bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Conventional and Organic Production Practices on the Prevalence and Antimicrobial Resistance of
Campylobacter
spp. in Poultry
Authors: Luangtongkum Taradon , Morishita Teresa Y. , Ison Aaron J. , Huang Shouxiong , McDermott Patrick F. , Zhang Qijing
Published: May 2006

Intestinal tracts of broilers and turkeys from 10 conventional broiler farms and 10 conventional turkey farms, where antimicrobials were routinely used, and from 5 organic broiler farms and 5 organic turkey farms, where antimicrobials had never been used, were collected and cultured for
Campylobacter
species. A total of 694
Campylobacter
isolates from the conventional and organic poultry operations were tested for antimicrobial resistance to nine antimicrobial agents by the agar dilution method. Although
Campylobacter
species were highly prevalent in both the conventional and organic poultry operations, the antimicrobial resistance rates were significantly different between the organic operations and the conventional operations. Less than 2% of
Campylobacter
strains isolated from organically raised poultry were resistant to fluoroquinolones, while 46% and 67% of
Campylobacter
isolates from conventionally raised broilers and conventionally raised turkeys, respectively, were resistant to these antimicrobials. In addition, a high frequency of resistance to erythromycin (80%), clindamycin (64%), kanamycin (76%), and ampicillin (31%) was observed among
Campylobacter
isolates from conventionally raised turkeys. None of the
Campylobacter
isolates obtained in this study was resistant to gentamicin, while a large number of the isolates from both conventional and organic poultry operations were resistant to tetracycline. Multidrug resistance was observed mainly among
Campylobacter
strains isolated from the conventional turkey operation (81%). Findings from this study clearly indicate the influence of conventional and organic poultry production practices on antimicrobial resistance of
Campylobacter
on poultry farms.
Isolation and Biochemical Characterization of Two Novel Metagenome-Derived Esterases
Authors: Elend C. , Schmeisser C. , Leggewie C. , Babiak P. , Carballeira J. D. , Steele H. L. , Reymond J.-L. , Jaeger K.-E. , Streit W. R.
Published: May 2006

The metagenomes of uncultured microbial communities are rich sources for novel biocatalysts. In this study, esterase EstA3 was derived from a drinking water metagenome, and esterase EstCE1 was derived from a soil metagenome. Both esterases are approximately 380 amino acids in size and show similarity to β-lactamases, indicating that they belong to family VIII of the lipases/esterases. EstA3 had a temperature optimum at 50°C and a pH optimum at pH 9.0. It was remarkably active and very stable in the presence of solvents and over a wide temperature and pH range. It is active in a multimeric form and displayed a high level of activity against a wide range of substrates including one secondary ester, 7-[3-octylcarboxy-(3-hydroxy-3-methyl-butyloxy)]-coumarin, which is normally unreactive. EstCE1 was active in the monomeric form and had a temperature optimum at 47°C and a pH optimum at pH 10. It exhibited the same level of stability as EstA3 over wide temperature and pH ranges and in the presence of dimethyl sulfoxide, isopropanol, and methanol. EstCE1 was highly enantioselective for (+)-menthylacetate. These enzymes display remarkable characteristics that cannot be related to the original environment from which they were derived. The high level of stability of these enzymes together with their unique substrate specificities make them highly useful for biotechnological applications.
Twofold alkylations of ketone and aldehyde phenylhydrazones with methylene halides by means of alkali amides to form bis-N-derivatives
Authors: Henoch Fred E. , Hauser Charles R.
Published: May 2006

The phenylhydrazones of benzophenone, acetophenone, and benzaldehyde were converted by a molecular equivalent of an alkali amide in liquid ammonia to their mono-alkali derivatives, which underwent twofold alkylation with 1,3-dibromopropane or higher methylene halides or with α,α′-dichloro-p-xylene to form corresponding bis-N-derivatives. Two of the products were reduced by means of lithium in liquid ammonia to give corresponding substituted bis-hydrazines. These reactions furnish convenient methods of synthesis of such compounds.
The transmission of polar effects. Part IX. The ionization and esterification with diazodiphenylmethane of 9-substituted 10-triptoic acids
Authors: Bowden Keith , Parkin D. C.
Published: May 2006

A series of 9-substituted 10-triptoic acids have been prepared. Their pKa values in 80% 2-methoxy-ethanol–water and 50% ethanol–water at 25° and rate coefficients for esterification with diazodiphenyl-methane in five alcohols at 30° have been measured. The results have been analyzed by linear free energy relations. The π-inductive effect is shown to be unimportant in such systems, while the field effect model can account for the transmission.
The transmission of polar effects. Part X. The esterification with diazodiphenyl-methane and the ionization of 9-substituted 10-anthroic and 8-substituted 1-naphthoic acids
Authors: Bowden Keith , Parkin D. C.
Published: May 2006

The rate coefficients for the reaction with diazodiphenylmethane in methanol, ethanol, isopropyl alcohol, t-butyl alcohol, 2-methoxyethanol, 2-n-butoxyethanol, and ethyl acetate at 30° and the pKa values in 80% 2-n-butoxyethanol–water of a series of 9-substituted 10-anthroic and 8-substituted 1-naphthoic acids have been determined. The effect of substitution has been analyzed by linear free energy relations. The variation in the susceptibilities of the systems to polar substituent effects with the medium are examined. The occurrence of reversed dipolar substituent effects in the reactions of the 1,8-naphthoic acids is detected. The implications of the results for the inductive and field effect models for the transmission of polar effects are discussed.
Substituent effects on H—F couplings and additivity of these effects in a series of fluorobenzene derivatives
Authors: Loemker J. E. , Pryse K. M. , Read Jr. J. M. , Goldstein J. H.
Published: May 2006

The nuclear magnetic resonance spectra of a series of monosubstituted fluorobenzenes have been recorded and analyzed, and the substituent effects on the H—F couplings have been determined by comparison with the corresponding H—F couplings in fluorobenzene. These substituent effects have then been successfully employed in calculating the H—F couplings for a series of di- and tri-substituted fluorobenzenes.
Hydrogenation of methylacetylene. IV. The reaction of methylacetylene with hydrogen catalyzed by palladium, platinum, iridium, rhodium, and ruthenium catalysts
Authors: Mann R. S. , Khulbe K. C.
Published: May 2006

The reaction between methylacetylene and hydrogen over pumice supported and unsupported palladium, platinum, iridium, rhodium, and ruthenium catalysts has been investigated between 12 and 160 °C for a wide range of reactant ratios. The order of reaction with respect to hydrogen was one and with respect to methylacetylene was zero to slightly negative. The overall apparent activation energies for supported and unsupported palladium, platinum, iridium, and rhodium were 10.5, 9.5, 12.4, 14.7, 8.6, 6.2, 10.7, and 11.7 kcal/mole respectively.
Formation of radicals in the amine inhibited decomposition of t-butyl hydroperoxide
Authors: Adamic K. , Ingold K. U.
Published: May 2006

The radicals formed in the amine inhibited, α,α′-azo-bis-isobutyronitrile initiated, decomposition of t-butyl hydroperoxide at 65° have been examined by electron spin resonance. In the absence of amine a strong peroxy radical signal is obtained. Amines with structures that do not correspond to those of conventional antioxidants (i.e. primary and secondary aliphatic amines and tertiary amines) generally have little or no effect on this signal. Nitroxide radicals are generated from secondary aromatic (diaryl and alkaryl) amines. The rate of conversion of these amines to nitroxides reached a maximum of 50–60% of the rate of chain initiation for some diphenylamines. A maximum concentration of nitroxide of about half the initial amine concentration was obtained with 4,4′-dimethyldiphenylamine.N,N,N′,N′-Tetramethyl-p-phenylenediamine is very rapidly oxidized by t-butyl hydroperoxide to give Wurster's Blue cation and, presumably, a t-butoxy radical. This amine is therefore an initiator of oxidation rather than an inhibitor as has commonly been supposed.Primary aromatic amines do not appear to form simple aryl nitroxides. It is proposed that arylamino radicals [Formula: see text] are directly oxidized to nitroso compounds by peroxy radicals.
Lignans of Western Red Cedar (Thujaplicata Donn). VIII. Plicatinaphthol
Authors: MacLean Harold , MacDonald B. F.
Published: May 2006

The isolation and structure of a new lignan, 1,6-dihydroxy-2-(hydroxymethyl)-7-methoxy-4-(3′,4′-dihydroxy-5′-methoxyphenyl)-3-naphthoic acid lactone (plicatinaphthol, 2), in which the 4-aryltetrahydronaphthalene structure of plicatin (1) has been aromatized to a 4-arylnaphthol nucleus are described. Proof of structure of the parent compound and its tetramethyl, tetraacetyl, and tetraethyl derivatives is presented both by analytical and spectral techniques, in addition to the synthesis of the tetramethyl derivative starting from podophyllotoxin.
Diethyl malonate as leaving group: Facile synthesis of some 1,3,4-benzotriazepines and benzotriazepinones
Authors: Podesva C. , Kohan G. , Vagi K.
Published: May 2006

Reaction between 2-(2′,2′-bis-carboethoxyvinylamino)-benzophenones, resulting from the condensation of 2-aminobenzophenones with diethyl ethoxymethylenemalonate, and hydrazine hydrate yields 5-hydroxy-5-phenyl-1,3,4-3H-4,5-dihydrobenzotriazepines or their double bond isomers. These products on acetylation afford O,N,N-triacetates, which on treatment with ammonia are transformed into 4-phenylquinazolines. Structure proof of these substances is reported.
Conversion of uridine 2′,3′-carbonates to anhydrouridines
Authors: Ogilvie K. K. , Iwacha D.
Published: May 2006

Uridine 2′,3′-carbonates are readily converted to 2,2′-anhydrouridines in hot dimethyl formamide with base catalysis. 3′,5′-Di-O-trityluridine is converted to 3′,5′-di-O-trityl-2,2′-anyhdro-1-β-D-arabinofuranosyluracil with diphenyl carbonate in the presence of sodium bicarbonate in hot dimethyl formamide.
Electron paramagnetic resonance studies on copper(II) benzoate
Authors: Herring F. G. , Thompson R. C. , Schwerdtfeger C. F.
Published: May 2006

An electron paramagnetic resonance (e.p.r.) study at 9.1 and 12.0 GHz on polycrystalline copper(II) benzoate has given the following Spin Hamiltonian parameters for the binuclear molecule: D = 0.3311 ± 0.0006 cm−1, E = 0.0147 ± 0.0003 cm−1, gx = 2.048 ± 0.004, gy = 2.074 ± 0.004, gz = 2.345 ± 0.004. Using the average g value of 2.160 ± 0.004 obtained from e.p.r. and previously published magnetic susceptibility studies, 2J is estimated to be 333 cm−1.
The silver–calcium phase diagram
Authors: Alexander W. A. , Calvert L. D. , Desaulniers A. , Dunsmore H. S. , Sargent D. F.
Published: May 2006

The silver–calcium system has been reinvestigated over the whole composition range by thermal analysis, X-ray diffraction, and metallography. A novel technique has been used to prepare and examine these reactive alloys. In the course of this project four intermetallic compounds have been observed for the first time; while two others, viz., Ag2Ca and AgCa, which were reported before by others, have been confirmed. Three of the new compounds are: Ag8Ca3, Ag3Ca5, and AgCa3, while the fourth was not isolated or examined in detail. Two other compounds which were described in earlier work as Ag4Ca and Ag3Ca, have been found to be Ag9Ca2 and Ag7Ca2, respectively. Major modifications have been made in the liquidus curve and possible reactions in the solid state are indicated.
Medium effects in nuclear magnetic resonance. VII. Vapor phase studies of hydrogen bonding in methanol and methanol–trimethylamine mixtures
Authors: Clague A. D. H. , Govil G. , Bernstein H. J.
Published: May 2006

The self association of methanol, and the intermolecular association of methanol and trimethylamine have been examined in the vapor phase using nuclear magnetic resonance spectroscopy. Values of ΔH and ΔS for the two systems have been found to be −4.1 ± 0.5 kcal/mole and −17.5 ± 3 e.u., and −5.8 ± 0.7 kcal/mole and −22.6 ± 3 e.u., respectively.
A novel aromatic ketone photoproduct: para-coupling of a phenyl-ketyl radical
Authors: Challand B. D.
Published: May 2006

Three minor products from the irradiation of acetophenone in ether are described, and the mechanism of their formation is discussed.
One-step conversion of isatins to oxindoles and phthalonimides to homophthalimides
Authors: Muchowski J. M.
Published: May 2006

The palladium-catalyzed hydrogenation of isatins and phthalonimides in acetic acid containing perchloric acid produced oxindoles and homophthalimides directly.A general, one-step synthesis of phthalonimides from isocarbostyrils is described.
The effects of pressure on the density, dielectric constant, and viscosity of several hydrocarbons and other organic liquids
Authors: Brazier D. W. , Freeman G. R.
Published: May 2006

The effects of pressures up to 4 kbar on the density, dielectric constant, and viscosity of n-pentane, n-hexane, n-octane, cyclopentane, methylcyclohexane, and 2,2-dimethylbutane (DMB) were measured at 30 °C. The pressure effects on the viscosities of n-hexane and n-octane were also determined at 0 and 60°. The densities of diethyl ether and cyclopentanone and the dielectric constant of carbon tetrachloride at high pressures are also recorded. The densities of the hydrocarbons increased by 20–30% and the dielectric constants increased by 11–16% as the pressure was increased from 1 to 4000 bars at 30°, but the viscosities increased by 695–2352% over the same pressure range. Carbon tetrachloride froze at 1500 bars at 30°, and cyclopentanone froze at 3500 bars at about 20°. In agreement with earlier work on other liquids, the value of the Clausius–Mosotti function (ε − 1)V/(ε + 2) for the present compounds decreased slightly with increasing pressure. The viscosity at a given pressure decreased slightly with increasing temperature, and temperature effect increased with increasing pressure. In general, the smaller the compressibility of the liquid, the greater was the effect of pressure on the viscosity; DMB was an exception because its viscosity increased abnormally rapidly with pressure. Molecular structure and liquid structure have greater influences on the pressure dependence of viscosity than on that of density or dielectric constant.
γ-Radiolysis of disulfides in aqueous solution. II. D-Penicillamine disulfide
Authors: Purdie J. W.
Published: May 2006

The γ-radiolysis of D-penicillamine disulfide (PenSSPen) in 3 × 10−4 M aqueous solution has been studied under aerated and deaerated conditions. G values were determined for the following products: penicillamine sulfinic acid (PenSO2H), penicillaminic acid (PenSO3H), β-hydroxyvaline (PenOH), 2-amino-3-methylbut-3-enoic acid (HOOC•CH(NH2)•C(CH3)=CH2), penicillamine (PenSH), penicillamine disulfide-S-monoxide (PenS(O)SPen), valine (PenH), penicillamine trisulfide (PenSSSPen), and ammonia. The low yield of PenSO3H in aerated solution indicated that PenSOH did not react with oxygen or O2−. The trisulfide, which was obtained in high yield, was found to come mainly from the reactions:[Formula: see text]Experiments with •OH radicals produced chemically (TiCl3/H2O2) and irradiations with cysteine or penicillamine present were used to confirm these reactions. These and the other reactions were tested with radical scavengers; formate and monochloroacetate ions and nitrous oxide.
Hydroboration of acyclic allenes with disiamylborane
Authors: Sethi D. S. , Joshi G. C. , Devaprabhakara D.
Published: May 2006

The present investigation demonstrates the hydroboration of 1,2-nonadiene, phenylpropadiene, 3-phenyl-1,2-butadiene, 4,5-nonadiene, and tetramethylallene with disiamylborane. All the allenes except tetramethylallene underwent 100% conversion. Examination of the products indicated preferential electrophilic attack of boron on the least substituted terminal carbon atom in the case of 1,2-nonadiene, phenylpropadiene, 3-phenyl-1,2-butadiene, and on the central carbon atom in 4,5-nonadiene. In tetramethylallene boron, attack was exclusively on the central carbon atom. These results have been explained in terms of steric effects on a four-centered transition state.
Synthesis of exaltone and dl-muscone based on 1,5,9-cyclododecatriene
Authors: Nozaki H. , Yamamoto H. , Mori T.
Published: May 2006

Bicyclo[9•4•1]hexadecan-16-one is prepared from cyclododecanone via four steps: ethoxycarbonylation, condensation with 1,4-dibromobutane, saponification, and decarboxylation. Photolysis of the bicyclic ketone yields a ketene which is trapped with methanol to afford methyl cyclopentadecanecarboxylate or alternatively oxidized to exaltone directly. The ester is also converted into exaltone via five steps. dl-Muscone is prepared by applying the same scheme to cyclotridecanone with 14-methylbicyclo-[10•3•1]hexadecan-16-one as the key intermediate.
Ortho lithiation of N,N-dimethylbenzenesulfonamide by n-butyllithium. Condensation with electrophilic compounds
Authors: Watanabe Hamao , Schwarz Richard A. , Hauser Charles R. , Lewis J. , Slocum D. W.
Published: May 2006

N,N-Dimethylbenzenesulfonamide was converted by n-butyllithium to the ortho-lithiosulfonamide, which was condensed with benzophenone, benzonitrile, phenylisocyanate, and carbon dioxide to form a carbinol, an imine, an amide, and an acid, respectively. The carbinol was cyclized thermally to give a sultone. The imine was converted to the corresponding ketone, oxime, and phenylhydrazone. The oxime underwent a Beckmann rearrangement to afford the same amide that was obtained in the reaction of the ortho-lithiosulfonamide with phenylisocyanate.
Ferric benzoylacetanilides
Authors: Syamal A.
Published: May 2006

Ferric chelates with benzoylacetanilide and benzoyl-metanitroacetanilide have been prepared and characterized. The complexes are dark red in color and are paramagnetic (μeff = 5.8 B.M.). Electrolytic conductance, electronic spectra, and infrared spectra of the complexes are reported. Absorption spectra point to weak donor ability of the ligands in comparison to acetylacetone. The complexes are octahedral.
Comments, Replies, and Summary
Authors: Niles F. E.
Published: May 2006

not available
Time of flight measurement of N2 and N2+ lifetimes
Authors: Hollstein M. , Lorents D. C. , Peterson J. R. , Sheridan J. R.
Published: May 2006

Lifetime measurements have been carried out on the N2 first positive and N2+ Meinel systems by observing the spatial decay of radiation from fast beams. The neutral beam is excited by near-resonant charge transfer, and the N2+ excitation originates in the ion source. The (2,0), (3,0), (3,1), (5,2), (9,5), and (12,8) first positive bands have been measured and the results compare favorably with Jeunehomme's values. The Meinel studies are apparently the first to yield well-defined values for that system. We obtained 12.2 ± 0.2, 11.4 ± 0.2, and 12.2 ± 0.9 μs for the ν' = 3, 4, and 5 levels, respectively.
Neutral reactions involving hydrogen and other minor constituents
Authors: Kaufman Frederick
Published: May 2006

Experimental laboratory work is reviewed for the kinetics of 21 neutral, elementary reactions involving H, OH, HO2, H2, CO, N2O, CH4, and Na.
Reactions of cysteine with N-methyl-N-nitroso-p-toluenesulfonamide and N-methyl-N′-nitro-N-nitrosoguanidine
Authors: Schulz Uwe , McCalla D. R.
Published: May 2006

The reaction between cysteine and N-methyl-N-nitroso-p-toluenesulfonamide affords almost quantitative yields of cystine and N-methyl-p-toluenesulfonamide. A mechanism based on the intermediacy of the S-nitroso derivative of cysteine and the intermediate formation of nitric oxide is proposed. Nitrous oxide is shown to be a final product. In the reaction of cysteine with N-methyl-N′-nitro-N-nitrosoguanidine a substantial yield of 2-nitramino-4-carboxyl-thiazoline is obtained. Cystine, N-methyl-N′-nitro-guanidine and S-methylcysteine are formed in lesser amounts. The major product arises from nucleophilic attack on the imino carbon of N-methyl-N′-nitro-N-nitrosoguanidine. Concomitant elimination of the methylnitrosamino group accounts for the mathylating ability of the system.
Reactions of some 1,3-dipolarophiles with 1,2-dithioles and 1,2,4-dithiazoles
Authors: Buchshriber J. M. , McKinnon D. M. , Ahmed M.
Published: May 2006

The reactions of 1,2-dithiole-3-thiones and 1,2,4-dithiazole-3-thiones with acetylenic esters provide initial 1,3-dithiole products by 1,3-dipolar additions. 3-Imino-1,2-dithioles react similarly to form thiazoles. Both these initial adducts react further with more acetylenic ester to form spiran type structures. The stereochemistry of these is discussed briefly and applied to their reactivity and spectroscopic properties.
Convenient new synthesis of 1,3-diaroylureas
Authors: Wolfe James F. , Trimitsis George B.
Published: May 2006

It has been found that symmetrical 1,3-diaroylureas can be prepared in good yields by allowing urea to react with aromatic esters and excess sodium hydride in refluxing 1,2-dimethoxyethane. Applications of this method to the synthesis of unsymmetrical 1,3-diaroylureas and substituted monoaroylureas are also described.
Solvolysis of alkyl chlorosulfates. Part III. Alcoholysis of n-propyl chlorosulfate
Authors: Buncel E. , Millington J. P.
Published: May 2006

The propanolysis reaction of n-propyl chlorosulfate has been examined quantitatively. Reaction at 25° yields the following products: di-n-propyl ether, n-propyl chloride, isopropyl chloride (trace), n-propyl hydrogen sulfate, di-n-propyl sulfate, and hydrogen chloride. It is found that the product distribution bears a direct relationship to the initial concentration of n-propyl chlorosulfate.It is concluded that only di-n-propyl ether and di-n-propyl sulfate are formed in primary processes, that is solvolytic displacement at carbon and sulfur respectively, and that the other products arise through secondary reactions. Carbon displacement is the predominant primary process.
Electron spin resonance studies of radicals condensed from irradiated water vapor: paramagnetic relaxation of trapped electrons in ice
Authors: Wardman P. , Seddon W. A.
Published: May 2006

The spin–lattice relaxation time T1 of electrons (et−) trapped in several ice matrices at 77 °K has been estimated to be of the order of 10−2 s by observation of the electron spin resonance (e.s.r.) dispersion signal under fast passage conditions. These studies, together with measurements of the microwave power saturation of the e.s.r. absorption signal indicate that there is little difference in T1 at 77 °K for et− in solute-free polycrystalline H2O or D2O ice, γ-irradiated 8 M NaOH/H2O or NaOD/D2O glassy ices, and in 8 M NaOD/D2O glasses in which the electrons were produced by photoionization of ferrocyanide ion. This indicates that the predominant spin–lattice relaxation mechanism is not cross relaxation, and that correlations between T1 and line width or trap depth are inappropriate.
Electrochemical reactions at PbO2 electrodes. Part IV. Electrochemical behavior of α-PbO2 in acid perchlorate electrolytes
Authors: Hampson N. A. , Jones P. C. , Phillips R. F.
Published: May 2006

The cathodic passivation and the exchange reactions at α-PbO2 electrodes in acid perchlorate electrolytes have been investigated using the galvanostatic technique. The results are generally closely similar to those previously reported for β-PbO2 but some differences occur and these are explained in terms of an α–β-PbO2 equilibration process.
Protonation of conjugated carbonyl groups in sulfuric acid solutions. II. Protonation and basicity of α,β-unsaturated alicyclic ketones
Authors: Zalewski R. I. , Dunn G. E.
Published: May 2006

The protonation of 14 α,β-unsaturated alicyclic ketones, B, by sulfuric acid leads to values of log [B]/[BH+] which, when plotted against the amide acidity function, HA, give straight lines of unit slope. The [Formula: see text] values thus obtained show substituent effects which are additive and can be interpreted in terms of polar and resonance effects.
Conformations of some dianhydrohexitols
Authors: Hopton F. J. , Thomas G. H. S.
Published: May 2006

Proton magnetic resonance spectra of three known diastereoisomers 1,4:3,6-dianhydro-D-glucitol, 1,4:3,6-dianhydro-D-mannitol, 1,4:3,6-dianhydro-L-iditol, and their diacetyl and dimesyl derivatives have been analyzed. The coupling constants obtained have been utilized to determine the conformation of the five-membered rings. Constancy of the couplings between ring protons throughout the series of compounds indicates the existence of one conformation common to all, and this appears to be a composite of the Cs and C2 forms. It is significant that intramolecular hydrogen bonding, which occurs in two of the three diastereoisomers, has little or no effect on ring conformation.
Leaf coumarins of Angelicaarchangelica
Authors: Steck Warren , Bailey B. K.
Published: May 2006

Coumarin derivatives are abundant in leaves of Angelicaarchangelica, and differ in kind from those of the roots. Angelicin, bergapten, imperatorin, isopimpinellin, xanthotoxin, oxypeucedanin, and five unidentified coumarins were isolated from leaves. A time study of their development was carried out. Methods for the isolation of leaf neutral coumarins are described.
Synthesis of 3-hexuloses
Authors: Jackson K. G. A. , Jones J. K. N.
Published: May 2006

A general procedure for the syntheses of derivatives of 3-hexuloses from L-threo-hexeno-furano lactone is described.
Diffusion coefficients of sodium and lithium chlorates in water, at 25°
Authors: Campbell A. N. , Oliver B. G.
Published: May 2006

The diffusion coefficients of sodium chlorate and lithium chlorate in water have been determined, using the Stokes' diaphragm technique. The diffusion coefficients of the solutions have been treated by the extended Hartley–Crank analysis to obtain hydration numbers for the electrolytes.
Structure of rhodocladonic acid
Authors: Baker Paul M. , Bullock E.
Published: May 2006

The currently accepted formulation of rhodocladonic acid, the red pigment from numerous lichens of the genus Cladonia, is revised. The compound is a naphthoquinone derivative, apparently the first isolated from a lichen.
Raman spectra of liquid and crystalline HCN and DCN
Authors: Pézolet M. , Savoie R.
Published: May 2006

Raman spectra of liquid and crystalline HCN and DCN have been recorded at various temperatures down to 77 °K. The spectra of the liquids are characteristic of hydrogen-bonded compounds. The two solid phases have very similar spectra, in which each fundamental is complicated by an anomalous shoulder on the high-frequency side. Possible explanations for these are given.
Magnetic nonequivalence in asymmetric phosphorus compounds
Authors: Frankel L. , Cargioli J. , Klapper H. , Danielson R.
Published: May 2006

The nuclear magnetic resonance (n.m.r.) spectra of seven compounds of the type (CH3)P(O)(SCH2SR)(OR′) have been examined as a function of solvent. The resonance pattern of the methylene protons, SCH2S, is strongly solvent dependent. In solvents of low dielectric constant, the methylene protons are magnetically nonequivalent and are observed as the AB part of an ABX spin system, where X is the phosphorus atom. In high dielectric constant medium (DMSO d6) only a well-resolved doublet is obtained indicating magnetic equivalence. When R′ = CH(CH3)2, nonequivalent methyl groups which show analogous solvent effects are observed.Eight compounds of the type (CH3)P(O)(OCH(CH3)2)(X) have been studied. The chemical shift between the magnetically nonequivalent isopropyl methyl groups does not correlate with any simple property of X.
Permanganate oxidation of aromatic alcohols in acid solution
Authors: Banoo Fariza , Stewart Ross
Published: May 2006

The mechanism of the permanganate oxidation of di- and tri-arylcarbinols has been studied in aqueous sulfuric acid. With both kinds of alcohols the rate-controlling step in solutions more acidic than H0 −0.50 was found to be the ionization of the carbinol to give the carbonium ion followed, it is believed, by rapid reaction with permanganate ion to form the ester which decomposes rapidly to products. In the case of the tertiary alcohols the decomposition probably proceeds via a 1,2-aryl shift. The effect of substituents is correlated with σ+ in both cases, ρ+ being −1.02 and −1.39 for the secondary and tertiary series. The acidity function which governs both reactions is H0. Tri(p-tolyl)carbinol is exceptional in that its oxidation in solutions more acidic than HR −2.6 is second-order and is governed by the HR acidity function.
Etude du coefficient d'expansion linéaire de polymères en solution par sédimentation et par viscosimétrie
Authors: Ho-Duc Nga , Daoust Hubert
Published: May 2006

not available
Phosphinohydrazines. Part III. Coordination compounds of N,N-dimethyl,N′-diphenylphosphinohydrazine and N,N-dimethyl,N′-diphenylthiophosphinatohydrazine
Authors: Ainscough E. W. , Peterson L. K. , Thé K. I. , Wilson G. L.
Published: May 2006

Reactions between N,N-dimethyl,N′-diphenylphosphinohydrazine, Me2NNHP(C6H5)2, (DPH), or N,N-dimethyl,N′-diphenylthiophosphinatohydrazine, Me2NNHP(S) (C6H5)2, (DPS), and appropriate metal salts have yielded the new coordination complexes Pd(DPH)Cl2, Pd(DPH)2Cl2, Pd(DPH)2Cl(ClO4), Pt(DPH)2Cl2, Pt(DPH)Cl4, Hg(DPH)Cl2, Pd(DPS)Cl2, Pt(DPS)Cl4, Ag(DPS)NO3, Zn(DPS)Cl2, Cd(DPS)Cl2, and Hg(DPS)Cl2. Notably, complexes of 1:1 ligand:metal stoichiometry predominate, the only exceptions being Pd(DPH)2Cl2 and Pt(DPH)2Cl2. In reactions between DPH and Zn(II) or Cd(II) salts, ready cleavage of the P—N bond was observed; the metal complexes of dimethylhydrazine were isolated in both instances. With the ligand DPS, however, the P—N bond was consistently stable against cleavage. Many reactions involving Co(II), Ni(II), Ag(I), Au(III), In(III), and Sn(II) resulted in the formation of intractable oils, or in reduction to the metallic state.
Signs of spin–spin coupling constants between aldehydic and ring protons in 2,6-dinitrobenzaldehyde. Evidence for a hyperconjugative contribution to JpH,CHO
Authors: Bell C. L. , Danyluk S. S. , Schaefer T.
Published: May 2006

The spin–spin coupling constant between the aldehydic proton and the proton in the para position, JpH,HCO is negative in 2,6-dinitrobenzaldehyde. JpH,CHO is also very likely negative in 2,6-dichlorobenzaldehyde. It is suggested that steric interaction with the ortho substituents forces the aldehyde group out of a coplanar conformation and leads to an interaction of the aldehydic C–H bond with the π system of the ring. Tentative values of θ, a measure of the deviation from coplanarity, are given.
Calculation of "Dewar" resonance energies in conjugated organic molecules
Authors: Baird N. C.
Published: May 2006

Dewar's recent definition of resonance energy (1) for hydrocarbons is extended to molecules containing oxygen, and resonance energy values are calculated from experimental heats of formation for a variety of conjugated organic compounds. A simple additivity scheme is proposed whereby resonance energies and heats of formation can be accurately estimated for benzenoid systems.
Alkylation of solid sodium and lithium 2,6-dimethylphenoxide with methyl halide vapor
Authors: Curtin David Y. , Stein Allan R.
Published: May 2006

The generally accepted hypothesis that the alkylation of metal phenoxides is forced to occur at the ortho-carbon in heterogeneous reactions was investigated. Methyl iodide and bromide vapor reacts with crystalline sodium and lithium 2,6-dimethylphenoxides to give ortho-carbon/oxygen alkylation ratios not unlike those obtained in sealed tube reactions with an excess of methyl iodide or with added toluene as solvent. However, an unprecedented amount of para-methylation also occurred. The implications of these and related observations in other systems are discussed.
Condensation de la poly-L-lysine et de la poly- L-ornithine avec des dérivés de bases puriques et de sulfamides
Authors: Berlinguet Louis , Gautier Jacky
Published: May 2006

Free ε-amino groups of poly-L-lysine and poly-L-ornithine were alkylated in aqueous solution with 6-chloropurine and 6-chloropurine-riboside, were acylated with 4-acetylamino benzene sulfonyl chloride, and were condensed with N-(4-acetylamino benzene sulfonyl)-glycine using carbodiimide method. Approximately 50% of the free amino groups of the basic polypetides were substituted. The same method was used to prepare poly-α-amino acids bearing radioactive substituants.
Amination of tetrazoles with hydroxylamine-O-sulfonic acid: 1- and 2-aminotetrazoles
Authors: Raap R.
Published: May 2006

1-Aminotetrazoles and 2-aminotetrazoles can be prepared by reacting tetrazoles with hydroxylamine-O-sulfonic acid in weakly alkaline aqueous solutions. The nuclear magnetic resonance spectra and some of the properties of these aminotetrazoles are described.
Conformational dependence of long-range spin-spin coupling constants in 2,6-dichlorobenzylfluoride
Authors: Schaefer T. , Wong C. M. , Tam K. C.
Published: May 2006

Double resonance experiments on the proton magnetic resonance spectrum of 2,6-dichlorobenzylfluoride yield the signs of the long-range coupling constants between the ring protons and the fluorine nuclei and protons in the fluoromethyl group. The signs and magnitudes of the long-range couplings are discussed in terms of their dependence on the conformation of the fluoromethyl group.
Cryptosporiopsin, an amended structure
Authors: Strunz G. M. , Court A. S. , Komlossy J. , Stillwell M. A.
Published: May 2006

The structure 1 (R1 = OH, R2 = Cl), previously proposed for cryptosporiopsin, has been amended on the basis of new evidence to 1 (R1 = Cl, R2 = OH).
Isomer ratios of 90Y and 91Y in the fission of 235U and 238U by protons of energies 20–85 MeV
Authors: Khan A. H. , Saha G. B. , Yaffe L.
Published: May 2006

Isomer ratios of 90Y and 91Y formed in the fission of 235U and 238U induced by protons of energies 20–85 MeV have been determined. For both 90Y and 91Y the isomer ratios are always higher in 235U fission than in 238U fission. Isomer ratios of 90Y in 238U fission and those of 91Y in 235U and 238U fission remain almost constant in the energy range of 20–85 MeV, whereas those of 90Y in 235U fission increase with increasing bombarding energy. A theoretical calculation of these ratios indicates that the primary fragments leading to the formation of these isomers possess [Formula: see text] units of angular momentum.
Crystal and molecular structure of CuSiF6•4H2O
Authors: Clark M. J. R. , Fleming J. E. , Lynton H.
Published: May 2006

The structure of CuSiF6•4H2O has been shown to consist of chains of [Cu(H2O)4F2] and [SiF6] octahedra linked through a common fluorine atom. The space group is monoclinic P21/a, with cell dimensions a = 7.22 ± 0.01 Å, b = 9.64 ± 0.01 Å, c = 5.36 ± 0.01 Å and β = 105.2 ± 0.3°. There are 2 molecules in the unit cell and the copper and silicon atoms occupy centers of symmetry. Atomic parameters have been obtained from a block diagonal least squares refinement using anisotropic temperature parameters. The final agreement residual for 574 observed reflections is R = 0.083.
Dual interaction of anisole with surface hydroxyls
Authors: Low M. J. D. , Cusumano J. A.
Published: May 2006

Infrared spectra were recorded of anisole adsorbed on porous glass which had been dehydroxylated to various extents, on highly dehydroxylated silica, and on fully fluoridated porous glass. Spectra recorded at various surface coverages showed 2 broad bands near 3600 and 3400 cm−1 due to perturbed surface hydroxyls, indicating that the adsorbed anisole was weakly held to the surface in 2 ways. The surface structures and mechanism are discussed.
Investigations of copper(II) complexes of bispyridylglycol and 6,6′-dimethyl bispyridylglycol
Authors: Manku G. S. , Gupta R. D. , Bhat A. N. , Jain B. D.
Published: May 2006

The formation of a greenish blue 1:1 metal:ligand chelate at pH 5–7 and a faint violet 1:1:1 metal:ligand:hydroxyl chelate at pH > 10 has been observed in Cu(II) complexes with bis-2-pyridylglycol and its 6,6′-dimethyl derivative using spectrophotometric, conductometric, and pH-metric methods.
Long-range spin–spin coupling constants between ring protons and aldehydic protons in some para-substituted benzaldehydes
Authors: Danyluk S. S. , Bell C. L. , Schaefer T.
Published: May 2006

The long-range proton–proton coupling constants between the ring protons and the aldehydic proton are reported for a series of para-substituted benzaldehyde derivatives. It was found that JoH,CHO < 0 and JmH,CHO > 0. Furthermore, JoH,CHO increases in magnitude as the electron donating power of the sub-stituent increases. A similar trend is observed forJmH,CHO but the ratio of the increase to the magnitude of JmH,CHO is much less than for JoH,CHO. A good correlation is obtained between JoH,CHO and the sub-stituent parameters of Swain and Lupton.The coupling constant data are discussed in terms of σ and π coupling mechanisms and it is concluded that σ electron mechanisms are dominant for both JoH,CHO and JmH,CHO.
pH Effects in trypsin catalysis
Authors: Kasserra H. P. , Laidler K. J.
Published: May 2006

A kinetic study has been made of the trypsin-catalyzed hydrolysis of N-benzoyl-L-alanine methyl ester, at pH values ranging from 6 to 10. The substrate concentrations varied from 1.7 × 10−3 to 4.3 × 10−2 M. From the rates were calculated, at each pH, values of [Formula: see text] (corresponding to [Formula: see text]), [Formula: see text] (corresponding to [Formula: see text]) and [Formula: see text] The specific levorotation of trypsin was measured and found to vary with pH in the pH region 5–11, the change in specific rotation following the ionization of a single group with pK(app) of 9.4. At pH 11 the specific rotation of trypsin, its zymogen, and its phosphorylated derivative were approximately the same, suggesting similar conformations for all three forms of the protein.The kinetic results on the acid side were very similar to those obtained by other investigators for chymotrypsin; they imply that there is a group of [Formula: see text] in the free enzyme, presumably the imidazole function of a histidine residue, and that this group is involved in acylation and deacylation, which can only occur if it is unprotonated. The behavior on the basic side was found to be different from that with chymotrypsin revealing a decrease in [Formula: see text] at high pH corresponding to a value of [Formula: see text] whereas [Formula: see text] showed sigmoid pH-dependence. An interpretation of these results that is consistent with all available information is that a group of [Formula: see text] (presumably the —NH3+ function of the terminal isoleucine) controls the conformation and thereby the activity of the enzyme at different stages of complex formation. In contrast to chymotrypsin, the pK of this ionizing group appears to be generally lowered by covalent complex formation between trypsin and its substrates.
Pyrolytic rearrangement of norbornene oxide
Authors: Garin David L.
Published: May 2006

Norbornene oxide (4), stable to pyrolysis at 500°, rearranges at 550° to give Δ3-cyclohexenylcarbox-aldehyde (8), norcamphor (6), and Δ2-cyclopentenone (7).
Equilibrium constants for σ-complex formation between cyanide ion and 1,3,5-trinitrobenzene in alcoholic solvents
Authors: Buncel E. , Norris A. R. , Proudlock W. , Russell K. E.
Published: May 2006

Equilibrium constants have been determined spectrophotometrically for the reaction of cyanide ion with 1,3,5-trinitrobenzene in methanol, ethanol, n- and iso-propanol, and n- and t-butanol. The equilibrium constants at 25 °C vary from 39 1 mole−1 for the reaction in methanol to 500 000 1 mole−1 with t-butanol as solvent. Enthalpy changes, determined from equilibrium measurements and by direct calorimetry, vary from 0 to −15.5 kcal mole−1 and the calculated entropy changes decrease from 7 to −26 cal deg−1mole−1 as the solvent is changed from methanol to t-butanol. These results are interpreted on the basis that desolvation of the small cyanide ion is the primary factor influencing enthalpies and entropies of reaction. The equilibrium constant in t-butanol is comparable to the values observed for aprotic solvents such as chloroform and acetone.
Electronic spectra of carbonato and oxalato ammine complexes of cobalt(III); average field model for singlet, triplet, and charge transfer bands
Authors: Sastri V. S. , Langford C. H.
Published: May 2006

The electronic spectra in ligand field (singlet and triplet) and charge transfer regions have been determined for a series of mixed carbonato and oxalato ammine complexes of Co(III). An average field model is shown to be quite adequate to complete interpretation of the spectra. The values of Δ appear to be dominated by σ bonding interactions. Full analysis of triplet bands reveals an abnormal C/B ratio which emphasizes the limitations to be placed on the interpretation of the values of parameters derived from first order perturbation theory parameterization of experimental spectra.
The sign of the long-range spin–spin coupling constant between 19F and the aldehydic 1H in p-fluorobenzaldehyde: evidence for a negative QCCHO
Authors: Schaefer T. , Danyluk S. S.
Published: May 2006

The spin–spin coupling constant of −0.50 ± 0.03 Hz between the 19F nucleus and the aldehydic proton in p-fluorobenzaldehyde contrasts with a positive coupling between 19F and methyl protons in p-fluorotoluene derivatives. If the former coupling is dominated by a π electron mechanism, it implies a negative hyperfine interaction constant between the aldehydic proton and the aromatic π system.
Solvation thermodynamics of ions: free energies in water, ammonia, and fused LiCl–KCl eutectic
Authors: Plambeck James A.
Published: May 2006

not available
Annelation of 2,3-dimethylcyclohexanone. Synthetic proof for the stereochemistry of the sesquiterpene aristolone
Authors: Piers Edward , Britton Ronald W. , Waal William de
Published: May 2006

An efficient annelation of 2,3-dimethylcyclohexanone is described. The key step of this process involves the reaction of the enol lactone 16 with methyllithium, under carefully controlled conditions. The completely stereoselective conversion of the sesquiterpene (−)-aristolone (1) into the levorotatory decalone 22b is described. Comparison of the latter with the unambiguously synthesized racemic decalone 22a conclusively establishes the relative stereochemistry of aristolone (1).
Norditerpene alcohols in the bark of Thuja plicata Donn
Authors: Quon H. H. , Swan Eric P.
Published: May 2006

The neutral extractives from the bark of western red cedar (Thuja plicata Donn) contained, among other components, three alcohols. One was the known diterpene alcohol, isopimarinol, the other two were the new Δ8(14),15-4α- and Δ8(14),15-4β-hydroxy-18-norisopimaradienes. The syntheses of these two alcohols are described. The greater amount of the 4α compound found in nature, and its relative ease of synthesis compared to the 4β isomer, showed it to be formed preferentially.
Synthesis of olivomycose (2,6-dideoxy-3-C-methyl-L-arabino-hexose)
Authors: Williams E. H. , Szarek W. A. , Jones J. K. N.
Published: May 2006

Oxidation of methyl 4,6–O-benzylidene-2-deoxy-α-L-arabino-hexopyranoside (1) with ruthenium tetroxide gave the 3-ketone 2 in high yield. A Wittig reaction between methylenetriphenylphosphorane and compound 2 gave methyl 4,6-O-benzylidene-2,3-dideoxy-3-C-methylene-α-L-erythro-hexopyranoside (3), which was hydrated by the oxymercuration–demercuration procedure to afford methyl 4,6-O-benzylidene-2-deoxy-3-C-methyl-α-L-arabino-hexopyranoside (4). The reaction of compound 4 with N-bromosuccinimide gave methyl 4-O-benzoyl-6-bromo-2,6-dideoxy-3-C-methyl-α-L-arabino-hexopyranoside (5) in high yield. Treatment of compound 5 with lithium aluminium hydride followed by acid-catalyzed hydrolysis of the resultant product, gave L-olivomycose (6).
Chelate-exchange titrimetry in nonaqueous solvents. I. Determination of dithizone and metal dithizonates
Authors: Grey Peter , Cave G. C. B.
Published: May 2006

A new spectrophotometric titration method is proposed for determination of the amounts of metal chelates present in nonaqueous solvents. The titrant is a standard solution of a chelating agent which quantitatively displaces the chelate anion of the metal chelate. The method is exemplified by the titration of μg amounts of the dithizonates of Ag, Pb, Cu(II), Cd, Zn, and In in chloroform, both in the absence and the presence of free dithizone. Some binary and ternary mixtures were also successfully analyzed for the individual metal dithizonates. The titrant was a standard solution of sodium diethyldithiocarbamate in ethanol. Precision and accuracy were good. The preparation and analysis of the metal dithizonates are described. New titrimetric procedures are also proposed and shown to be satisfactory for determination of the free dithizone content of a chloroform solution.
Chelate-exchange titrimetry in nonaqueous solvents. II. Determination of 8-quinolinol and metal 8-quinolinates
Authors: Grey Peter , Cave G. C. B.
Published: May 2006

Chelate-exchange titrimetry has been applied to the determination of μg amounts of some metal 8-quinolinates in benzene. The titrant was a standard solution of diphenylthiocarbazone in benzene. Accuracy and precision were good in the cases of Pb, Cu(II), Cd, Zn, and In. Very slow reaction rates made titrations of Ag and Ni impracticable, and chelate-exchange was negligible in the case of Co(II). A new titrimetric method is also shown to be precise and accurate for the determination of free 8-quinolinol in benzene; the titrant was a standard solution of Cu(NO3)2 in ethanol.
Mössbauer spectra of toluene-3,4-dithiolene and cis-1,2-bistrifluoromethyl-1,2-ethylenedithiolene complexes of iron(III)
Authors: Birchall T.
Published: May 2006

The Mössbauer spectra of a number of dithiolene complexes of iron have been examined at 77 °K. The data obtained are discussed in relation to the known structural data.
Reactions of hexacarbonylrhenium(I) perchlorate with phosphines and other ligands
Authors: Abel E. W. , Tyfield S. P.
Published: May 2006

Hexacarbonylrhenium perchlorate, [Re(CO)6]ClO4, reacts on heating above 120° with 1,2-bis(diphenylphosphino)ethane and with triphenylphosphine to form respectively [Re(CO)4(Ph2C2H4PPh2)]ClO4 and trans-Re(CO)3(PPh3)2Cl. The stereochemistry of trans-Re(CO)3(PPh3)2Cl was established by dipole moment and infrared measurements. Other phosphines failed to yield clean products. The reactions of phosphines and other ligands with [Re(CO)6]ClO4 are discussed, in particular the reaction with triphenylphosphine in which the perchlorate is reduced to chloride and incorporated by rhenium to form trans-Re(CO)3(PPh3)2Cl.
Versatile heteronuclear-decoupler for use with a Varian HA-100 spectrometer
Authors: Burton R. , Hall L. D.
Published: May 2006

Specific details are given for double-tuning the Varian V-4333 probe for use in the following heteronuclear magnetic double resonance experiments: observe 1H at 100 MHz; irradiate 2H, 19F, or 31P; observe 19F at 94 MHz; irradiate 1H, 2H, or 31P. An inexpensive source of audiofrequency-noise is described which, in conjunction with the double-tuned probe and several commercially available components, constitutes the basis of a versatile heteronuclear-decoupler. Examples are given which illustrate the effectiveness of this decoupler. Double-tuning of the Varian V-4333 probe by introducing a second transmitter coil is also described.