid aerosols of 0.1 μ or less.
THE THERMODYNAMIC PROPERTIES AND PHASE DIAGRAM OF THE GOLD–CADMIUM SYSTEM BY THE ISOPIESTIC METHOD
Authors: Bartha L. J. , Alexander W. A.
Published: May 2006

Activities of cadmium in gold alloys with up to 50 atom % Cd have been determined by an isopiestic method. The partial molar free energy, entropy, and heat of solution in the alpha and beta phases are calculated between 500 and 600 °C. The phase boundaries have been observed between 16 and 60 atom % above 400 °C. The boundaries of the two-phase regions α2 + β and β + δ′ are found at somewhat different concentrations than before, but the two-phase region α + α2 was not observed.
THE OXIDATION OF DITERPENOID ALKALOIDS
Authors: Achmatowicz Jr. O. , Tsuda Y. , Marion Léo
Published: May 2006

The highly oxygenated diterpenoid alkaloids possessing the same C—N ring structure fall into two groups: group A containing the aconitine-like bases in which the C-6 methoxyl is α-oriented, and group B containing the lycoctonine-like bases in which the C-6 methoxyl is β-oriented. The alkaloids of both groups are oxidized rapidly at room temperature by neutral potassium permanganate. The oxidation dealkylates the amino group in the bases of group A giving rise to secondary bases while it converts the bases of group B to the corresponding lactams. The different course of the oxidation from one group to the other is due to the different orientation of the C-6 methoxyl, and can be used to determine the stereochemistry at C-6.
THE MAGNETIC ANISOTROPY OF THE CARBONYL BOND
Authors: Hooper D. L. , Kaiser R.
Published: May 2006

The magnetic susceptibility components of the carbonyl bond have been determined from chemical shift differences in the n.m.r. spectra of amides. Correction of the experimental chemical shift differences for the effect of internal electric fields is found to overestimate the shielding of groups close to the carbonyl bond and it is shown that the sets of susceptibility components determined without this correction give a satisfactory correlation of structure and chemical shifts in amides, α,β-unsaturated ketones, and exo-methylene cycloketones.Four sets of susceptibility components are derived from formamide or acetamide spectra and depending on whether the effect of the carbonyl bond is assumed to be shielding or deshielding. These sets are, in units of 10−6 cm3 mole−1:[Formula: see text]Spectra of 1-ethylpyrrolidinone-2 are interpreted as showing that the effect of the carbonyl bond is to shield distant protons in the plane of the carbonyl group and its substituents.
CYCLOHEXANE COMPOUNDS: V. THE REACTION OF 1-METHOXYCYCLOHEXENE-2 WITH AQUEOUS N-BROMOSUCCINIMIDE. THE 1-METHOXY-2-BROMO-3-HYDROXYCYCLOHEXANES
Authors: Bannard R. A. B. , Casselman A. A. , Hawkins L. R.
Published: May 2006

Interaction of 1-methoxycyclohexene-2 and aqueous N-bromosuccinimide gave a mixture of stereoisomeric bromohydrins, which, on treatment with aqueous sodium hydroxide, furnished 1β-methoxy-2α,3α-epoxycyclohexane (I) and 1α-methoxy-2α,3α-epoxycyclohexane (II) in the ratio 3:1. The mixture from the N-haloimide-olefin reaction was separated by preparative vapor phase chromatography into three isomeric bromohydrins, 1α-methoxy-2α-hydroxy-3β-bromocyclohexane (IV), 1α-methoxy-2α-bromo-3β-hydroxycyclohexane (V), and 1α-methoxy-2β-bromo-3α-hydroxycyclohexane (VI) in the relative proportions 1:10:4. The 3-bromo isomer IV was identified by comparison with an authentic specimen prepared by the action of hydrobromic acid on the oxide II. Compounds V and VI were shown to have the indicated structures by deetherification to the corresponding bromodiols VII and VIII in high yield, followed by debromination of the latter to trans- and cis-1,3-cyclohexanediol respectively. The product distribution is considered in relation to the intervention of electronic and steric factors in a possible mechanism suggested for the reaction between aqueous N-bromosuccinimide and 1-methoxycyclohexene-2.
SYNTHESIS OF THE ISOMERIC METHYL vic-BROMOFLUOROPROPANOATES
Authors: Dean F. H. , Pattison F. L. M.
Published: May 2006

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LIGNIN MODEL COMPOUNDS. III. DETECTION OF 1-HYDROXY-1-(4-HYDROXY-3-METHOXYPHENYL)-2-PROPANONE IN THE ACIDOLYSIS PRODUCTS OF LIGNIN
Authors: Gardner J. A. F. , MacLean Harold
Published: May 2006

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THE SYNTHESIS OF POTENTIALLY PHYSIOLOGICALLY ACTIVE β-PHENYLETHYLAMINES. PART III. SOME β-ALKOXY-β-(3,4-DIHYDROXYPHENYL)ETHYLAMINES
Authors: Heacock R. A. , Hutzinger O. , Scott B. D.
Published: May 2006

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AN ELECTRON SPIN RESONANCE STUDY OF ULTRAVIOLET PHOTOLYZED SOLID CARBONYL SULFIDE
Authors: Stiles D. A. , Kewley R. , Strausz O. P. , Gunning H. E.
Published: May 2006

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ERRATUM: CARBON-13 ISOTOPE EFFECTS IN SYSTEMS CONTAINING CARBON DIOXIDE, BICARBONATE, CARBONATE, AND METAL IONS
Authors: Thode H. G. , Shima M. , Rees C. E. , Krishnamurty K. V.
Published: May 2006

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EFFECT OF PRESSURE AND TEMPERATURE ON THE RATE OF THE ACID-CATALYZED HYDRATION OF ETHYLENE
Authors: Baliga B. T. , Whalley E.
Published: May 2006

The rate of hydration of ethylene in dilute aqueous perchloric acid has been measured in the range 170–190 °C at 100 bars and 100 to 3 000 bars at 180 °C. The energy, entropy, and volume of activation are 33.3 ± ~1 kcal mole−1, −5.7 ± ~2.5 cal deg−1 mole−1, and − 15.5 ± ~1.5 cm3 mole−1 respectively. The volume of activation shows that at least one molecule of water is strongly bound in the transition state.
STUDIES IN THE WAGNER–MEERWEIN REARRANGEMENT: PART V. RATES OF FORMOLYSIS OF SOME 9-ALKYL-9-FLUORENYLMETHYL TOSYLATES
Authors: Anet F. A. L. , Bavin P. M. G.
Published: May 2006

For a series of 9-alkyl-9-fluorenylmethyl p-toluenesulfonates, the rates of decomposition in formic acid increase with the size of the alkyl group. Changes in the rate constants are associated with changes in ΔS≠.
INDEPENDENT YIELDS OF 124Sb AND 126sb IN THERMAL NEUTRON INDUCED FISSION AND THEIR IMPLICATION ON THE EMPIRICAL Zp FUNCTION
Authors: Strom P. O. , Grant G. R. , Pappas A. C.
Published: May 2006

The independent fission yields in thermal neutron induced fission of 235U have been measured to be (9.5 ± 1.4)•10−6% and (1.04 ± 0.17)•10−3% for 124gSb and 126gSb, respectively. The total independent yields for all isomers of these nuclides are estimated to be (1.2 ± 0.2)•10−5% for 124Sb and (3.7 ± 0.6)•10−3% for 126Sb using a Huizenga–Vandenbosch approach for estimating population of isomeric states.These data do not seem to support a 50 proton shell effect on the Zp function, using the "unique" charge distribution curve of Wahl. A revised Wahl plot based on recent information on neutron emission from individual fission fragments is given and discussed in view of shell effects in fission. It is shown that the effect of the Zp function of the 50 proton shell is very small.
STEREOSPECIFIC SYNTHESIS OF A DIBENZO[a,g]QUINOLIZINE ANALOG OF 18-HYDROXYALLOYOHIMBANE
Authors: Belleau B. , Dvornik D.
Published: May 2006

Starting from 4-cyclohexene-cis-1,2-dicarboxylic acid, the stereospecific synthesis of the dibenzo[a,g]quinolizine analog IV of epialloyohimbane is described. The synthetic method of approach is outlined in Chart 1. As the trimethoxybenzoic acid ester, the base IV proved to be devoid of significant pharmacological properties.
A L.E.T. INDEPENDENT DOSIMETER BASED ON THE CHEMILUMINESCENT DETERMINATION OF H2O2
Authors: Armstrong W. A. , Humphreys W. G.
Published: May 2006

A sensitive method for the determination of H2O2based on the copper-catalyzed chemiluminescent reaction between luminol and H2O2has been developed. The integral luminescence measured with a modified spectrophotofluorometer was found to increase linearly with concentration for 3 × 10−8to 1.5 × 10−5 M H2O2solutions. This method was applied to the determination of H2O2formed in irradiated water and it was shown that this system may be used as a dosimeter in the range 30 to 3 000 rads. The following values were obtained for the initial H2O2yields: G(H2O2) = 1.22 ± 0.07 for60Co γ-radiation, 1.28 ± 0.09 for 250 kVcp (105 keV effective) X-radiation and 1.31 ± 0.04 for 14 MeV neutrons. These results and those of other workers demonstrate that the initial yield of H2O2in aerated water increases only by about 15% for an increase in radiation l.e.t. of 0.02 to 14 eV/Å.
THE FEIST SYNTHESIS OF PYRROLE-3-CARBOXYLIC ESTERS
Authors: McKinnon D. M.
Published: May 2006

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HYDROGEN ATOM ABSTRACTION FROM ETHYLENEIMINE AND ETHYLENEIMINE-d4
Authors: Klemm R. F.
Published: May 2006

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THE PREPARATION AND HYDROLYSIS OF ALKYL HYDROGEN METHYLPHOSPHONATES
Authors: Keay Leonard
Published: May 2006

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ERRATUM: THE SYNTHESIS AND REACTIONS OF DIVINYL CARBONIUM IONS
Authors: Sorensen T. S.
Published: May 2006

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STUDIES IN THE PYRROLINE SERIES: V. 3,3-DIMETHYL-1-PYRROLINE-1-OXIDE
Authors: Bonnett R. , Ho S. C. , Raleigh J. A.
Published: May 2006

The pyrolysis of 1-ethyl-3,3-dimethylpyrrolidine-1-oxide gives 1-hydroxy-3,3-dimethylpyrrolidine, which, on dehydrogenation, yields 3,3-dimethyl-1-pyrroline-1-oxide. The identification of the nitrone is described. The cyclo-additions of styrene to this nitrone and to 5,5-dimethyl-1-pyrroline-1-oxide were investigated, and the direction of addition was deduced from the n.m.r. spectra of the adducts.
THE MONO-OXALATO COMPLEXES OF IRON(III): PART I. EQUILIBRIA
Authors: Bauer R. F. , Smith W. MacF.
Published: May 2006

The formation of the mono-oxalato complexes of iron(III) has been examined spectrophotometrically at ionic strength 0.50, between 5 and 25 °C and hydrogen ion concentrations 0.2 to 0.5 M. Evidence is presented that the protonated complex FeHC2O4++ is present in significant concentration in these solutions. The formation quotients of the species FeC2O4++ and FeHC2O4++ for temperatures 5, 15, and 25 °C have been determined and the extinction coefficients at 310 mμ have been estimated.
RADIATION-INDUCED CHANGES IN THE UNSATURATION OF POLYISOPRENE
Authors: Golub Morton. A. , Danon Jeanne.
Published: May 2006

Polyisoprene in the solid state and in benzene solution undergoes radiation-induced cis-trans isomerization and loss of unsaturation. Starting with various cis or trans polymers, the isomerization approaches an equilibrium in which the cis/trans ratio is around 50/50 for polyisoprenes irradiated in solution or in the solid state. The G(isom.) values for either cis → trans or trans → cis isomerization, i.e., the number of cis (or trans) units isomerized initially per 100 eV absorbed by both polymer and solvent, in 1% solution, and by polymer alone, in the solid state, are about 1.0 and 10, respectively. The energy transfer mechanism proposed previously for polybutadiene and squalene isomerization is assumed to hold for polyisoprene as well. The loss of unsaturation in films irradiated with electrons under nitrogen is twice as rapid as in films γ-irradiated in vacuo, the G(-d.b.) (d.b. = double bond) values being 13.4 and 6.7, respectively. Correspondingly, G(-d.b.) for a γ-irradiated solution is 27, calculated in terms of energy absorbed directly by the polymer; intermolecular energy transfer is again indicated, although phenylation may also contribute to the loss of double bonds in solution. The large drop in unsaturation in solution and in the solid state is attributed to a chain process involving cyclization and some cross-linking, with the participation of both free radicals and carbonium ions. Work with polyisoprene-3-d confirmed the importance of isomerization and loss of unsaturation and gave an activation energy of 1.1 kcal/mole for the latter reaction.
SULFUR ISOTOPE EFFECTS IN THE HYDROGEN ION DECOMPOSITION OF THIOSULFATE
Authors: Agarwala U. , Rees C. E. , Thode H. G.
Published: May 2006

Sulfur isotope effects in the decomposition of thiosulfate have been studied. There are two distinct intermolecular isotope effects and these have been used to examine various mechanisms for the reaction. By use of the theory of competing isotope reactions the thiosulfate decomposition mechanisms of La Mer and Davis have been shown to predict isotope effects not in accord with experiment, while a simple bimolecular three-centered reaction has been shown to predict sulfur and sulfite isotope effects in good agreement with the experimentally determined values of 1.9% and 0.9%.
DETERMINATION OF THE CRYSTAL STRUCTURE OF ERBIUM TITANATE, Er2Ti2O7, BY X-RAY AND NEUTRON DIFFRACTION
Authors: Knop Osvald , Brisse François , Castelliz Lotte
Published: May 2006

The crystal structure of erbium titanate, Er2Ti2O7, has been shown by X-ray and neutron powder diffraction to be of the cubic pyrochlore type, with ao = 10.0762 ± 6 Å. Least-squares isotropic refinement based on resolved single reflections gave x(O2) = 0.4200 ± 10 and R = 2.25%. Ionic and neutral X-ray scattering factors gave practically identical results. The six equal Ti—O2 distances in the distorted coordination octahedron of the Ti atom are 1.955 ± 5 Å. The two short (apparent) Er—O distances are 2.1815 ± 5 Å (Er—O1) and 2.471 ± 8 Å (Er—O2). The infrared spectrum of the titanate in the region 1 600 to 250 cm−1 shows features similar to those encountered in the spectra of other simple oxygen compounds of titanium.
THE DIFFUSE LAYER CORRECTION TO THE DISCRETE-ION EFFECT IN ELECTRIC DOUBLE LAYER THEORY
Authors: Levine S. , Mingins J. , Bell G. M.
Published: May 2006

The screening effect of the diffuse layer on the self-atmosphere (or discrete-ion) potential of a counter-ion adsorbed from aqueous electrolyte on to a plane charged interface is investigated. A theory based on Fourier–Bessel integrals and the approximate method of Loeb and Williams for treating the potential distribution in the diffuse layer is presented. The distribution of counter-ions in the adsorption plane surrounding a specified ion adsorbed in the plane is expressed in terms of a two-dimensional grand canonical ensemble and this is approximated by a 'revised cut-off model'. The 'Grahame cut-off model' is an approximation to the adsorbed counter-ion distribution based on a canonical ensemble and we present arguments to show that this interpretation is incorrect. We also show that the radius of the revised disc is, in general, smaller than that of the Grahame disc but approaches it at large charge densities (σβ) of counter-ions in the Stern inner region. Comparison is made with an alternative approach to this discrete-ion effect by Buff and Stillinger, who also applied a Fourier–Bessel technique to the mercury – aqueous electrolyte system. Their results provide a lower estimate to the magnitude of the self-atmosphere potential, whereas our revised cut-off model gives an upper estimate. A third method, which assumes the adsorbed ions to be situated on a hexagonal lattice, is also discussed and is found to give a potential larger than the upper estimate of the revised cut-off approach.It is shown that the effect of the diffuse layer is to diminish the discrete-ion potential at the adsorbed ion. When the electrolyte concentration tends to zero the results with the Grahame model reduce to those derived in an earlier paper from the method of multiple electrostatic images. Calculations on the discrete-ion potential at an adsorbed counter-ion are given for metallic and dielectric surfaces in contact with an aqueous 1–1 electrolyte solution and the parameters of the inner region are chosen to be consistent with known data on mercury and silver iodide systems. It is shown in both cases that on dilute salt solutions [Formula: see text] the diffuse layer screening is small compared to the unscreened term except at small charge densities of counter-ions in the inner region.
STEROIDS AND RELATED NATURAL PRODUCTS. XXV PHOTOCHEMICAL TRANSFORMATION OF 3β-NITRITO-5α-LANOSTANE
Authors: Pettit George R. , Kadunce Raymond E. , Sunder-Plassmann Paul. , Occolowitz John.
Published: May 2006

Ultraviolet irradiation of 3β-nitrito-5α-lanostane was found to follow an unusual reaction pathway and yield 2-oximo-3-oxo-3,4-seco-5α-lanostane (IV). The new aldehyde was easily converted to oxime and phenylhydrazone derivatives. Acetylating the photolysis product led to an oxime acetate (IX) which readily rearranged to 1-cyano-3,4-seco-5α-lanostane (III). Confirmation for the structural assignments was obtained from a series of proton magnetic resonance and mass spectral studies. Application of the new photochemical reaction was suggested to preparation of certain aldehydes otherwise accessible only with difficulty.
CHLORIDE AND SULFATE ION ASSOCIATION WITH SOME LANTHANIDE AND ACTINIDE IONS
Authors: Manning P. G.
Published: May 2006

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NUCLEOPHILIC CATALYSIS IN THE HYDROLYSIS OF DICHROMATE
Authors: Perlmutter-Hayman Berta , Wolff Michael A.
Published: May 2006

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EVIDENCE FOR ZnF2•2H2O
Authors: Secco E. A. , Srivastava O. K.
Published: May 2006

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STRUCTURAL FEATURES OF TWO EXTRACELLULAR POLYSACCHARIDES FROM SERRATIA MARCESCENS
Authors: Young Robert , Adams G. A.
Published: May 2006

A polysaccharide insoluble in acidified ethanol solution has been isolated from a culture filtrate of Serratia marcescens. Fractionation by cetyltrimethylammonium bromide ("Cetavlon") and by diethylaminoethyl (DEAE) cellulose yielded a polysaccharide which was electrophoretically homogeneous and contained D-glucose, L-rhamnose, D-galactose, L-glycero-D-mano-heptose, D-glycero-D-manno-heptose, glucosamine, and galactosamine in an approximate molar ratio of 6.5:3.5:0.5:1.0:0.5:1.0:0.2. However, following methylation it was found that the fully methylated polysaccharide could be fractionated by organic solvents into a rhamnoglucan and a heptoglucan. Both polysaccharides contained lipid material consisting mainly of hydroxy myristic acid and hydroxy lauric acid. The main chain of the rhamnoglucan was composed of (1 → 3) linked L-rhamnopyranose units and (1 → 4) linked D-glucose units with the non reducing end groups being D-glucose; some branching occurred through D-glucose units. The heptoglucan was composed mainly of chains of (1 → 4) linked D-glucose units with smaller amounts of (1 → 6) linked D-glucose and (1 → 2) linked D-glycero-D-manno-heptose units; these chains were terminated by D-glucopyranose and L-glycero-D-manno-heptose end groups.
CONSTITUTION OF AN EXTRACELLULAR ACIDIC GLUCOMANNAN FROM SERRATIA MARCESCENS
Authors: Adams G. A. , Young Robert
Published: May 2006

An acidic glucomannan isolated from culture filtrate of Serratia marcescens contained D-glucose and D-mannose (3.5:1), D-glucuronic acid (5.5%), and "bound" fatty acids (7.4%). The polysaccharide, on examination by moving boundary electrophoresis and by sedimentation in the ultracentrifuge, was homogeneous. Degree of polymerization was estimated to be ca. 20 by vapor pressure osmometry. Isolation of nigerose (3-O-α-D-glucopyranosyl-D-glucopyranose) established the glycosidic linkage between the D-glucose units as α (1 → 3). Methylation and periodate oxidation data showed that the D-glucose and D-mannose units were joined by (1 → 3) linkages in a straight chain structure terminated at the non-reducing end by a unit of D-glucuronic acid which was attached to C3 of a D-mannose residue. The reducing end of the molecule was terminated by a D-glucose unit. The fatty acids, consisting mainly of hydroxymyristic acid and myristic acid, were attached to the molecule mainly by ester linkages.
FORMATION OF CYCLIC O-2′-HYDROXYETHYLIDENE ACETALS FROM POLYALCOHOLS OF 4-O-LINKED POLYSACCHARIDES
Authors: Gorin P. A. J. , Spencer J. F. T.
Published: May 2006

Partial acid hydrolysis of polyalcohols derived from some 1,4-O-linked polysaccharides gave cyclic O-2′-hydroxyethylidene derivatives as by-products in yields of 6–18%. Polysaccharides containing β-links such as Rhodotorula glutinis mannan and cellulose gave rise to 6-membered ring acetals with lesser amounts of the 5-membered ring form. On the other hand, two α-linked polyalcohols, obtained following partial and complete oxidation of starch with sodium periodate, were converted to 5-membered O-2′-hydroxyethylidene acetals.