bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of organotin compounds. IX. The reactions of tin hydrides with perfluorovinyl germanium and tin compounds
Authors: Akhtar M. , Clark H. C.
Published: May 2006

The formation of addition products (CH3)3MCFHCF2Sn(CH3)3 and (CH3)3MCF[Sn(CH3)3]CF2H where M = Ge or Sn has been observed in reactions involving the ultraviolet irradiation of (CH3)3MCF=CF2 with trimethyltin hydride. The former type of addition product is more stable than the latter, and the stability of both types decreases in the order M = Si, Ge, or Sn. Evidence is presented that decomposition occurs in all cases by a β-fiuorine elimination with the formation of fluorovinyl derivatives of M and trimethyltin fluoride. Similar reactions occur between (CH3)3GeCF=CF2 and dimethyltin dihydride and between (CH3)2Ge(CF=CF2)2 and dimethyltin dihydride or trimethyltin hydride. The evidence indicates that a free radical process is involved. Spectroscopic data are presented for new organogermanium compounds.
Steroids and related products. XXVIII. Cardiotonic steroids. III. The synthesis of 3β-hydroxy steroids of the A/B-cis series
Authors: Bouchard R. , Engel Ch. R.
Published: May 2006

In the course of the synthesis of 3β-hydroxy-21,21-dimethoxy-5β-pregnan-20-one (8), a method was developed for the preferential reduction of steroid 3-ketones of the A/B-cis series to the axial 3β-alcohols, the stereochemistry in positions-3 and -5 of which corresponds to that of the truly active steroid cardiotonics. This method, which seems the best available to date, consists of a Meerwein–Ponndorf reduction carried out over a very short reaction period.
Studies on the azidolysis of 4-arylidene and 4-alkylidene 5(4)-oxazolones. Part II
Authors: Awad William Ibrahim , Fahmy Ameen Farouk Mohamed
Published: May 2006

4-Alkylidene-5(4)-oxazolones (1) react with sodium azide in acetic acid in 5 min, or with hydrazoic acid m benzene to give the diazide 2. The latter gives by thermolysis the oxadiazine (4), which forms on hydrolysis the diamide (5). The corresponding monoazides (3) react with sodium azide – acetic acid mixture to give the corresponding diazides.4-Arylidene-5(4)-oxazolones (8) react under the same conditions to give α-[tetrazolyl-(1)]-acryhc acid derivatives (9).The work of Deorha and Gupta (6) is reinvestigated. The constitution of the products is discussed chemically and spectroscopically.
Reaction of halogenated carbohydrates with sodium cobalt tetracarbonyl and carbon monoxide. A new novel synthesis of unsaturated sugars
Authors: Rosenthal Alex , Whyte J. N. C.
Published: May 2006

Methyl tri-O-acetyl 2-deoxy-2-iodo-β-D-glucopyranoside reacted at room temperature with sodium cobalt tetracarbonyl and carbon monoxide in ether to give in high yield methyl 4,6-di-O-acetyl-2,3-dideoxy-β-D-erythro-hex-2-enoside (5). Under the same reaction conditions the corresponding 2-iodo-α-D-mannopyranoside failed to react, but at 100 ° it was smoothly converted into the anomeric α-D-erythro-hex-2-enoside (7). When methanol was used in place of ether no appreciable ester formation took place but elimination of iodine and an acetoxy group occurred, accompanied by complete deacetylation of the remaining ester groups.
22-Dihydrostigmasterol from Saussurea lappa Clarke
Authors: Jain Tikam C. , Banks Calvin M.
Published: May 2006

The identity of a natural product, erroneously reported as a diterpene alcohol from Saussurea lappa Clarke, has been established as 22-dihydrostigmasterol.
Partial molal Volumes of tetraalkylammonium chlorides in ethanol–water mixtures
Authors: Lee Ikchoon , Hyne J. B.
Published: May 2006

The partial molal volumes of four tetraalkylammonium chlorides, Me4NCl, Et4NCl, Pr4NCl, and Bu4NCl, in a series of ethanol–water mixtures have been determined. The experimental results are discussed in terms of the varying size and surface charge of the ions and the structure of the binary solvent mixtures. The results indicate that at 0.1 mole fraction ethanol the maximum structuredness of water causes a minimum in the partial molal volumes, while at 0.3 mole fraction the solvent structure is such that the free volume is a minimum but the effect of surface charge on the salts is a maximum.
Proton magnetic resonance spectra of vinylmetallic compounds. Part I. Tetravinyl and triphenylvinyl derivatives of Group IVB elements
Authors: Cawley Seán , Danyluk Steven S.
Published: May 2006

A study has been made of the proton magnetic resonance spectra for all of the Group IVB derivatives of the series MVi4 and [Formula: see text]([Formula: see text] = phenyl group and Vi = vinyl group). The spectra were measured at 60 MHz as accurately as possible and the assignment of transitions was checked with a variety of supplemental aids including double irradiation, multiple quantum transitions, and medium effects Final, accurate spectral parameters were derived using both iterative and exact computational methods for solution of the three-spin problem Excellent agreement was obtained between the sets of parameters determined by the two methodsThe chemical shifts for both series of compounds display a number of characteristic trends of which the most notable is a displacement of the vinyl proton signals to low field with increasing atomic number of the M atom In each series the largest shift change is noted in going from the carbon to the silicon derivative These deshieldings have been attributed to the enhanced possibility of dπ–pπ interaction between the central M atom and the vinyl group in higher members of the series Marked changes are also the internal shifts of the vinyl protons down both series of compounds It is concluded that these changes are principally due to the effects of the M—C bond diamagnetic anisotropy The trends in internal shifts can be satisfactorily reproduced by the dipole approximation using Δχ values of 4, 6, 8, 12, and 18 × 10−6 cm3 mole−1 for the C, Si, Ge, Sn, and Pb–carbon bonds respectivelyThe signals for the vinyl protons of the [Formula: see text] series are all located to low field relative to the MVi4 series This deshielding is satisfactorily accounted for by the effects of the phenyl ring diamagnetic anisotropy in the former seriesA linear correlation is observed between the sums of the coupling constants and the electronegativities, Em, of the central M atom for both series of compounds However, the ΣJ values for the [Formula: see text] series are all slightly lower than the corresponding sums for the MVi4 series, indicating that the electronegativity of the phenyl group is somewhat larger than for the vinyl groupA significant solvent and concentration dependence is only noted for compounds belonging to the [Formula: see text] series For example, the trans proton of [Formula: see text] shifts up-field by 4 Hz while the cis proton is displaced down-field by 4 Hz as the concentration of [Formula: see text] is increased to 50 mole % in carbon tetrachloride These changes have been interpreted on the basis of a solute–solute interaction scheme of the type proposed previously for phenyl proton shifts.
Partially miscible liquid systems: The density, change of volume on mixing, vapor pressure, surface tension, and viscosity in the system: aniline–hexane
Authors: Campbell A. N. , Kartzmark E. M. , Anand S. C. , Cheng Y. , Dzikowski H. P. , Skrynyk S. M.
Published: May 2006

The following properties have been investigated experimentally: density, change of volume on mixing, vapor pressure, surface tension, and viscosity, at temperatures above and below the critical solution temperature. The question at issue is: How does the chemical potential, or any property dependent on chemical potential, change, at constant temperature, over a range of composition, just above the critical solution temperature? In the present case, the vapor pressure and surface tension, properties directly dependent on chemical potential, are constant within the range of experimental accuracy (which, however, may not be sufficient) over a range of concentration. The viscosity is complicated by the occurrence of anomalous viscosity. The change of volume on mixing is negative, and this is usually associated with compound formation. In all other systems investigated by us, except the system triethylamine–water, ΔV is positive. We have shown elsewhere, however, that a very stable chemical compound is formed between water and triethylamine.
Kinetics of the thermal reactions of ethylene. Part I
Authors: Boyd M. L. , Wu T-M. , Back M. H.
Published: May 2006

The pyrolysis of ethylene has been studied in the temperature range 500–600 °C and the pressure range 15–60 cm. The main products were ethane, propylene, butene, butadiene, and a polymer of molecular weight corresponding to C8 or higher. Small amounts of methane, butane, unsaturated C5, unsaturated C6, and benzene were also measured. Of the main products, propylene, butene, and butadiene showed an induction period, as long as several minutes at the lowest temperature. The order with respect to ethylene of ethane, propylene, and butene was close to two and the activation energy of the rates was approximately 40 kcal/mole. The results have been interpreted in terms of a free radical chain polymerization. It is suggested that the polymer formed is unstable and decomposes to yield the products for which an induction period was observed.
Reactions of triplet methylene radicals with alkanes
Authors: Ring D. F. , Rabinovitch B. S.
Published: May 2006

Studies have been made of the products resulting from reaction between triplet methylene and several alkanes, propane, n-butane, and isobutane. Triplet methylene was produced by photolysis of diazomethane in the presence of a large excess of inert nitrogen gas. Complicating side reactions involving diazomethane were encountered.Observation of higher products allowed the determination of the relative rates of 1°:2°:3° H abstraction from C—H bonds; these are ~1:14:150. The rate of addition of 3CH2 to the C=C bond in ethylene appears to proceed ~ 3.5 times faster than H abstraction from a 3 °C—H bond. The possible occurrence of insertion by 3CH2 into C—H bonds is discussed and relative rates of insertion for 1°:2°:3° bonds are deduced to be ~ 1:2:7. Comparisons of the relative rates of insertion abstraction are also given. Studies with propane-d6 indicated an isotope effect for abstraction of H:D from the 1 position of ~ 3.9; insertion by 3CH2 into the same position showed an isotope effect of ~ 2.
Thermal analysis of germanium(II) sulfide
Authors: Ross L. , Bourgon M.
Published: May 2006

Germanium(II) sulfide has been studied by the technique of differential thermal analysis. The results show that the reported Ge—S phase diagram may be in error: no evidence has been found for a solid-state transition at 590 °C and GeS appears to undergo peritectic disproportionation at approximately 650 °C.
Infrared spectra of 2-pyridone-16O and 2-pyridone-18O
Authors: Keller G. H. , Bauer L. , Bell C. L.
Published: May 2006

A comparison of the infrared spectra of natural 2-pyridone with that of the oxygen-18 labelled compound indicated modest shifts not only for the CO stretching mode (8.3−17.8 cm−1) for the various species in solution, but also for ring modes (0−13 cm−1) indicating a considerable mixing of the vibrations. The infrared spectrum of 2-pyridone at high concentrations revealed a new absorption band in chloroform solutions at 1685.0 and 1667.2 cm−1 for the unlabelled and labelled compound, respectively. In addition, absorption at 1614.9 cm−1 in the spectrum of 2-pyridone-18O in chloroform was found to be concentration dependent.
Isolation, structure, and synthesis of a stilbene glucoside from the bark of: Picea glauca (moench) voss.
Authors: Andrews D. H. , Hoffman J. C. , Purves C. B. , Quon H. H. , Swan E. P.
Published: May 2006

The fractionation of phlobaphenes from white spruce bark by column chromatography gave the non-crystalline stilbene glucoside trans 3,4′5-trihydroxy-3′-methoxystilbene-3-O-β-D-glucopyranoside (1). Purification was achieved through deacetylation of its hexaacetate (2). Compound 1 was cleaved with emulsin or dilute acid to the aglycone 4, and D-glucose. The acetate, benzoate, and dihydro-derivatives of 1, and the acetate, benzoate, methyl ether, and dihydro-derivatives of 4 were prepared. Oxidation of the benzoate derivative of 1 with chromic acid gave dibenzoyl-α-resorcylic acid. Similar oxidation of 2 gave acetylvanillic acid together with an uncharacterized acid which was hydrolyzed to D-glucose and β-resorcylic acid. The structure of 1 was therefore as shown, and its derivative 2 was synthesized. Vanillin was condensed with 3,5-dihydroxyphenylacetic acid and the product was decarboxylated and deacetylated. This compound was condensed with tetra-O-acetyl-α-D-glucopyranosyl bromide to yield a mixture of products which, after acetylation, were separated, using preparative thin-layer chromatography, to give the desired 2.
Intramolecular hydrogen bonding in cycloalkane-1,2-diol monoacetates
Authors: Wright Robert W. , Marchessault R. H.
Published: May 2006

Intramolecular hydrogen bonding in cyclopentane- and cyclohexane-1,2-diol monoacetates was studied by high resolution infrared spectroscopy in the 3μ region. Intramolecular hydrogen bonding was exhibited by all compounds and the data are interpreted in terms of preferred conformations, assuming the acetate group to be exclusively in the "planar trans" form.trans-Cyclopentane-1,2-diol monoacetate exhibited two hydroxyl absorption bands. One band was assigned to free hydroxyl stretching and the other to hydrogen bonding with the carbonyl oxygen so that an equilibrium between two ring conformations must be assumed to exist in solution. With cis-cyclopentane-1,2-diol monoacetate only a strong high frequency band was observed, and this was attributed to hydrogen bonding to the alkoxyl oxygen.trans- and cis-cyclohexane-1,2-diol monoacetate both exhibited two hydroxyl absorption bands. With the former, the hydroxyl group was assumed to be exclusively in an equatorial position to permit hydrogen bonding to both the alkoxyl and carbonyl oxygens. Similarly, in the latter, the high frequency band was attributed to hydrogen bonding to the alkoxyl oxygen atom while the low frequency band was assigned to hydrogen bonding to the carbonyl oxygen.
3-D-Hydroxypalmitic acid: a metabolic product of the yeast NRRL Y-6954
Authors: Vesonder R. F. , Wickerham L. J. , Rohwedder W. K.
Published: May 2006

An extracellular lipid produced by the yeast NRRL Y-6954 was shown to be free 3-D-hydroxypalmitic acid. The structure of the hydroxy acid was established by the mass spectrum of its methyl ester and a direct comparison with an authentic sample of methyl 3-D-hydroxypalmitate.
Studies on hydrogen–oxygen systems in the electrical discharge. II. The reactions of hydrogen atoms with liquid ozone
Authors: Herman Kazimiera , Giguère Paul A.
Published: May 2006

We have reinvestigated in detail the infrared spectra between 4000 and 600 cm−1 of the solid products formed by reacting liquid ozone at −190 °C with a stream of hydrogen gas dissociated in an electrodeless discharge. Extreme care was exercised to get "clean" spectra, free from any contaminants. All the spectra thus obtained showed very clearly the characteristic absorption bands of H2O2 at 2840 and 1430 cm−1, and the much weaker one at 880 cm−1; with deuterium atoms the former bands were shifted to 2100 and 1080 cm−1 respectively. Thus previous contentions that hydrogen peroxide is not one of the primary products of that reaction are disproved. The other infrared bands of H2O2 were not conspicuous, due either to their diffuse nature in the vitreous spectra or to extensive overlapping by the strong absorption of H2O, the other major component. Warming the material up to −110 °C caused some devitrification, but no significant change in the spectra. No new bands which could be assigned unambiguously to the hypothetical molecule H2O4 were observed.
Electron spin resonance study of γ-irradiated tetraethylammonium iodide
Authors: Fabes L. , Wan J. K. S.
Published: May 2006

γ-Irradiation of polycrystalline tetraethylammonium iodide at 77°K leads to the breaking of a C—C bond and the primary radicals ĊH3 and [Formula: see text] were detected by electron spin resonance. The methyl radicals were found to disappear readily at 120°K. In the range of 263–273°K a secondary reaction between [Formula: see text] and the parent ion [Formula: see text] was observed; the resulting secondary radical [Formula: see text] was found to be stable up to 373°K.
Configuration of the ring nitrogen in N-oxides and the conformation of tropanes. Part XVIII
Authors: Mandava Nagabhushanam , Fodor Gabor
Published: May 2006

The configurations of ring nitrogen in the amine oxides of tropine, oscine, atropine, and scopolamine have been investigated by nuclear magnetic resonance (n.m.r.) spectroscopy. Oxygen function(s) at C-6β (and 7β) were found to deshield the low-field, equatorial N-methyl signal. Analysis of the n.m.r. spectra of epoxides of some tropane bases, in particular the coupling constants, clearly indicates preponderance of the (slightly distorted) chair conformation even in the tropanes with a bulky group in the 3α (endo) position. The protons on the epoxide carbons are magnetically non-equivalent in scopolamine (5b) and its N-oxide while appearing as a singlet in the alkamine, i.e. scopine (5a).
Reactions of ozonides. VI. Conditions for by-product ester production in the oxidative ozonolysis of oleic acid
Authors: Diaper D. G. M. , Pasero J. , Naudet M.
Published: May 2006

Addition of water to various solvents used for oxidative ozonolysis of oleic acid increases acid product yield and diminishes ester by-product yield but the effect is non-stoichiometric. Hydrolysis of peranhydride intermediates and chain-termination mechanisms are possible explanations. Octyl nonanoate is identified as a by-product of nonanal autoxidation; its yield is diminished by adding water or ethanol. Reduced platinum oxide catalyzes oleic acid and 5-decene ozonide autoxidation but platinum on charcoal is without significant effect.
Transannular reactions in the dibenzo[a,d]cycloheptene series. II. Preparation of 10,11-dihydro-10,5-(epoxymethano)-5H-dibenzo [a,d] cyclohepten-13-one and derivatives
Authors: Dobson T. A. , Davis M. A. , Hartung A.-M. , Manson J. M.
Published: May 2006

The reaction of electrophilic reagents with the 5-substituted 5H-dibenzo[a,d]cycloheptene derivatives (13a–e) and with their 10,11-dihydro analogues (19a–b) occurs with transannular participation of the 5-substituent to yield derivatives of 10,11-dihydro-10,5-(epoxymethano)-5H-dibenzo[a,d]cycloheptene. The epimeric 10,11-dihydro-10-hydroxy-5H-dibenzo[a,d]cycloheptene-5-carboxamides (22, 23) are described. The syn-hydroxy isomer 22 is readily transformed to the lactone 16c under neutral conditions whereas the anti isomer 23 requires acid catalysis for this conversion. Treatment of anti-11-bromo-10,11-dihydro-10,5-(epoxymethano)-5H-dibenzo[a,d]cyclohepten-13-one (16b) with ammonia or primary aliphatic amines gives the epoxyamides 21a–d which can react with secondary aliphatic amines to give the anti-11-dialkylamino-10,11-dihydro-10,5-(epoxymethano)-5H-dibenzo[a,d]cyclohepten-13-ones (25a–d). The epimeric syn-11-dialkylamino compounds 24a–e are obtained from the interaction of 16b with secondary aliphatic amines. The nuclear magnetic resonance spectra of the products are tabulated.
Mass-spectral rearrangements of acyloxysilanes and -germanes
Authors: Brook A. G. , Harrison A. G. , Jones Peter F.
Published: May 2006

The mass spectra of some acyloxytriphenylmethanes, -silanes, and -germanes have been studied. The latter two classes show unusual fragmentation–rearrangement processes.
Reactor-neutron fission yields of 232Th
Authors: Harvey J. W. , Clarke W. B. , Gorman D. J. , Tomlinson R. H.
Published: May 2006

Mass spectrometric methods and a Ge(Li) γ-ray detector have been used to obtain reactor-neutron (> 1 MeV) fission yields of 232Th. The results have been combined with earlier mass spectrometric and radiochemical work.
Infrared studies on rotational isomerism. II. 2-Fluoroethanol
Authors: Buckley Paul , Giguère Paul A. , Yamamoto Daijiro
Published: May 2006

The infrared spectra of CH2FCH2OH were measured in the vapor, liquid, and solid states from 4000 to 200 cm−1. The Raman spectrum of the liquid was also measured over the same frequency range. From the results it appears that the free molecules exist almost entirely in the gauche configuration, which is stabilized by intramolecular hydrogen bonding. Only in the vapor at temperatures above 60 to 70 °C is there any indication of weak bands due to trans isomers. In the condensed phases the molecules are associated through strong hydrogen bonds (3–4 kcal/mole).
A series of stable platinum–acetylene complexes
Authors: Rochon F. D. , Theophanides T.
Published: May 2006

The synthesis of a new series of platinum acetylenic complexes of the general formula Pt(ac)2 are reported.
Study of base hydrogen bond in N,2,6-trichloro-p-benzoquinone imine with nuclear magnetic resonance and infrared spectroscopy. The assignment of syn and anti proton signals in the chloroimino group
Authors: Saitô Hazime , Nukada Kenkichi
Published: May 2006

The nuclear magnetic resonance (n.m.r.) spectra of N,2,6-trichloro-p-benzoquinone imine (1) and the anisotropy effect of the chloroimino group are investigated. A comparison of the n.m.r. spectra of 1 with those of oximes with a similar structure shows that the extent of the anisotropy effect is the same for both the chloroimino and the hydroxyimino group. This is also confirmed by comparison of N-chlorocyclohexanimine with cyclohexanone oxime. A downfield shift of the C—H proton signal in solvents acting as a base is observed, which is interpreted in terms of a [Formula: see text] base hydrogen bond. The extent of the shift is different between syn and anti sides and this gives the definite assignment for these two types of proton signals. Namely, the high-field signal, the extent of the downfield shift being larger, is assigned to anti protons, and the low-field one to syn protons. This assignment is extended to oximes owing to the equality of the anisotropy effects of the hydroxyimino and the chloroimino group. The formation of the [Formula: see text] base hydrogen bond is confirmed by the infrared (i.r.) spectra, and the correlation between the extents of n.m.r. downfield shift and i.r. low wave number shift is discussed. Furthermore it is found that the behavior of benzene molecule as solvent is different between the chloroimino and the hydroxyimino compounds.
Studies with halogeno sugars. II. A stable free glycosyl chloride
Authors: Bradley P. R. , Buncel E.
Published: May 2006

Dehydrochlorination of 3,4,6-tri-O-acetyl-2-chloro-2-deoxy-α-D-glucopyranosyl chloride with diethyl-amine yielded 3,4,6-tri-O-acetyl-2-chloro-D-glucal. The latter was further chlorinated to 3,4,6-tri-O-acetyl-2-deoxy-2,2-dichloro-α-D-ararbino-hexopyranosyl chloride, which on deacetylation provided the first example of a stable, free glycopyranosyl chloride.A 3,4,6-tri-O-acetyl-2-chloro-2-deoxymannopyranosyl chloride, also isolated in this work, was characterized by properties which correspond closely to the recently reassigned β anomer.
Sur la photodimérisation de l'acétate de la vitamine A
Authors: Giannotti Charles
Published: May 2006

not available
Bridgehead free radical stability. The decomposition of t-butylperoxyesters of the 1-adamantyl, 1-bicyclo[2•2•2]octyl, and 1-norbornyl systems
Authors: Humphrey Leonard B. , Hodgson Bruce , Pincock Richard E.
Published: May 2006

The t-butylperoxyesters of 1-adamantyl, 1-bicyclo[2•2•2]octyl, and 1-norbornyl carboxylic acids thermally undergo first order, free radical decomposition in cumene with relative rate constants at 80° of 1.0, 0.07, and 0.001 respectively. As measures of the stability of the derived bridgehead free radicals, the rates span a range much narrower than that for carbonium ion formation at these strained positions. The results are consistent with suggestions that free radicals have smaller force constants for out-of-plane bending than do the corresponding carbonium ions.
(p,n) and (p,pxn) reactions in 127I
Authors: Narang V. P. , Yaffe L.
Published: May 2006

Absolute values of the cross sections of (p,n), (p,pn), (p,p2n), and (p,p3n) reactions in 127I have been measured by radiochemical methods for incident proton of energies up to 80 MeV. The initial portion of the excitation function for the (p,n) reaction is characteristic of the compound nucleus mechanism, but evidence for direct interaction is present at higher energies. Above 50 MeV, cross sections are close to the predictions of Monte Carlo calculations based on the cascade–evaporation model. This is particularly true in the case of the (p,pn) and (p,p2n) reactions.
Spectrofluorometric studies. III. Ortho- and para-difluorobenzene
Authors: Durham J. L. , Semeluk G. P. , Unger I.
Published: May 2006

Spectrofluorometric techniques have been used to determine gas phase singlet and triplet yields in ortho- and para-difluorobenzene as a function of exciting wavelength and pressure. The importance of the "around the corner effect" in such measurements as the cause of large errors is briefly discussed.In the case of ortho-difluorobenzene, maxima in fluorescent yield are produced by the exciting wavelengths 2490, 2580, and 2700 Å; minima at 2540 and 2660 Å. Triplet yields, using the sensitized biacetyl emission technique, have been determined at 2500, 2580, 2660, and 2700 Å. The sums of the singlet and triplet yields at these wavelengths are 0.34, 0.52, 0.75, and 0.97 respectively.Para-difluorobenzene has the largest quantum yield of fluorescence of any fluorinated benzene yet examined. The fluorescent yield shows only one definite minimum at 2740 Å. Triplet yields have been determined at 2660, 2740, and 2760 Å. The sums of the singlet and triplet yields at these wavelengths are 0.5, 0.5, and 0.7 respectively.
Preferential solvation of Co2+ and Ni2+ ions in mixed solvents: n.m.r. methods
Authors: Frankel L. S. , Stengle T. R. , Langford C. H.
Published: May 2006

A method for the study of preferential solvation in the outer coordination spheres from paramagnetic broadening of solvent proton n.m.r. signals was proposed by Frankel, Stengle, and Langford. It is now extended to determinations of the relative concentrations of water and dioxane, dimethylformamide, or dimethylsulfoxide in the inner coordination spheres of Co2+ and Ni2+ ions in the binary solvent mixtures. The assumptions of the analysis are cross-checked by a new method based on the contact shifts experienced by protons on solvent molecules in the coordination spheres of paramagnetic ions. The second method depends upon assumptions independent of the first. Three cases are presented as tests of these n.m.r. approaches. It is clear that highly precise solvation sphere populations will be difficult to obtain but that useful and significant information can be obtained in situations to which alternative methods are almost totally inapplicable.The results indicate that dimethylsulfoxide and dimethylformamide are good competitors for coordination sites but that dioxane is excluded by water.
Radiolysis of methylcyclopentane. III. Liquid phase mechanism and comparison of cycloalkanes
Authors: Freeman Gordon R. , Stover E. Diane
Published: May 2006

The initial yields of the major products of the gamma radiolysis of liquid methylcyclopentane (MCP) at 25° are: G(H2) = 4.2, G(1-methylcyclopentene plus methylenecyclopentane) = 2.7, G(3- plus 4-methyl-cyclopentene) = 1.0, G(open chain hexene) = 1.0, and G(bimethylcyclopentyl) = 0.9. The effects of scavengers on the product yields are reported and the mechanism is discussed.The liquid phase radiolytic decompositions of cyclohexane (CH), methylcyclohexane (MCH), cyclopentane (CP), and MCP are compared. The net amount of C—C bond cleavage is much greater in the five-membered than in the six-membered rings. Methyl substitution on the ring reduces G(H2) by about one unit, mainly because of the formation of a type of ion (QH+) that does not yield hydrogen when neutralized by an electron. The QH+ type ions are formed in MCH and MCP, but not in CH and CP. In all the systems, another type of ion (N+) that does not yield hydrogen when neutralized by an electron is formed with a G value of about unity. The type of ion (PH+) that does yield hydrogen when neutralized by an electron has a G value of 3.4 in CH and CP, but only 2.0 in MCP. It is concluded that G(total ionization) is in the vicinity of 4.4 in the liquid compounds, virtually the same as the gas phase values.
The hydrogenation of allene. II. The reaction of allene with hydrogen catalyzed by nickel, cobalt, and iron
Authors: Mann R. S. , Tiu D. E.
Published: May 2006

The reaction between allene and hydrogen over unsupported nickel, iron, and cobalt catalysts has been studied in a static constant volume system for a wide range of temperature and reactant ratios. The reaction over metals is largely simple hydrogenation, the early stages being principally a selective formation of propylene with small yields of reduced polymers of allene. The orders of the hydrogenation were 1 and 0 with respect to hydrogen and allene respectively, and were temperature independent. The overall apparent activation energies for nickel, iron, and cobalt were 6.5, 7.6, and 6.9 kcal/mole respectively. Selectivity was highest with nickel, and least with cobalt.
Solvent effects on the electronic spectrum of trans-dichlorobis(diphenyl sulfide)platinum(II)
Authors: Senoff C. V.
Published: May 2006

The electronic spectrum of trans-PtCl2(Ph2S)2 has been measured in a variety of organic solvents and the effect of the solvent on the observed absorption bands is discussed.
Friedel–Crafts rearrangements. III. Deuterium tracer studies of the mechanism of cyclialkylation of phenylalkyl chlorides
Authors: Barclay L. R. C. , Sanford E. C.
Published: May 2006

A series of dideuterated primary phenylalkyl chlorides 1-chloro-3-phenylpropane-2,2-d2 (4), 1-chloro-3-phenylpropane-1,1-d2 (9), 1-chloro-4-phenylbutane-2,2-d2 (8), 1-chloro-5-phenylpentane-4,4-d2 (5), 1-chloro-5-phenylpentane-3,3-d2 (6), and 1-chloro-5-phenylpentane-2,2-d2 (7) were synthesized by alkylations of malonic ester with phenylalkyl chlorides. Deuterium was introduced by exchange of the sodium salt of the alkylated malonic ester with D2O, followed by hydrolysis and decarboxylation. The resulting acids were reduced by hydride to primary alcohols and these were converted to the dideuterated primary chlorides by decomposition of the intermediate chlorosulfite esters. Nuclear magnetic resonance (n.m.r.) spectra confirmed the position of the deuterium in the chlorides. Friedel–Crafts cyclialkylation of the deuterated phenylpentyl chlorides yielded labelled 1-methyltetralins in which the label was located by n.m.r. and mass spectroscopy. The results demonstrated that rearrangement precedes cyclialkylation of 1-chloro-5-phenylpentane. Extensive deuterium scrambling between C-1, C-2, and C-3 accompanied the cyclialkylation of 5 but not that of 8. Reaction mechanisms are suggested to account for these results.
Structure and reactions of lactonic and acidic sophorosides of 17-hydroxyoctadecanoic acid
Authors: Tulloch A. P. , Hill A. , Spencer J. F. T.
Published: May 2006

The complete structures of the major components of the mixture of lactonic and acidic sophorosides of 17-L-hydroxyoctadecanoic acid, which is produced by a yeast of the genus Torulopsis, have been determined. The principal lactonic component (1) (41%) has acetate groups at the 6′- and 6″-positions and the fatty acid carboxyl group is linked to the 4″-position to form a macrocyclic lactone ring. The other lactonic component (2) (8%) differs from the first only in the absence of the acetate group at the 6′-position. The principal acidic component (5) (31%) also has acetate groups at the 6′- and 6″-positions but the fatty acid carboxyl group is free. The structures were deduced by a combination of glycol cleavage and nuclear magnetic resonance studies and by examination of the products of acetobrominolysis of the acetylated lactones and acid.The 2″,3″-glycol group of the lactones is resistant to oxidation by periodate and by lead tetraacetate in acetic acid. Studies of the rate of glycol cleavage of methyl 4,6-di-O-acyl-β-D-glucopyranosides showed that though an acyl group at C-4 retarded the oxidation of the 2,3-diol it did not stop it completely. The conformation of the lactone ring is probably responsible for the unreactivity of the 2″,3″-glycol group. The lactone ring, however, considerably increases the rate of acetobrominolysis of the fully acetylated lactone compared to that of the acetylated sophorosyl acid methyl ester.
Some structural features of the heteropolysaccharides of Candida bogoriensis
Authors: Gorin P. A. J. , Spencer J. F. T.
Published: May 2006

The two exocellular polysaccharides of Candida bogoriensis contain D-mannose, D-fucose, L-rhamnose, D-glucuronic acid, and D-galactose residues. The main heteropolymer (> 80%) has an α-D-(1 → 3)-linked mannan main-chain as shown by successive Smith degradations. Partial hydrolysis of the heteropolymers provided several methylpentose-containing oligosaccharide fragments corresponding to possible side-chain components.
7-(1-Isoquinolinylmethyl)-theophyllines
Authors: Bariana D. S.
Published: May 2006

A number of 7-(1-isoquinolinylmethyl)-theophyllines were synthesized. The route of synthesis and the pharmacology results of these compounds are described.
Determination of erythro and threo configurations by nuclear magnetic resonance spectroscopy
Authors: Schmid George H.
Published: May 2006

An examination of the nuclear magnetic resonance spectra of ten pairs of racemic erythro and threo isomers of 1,2-disubstituted-1-arylpropanes shows that the signals of the methyl protons of the erythro isomer always appear at lower field than the threo isomer. The vicinal coupling constant (Jab) of the erythro isomer is found to be smaller than that of the threo isomer in six of the isomeric pairs indicating that the magnitude of Jab is a poor criterion of configuration of the 1,2-disubstituted-1-arylpropanes.
Essential oils and their constituents. XLII. Isomerization of epoxides on active alumina
Authors: Nigam Ishwar C. , Levi Leo
Published: May 2006

not available
Fischer indole synthesis. The reaction of N′-alkyl-2,6-dialkylphenyl-hydrazines with cyclohexanone
Authors: Bajwa G. S. , Brown R. K.
Published: May 2006

not available
Fully fluorinated alkoxides. Part IV. Derivatives of perfluoropinacol
Authors: Allan M. , Janzen A. F. , Willis C. J.
Published: May 2006

The reductive dimerization of hexafluoroacetone, by reaction with sodium in a donor solvent, leads to the ionic disodium alkoxide of perfluoropinacol, a valuable intermediate for the preparation of pinacol derivatives. Cyclic alkoxides of silicon, germanium, tin, and boron are made by the reaction of this disodium alkoxide with various dihalides.Reaction with thionyl chloride, sulfuryl chloride, or sulfur(II) chloride gives perfluoropinacol sulfite, sulfate, and ortho-sulfite. respectively. The stereochemistry of the last compound is discussed.
Synthesis and spectra of some diarylidenecyclanones
Authors: Farrell P. G. , Read B. A.
Published: May 2006

The synthesis and spectra (ultraviolet, infrared, and nuclear magnetic resonance) of some previously unknown 2,n-dibenzylidene and dicinnamylidenecyclanones where n = 5–10 are described. The spectra are in accord with the expected decrease in coplanarity of the conjugated groups with increasing ring size. trans-Ring hydrogen bonding may occur in 2,10-dibenzylidenecyclodecanone but no evidence is found for this effect in the parent cyclanone.
Stéréochimie de l'époxydation du tert-butyl-3 cyclohexène
Authors: Richer Jean-Claude. , Freppel Christian
Published: May 2006

not available
Absolute configurations of 13-hydroxydocosanoic and 17-hydroxyoctadecanoic acids
Authors: Tulloch A. P.
Published: May 2006

Methyl 13-D- and 13-L-hydroxydocosanoates have been synthesized from 9-D- and 9-L-hydroxy-octadecanoic acids. Comparison of these esters with the methyl ester of 13-hydroxydocosanoic acid, produced by Candida bogoriensis, shows that the natural product has the L-configuration. The known 2-D-octadecanol has been prepared from 17-hydroxyoctadecanoic acid, produced by Torulopsis apicola, showing that this acid also has the L-configuration. Most naturally occurring long-chain hydroxy acids, however, have the D-configuration.
Photo-addition of alkenes and alkynes to 3-carene-2,5-dione
Authors: Still Ian W. J. , Kwan M-H. , Palmer G. E.
Published: May 2006

A number of photo-addition reactions have been carried out on the enedione system of 3-carene-2,5-dione by direct irradiation in the presence of a variety of alkenes and alkynes. Addition to the carbon–carbon double bond is by far the major pathway, and indeed in only one case is there evidence for formation of an oxetane ring. In the case of the unsymmetrical addends, the direction of addition which produces the cyclobutane or cyclobutene appears to be in accord with previous experiments on simpler systems.
Second order Beckmann rearrangement of norcamphor oxime
Authors: Schmid George H. , Fitzgerald Patrick H.
Published: May 2006

The product of the second order Beckmann rearrangement of norcamphor oxime is not Δ3-cyclo-pentenylacetonitrile but rather a mixture of Δ2- and Δ3-cyclopentenylacetonitrile.
Détermination d'un équilibre conformationnel par résonance magnétique nucléaire de polyesters
Authors: Perrault Guy
Published: May 2006

The conformation of the 2-hydroxypropyl group in the polysebacates of the N-methyl bis-(2-hydroxypropyl)-amine and the N-methyl (2-hydroxyethyl, 2-hydroxypropyl)-amine has been studied by nuclear magnetic resonance spectroscopy.
Structure of β-mangostin
Authors: Yates Peter , Bhat H. B.
Published: May 2006

β-Mangostin, a minor coloring matter of the dried latex of Garcinia mangostana, is shown to be 1,6-dihydroxy-3,7-dimethoxy-2,8-di-(3-methyl-2-butenyl)xanthone (4).
Pyrochlores. IV. Crystallographic and Mössbauer studies of A2FeSbO7 pyrochlores
Authors: Knop Osvald , Brisse François , Meads R. E. , Bainbridge J.
Published: May 2006

The lattice parameters and the quadrupole splittings of the room-temperature Mössbauer spectra of the cubic A2FeSbO7 pyrochlores (A = Sm, Eu, Gd, Tb, Y, Er, Lu) have been found to vary linearly with the Templeton–Dauben radii of the A3+ ions. The variation of the quadrupole splitting can be correlated with the positional parameter of the majority oxygen atom, x(O2), which determines the degree of distortion of the BO6 octahedron in cubic A2B2O7 pyrochlores. An increase of 0.1 Å in r(A3+) corresponds to a decrease of ca. 0.20 mm/s in the quadrupole splitting in the A2FeSbO7 series, and to an estimated increase of ca. 0.005 in x(O2). The isomer shift and quadrupole splitting at room temperature are typical of Fe3+(high spin) in octahedral coordination of relatively high distortion. Y2FeSbO7 at 4.2°K was found to exhibit magnetic order with a hyperfine magnetic field of approximately 400 kOe. An attempt to prepare a cubic La2FeSbO7, pyrochlore by the standard procedure was not successful.
Kinetics of formation of ethylene oxide hydrate. Part II. Incongruent solutions and discussion
Authors: Glew D. N. , Haggett M. L.
Published: May 2006

Equations were developed to describe the experimental rates of formation of ethylene oxide hydrate from stirred, incongruent solutions. Heat conduction through the walls of the dilatometer bulb was rate-controlling. Results for congruent solutions were consistent with these equations during the early stages of hydrate growth.
Physical nature of the chemical bond. III. A quasi-optimized l.c.G.t.o.-m.o.-s.c.f. wavefunction for the neon hydride ion
Authors: Moffat J. B.
Published: May 2006

Quasi-optimized wavefunctions for the neon hydride positive ion (NeH+) have been obtained for various sizes of basis sets of Gaussian orbitals. The effect of varying the size of basis set and the exponents has been examined.
CHARGE CRYSTAL MODEL FOR THE HIGH-Tc SUPERCONDUCTIVITY
Authors: KIM Y. H. , HOR P. H.
Published: May 2006

We propose a charge crystal model that captures all the essential physics of the high temperature superconductivity (HTS) in the long wavelength limit. Based on the recent transport and the far-infrared (far-IR) experiments, we argue that the three-dimensional (3D) ordering of the pinned two-dimensional (2D) square electronic lattice (EL) in each CuO 2 plane is the building block of HTS. Incorporating the physical picture derived from the neutron scattering experiments, we demonstrate that our model presents a coherent picture of the HTS. We suggest that the charge crystal model serves as a model for the microscopic theory and, hence, offers the key to the mechanism for the HTS.
Carbohydrate ingestion does not alter skeletal muscle AMPK signaling during exercise in humans
Authors: Lee-Young Robert S. , Palmer Matthew J. , Linden Kelly C. , LePlastrier Kieran , Canny Benedict J. , Hargreaves Mark , Wadley Glenn D. , Kemp Bruce E. , McConell Glenn K.
Published: May 2006

There is evidence that increasing carbohydrate (CHO) availability during exercise by raising preexercise muscle glycogen levels attenuates the activation of AMPKα2 during exercise in humans. Similarly, increasing glucose levels decreases AMPKα2 activity in rat skeletal muscle in vitro. We examined the effect of CHO ingestion on skeletal muscle AMPK signaling during exercise in nine active male subjects who completed two 120-min bouts of cycling exercise at 65 ± 1% V̇o2 peak. In a randomized, counterbalanced order, subjects ingested either an 8% CHO solution or a placebo solution during exercise. Compared with the placebo trial, CHO ingestion significantly ( P < 0.05) increased plasma glucose levels and tracer-determined glucose disappearance. Exercise-induced increases in muscle-calculated free AMP (17.7- vs. 11.8-fold), muscle lactate (3.3- vs. 1.8-fold), and plasma epinephrine were reduced by CHO ingestion. However, the exercise-induced increases in skeletal muscle AMPKα2 activity, AMPKα2 Thr172phosphorylation and acetyl-CoA Ser222phosphorylation, were essentially identical in the two trials. These findings indicate that AMPK activation in skeletal muscle during exercise in humans is not sensitive to changes in plasma glucose levels in the normal range. Furthermore, the rise in plasma epinephrine levels in response to exercise was greatly suppressed by CHO ingestion without altering AMPK signaling, raising the possibility that epinephrine does not directly control AMPK activity during muscle contraction under these conditions in vivo.
Smooth Pursuit of Nonvisual Motion
Authors: Berryhill Marian E. , Chiu Tanya , Hughes Howard C.
Published: May 2006

Unlike saccades, smooth pursuit eye movements (SPEMs) are not under voluntary control and their initiation generally requires a moving visual target. However, there are various reports of limited smooth pursuit of the motion of a subject’s own finger in total darkness (pursuit based on proprioceptive feedback) and to the combination of proprioception and tactile motion as an unseen finger was moved voluntarily over a smooth surface. In contrast, SPEMs to auditory motion are not distinguishable from pursuit of imagined motion. These reports of smooth pursuit of nonvisual motion cues used a variety of paradigms and different stimuli. In addition, the results have often relied primarily on qualitative descriptions of the smooth pursuit. Here, we directly compare measurements of smooth pursuit gain (eye velocity/stimulus velocity) to visual, auditory, proprioceptive, tactile, and combined tactile + proprioceptive motion stimuli. The results demonstrate high gains for visual pursuit, low gains for auditory pursuit, and intermediate, statistically indistinguishable gains for tactile, proprioceptive, and proprioceptive + tactile pursuit.
The integral limit theorem in the first passage problem for sums of independent nonnegative lattice variables
Authors: Virchenko Yuri P. , Yastrubenko M. I.
Published: May 2006

The integral limit theorem as to the probability distribution of the random number νm of summands in the sum is proved. Here, ξ1, ξ2, … are some nonnegative, mutually independent, lattice random
variables being equally distributed and νm is defined by the condition that the sum value exceeds at the first time the given level m ∈ ℕ when the number of terms is equal to νm.
Robustness of solutions of linear differential equations with infinite delay
Authors: Al-Badarneh (Al-Nayef) Anwar A. , Maaitah Rabaa K.
Published: May 2006

We use some consequences of the concept of semihyperbolicity of
the solution operator to show robustness of solutions of the
linear delay differential equation x′(t) = Ax(t) + Bx(t − r) with infinite delay with respect to a small nonlinear perturbation.
Mitochondrial Oxidative Damage in Aging and Alzheimer′s Disease: Implications for Mitochondrially Targeted Antioxidant Therapeutics
Authors: Reddy P. Hemachandra
Published: May 2006

The overall aim of this article is to review current therapeutic
strategies for treating AD, with a focus on mitochondrially
targeted antioxidant treatments. Recent advances in molecular,
cellular, and animal model studies of AD have revealed that
amyloid precursor protein derivatives, including amyloid beta (Aβ) monomers and oligomers, are likely key factors in tau
hyperphosphorylation, mitochondrial oxidative damage, inflammatory
changes, and synaptic failure in the brain tissue of AD patients.
Several therapeutic strategies have been developed to treat AD,
including anti‐inflammatory, antioxidant, and antiamyloid
approaches. Among these, mitochondrial antioxidant therapy has
been found to be the most efficacious in reducing pathological
changes and in not producing adverse effects; thus, mitochondrial
antioxidant therapy is promising as a treatment for AD patients.
However, a major limitation in applying mitochondrial antioxidants
to AD treatment has been the inability of researchers to enhance
antioxidant levels in mitochondria. Recently, however, there has
been a breakthrough. Researchers have recently been able to
promote the entry of certain antioxidants—including MitoQ,
MitoVitE, MitoPBN, MitoPeroxidase, and amino acid and
peptide‐based SS tetrapeptides—into mitochondria, several
hundred‐fold more than do natural antioxidants. Once in the
mitochondria, they rapidly neutralize free radicals and decrease
mitochondrial toxicity. Thus, mitochondrially targeted
antioxidants are promising candidates for treating AD patients.
On the Receiving End
Authors: Bartunek Jean M. , Rousseau Denise M. , Rudolph Jenny W. , DePalma Judith A.
Published: May 2006

This study focuses on the interpretations and experiences of change recipients, those who carry out organizational interventions initiated by others. Based on the ways nurses experienced a shared governance initiative implemented in their hospital, the authors investigated change recipients’ sensemaking about organizational change through their ascribed meanings, emotional responses, and perceptions of its impacts on them. Survey data demonstrated how nurses subjectively assessed their gains and losses from the change initiative. Participation in the initiative increased the experience of gains, as did membership in a unit where change was implemented more fully. Textual analysis of open-ended responses to the survey indicated that gains were linked with interpretations of the change initiative and pleasant feelings and that there was considerable emotional contagion within work units. Such effects are particularly likely in employee empowerment initiatives as experiences are linked to interpretation and mood among change recipients.