bluuebunny/crossref_metadata_2025 huggingface dataset:
Mass spectra of some deuterated ethanes. II. An empirical method of calculation of the spectra
Authors: Amenomiya. Y. , Pottie R. F.
Published: May 2006

Relative intensities of the C2 fragment ions in deuterated (d1–d5) ethanes have been calculated on a statistical basis from the mass spectrum of C2H6 and have been compared with experimental mass spectra previously reported in Part I. For these calculations we have introduced a correction for the relative probabilities of loss of two hydrogen atoms in addition to weighting factors for the loss of H and D atoms. The isotopic weighting factors have been expressed in terms of power series. By this means satisfactory agreement was obtained between the calculated and experimental mass spectra.This treatment also made it possible to calculate the intensities of doubly charged C2 fragments that appear in the C1 mass spectra. We then estimated the degree of reshuffling of hydrogen atoms prior to C—C bond rupture and obtained calculated mass spectra that were in reasonable agreement with the experimental data for the C1 region of the mass spectrum.Experimental mass spectra have been newly obtained for 1,1-d2 ethane and 1,1,1,2-d4 ethane and are included here for completeness.
Recherches sur le point isohydrique et les équilibres acido–basiques de condensation ou association en chimie. XXVII. Les hydroxocomplexes des sels organostanniques (CH3)3SnCl et (C2H5)2SnCl2, en solutions aqueuses, à 25 °C et à différentes forces ioniques
Authors: Asso Marcel , Carpéni Georges
Published: May 2006

The electrometric study of the trimethyltin chloride and diethyltin dichloride, at 25 °C, and at different ionic strengths, leads to ph = f(x,c) networks, each of which shows an isohydric point (i.p.), proof of the existence in solution of an associated preponderant form in equilibrium with the monomeric. The theoretical study permitted us to determine the different equilibrium constants. The values of the experimental isohydric coordinates and of the calculated constants, for each of the previous networks, are:[Formula: see text]Furthermore, the "isohydric salt" ((CH3)6Sn2(OH)Cl), corresponding to x1 = 0.50 but not known until now, was obtained.
Réactions des époxydes de quelques stéroides avec le glycinate d'éthyle
Authors: Jankowski Krzysztof , Berse Casimir
Published: May 2006

not available
Preparation of some isothiazolium salts
Authors: McKinnon D. M. , Robak E. A.
Published: May 2006

Certain 1,2-dithiolium salts react with primary amines in alcoholic solution to provide 1-aminopropene-3-thiones, which can be oxidized by iodine to form isothiazolium salts. These react with sulfur in pyridine to form isothiazole-3-thiones, which react with methyl iodide to form 3-methylthioisothiazolium iodides.
Reaction of bicyclobutanes with electrophiles
Authors: Lee-Ruff E. , Just G.
Published: May 2006

Reactions of Bicyclobutanes 1 and 1a, obtained from the corresponding cholesta-3,5-dienes, with ketones, phosgene, halogens, and tetracyanoethylene gave the A-norcholest-5-ene derivatives 3 – 14. A possible mechanism for these reactions is postulated.
Partition coefficients of some conjugated heteroenoid compounds in the system cyclohexane–water
Authors: Lough C. E. , Silver R. F. , McClusky F. K.
Published: May 2006

Partition coefficients in cyclohexane–water were determined for 160 conjugated heteroenoid compounds and were used to calculate π constants for several component groupings of molecules.
Thermal condensation of formaldehyde with 3-p-menthene, 1-p-menthene, and cyclooctene
Authors: Watanabe Shoji , Suga Kyoichi , Kuniyoshi Masayuki
Published: May 2006

When a mixture of 3-p-menthene, paraformaldehyde, and acetic anhydride was heated at 200 °C in an autoclave, an acetate was obtained. By saponification of the acetate with alcoholic potassium hydroxide, 3-hydroxylmethyl-4-p-menthene was obtained. Similarly, 2-hydroxymethyl-6-p-menthene was produced from 1-p-menthene, and 1-hydroxylmethyl-2-cyclooctene was produced from cyclooctene.
Thermodynamics of ionization of aqueous toluidinium ions
Authors: O'Hara W. F.
Published: May 2006

Standard heats of ionization of ortho-, meta-, and para-toluidinium ions in water at 25 °C have been determined in a high precision solution calorimeter. Entropies of ionization have been calculated from these heats and well-defined free energy changes. As predicted by theory, a linear relation is found between ΔS0Ion and ΔG0Ion and between ΔH0Ion and ΔS0Ion for these compounds.
Influence des effets inductifs et stériques sur la basicité des amines tertiaires. Détermination et interprétation des ΔH et des ΔS
Authors: Perrault Guy.
Published: May 2006

ΔH and ΔS were obtained by pKa measurements in water at different temperatures for a series of dihydroxylated tertiary amines. The thermodynamic factors seem to confirm that the diminution in basicity introduced by long chain substituents is caused by frontal hindrance to solvation, accompanied by a new type of back-strain. With short chain substituents, the formation of intramolecular hydrogen bonds can be seen by the variations of the entropy factor.
Infrared spectra of phenylboronic acid (normal and deuterated) and diphenyl phenylboronate
Authors: Faniran J. A. , Shurvell H. F.
Published: May 2006

The infrared spectra of phenylboronic acid, normal and deuterated, and diphenyl phenylboronate have been recorded in the range 4000–300 cm−1 and assignments of the observed frequencies have been made. The spectrum of the acid in the OH stretching region shows evidence of intramolecular hydrogen bonding. The spectrum of diphenyl phenylboronate has been interpreted by analogy with monosubstituted benzene derivatives. The two different environments of the phenyl groups in this molecule give rise to splitting of two of the characteristic vibrations of the benzene ring near 760 and 680 cm−1.
Méthode directe de mesure d'intensité intégrée d'une bande d'absorption infrarouge en phase liquide. Application à la bande ν1 de quelques haloformes en solution dans le CCl4 et dans le CS2
Authors: Rossi I. , Levy A. , Haeusler C.
Published: May 2006

not available
Preparation and reactions of sulfoxides and phosphine oxides containing silicon and germanium
Authors: Brook A. G. , Anderson D. G.
Published: May 2006

The preparation of several sulfoxides containing silicon or germanium is reported. The thermal rearrangement of the silicon-containing sulfoxides has been observed but neither germanium-containing sulfoxides nor silicon-containing phosphine oxides were found to rearrange thermally at a detectable rate.
Ion–molecule reactions in formic-d acid and methyl formate
Authors: Pritchard Howard , Thynne J. C. J. , Harrison A. G.
Published: May 2006

The following ion–molecules reactions have been found to occur in DCOOH for ions produced by bombardment with electrons of 10–15 eV energy (all rate constants in cm3 molecule−1 units).[Formula: see text]In methyl formate the following reactions have been identified and rate constants measured for ions formed by bombardment with electrons of 10–15 eV energy.[Formula: see text]Experiments using DCO2CH3 show that reaction [f] involves transfer of the methyl hydrogen at a rate 1.5 times that of the formyl hydrogen while reaction [g] involves transfer from only the methyl position of CH3OH+. The rate constants for all reactions are considerably higher than predicted on the basis of ion–induced dipole interactions only but are in good agreement with values calculated by including ion–dipole interactions.
Chemical and biological properties of some oxindolidyl-3-methines
Authors: Hodges R. , Shannon J. S. , Jamieson W. D. , Taylor A.
Published: May 2006

Several 1-methyloxindohdyl-3-methines have been synthesized, either by condensation of 1-methyloxindole with an aldehyde, or by a Wittig reaction of a chloromethylene compound with a 1-methylisatin When examined m the mass spectrometer the expected ion reactions were observed and, in addition, a reaction involving expulsion of the carbonyl group of the oxindole moiety and rearrangement of the residual fragment, to give a 1-methylbenzo[b]azepinium ion was observed. The anions of the oxindolidyluracilmethines 4 and 5, (R = Me, R′ = OH) had an absorption band near 380 mμ but the corresponding neutral molecules absorbed at 325–350 mμ. The 5-nitrofuran derivatives 3 were the only compounds that inhibited the growth of Bacillus subtilis.
Proton chemical shifts of polyhalobenzenes in cyclohexane and carbon tetrachloride. An additivity scheme based on pairwise parameters
Authors: Richardson B. , Schaefer T.
Published: May 2006

An additivity scheme which takes into account the interactions between ortho substituents is applied to 39 proton shifts in 22 tri-, tetra-, and pentasubstituted halobenzenes as 3 mole % solutions in cyclohexane and carbon tetrachloride. The shift of any proton can be written as the sum of two parameters D(X,Y) and one parameter dp. D(X,Y) refers to a pair of substituents placed ortho (X) and meta (Y) to the proton and dp refers to a substituent placed para to the proton. The mean deviation between observed and calculated shifts is found to be 0.010 p.p.m. for the cyclohexane solutions and 0.012 p.p.m. for the carbon tetrachloride solutions. The scheme also works reasonably well for mono and dihalobenzenes. The parameter D(X,Y)–D(H,Y) is a measure of the steric interaction between the X and Y substituents. It is also suggested that the steric environment of a proton is important in determining the shift in carbon tetrachloride solution.
Reaction of anhydro sugars with sodium cobalt tetracarbonyl and carbon monoxide
Authors: Rosenthal Alex , Whyte J. N. C.
Published: May 2006

5,6-Anhydro-1,2-O-isopropylidene-α-D-glucofuranose reacts with sodium cobalt tetracarbonyl and carbon monoxide in methanol to afford methyl 6-deoxy-1,2-O-isopropyhdene-α-D-gluco-heptofuranouronate (3) in 82% yield. Treatment of tri-O-acetyl-1,2-anhydro-D-glucopyranose with sodium cobalt tetracarbonyl in ether gives 3,4,6-tri-O-acetyl-D-glucal. The 2,3-anhydro sugars are resistant to cleavage by cobalt tetracarbonyl anion in ether or in methanol. Sugar acetates are de-O-acetylated by treatment with sodium cobalt tetracarbonyl in ether–methanol.
Reaction of 1,2,3-thiadiazoles with base. II. Thioneesters from thioketene intermediates
Authors: Raap R.
Published: May 2006

Alkynethiolates, generated from 1,2,3-thiadiazoles by a strong base, react with alcohols and alkanethiols to give thioneesters and dithioesters respectively. In this manner were prepared: dimethyl monothionemalonate, (methoxythiocarbonyl)acetamide, methyl phenylthioneacetate, and ethyl phenyldithioacetate. 2,ω-Diphenyl-1,4-dithiafulvene results from the reaction between lithium 2-phenylethynethiolate and water.
Some syntheses with dimethyl monothionemalonate
Authors: Raap R.
Published: May 2006

Reactions are described in which the S-alkylation products of dimethyl monothionemalonate and the reaction products with amino compounds have been employed to prepare compounds such as 3-hydroxythiophenes, 1-tetrazolylacetates, 1,3,4-oxadiazolylacetates, and methyl 3,3-di-N-morpholinoacrylate.
Stereospecificity of the Curtius rearrangement
Authors: Hocking Martin B.
Published: May 2006

Jones and Mason claimed a number of years ago (1) that rearrangement of cis-olefinic acyl azides gave trans-olefinic isocyanates. However, several other workers have found that rearrangement of an acyl azide group attached to an optically active carbon gives configurationally identical products, a discovery which apparently conflicts with Jones and Mason's findings. We have reexamined the rearrangement of cis-crotonyl azide with stringent checks at each reaction step and found perfect retention of geometry in the product. Details of this finding are discussed.
Galactomannans of Trichosporon fermentans and other yeasts; proton magnetic resonance and chemical studies
Authors: Gorin P. A. J. , Spencer J. F. T.
Published: May 2006

A survey of the alkali soluble polysaccharides of yeast cells shows that galactomannans are formed by certain species of the genera Trichosporon, Schizosaccharomyces, and Nadsonia. Different species of Trichosporon form galactomannans, pentosylmannans, and a mannan. The galactomannans are distinguishable from those of Schizosaccharomyces by the H-1 region of their proton magnetic resonance spectra (recorded at 70° in D2O using an HA-100 Varian spectrometer), but the spectra of Trichosporon hellenicum and Nadsonia fulvescens galactomannans are virtually indistinguishable.The proton magnetic resonance spectrum of the Trichosporon fermentans galactomannan contains fewer signals than those of other Trichosporon galactomannans. The polymer consists predominantly of a main-chain containing a high proportion of (1 → 6)-mannopyranosyl units substituted in their 2-positions by O-α-D-galactopyranosyl-(1 → 2)-O-α-D-mannopyranosyl side-chains (1).
Rearrangement studies with 14C. XXXII. Solvent effects in the solvolyses of 2-phenyl-1-14C-ethyl tosylate and 2-phenyl-1-14C-ethylmercuric perchlorate
Authors: Lee C. C. , Tewari R. J.
Published: May 2006

The extents of isotope position rearrangement accompanying the solvolyses of 2-phenyl-1-14C-ethyl bromide (I–Br), 2-phenyl-1-14C-ethyl tosylate (I–OTs), and 2-phenyl-1-14C-ethylmercuric perchlorate (I–HgClO4), in three aqueous dioxane solvent pairs with different ionizing power Y were determined. No rearrangement was found for I–Br For I–OTs and I–HgClO4 the results are considered together with similar data previously obtained from ethanolysis, acetolysis, and formolysis. Linear correlations between log % rearrangement and Y are found for the solvolyses in ethanol and the aqueous dioxane solvent pairs. The mechanistic implications of these observations are discussed.
Decomposition of a phosphoryl azide adduct of norbornylene
Authors: McDaniel R. S. , Oehlschlager A. C.
Published: May 2006

The thermal decomposition of the diethyl phosphoryl azide adduct of norbornylene has been shown to proceed directly to the phosphoryl amidate, 5a. The aziridine 4a has been shown to be stable under the reaction conditions. Contrary to an earlier report, the product of the photolytic decomposition of the diethyl phosphoryl azide – norbornylene adduct is aziridine 4a.
Photolysis of ketene. I
Authors: Strachan A. N. , Thornton D. E.
Published: May 2006

Ketene has been photolyzed at 3660 and 3130 Å both alone and in the presence of the inert gases C4F8 and SF6. The quantum yield of carbon monoxide has been determined at both wavelengths as a function of pressure and temperature. At 3660 Å the quantum yield decreases with increasing pressure but increases with increasing temperature. At 3130 Å the quantum yield with ketene alone remains 2.0 at both 37 and 100 °C at pressures up to 250 mm. At higher pressures of ketene or with added inert gas the quantum yield decreases with increasing pressure. The results are interpreted in terms of a mechanism in which intersystem crossing from the excited singlet state to the triplet state occurs at both wavelengths, and collisional deactivation of the excited singlet state by ketene is single stage at 3660 Å but multistage at 3130 Å.
Kinetics of the thermal reactions of ethylene. Part II. Ethylene–ethane mixtures
Authors: Boyd M. L. , Back M. H.
Published: May 2006

Mixtures of ethane and ethylene have been pyrolyzed in the temperature range 563–600 °C and at pressures from 30–60 cm. The products were similar to those obtained from the pyrolysis of ethylene by itself, described m Part I, with a marked increase in the yields of the saturated products. The initial rates of product formation and the dependence of these rates on the concentration of ethane suggest that the initiation step is the same as that proposed in the pyrolysis of ethylene alone, viz.[Formula: see text]and that the reaction[Formula: see text]is not an important source of radicals. A simplified mechanism is outlined to account for the main effects of ethane on the free radical chain polymerization.
Radical displacement reactions: The vapor phase reaction of methyl radicals with allyl formate
Authors: Greig G. , Thynne J. C. J.
Published: May 2006

Trideuteromethyl radicals have been reacted in the vapor phase with allyl formate and the principal reaction over the temperature range 100–250 °C has been shown to be the displacement reaction[Formula: see text][Formula: see text]Hydrogen atoms generated by this decomposition also react readily to produce propylene by the reaction[Formula: see text]
Thermal decomposition of propylene oxide
Authors: Hardwick T. J.
Published: May 2006

In the temperature range 402–425 °C, propylene oxide in a toluene medium decomposes to form propionaldehyde (60–70%), acetone (14%), and free radicals (25%). The ratio of products is invarient with temperature, suggesting a common precursor to all three products. Propionaldehyde further decomposes into free radicals. The first order rate expression for propylene oxide disappearance is3.7 × 1012 e−51900/RT s−1.
Protonation of conjugated carbonyl groups in sulfuric acid solution. I. Adaptation of the amide acidity function HA for protonation of the carbonyl group in non-Hammett bases
Authors: Zalewski R. I. , Dunn G. E.
Published: May 2006

The protonation of a number of aromatic and α,β-unsaturated aliphatic aldehydes, ketones, and carboxylic acids in sulfuric acid has been found to obey the HA acidity function, rather than H0.
Vibrational absorption of the trapped diazomethyl radical
Authors: Ogilvie J. F.
Published: May 2006

Vibrational absorption lines newly discovered after the photolysis, with a low-pressure mercury lamp, of isotopic diazomethanes in inert-gas matrices at 4 °K have been assigned to the diazomethyl radical, HCNN and DCNN.
Reactions of nitro sugars. IX. The synthesis of branched-chain dinitro sugars by Michael addition
Authors: Baer Hans H. , Ong K. S.
Published: May 2006

The reaction of methyl 2-O-acetyl-4,6-O-benzylidene-3-deoxy-3-nitro-β-D-glucopyranoside (1) or of methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-β-D-erythro-hex-2-enopyranoside (2) with nitroalkanes led to branched-chain dinitro sugar derivatives, namely methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-2-nitroalkyl-β-D-glucopyranosides (3). The nitroalkanes employed included nitromethane, nitroethane, 1-and 2-nitropropane, and methyl nitroacetate. The three first-mentioned nitroalkanes were added in similar fashion to methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-β-D-threo hex-2-enopyranoside (5) to give methyl 4,6-O-benzylidene-2,3-dideoxy-3-nitro-2-nitroalkyl-β-D-galactopyranosides (6). Analogous reactions of 1 and 5 with diethyl malonate produced the corresponding branched-chain glycosides 7 and 8. The reactions appear to be highly stereoselective as far as the configurations at C-2 and C-3 in the products are concerned. However, there is evidence for the formation of side-chain epimers in three cases where the nitroalkyl side chain possesses an asymmetric carbon.
Additivity of substituent effects on the proton–proton coupling constants in substituted benzenes. Investigation of some trisubstituted benzenes
Authors: Schaefer T. , Kotowycz G. , Hutton H. M. , Lee J. W. S.
Published: May 2006

An additivity scheme based on the changes in ortho, meta, and para proton coupling constants of benzene induced by a single substituent is applied to a number of trisubstituted benzenes. Ortho coupling constants are well reproduced (root mean square deviations = 0.05 c.p.s.) by the scheme but for meta and para couplings saturation effects are indicated. For the latter two couplings there are two substituents ortho to one of the protons involved. Measurements indicate that a temperature range of 100 °C has a negligible effect on the couplings but that polar solvents are to be avoided in obtaining data for the testing of additivity schemes.
Photochemical synthesis, 22. On photochemical cycloaddition: Cyclopentenone
Authors: Mayo P. de , Pete J-P. , Tchir M.
Published: May 2006

Cyclopentenone has been added photochemically to a wide variety of olefins and the quantum efficiency determined. Mechanistic studies indicate a rapid reaction involving a triplet state by a process which is not stereospecific, but which does not allow complete equilibration. Evidence is provided which suggests that cyclopentenone reacts photochemically from two triplet states, but that only the higher leads to cycloaddition.
Solvent effects on the conformations of ortho-substituted acetanilides
Authors: Rae Ian D.
Published: May 2006

In acetanilides bearing nitro, halogen, alkoxyl, or carboxyl substituents in the ortho position, the intramolecular hydrogen bond is disrupted by polar solvents and the acetamido group adopts a position out of the plane of the aromatic ring. These changes are studied by means of changes in the deshielding effect of the amide carbonyl group on the remaining ortho proton.
Oligomerization of isoprene
Authors: Suga Kyoichi , Watanabe Shoji , Kikuchi Hideo , Watanabe Toru
Published: May 2006

The oligomerization of isoprene with lithium naphthalene and the dimerization of isoprene with alkali dispersion are described. Isoprene dimer, prepared by the action of lithium naphthalene, is a mixture of 2,6-dimethyl-2,6-octadiene and 2,7-dimethyl-2,6-octadiene, but the trimer, tetramer, and hexamer are a mixture of 3,4-adducts of isoprene to the above mentioned isoprene dimer. The authors have found that alkali dispersion in the presence of a Lewis base is able to dimerize isoprene.
The gold/selenium system and some gold seleno-tellurides
Authors: Cranton G. E. , Heyding R. D.
Published: May 2006

The phase relationships in the gold/selenium system have been examined using X-ray powder diffraction techniques and differential thermal analysis. Only one stable phase, α-AuSe, is formed. A metastable modification of this compound, β-AuSe, is also formed by reaction of the elements. Both forms are monoclinic:α-AuSe: space group C2, Cm, or C2/m; a = 12.21 ± 2, b = 3.693 ± 4, c = 8.434 ± 6 Å, β = 103.20 ± 3°; cell content, 8(AuSe).β-AuSe: primitive monoclinic (space groups P21 or P21/m are likely); a = 6.27 ± 1, b = 3.668 ± 4, c = 8.35 ± 1 Å, β = 105.95 ± 13°; cell content, 4(AuSe).Both modifications decompose peritectoidally at ca. 400 °C. Gold and selenium form a monotectic at 754 °C at a composition just above 50 at. % selenium; some evidence was obtained for the presence of two liquid phases above the monotectic.Tellurium does not substitute in the AuSe lattice to a detectable extent. However, a ternary phase which includes the composition Au2SeTe is formed. Au2SeTe is primitive orthorhombic with a = 8.924 ± 6, b = 7.56 ± 1, c = 5.741 ± 8 Å. The cell contains 4 formula units. Selenium will substitute for at least 15 at. % of the tellurium atoms in the monoclinic AuTe2 calaverite lattice at ca. 400 °C.
Absolute rate constants for hydrocarbon oxidation. XII. Rate constants for secondary peroxy radicals
Authors: Howard J. A. , Ingold K. U.
Published: May 2006

Rate constants have been measured for hydrogen abstraction from four aralkanes and addition to two aralkenes by five secondary and one primary peroxy radical. These rate constants appear to show a slight dependence on the structure of the attacking peroxy radicals which may be due to the inductive effects of the substituents on the radical. The secondary and primary peroxy radicals are generally about 2–4 times more reactive than tertiary peroxy radicals in abstraction and 4–8 times more reactive in addition. The lower reactivity of tertiary peroxy radicals is probably due to steric factors.
Cyanide ion complexes of some aromatic nitro compounds
Authors: Buncel E. , Norris A. R. , Proudlock W.
Published: May 2006

The results are presented of spectral studies which characterize the complexes formed in deuterochloroform solution between cyanide ion and 1,3,5-trinitrobenzene, 2,4,6-trinitrotoluene, and 2,4,6-trinitrobenzaldehyde.
Analysis of the proton and fluorine magnetic resonance spectra of 1,3,5-trifluorobenzene dissolved in a nematic liquid crystal
Authors: Yim C. T. , Gilson D. F. R.
Published: May 2006

The proton and fluorine magnetic resonance spectra of 1,3,5-trifluorobenzene oriented in a nematic liquid crystal have been analyzed. The proton and fluorine chemical shift anisotropies are −2.98 p.p.m. and 104 p.p.m. respectively. The absolute signs of the indirect spin–spin coupling constants are: JHH′, JFF, and JHF (ortho) all positive, and [Formula: see text] (para) negative.
Synthesis of steroidal pyrimidine N-oxides
Authors: Romo J. , Rodríguez-Hahn L. , Jiménez M.
Published: May 2006

Several steroidal pyrimidine N-oxides were synthesized by treatment of different N-acyl derivatives of steroidal β-amino-α,β-unsaturated ketones with hydroxylamine. This procedure has been applied to obtain steroidal pyrimidine N-oxides with the heterocyclic ring condensed with rings A and B of the steroidal moiety. Some chemical and spectral properties of these derivatives are discussed.
Syntheses of α-agarofuran and isodihydroagarofuran
Authors: Asselin A. , Mongrain M. , Deslongchamps P.
Published: May 2006

A new synthesis of α-agarofuran (1) has been realized in four steps from ketol 3 and a stereospecific synthesis of isodihydroagarofuran (dihydro-α-agarofuran) has been achieved in four steps.
Kinetics of hexagonal–cubic phase transformation of zinc sulfide in vacuo, in zinc vapor, and in sulfur vapor
Authors: Bansagi Tamas , Secco E. A. , Srivastava O. K. , Martin Ronald R.
Published: May 2006

The kinetics of the hexagonal–cubic phase transformation of zinc sulfide have been studied in vacuo, in zinc vapor, and in sulfur vapor in the temperature range 800–900 °C by a powder X-ray diffraction technique. The transformation rate is enhanced in the presence of sulfur and zinc vapor. In vacuo and in sulfur vapor the reaction is nucleation-controlled with activation energies of 95.0 and 98.5 ± 5 kcal, respectively. In zinc vapor the reaction is diffusion-controlled with the diffusion coefficient expressed as[Formula: see text]The modes of catalytic action by sulfur and zinc vapor on the solid phase transformation reaction are discussed.
Mechanism of decarboxylation of substituted salicylic acids. I. Kinetics in quinoline solution
Authors: Dunn G. E. , Janzen E. G. , Rodewald W.
Published: May 2006

First-order rate constants for the decarboxylation of fourteen 4- and 5-substituted salicylic acids have been determined in quinoline solution in the temperature range 90–230 °C. Substituents have almost no effect on the rate constants, except those with large negative σ-constants: p-amino, p-hydroxy, p-ethoxy. The enthalpies and entropies of activation do not fit the isokinetic relationship, with the same three substituents deviating. It is suggested that the decarboxylation involves a preliminary ionization of the carboxyl group, followed by protonation of the aromatic ring of the anion so formed, and then loss of carbon dioxide. The isokinetic relationship fails because substituents affect all three steps differently, and the Hammett relationship fails because the substituent effect on the ionization is related to σ while that on the other two steps follows σ+. The three substituents which deviate are those for which σ and σ+ differ widely.
Reaction of α-hydrazino carboxylic acids with ninhydrin
Authors: Ronwin Edward , Roach Jerry V. , Tucker Burrell L.
Published: May 2006

Several α-hydrazino carboxylic acids and their m-nitrobenzal hydrazones have been prepared and characterized. The latter and two of the former have not been previously reported. The α-hydrazino acids were found to react with ninhydrin to yield Ruhemann's purple, but in much lower yield than the corresponding amino acids. However, hydrazine itself yields a different colored product. Various aspects of the reaction between ninhydrin and the α-hydrazino acids were investigated and a mechanism for the formation of Ruhemann's purple is suggested.
Interaction between aliphatic and aromatic nitro compounds in basic media
Authors: Fyfe C. A.
Published: May 2006

The interaction between aromatic and aliphatic nitro compounds in basic media has been investigated. Evidence based mainly on nuclear magnetic resonance spectroscopy suggests that the brightly colored species formed are sigma complexes. The generality of the reaction is investigated and its relation to the Janovsky reaction discussed.
Medium heterocyclic rings from carbohydrate precursors
Authors: Stoddart J. F. , Szarek W. A.
Published: May 2006

Chemical and physical evidence is presented to show that the structure of a dianhydride of D-ribose is di-β-D-ribofuranose 1,5′:1′,5-dianhydride. Partial acid hydrolysis of this dimer affords a ribobiose, which is shown to be 5-O-β-D-ribofuranosyl-D-ribose, since examination of the O-methyl derivative of this disaccharide yields 2,3,5-tri- and 2,3-di-O-methyl-D-ribose, and since quantitative measurements of the periodate consumption of the derived glycitol (4 moles of periodate per mole) are consistent with a structure corresponding to 5-O-β-D-ribofuranosyl-D-ribitol. In addition to confirming that both the 1 → 5′- and 1′ → 5- linkages have the β configuration, n.m.r. spectral data for the dianhydride tetraacetate leads to a conformational assignment for this derivative in chloroform at room temperature.Periodate oxidation of the dianhydride, followed by borohydride reduction and acetylation, yields a 2,4,7,9-tetraacetoxymethyl-1,3,6,8-tetraoxacyclodecane. The conformational properties of this compound are discussed.
Glycolipids of soft wheat flour. I. Isolation and characterization of 1-O-(6-O-acyl-β-D-galactopyranosyl)-2,3-di-O-acyl-D-glyceritols and phytosteryl 6-O-acyl-β-D-glucopyranosides
Authors: Myhre D. V.
Published: May 2006

Two groups of glycolipids were isolated from soft wheat flour. The first group, 1-O-(6-O-acyl-β-D-galactopyranosyl)-2,3-di-O-acyl-D-glyceritols (1), was saponified to yield fatty acids and 1-O-β-D-galactopyranosyl-D-glyceritol in the molar ratio 3:1. Methylation of 1 followed by saponification of the methylated product gave 1-O-(2,3,4-tri-O-methyl-β-D-galactosyl)-D-glyceritol which provided 2,3,4-tri-O-methyl-D-galactose and glyceritol upon hydrolysis. In periodate oxidation studies 1 consumed two moles of oxidant and yielded tri-O-acyl dialdehydes (6) without liberating fatty acids. Sodium borohydride reduction of 6 followed by saponification, acid hydrolysis, and another borohydride reduction gave glyceritol and ethylene glycol in the expected manner.The second group of glycolipids, phytosteryl 6-O-acyl-β-D-glucopyranosides, was methylated and the products were saponified to give phytosteryl 2,3,4-tri-O-methyl-β-D-glucopyranosides (12) and fatty acids. Methanolysis of 12 gave principally β-sitosterol, campesterol, and methyl 2,3,4-tri-O-methyl-α- and β-D-glucosides.
Electrophoresis of dyed polysaccharides on cellulose acetate
Authors: Dudman W. F. , Bishop C. T.
Published: May 2006

Polysaccharides have been shown to react with Procion dyes to give colored products. The degree of substitution varies with the dye to polysaccharide ratio used in the reaction and with the structure of the polysaccharide. The dyed polysaccharides give visible bands on gel filtration and on electrophoresis on cellulose acetate strips. Separations of mixtures of colored polysaccharides by the latter method are complete within 5 min and match the results obtained with the undyed polysaccharides by free-boundary, Tiselius electrophoresis.
Reaction of iron carbonyls with amides and thionamides
Authors: Alper Howard , Edward John T.
Published: May 2006

Iron pentacarbonyl in boiling butyl ether converts primary amides or thionamides to nitriles, and benzanilide or thionbenzanilide to N-benzylideneaniline. Diiron nonacarbonyl reacts with p-methoxy-thionbenzamide to form a complex C22H16N2S2O8Fe2; a possible structure is proposed.
Complexes of nickel(II) with substituted thioureas
Authors: Bailey R. A. , Peterson Terry Roy
Published: May 2006

A series of Ni(II) complexes with methyl-, ethyl-, and sym-dimethyl-, sym-diethyl-, and sym-di-n-butyl- thioureas and halide, perchlorate, and thiocyanate anions have been prepared and characterized. Spectral and magnetic studies show that compounds NiL4X2 (L = N,N′-dimethyl and N,N′-diethylthiourea, X = halide) are tetragonally distorted octahedral species with a singlet ground state and a thermally populated triplet excited state. The remaining compounds are octahedral. Infrared evidence shows sulfur bonding of the disubstituted ligands to the metal, but suggests nitrogen coordination of the methylthiourea compounds.
Radiolysis of ortho- and meta-terphenyl
Authors: Boyd A. W. , Tomlinson M.
Published: May 2006

A summary is presented of a series of investigations of the radiolytic decomposition of ortho- and meta-terphenyl by reactor radiation with varying proportions of fast neutrons and gamma rays and of meta-terphenyl by 1.3 MeV electrons in the temperature range 100 to 450 °C with radiation intensities from 0.01 to 2 Mrads/s. The observations indicate two regions of radiolytic decomposition with a transition zone at 350 to 400 °C. In the lower temperature region, G(decomposition) varied little with temperature, increased with linear energy transfer (l.e.t.), was independent of intensity, and yielded mainly high boiling products. Particular attention was given to the high temperature region, where G(decomposition) increased rapidly with temperature, was independent of l.e.t., was greater at low intensities than at high intensities, increased with increased pulse frequency for intermittent irradiation, and yielded a greater proportion of benzene and biphenyl. Thermally initiated reaction appeared unimportant except in the absence of radiation. A reaction sequence is given which accounts for these observations in terms of reactions of radical precursors and radicals of the cyclohexadienyl type. A chain reaction occurs in the higher temperature region.
Calculation of emission–concentration and absorption–concentration relationships for spectral lines
Authors: Demayo A. , Hunter L. W. , Kruus P.
Published: May 2006

A general expression is derived for the calculation of total multiplet intensities for radiation emitted from a homogeneous source or transmitted through a homogeneous medium. The theory is then applied to the emission of radiation due to vibration–rotation transitions of HCl in an oven, and compared with experimental results. Absolute values of transition probabilities for individual vibration–rotation lines could be obtained by such a comparison. Another application of the theory is made in obtaining absorption–concentration relationships for the mercury 4358 Å line (73S1–63P1) with several different initial line shapes. The results are compared to absorption − 63P1 concentration curves used in earlier work.
Average recoil ranges of 64Cu and 196Au produced by protons of 20–85 MeV energy in 65Cu and 197Au
Authors: Dewanjee M. K. , Saha G. B. , Yaffe L.
Published: May 2006

Thick-target recoil experiments were performed to study (p,pn) reactions induced in 65Cu and 197Au in the energy range of 20–85 MeV and the average ranges projected in the forward, backward, and perpendicular directions were determined. Recoil parameters have been calculated to show approximately the amount of energy transfer and their energy dependence. The average range results have been compared with statistical theory, cascade–evaporation (85 MeV only), and inelastic scattering model calculations. The statistical calculations show reasonable agreement up to 30–40 MeV. However, the calculated projected range values, based on the cascade–evaporation and the inelastic scattering models, are consistently lower than the measured values. The analyses of the projected range values support the prevalent view that at low energies (~ 30–35 MeV), the compound nucleus mechanism is predominant and at higher energies, the direct interaction mechanism makes a major contribution.
Reactions of acetylenes with noble-metal halides. VI. The reactions of 2-butyne with chlorodicarbonylrhodium dimer
Authors: Kang J. W. , McVey S. , Maitlis P. M.
Published: May 2006

Chlorodicarbonylrhodium dimer ([Rh(CO)2Cl]2) reacted with 2-butyne at 80° in benzene to give a mixture of compounds which contained hexamethylbenzene, duroquinone, chloro(π-duroquinone)-rhodium dimer, and chloro(π-tetramethylcyclopentadienone)rhodium. At 25° 2-butyne and [Rh(CO)2Cl]2 reacted to give a brown solid of variable composition (C), which could not be purified. Reaction of (C) with CO in methylene chloride gave a related solid (D) also of variable composition. Treatment of (C), or better (D), with an excess of triphenylphosphine gave chloro(dimethylmaleyl)bis(triphenylphosphine)-rhodium and (Ph3P)2RhCOCl. The former was identified by analysis, spectra, and its oxidation to dimethylmaleic anhydride. Reaction of (D) with p-toluidine gave chloro(dimethylmaleyl)carbonylbis(p-toluidine)rhodium, which on treatment with excess triphenylphosphine also gave chloro(dimethyl-maleyl)bis(triphenylphosphine)rhodium.
Thermal effects in flash photolysis with special reference to Br atom recombination
Authors: Burns George
Published: May 2006

Thermal effects, which accompany flash photolyses, are known to interfere with the determination of reaction rate constants. There are two approximate models currently being used in literature to estimate the magnitude of these effects (1, 8). The first model (1) is the more widely accepted. It is based on the assumption that thermal effects are due to the cooling of reacting gas at the walls of the reaction vessel. The second model (8) is based on the assumption that thermal effects are due to nonuniformity in the concentrations of free radicals produced in flash photolysis; it neglects the heat exchange at the wall of the reaction vessel.It is shown that the second model can be used to calculate the magnitude of thermal effects in reaction vessels of reasonable length. The model was applied to calculate [Formula: see text], the rate constant for the reaction 2Br + Br2 → 2Br2. The value of [Formula: see text], is found to be very sensitive to the choice of model for thermal effects. At room temperature the most reasonable value of [Formula: see text], using the second model, is (4.3 ± 1.3) × 1010 l2 mole−2 s−1. This value agrees very well with independent determinations of [Formula: see text] using a stationary photochemical technique. The first model for treatment of thermal effects (1) was used previously to show that such effects do not influence the measured rates of chemical reactions, and calculations of rate constants using this model have not usually been attempted. In one case (5), however, the first model (1) for thermal effects was employed to calculate a value for [Formula: see text] which was found to be six times larger than our value. Consequently, the second model (8) appears to be a better approximation for quantitative evaluation of thermal effects.Using the raw data (8) and [Formula: see text] = 43 × 109 l2 mole−2 s−1, the value of kAr, the recombination rate constant of Br atoms in excess of argon, was found to be (3.0 ± 0.2) × 109 l2 mole−2 s−1, which agrees well with data available in the literature.
Secondary deuterium kinetic isotope effects on the thermolysis of 1-pyrazolines
Authors: Al-Sader Basil H. , Crawford Robert J.
Published: May 2006

Secondary kinetic isotope effects on four deuterated 1-pyrazolines support the formation of a trimethylene intermediate during gas phase thermolysis. Calculation of cyclization relative rate constants for the trimethylene intermediates reveals that substitution of hydrogen by deuterium has no effect when the terminal methylenes are substituted, but the rate constants are decreased when the central methylene's hydrogens are substituted. Explanations are advanced for all of the observed effects.
Friedel–Crafts rearrangements. IV. Cyclialkylations and hydride transfers on phenylalkyl chlorides
Authors: Barclay L. R. C. , Sanford E. C.
Published: May 2006

A number of phenylalkyl chlorides were synthesized for a comparative study of Friedel–Crafts cyclialkylations and competing reactions involving hydride exchange. The synthetic work showed that phenylbutyl alcohols, especially a tertiary alcohol, may cyclize directly with chlorinating agents to yield tetralins. Cyclialkylation products from phenylpentyl chloride include 1-methyltetralin (4), n-pentylbenzene, 1-methyl-3,4-dihydronaphthalene, and methylnaphthalene. A reaction sequence is given involving dealkylation of 4 and hydride transfers. Phenylbutyl chloride yielded tetralin, n-butylbenzene, and naphthalene. 1-Chloro-4-methyl-4-phenylpentane yielded 1,1-dimethyltetralin (10), 2-methyl-5-phenylpentane (11), and a small amount of 2-methyl-2-phenylpentane (12). Hydrocarbon 11 formed from 10 after cyclialkylation, while 12 formed by hydride transfer preceding cyclization. Phenylpropyl chloride yielded mainly a hydride transfer product (propylbenzene) and not indane. Treatment of this chloride containing deuterium labels at C-1 and C-2 showed that the hydride ion rearranges from the carbon adjacent to the halogen. 1-Chloro-3-methyl-3-phenylbutane yielded a complex mixture including t-pentylbenzene, 2-phenyl-3-methylbutane, and products of higher molecular weight.
Synthesis of 6-deoxy-3-C-methyl-2-O-methyl-D-allose
Authors: Howarth G. B. , Szarek W. A. , Jones J. K. N.
Published: May 2006

The preparation of 6-deoxy-3-C-methyl-2-O-methyl-D-allose is described. The compound was compared with L-vinelose, a new branched-chain sugar with the same constitution recently isolated, bound to cytidine 5′-pyrophosphate, from Azotobacter vinelandii strain O; the two sugars were shown to differ in configuration.
Photochemistry of oximes. II. On the photo-induced formation of cycloalkanones and alkanoic acid amides from cycloalkanone oximes
Authors: Just G. , Ng L. S.
Published: May 2006

Cycloalkanone oximes were shown to give the corresponding alkanoic acid amides when irradiated in iso-propanol. α-Alkylated cyclohexanone oximes gave products corresponding to preferential cleavage on the side of the more substituted carbon atom. iso-Propanol was shown to transfer two hydrogen atoms specifically to the excited oxime molecule, acetone being formed in the process. In 1% aqueous solution, irradiation of oximes gave the corresponding ketones, ammonia, and oxygen.
Transannular reactions in the dibenzo[a,d]cycloheptene series. III. Preparation of 11-substituted-10,11-dihydro-10,5-(iminomethano)-5H-dibenzo[a,d]cycloheptenes
Authors: Dobson T. A. , Davis M. A. , Hartung A. M.
Published: May 2006

Treatment of the syn-epoxyamide 3 with either ammonium hydroxide or sodium hydride gives 10,11-dihydro-anti-11-hydroxy-10,5-(iminomethano)-5H-dibenzo[a,d]cyclohepten-13-one (1a). This compound is readily converted to the syn-epimer 1c by oxidation to 1b and subsequent hydrogenation. The ketone 1b reacts with Grignard reagents to give the tertiary alcohols 1k,l which undergo hydrogenolysis to give the 11-substituted lactams 1q,r. Reduction of the lactams with lithium aluminium hydride gives the corresponding amines.
Reaction of chromyl chloride with some olefins. II. The oxidation of tetraarylethylenes
Authors: Gatzke A. L. , Stairs R. A. , Diaper D. G. M.
Published: May 2006

Chromyl chloride oxidation of tetraphenylethylene results in a novel cyclization reaction giving 9,10-diphenylphenanthrene in high yield. Some cyclization between geminal phenyl groups and cleavage of the olefinic bond occurs as evidenced by the presence of fluorenone and benzophenone as minor products. Polynuclear hydrocarbons such as 1,1′-binaphthyl and o-terphenyl which can be cyclized by Lewis acids are unreactive towards chromyl chloride. The observation of rotation about the central bond of a substituted tetraphenylethylene and of retardation of cyclization by substituent chlorine suggest that the oxidative cyclization proceeds by initial electrophilic attack at the olefinic bond to give a carbonium ion.
Gas–liquid chromatography of terpenes. Part XVII. The volatile oil of the leaves of Juniperus virginiana L.
Authors: Vinutha A.R. , Rudloff E. Von
Published: May 2006

The leaf oil of the red juniper was found to contain mainly sabinene, as well as limonene, α-pinene, γ-terpinene, terpinolene, 3-carene, myrcene, 4-terpinenol, citronellol, elemol, γ-, α-, and β-eudesmol, the aromatic ethers estragole, safrole, methyl eugenol, and elemicin. Another aromatic ether, methyl vinyl anisole, was isolated which has not been found previously in essential oils. The acetates 1 and 2 obtained previously in two related juniper leaf oils were present and the first has been identified as elemol acetate. Small amounts of α-thujene, p-cymene, linalool, and δ-cadinene were also identified.Quantitative aspects were studied with a view of future chemosystematic investigations. The error in duplicate runs was 0.1% for well-resolved peaks, but the absolute error, as determined by use of internal standards, was larger. Leaf oils of different trees from Texas and Ontario were found to give wide quantitative variations of the individual components.
Coordination complexes of gallium(in) and indium(III) halides. III. Complexes of gallium(III) halides with 2,2′-bipyridyl
Authors: Carty A. J.
Published: May 2006

The new complexes GaCl3(bipy), GaBr3(bipy)2MeCN, GaBr3(bipy)2, Gala(bipy), and the related compounds [GaCl2(bipy)2]BF4, [GaCl2(bipy)2]PF6, [GaBr2(bipy)2]PF6 (bipy = 2,2′-bipyridyl) have been prepared and characterized. Conductivity and far-infrared measurements suggest the structures [GaCl2(bipy)2][GaCl4], [GaBr2(bipy)2]Br, and [GaI2(bipy)2][GaI4] for the trihalide adducts.
H—N3 and CH3—N3 bond dissociation energies
Authors: Chiang Mervyn , Wheeler Robert
Published: May 2006

The thermal emission of negative azide ions from a heated filament operating in gases of both HN3 and CH3N3 has been studied in a magnetron cell and the temperature variation of this current used to deduce the C—N bond dissociation energies in both molecules. Results indicate higher values than previous estimates. They are: D0(H—N3) = 90 ± 8 kcal/mole and D0(CH3—N3) = 88 ± 8 kcal/mole at 0°K.
Photolysis of HBr at 77 °K
Authors: Falconer W. E. , Sunder W. A.
Published: May 2006

The photolysis of HBr has been studied at 77 °K. The photodecomposition of solid state HBr is an inefficient process which is strongly inhibited by a reaction product, probably Br atoms, or by added Br2 or trans-butene-2. The results suggest H2 is formed by abstraction from HBr by thermal H atoms, the activation energy for the abstraction being ~350 cal mole−1. The photolysis of both pure HBr and HBr with added Br2 or trans-butene-2 can be described by an absorber complex mechanism similar to that inferred by Hughes and Purnell in the photolysis of HI. The absorption tail of solid HBr extends beyond the gas phase absorption into the wavelength region in which trapped radicals are generated in HBr–olefin mixtures but where there is no H2 evolution. The solid state absorption spectrum of Br2 is contrasted with that of gaseous Br2; an absorption peak is observed at 2725 Å which may be associated with (Br2)n aglomerates.
Evidence for the existence of an electric field effect from the vinyl proton magnetic resonance spectra of 4-substituted styrenes
Authors: Hamer G. K. , Reynolds W. F.
Published: May 2006

Vinyl proton chemical shifts of styrene and six 4-substituted styrenes have been determined at infinite dilution in cyclohexane. It is shown that changes in the chemical shift difference of the β protons, Δ(δC − δB) can be accounted for by electric field effects. Reasonable values of the constant in the Buckingham equation of(−3.11 ± 0.50) × 10−12 and (−4.77 ± 0.83) × 10−12 are obtained from two different types of field effect calculations. Residual chemical shift changes for β protons after correction for electric field effects can be explained in terms of mesomeric and possibly inductive mechanisms. α-Proton chemical shift values cannot be satisfactorily rationalized. Small concentration effects are noted, usually resulting in high field shifts with increasing concentration. Previous results are reexamined in order to resolve a conflict in the literature.