bluuebunny/crossref_metadata_2025_split huggingface dataset:
1‐chloro‐4‐nitronaphthalene from 1‐amino‐4‐nitronaphthalene
Authors: Bassilios H. F. , Shawki M. , Salem A. Y. 
Published: September 2010

AbstractDiazotisation of 1‐amino‐4‐nitronaphthalene with hydrochloric acid and sodium nitrite, and decomposition of the diazonium salt by the Sandmeyer or Gattermann reaction, is studied in order to check the work of Franzen and Helvert and of Ferrero and Caflish 4. The compound, m.p. 61°, reported by Franzen and Helvert to be a new 1‐chloro‐4‐nitronaphthalene, creating a new type of isomerism with the known 1‐chloro‐4‐nitronaphthalene, m.p. 85°, has not been found. Improper conditions of diazotisation, e.g., high temperature, or low concentration of hydrochloric acid, as used by Ferrero and Caflish, lead to decomposition with the formation of impure 1‐nitro‐naphthalene, m.p. 58‐61°.
Precipitate impregnated membranes: III. Membrane potentials and the behaviour of ions at the BaSO4‐cellophane membrane
Authors: Hirsch‐Ayalon P. 
Published: September 2010

Abstract1. The membrane potentials measured at the BaSO4‐cellophane membrane point to selectivity of its permeability, supporting the conclusions drawn from previously reported direct permeation experiments.2. In the presence of permeating ions other than H+ and OH−, the membrane potential at the BaSO4 membrane is not exclusively dependant on the pH's of the adjacent solutions. Other ions, e.g. K+ and Cl−, may even take over the predominating role in the development of the membrane potential – in non‐quilibrium states.3. In non‐equilibrium systems with other permeating ions besides H+ and OH−, spontaneous ion redistribution takes place and the system changes towards a Donnan equilibrium. The rate at which these changes take place greatly depends on the composition of the two adjacent solutions. The changes are often very slow.4. The eventually reached equilibrium state is a (double) Donnan equilibrium. The fact that Donnan equilibria could be established under favorable conditions, is a further proof for the selective permeability of the BaSO4 membrane.5. An electrochemical hypothesis is given as a possible explanation of the observations on BaSO4 membranes so far described.
Investigations on pyrazine derivatives. VII: On the conversion of pyrazine 2,5‐dicarboxylic acid into some derivatives of 2‐aminopyrazine 5‐carboxylic acid
Authors: Schut W. J. , Mager H. I. X. , Berends W. 
Published: September 2010

AbstractPyrazine 2,5‐dicarboxylic acid was prepared by oxidation of 2,5‐dimethylpyrazine with selenium dioxide. 2,5‐Diethoxycarbonylpyrazine appeared to be a suitable starting‐material for the preparation of monocarbamoyl‐ and monocarboxyhydrazide derivatives. Hofmann degradation of 2‐carbamoyl‐5‐ethoxycarbonylpyrazine into 2‐aminopyrazine 5‐carboxylic acid proved to be rather difficult. The monocarboxyhydrazides in this series could be readily converted into acid azides and eventually into pyrazine‐urethanes.
Synthesis of substituted benzophenones by a direct condensation of substituted benzoic acids with benzene in the presence of aluminium chloride
Authors: Reiding D. J. , Th. Nauta W. 
Published: September 2010

AbstractCondensation of substituted benzoic acids with benzene in the presence of aluminium chloride is found to be possible, in general, only in the case of ortho‐substituted acids. No reaction could be obtained with benzoic acid itself, with meta‐ or para‐toluic acids, or, somewhat unexpectedly, with 2,4,6‐trimethylbenzoic acid.
The system NbCl5‐Nb2O5
Authors: Meyer G. , Oosterom J. F. , van Oeveren W. J. 
Published: September 2010

AbstractThe following three phase equilibria (dependence of pressure on temperature) have been determined in order to find out which compounds occur in the above mentioned system:magnified imageFrom these measurements it follows that in all probability NbOCl3 is the only compound occurring in this binary system.An analytical method has been worked out for the determination of NbCl5 in the presence of NbOCl3.By extrapolation from the binary‐melt‐diagram, the melting point of NbCl5 is found to be 206.8° ± 0.3°.
Studies in IVth group organometallic chemistry. VII: Synthesis of some hetero‐polymers containing germanium, tin, and lead in the main polymer chain
Authors: Noltes J. G. , van der Kerk G. J. M. 
Published: September 2010

AbstractIt has been shown that di‐p‐styrenyl derivatives of germanium, tin, and lead as well as 1,4‐divinylbenzene and 3,9‐divinylspirobi(meta‐dioxan) react with diphenyltin dihydride to yield linear poly‐addition polymers containing tin or tin and germanium or lead in the main polymer chain. The polymeric products have been characterized by infrared spectroscopy, analytical data and molecular weight.Reactions of triphenyltin hydride and diphenyltin dihydride with mono‐ and di‐p‐styrenyl derivatives of germanium, tin, and lead yielding monomeric compounds containing two and three hydrocarbon‐linked metal atoms, have also been carried out.
Contact angles; wetting and de‐wetting of mercury: Part III. Contact angles on mercury
Authors: Smolders C. A. 
Published: September 2010

AbstractIn the system mercury/aqueous Na‐decane sulfonate/hydrogen contact angles are obtained by calculation from the three interfacial tensions, and by direct measurement.Electrocapillary measurements are described, by which the influence of the surface charge (surface potential) on the adsorption of Nadecane sulfonate at the mercury/solution interface is studied.Using the sessile drop method, equilibrium surface tension data are obtained for all three interfaces, and for different values of the surface potential of the mercury.Calculated and measured contact angles are in good agreement over a range of concentrations of Na‐decane sulfonate.The problem of the thickness of the solution layer at the mercury/gas interface is discussed.
The applicability of Hammett's acidity function H0 to solutions in methanol‐water mixtures
Authors: de Ligny C. L. , Loriaux H. , Ruiter A. 
Published: September 2010

AbstractThe dissociation constants of 4‐aminoazobenzene‐4′‐sulphonic acid, 4‐(methylamino)azobenzene‐4′‐sulphonic acid, 4‐(phenylamino)‐azobenzene‐4′‐sulphonic acid, 4‐(dimethylamino)azobenzene‐4′‐sulphonic acid and p‐nitrophenol were determined in water and in several mixtures of methanol and water at 25°. The influence of the percentage of methanol on the dissociation constant differs greatly for the various indicators, even for indicators of the same charge type.From this it follows that Hammett's acidity function H0 for solutions in mixtures of methanol and water depends on the indicator used for determining H0. Thus, for solutions in mixtures of methanol and water and presumably also in mixtures of water and other non‐electrolytes, H0 is not a useful, unambiguous measure of the acidity.
Steric effects in the electronic spectra of substituted benzophenones. IV. Unsymmetrically substituted methylbenzophenones
Authors: Rekker R. F. , Nauta W. Th. 
Published: September 2010

AbstractThis article gives the experimental results of UV measurements made on an extensive series of unsymmetrically substituted methylbenzophenones in solution (ethanol and iso‐octane). The results obtained are compared with our previously published UV measurements on symmetrically substituted benzophenones and correlated with literature data on the UV absorption of acetophenones.From this investigation it appears that for the benzophenone series the oscillator strength f is an additive quantity, a fact which is very useful in comparing the various ketones with one another.The comparison with acetophenone ‐ in which not only f, but also the wavelength of the conjugative absorption band plays a part ‐ supplied useful information on the position of the phenyl rings relative to the CO group.
Chemistry of acetylenic ethers LIV: Addition of diazo compounds to acetylenic ethers and thioethers
Authors: Groen S. H. , Arens J. F. 
Published: September 2010

AbstractEthoxyethyne slowly adds diazomethane to yield 4‐ethoxypyrazole I, the structure of which has been proved by synthesis from 1,1,2,3,3‐pentaethoxypropane IV and hydrazine. Ethylthioethyne V, on the contrary, is converted by diazomethane into 3‐ethylthiopyrazole VI, the structure of which has been proved by synthesis from 3‐aminopyrazole X.Ethyl diazoacetate does not react with ethoxyethyne, but can be added to ethylthioethyne, yielding presumably 5‐ethoxycarbonyl‐3‐ethylthiopyrazole.
Reserpine analogues II
Authors: de Groot S. , Strating J. 
Published: September 2010

AbstractA new synthesis of cis‐(3H, 12bH)3‐ethoxycarbonyl‐1,2,3,4,6,7,42,12b‐octahydropyrido [2,1‐a]β‐carboline (VIa) is given.
Crystalline 3‐desoxy‐2‐keto‐gluconic acid
Authors: Paerels G. B. 
Published: September 2010

AbstractThe physical constants of crystalline 3‐desoxy‐2‐keto‐D‐ and L‐gluconic acid, prepared according to Kuhn's methodR. Kuhn, D. Weiser and H. Fischer, Ann. 628, 207 (1959).
, are described.
Spectrophotometric assay of α‐tocopherol
Authors: Mulder F. J. , Keuning K. J. 
Published: September 2010

AbstractThe benzene washing procedure for the isolation of unsaponifiable residues has been applied to vitamin E preparations containing α‐tocopheryl esters only.The isolation procedure is carried out once (after saponification) or twice (before and after saponification). In the solution thus obtained, β‐tocopherol is determined spectrophotometrically; the absorbance at the maximum is corrected for by‐absorption.By avoiding quantitative extractions and transfers, contact with air is reduced to a minimum; ascorbic acid is used as an antioxidant.
The chemistry of cycloheptatriene: Part II: Reduction of cycloheptatriene to cycloheptadiene and cycloheptene
Authors: Ter Borg A. P. , Bickel A. F. 
Published: September 2010

AbstractReduction of cycloheptatriene (I) and cycloheptadiene (II) with 2 equivalents of sodium in liquid ammonia yields ‐ after addition of ethanol ‐ cycloheptadiene and cycloheptene (III), respectively.These reactions proceed via coloured intermediates. Reduction of I with 4 equivalents of sodium gives only III.Carbonation of the reaction mixture of I and 2 equivalents of sodium yields a cycloheptadiene monocarboxylic acid whereas no carboxylic acid has formed upon carbonation of the reaction mixture of II and 2 equivalents of sodium.
The autoxidation of isopropylbenzenes to benzoic acids in acid media: III. Side‐reactions and by‐products
Authors: van Helden R. , Bickel A. F. , Kooyman E. C. 
Published: September 2010

AbstractIn the autoxidation of cumenes to benzoic acids at about 140° in butyric acid as solvent and with Co‐ and Mn‐acetates as catalysts the main side‐reaction is the formation of dimethylbenzyl alcohols. It may be suppressed by employing a low hydrocarbon concentration. The carbinols formed are partly dehydrated to α‐methylstyrenes, which are oxidized, via acetophenones, to benzoic acids (about 50%), and to 1‐methyl‐1‐phenylglycol derivatives, which are also oxidized — but less rapidly — to benzoic acids. Evidence is presented that the glycol derivatives are formed by interaction of the α‐methylstyrenes and peroxy radicals.The solvent is attacked to some extent by the cobalt catalyst, yielding various degradation products. The first step in this reaction is assumed to be the attack of the trivalent Co‐ions on the carboxyl group of the acid, yielding butyroyloxy radicals.A general scheme, describing the fate of an isopropyl group in the course of the autoxidation is given.
Peptide derivatives related to the active site of some hydrolytic enzymes: I. Syntheses of tetrapeptide ethyl esters containing glutamic acid and serine
Authors: Kienhuis H. , van De Linde A. , van Der Holst J. P. J. , Verweij A. 
Published: September 2010

AbstractThe syntheses of glycyl‐α‐L‐glutamyl‐L‐serylglycine ethyl ester and of glycyl‐α‐L‐glutamyl‐O‐acetyl‐L‐serylglycine ethyl ester are described. The mixed anhydride method and the carbodiimide method were used for condensing together two dipeptide derivatives. The latter were obtained by the azide method.
On the so‐called Auwers‐Skita Rule, The conformational rule, and the isomer sequence rule
Authors: van Bekkum H. , van Veen A. , Verkade P. E. , Wepster B. M. 
Published: September 2010

AbstractThe merits and defects of the so‐called Auwers‐Skita Rule and of the Conformational Rule are discussed. A new rule, the Isomer Sequence Rule, is proposed.
The condensation of ketones and the ethyl hemiacetal of ethyl glyoxylate
Authors: Noltes A. W. , Kögl F. 
Published: September 2010

AbstractThe ethyl hemiacetal of ethyl glyoxylate (ethyl ethoxy‐hydroxyacetate, I) has been found to undergo thermal condensation with various ketones. The new reaction presents a simple method of attaching a hydroxyacetic ester side chain to a carbon atom adjacent to the carbonyl function, giving 2‐hydroxy‐4‐keto‐alkanoic esters. Of several transformations to which these esters are readily accessible the dehydration reaction in particular has been investigated.
Iodo derivatives of 5‐methyl‐1‐phenyl‐1,2,3‐triazolecarboxylic acid
Authors: Bojarska‐Dahlig H. N. 
Published: September 2010

Abstract1‐(3′‐Iodophenyl)‐5‐methyl‐1,2,3‐triazolecarboxylic acid, 1‐(4′‐iodophenyl)‐5‐methyl‐1,2,3‐triazolecarboxylic acid and 1‐(3′‐4′‐di‐iodophenyl)‐5‐methyl‐1,2,3‐triazolecarboxylic acid were prepared by reacting ethyl acetylacetate with the corresponding 1‐azido‐di‐iodobenzene.5‐Methyl‐1‐phenyl‐1,2,3‐triazolecarbonyl chloride and 1‐(4′‐iodophenyl)‐5‐methyl‐1,2,3‐triazolecarbonyl chloride were condensed with 3‐amino‐2,4,6‐tri‐iodobenzoic acid, α‐ethyl‐3‐amino‐2,4,6‐tri‐iodohydrocinnamic (iopanoic) acid and α‐ethyl‐3‐amino‐2,4,6‐tri‐iodocinnamic (dehydroiopanoic) acid.
Note on the conversion of the amino group of amino acids into the nitroguanidino group
Authors: Heyboer N. , Visser G. Heymens , Kerling K. E. T. 
Published: September 2010

AbstractA study has been made of 2‐methyl‐1‐nitroisourea as a reagent for the conversion of amino groups of amino acids into guanidino groups. This reagent has proved its usefulness in modifying the ω‐amino groups of diaminocarboxylic acids in particular. The reaction of 2‐methyl‐1‐nitroisourea with glycine, L‐ornithine and D‐ and L‐lysine to yield nitroguanidinoacetic acid, L‐nitroarginine and D‐ and L‐nitrohomoarginine, respectively, is described.
The isomerization of toluene‐1‐ 14C under the influence of aluminium bromide and hydrogen bromide
Authors: Steinberg H. , Sixma F. L. J. 
Published: September 2010

AbstractThe homogeneous isomerization of toluene‐1‐14C under the influence of aluminium bromide and hydrogen bromide (mole ratio C6H5‐CH3: Al2Br6·HBr = 6:1) proceeds via a series of consecutive 1,2‐shifts of the methyl group. The energy of activation amounts to 21.9 kcal/mole (± 4%).
Intramolecular hydrogen bonds in some substituted aminoalcohols of the trihexyphenidyl‐type
Authors: de Roos A. M. , Bakker G. A. 
Published: September 2010

AbstractThe binding energy of the intramolecular hydrogen bond occurring in a limited series of substituted aminoalcohols was shown spectroscopically to increase from substituted 2‐aminoethanols, through 3‐aminopropanols to 4‐aminobutanols.
On the impedance of galvanic cells: IV. Determination of rate constants of rapid electrode reactions from electrode impedance measurements
Authors: Rehbach M. , Sluyters J. H. 
Published: September 2010

AbstractIf, at one particular frequency, the electrode impedance is plotted in the complex impedance plane at varying bulk concentrations C*ox and C*RED, keeping C*ox = C*RED, a circle is obtained. Moreover, through one of the points measured a semicircle can be drawn with its centre on the real axis.From the coordinates of the centres of these circles information can be gained on the rate constant of the electrode reaction. The ohmic resistance, the double layer capacity, diffusion polarization and activation polarization may contribute to the impedance of the electrode.The upper limit of the rate constant ksh that can be measured by this method is valued at 0.65 cm sec−1.
Reactions of 1‐bromo‐2‐phenylethane and aluminium bromide: Part II. Bromine exchange
Authors: Adema E. H. , Sixma F. L. J. 
Published: September 2010

AbstractThe kinetics of the reaction involving the exchange of bromine atoms between 1‐bromo‐2‐phenylethane‐[82Br] and aluminium bromide in carbon disulphide has been studied in the temperature range of −80° to −100°. The energy of activation is 10.6 kcals/mole.The kinetic results can only be explained if nearly all aluminium bromide is present as the complex C8H9Br: AlBr3.
On the synthesis of mixed‐acid L‐α‐phosphatidylethanolamines
Authors: Daemen F. J. M. , de Haas G. H. , van Deenen L. L. M. 
Published: September 2010

AbstractThe synthesis is described of phosphatidylethanolamine, involving a reaction between γ,β‐diacylglycerol‐L‐α‐iodohydrins and silver benzyl 2‐ phthalimidoethylphosphate. A comparison has been made between (γ‐oleoyl‐β‐stearoyl)‐L‐α‐phosphatidylethanolamine, obtained by this method and (γ‐oleoyl‐β‐stearoyl)‐L‐α‐phosphatidylethanolamine and the structurally isomeric (β‐oleoyl‐γ‐stearoyl)‐L‐α‐phosphatidylethanolamine, both synthesized by a different procedure, previously reported2. The structural identity of the two former compounds was proved by degradation experiments with the β‐fatty acid releasing phospholipase from snake venom. In addition, some physical properties of the enzymatically formed Iysophosphatidylethanolamine have been compared with those of a corresponding lyso compound and a glycol derivative, both synthesized by the method indicated.
Corrections of the theory of the stability of hydrophobic colloids (the specific influence of ions)
Authors: Sparnaay M. J. 
Published: September 2010

AbstractCalculations are given concerning various corrections upon the potential energy of two colloidal particles at various distances. The corrections arise from the considerations of finite ionic volumes and from the influence upon the dielectric constant of the solvent by added ions. The ionic volume effect is the most important correction. Limits of the applicability of the Derjaguin and Landau‐Verwey and Overbeek theory are given (see section 3.5). The flat plate approximation and 1‐1 electrolyte solutions are considered only. The paper is an extension of an earlier treatment by the author on corrections of the double layer potential 7, 872 (1958) in this Journal.
Ethylene hydrate at high pressures
Authors: van Cleeff A. , Diepen G. A. M. 
Published: September 2010

AbstractThe P‐t projection of the three phase equilibrium, hydrate ‐ liquid ‐ gas, up to pressures of 1000 atm is recorded. An explanation is given for the sharp rise occurring at ∼18° in the slope of the three phase curve HLG.
Synthèse de deux aldols aromatiques, aldéhyde tropique et hydroxy‐3 phényl‐3 propanal
Authors: van Dam Mathieu J. D. 
Published: September 2010

AbstractReduction of ethyl 3,3‐diethoxy‐2‐phenylpropionate by LiAlH4, followed by cautious hydrolysis with the help of a cation exchange resin, yields tropic aldehyde (3‐hydroxy‐2‐phenylpropanal). In the same way. 3‐hydroxy‐3‐phenylpropanal (phenaldol)is obtained from 3,3‐dimethoxypropiophenone. Both isomers, the simplest aromatic aldols, are isolated as crystalline dimers (aldolans).
Chemistry of acetylenic ethers. LXI: A simple method for the preparation of acetylenic thioethers, selenoethers and telluroethers (Preliminary publication)
Authors: Brandsma L. , Wijers H. , Arens J. F. 
Published: September 2010

AbstractThe compounds mentioned in the title have been prepared in accordance with the reaction scheme below, in yields between 50 and 75 %.
Synthesis and physiological properties of some heterocyclic‐aromatic sulphides and sulphones: IV Biological investigations
Authors: van Zwieten P. A. , Meltzer J. , Huisman H. O. 
Published: September 2010

AbstractThe acaricidal properties of some new halogen‐substituted heterocyclic‐aromatic sulphides and sulphones are described. As a rule, the adulticidal activity is negligible, though some compounds show interesting ovicidal properties. The sulphides possess a higher ovicidal activity than the sulphones. The pyridyl sulphides are the most active, the thiazolyl sulphides somewhat less, whereas the pyrimidyl and thienyl sulphides are almost inactive. The pyridine‐N‐oxides are also inactive. The polarity of the compounds synthesized seems to exert a considerable influence on the ovicidal properties.
Preparation of indan‐1‐one and 1‐methyl‐4,5‐benzindan‐3‐one
Authors: Rahman Aziz‐Ur , Gastaminza Alicia E. 
Published: September 2010

AbstractThe methods of preparation of indan‐1‐one and 1‐methyl‐4,5‐benzindan‐3‐one have been reviewed; the former has been prepared by Friedel‐Craft's condensation of β‐chloropropionyl chloride and benzene via β‐chloropropiophenone, while the latter was obtained by the cyclisation of β‐2‐naphthylbutyric acid, prepared either, by malonic ester synthesis on α‐chloro‐α‐(2‐naphthyl)ethane or by a Reformatsky reaction on 2‐acetylnaphthalene.
Physical properties of organic thiones: Part IV. The basicity of the thiocarbonyl group in various thiones
Authors: Janssen M. J. 
Published: September 2010

AbstractThe basicities of four N,N‐dimethylthioamides, of thiourea and all the N‐methylated thioureas, of ethylenethiourea, N,N′‐dimethylethylenethiourea and trimethylenethiourea, of S‐methyl N,N‐dimethyldithiocarbamate and ‐dimethyl trithiocarbonate, were determined. Measurements were made spectrophotometrically in aqueous sulphuric acid of various strengths and attempts were made to correct the absorption values for solvent effects. In methylated thioureas both electronic and steric effects influence the acidity constants. These effects appear to be of comparable magnitude. The results on the dithiocarbamate and trithiocarbonate show that in these compounds the basicity is determined by the negative inductive rather than by the positive mesomeric effect of the methylmercapto group. The amino group exerts a strong mesomeric action as expected.
Molecular volumes of selected boron‐containing compounds
Authors: Waugh John L. T. , Christopher Phoebus M. 
Published: September 2010

AbstractBy the use of a table of self‐consistent atomic parachor constants, which includes the value of 51.9 for boron, the calculated molar parachors for a variety of compounds of this element are found to be in close agreement with observed results. Equations relating the parachor to boiling point, critical temperature, critical volume, and critical pressure are derived for the n‐alkyl borates. Isothermal compressibilities are calculated for all of the compounds included in the present study.
Slow oxidation of hydrocarbons in the gas phase II. Neopentane
Authors: Zeelenberg A. P. 
Published: September 2010

AbstractThe slow oxidation of neopentane has been investigated in a static system at 260°. Analysis by means of gas‐liquid chromatography (GLC) during the early stages of the combustion showed the presence of isobutene, acetone, isobutyraldehyde, pivalaldehyde, methanol, neopentyl alcohol, isobutene oxide, 3,3‐dimethyloxetane, propene, carbon dioxide, acetaldehyde, propene oxide, isopropyl alcohol, t‐butyl alcohol and water.The formation of these products can be rationalized by a mechanism involving oxidation cycles with occasional chain branching. Oxidation cycles are thought to consist of three distinct steps, viz. (I) Oxygenation of alkyl radicals to yield peroxy radicals, (II) Intramolecular decomposition of peroxy radicals with formation of products and oxy radicals and (III) Interaction of the latter with the hydrocarbon to yield hydroxylic products and alkyl radicals. It would appear that in step (II) a C‐C bond is broken more readily than a C‐H bond. Chain branching is assumed to proceed via the hydroperoxide.Isomerization of neopentyl radicals and dimerization reactions of radicals do not occur.