bluuebunny/crossref_metadata_2025 huggingface dataset:
Orthothioesters and 1,1‐bis‐(ethylthio)‐1‐alkenes (thioacetals of ketenes)
Authors: Rinzema L. C. , Stoffelsma J. , Arens J. F.
Published: September 2010

A number of ethyl orthothioesters has been prepared by refluxing acid chlorides with ethanethiol and zinc chloride. The substances very easily lose one mole of ethanethiol by distillation in the presence of traces of acids, affording the thioacetals of substituted ketenes VII. The structure of the latter compounds follows from the hydrolysis of their sulphones VIII into the next lower aldehydes IX and bis (ethanesulphonyl) methane X.

It is pointed out, that interesting reactions can be carried out by making use of various methods for the introduction and elimination of thioether groups (see reaction schemes on pages 5 and 6).
Untersuchungen über Homologe Verbindungen von Isodehydracetsäure und deren Ester
Authors: Salemink C. A.
Published: September 2010

Die vorliegende Arbeit beschäftigt sich mit der Darstellung von bisher nicht beschriebenen höheren Homologen der Isodehydracetsäure und deren Ester. Diese Verbindungen zeigen antibakterielle Wirkungen bei verschiedenen Bakterienarten.
Preparation of a number of α‐ and β‐monoglycerides and determination of their purity by means of periodic acid
Authors: van Lohuizen O. E. , Verkade P. E.
Published: September 2010

The preparation of a number of α‐ and β‐monoglycerides and the behaviour of the compounds in question towards periodic acid is described.
Derivatives of amino‐acids and peptides IV: The synthesis of peptides by means of ethoxyethyne
Authors: Panneman H. J. , Marx A. F. , Arens J. F.
Published: September 2010

Dipeptides are obtained optically pure and in good yield by boiling equivalent amounts of N‐acylamino‐acids and amino‐ester hydrochlorides with ethoxyethyne in ethyl acetate containing 0.5% of water.

For the preparation of higher peptides it is preferable to add the amino‐component not as hydrochloride but as free ester, because otherwise partial racemisation may occur.

By means of this method the hexapeptide, pro‐val‐lys‐val‐tyr‐pro, a sequence present in β‐corticotropin, has been prepared.
Structure and musk odour: II. Benzene derivatives
Authors: Beets M. G. J. , Meerburg W. , van Essen H.
Published: September 2010

A number of simple benzene derivatives with musk odour are described.
The use of chromatography paper in the study of sterol adduct formation
Authors: Meijer J. W. A. , Böttcher C. J. F.
Published: September 2010

In order to investigate the adduct‐forming properties of sterols with very small quantities of these compounds a method has been developed which uses acetylated chromatography paper as the medium in which the adduct can be formed.

For the adduct formation of· cholesterol the results appear to be in agreement with those obtained on a larger scale by refluxing a solution of the sterol in the presence of the other component. The method is also suitable for the investigation of the adduct formation of sterols other than cholesterol.

The relative humidity of the atmosphere in which the reaction takes place has an important influence on the adduct formation.

Two colour reagents for detecting steroids on acetylated paper are described: a solution of benzenesulphonic acid in ether‐methanol, and a solution of antimony trichloride in tetrahydrofurane.
The reaction of phenol with formaldehyde. I. The separation and quantitative determination of low molecular reaction products by paper chromatography
Authors: Peer H. G.
Published: September 2010

A comprehensive survey is given of the possibilities created for the analysis of phenol formaldehyde (PF) condensates by the development of paper chromatography, in particular through the application of benzeneacetic acid‐water as an eluent. A method for the quantitative determination of low molecular condensation products employing this eluent is given in detail.
Interpretation of the structure of polyhalogen complexes by the mo‐method
Authors: Havinga E. E. , Wiebenga E. H.
Published: September 2010

The structure of interhalogen compounds, polyhalide ions, and positive polyhalogen ions is discussed in terms of the LCAO‐MO method. The molecular orbitals were represented by a linear combination of the outerp‐orbitals of the halogen atoms. The Coulomb integrals were considered as a function of the electro‐negativity and the formal charge of the atoms.

It is found that application of this method gives a consistent qualitative explanation of the bond angles, atomic configurations, and bond lengths in all polyhalogen complexes.
Methods for the analysis of lipids extracted from human arteries and other tissues
Authors: Böttcher C. J. F. , Woodford F. P. , Boelsma‐van Houte E. , van Gent C. M.
Published: September 2010

An investigation of methods for the extraction and analysis of lipids from human arteries is described. The analytical procedure developed has been tested for completeness of separation and absence of artefact formation. It can be applied to lipid mixtures amounting to as little as 50 mg or in some cases even less. The lipids can be separated into phospholipids, free fatty acids, sterol esters, and glycerides plus free sterols, and the fatty acid mixtures from these fractions analysed by gas chromatography after methylation. Examples of such analyses are given.
On the synthesis of derivatives of N‐(4‐pyridonyl)‐oxyacetic acid
Authors: Bojarska‐Dahlig H. N.
Published: September 2010

N‐(3,5‐diiodo‐4‐pyridonyl)‐oxyacetic acid was synthesized by reacting 4‐hydroxy‐3,5‐diiodopyridine‐N‐oxide with chloroacetic acid in neutral medium, the yield amounting to 85 %.

4‐Hydroxy‐3,5‐diiodo‐2‐methylpyridine‐N‐oxide was converted analogously, but in a lower yield, into the corresponding oxyacetic acid, but the 2,6‐dimethyl derivative of 4‐hydroxy‐3,5‐diiodopyridine‐N‐oxide did not react with chloroacetic acid.

The synthesis and properties of several starting substances and intermediates, which are not yet recorded in the literature, are described.
The isothermal compressibilities of pure non‐polar liquids
Authors: Steinhardt Ralph G.
Published: September 2010

A simple semi‐theoretical treatment shows that the relation χTγ3/2 = k between isothermal compressibility (χT) and surface tension (γ) implies that the isothermal compressibility of a non‐polar liquid is determined by its structure and average intermolecular distance, and by the electron polarizability of the molecules of which the liquid is composed. The temperature‐dependency of isothermal compressibility of non‐polar liquids composed of quasi‐spherical molecules may be attributed solely to the corresponding temperature‐dependency of the average intermolecular distance in such liquids.
Electron‐donor properties of the pyridine 1‐oxide ring
Authors: Katritzky A. R.
Published: September 2010

Available evidence for the electron‐donor properties of the pyridine and pyridine 1‐oxide rings is briefly reviewed. The positions and intensities of the CN stretching band in cyano‐pyridines and ‐pyridine 1‐oxides confirms that electron availability in the pyridine ring decreases at the nuclear positions in the order 3≫4>2 and in the pyridine 1‐oxide ring in the order 4 ≫ 3 ∼ 2.
Ester interchange equilibria from dimethyl terephthalate and ethylene glycol
Authors: Challa G.
Published: September 2010

Ester interchange equilibrium products prepared from dimethyl terephthalate and ethylene glycol, in the presence of zinc acetate as a catalyst, have been investigated at 180 and 195°. For the analysis of these products quantitative volumetric methods for the determination of free methanol and of free ethylene glycol have been developed. In addition, a method for the fractional vacuum distillation and sublimation of methanol, ethylene glycol, dimethyl terephthalate, and β‐hydroxyethyl methyl terephthalate has been worked out.

The analytical results are evaluated in terms of equilibrium constants for the various reversible reactions pertaining to the present system. All equilibrium constants are found to depend only slightly on temperature and composition. The small values of the equilibrium constants related to the removal of methyl ester groups are in line with the practical difficulty of achieving complete glycolysis of dimethyl terephthalate before polycondensation to polyethylene terephthalate starts.

The most important result is the fact that the “molecular” equilibrium constant KI of the first step of the glycolysis of dimethyl terephthalate equals the corresponding overall equilibrium constant Ke in terms of functional groups after correction for the functionality of reactants and products. Prom this fact it is concluded that the “molecular” equilibrium constants KI and KII for the first and second step of the glycolysis are equal.
Square wave electrolysis III. Apparatus for the cyclic potential‐step and cyclic current‐step methods
Authors: Wijnen M. D. , Smit W. M.
Published: September 2010

The experimental setups required for the cyclic potential‐step and cyclic current‐step methods are thoroughly discussed. Attention is paid to the following subjects: conditions for linear diffusion, reference electrode, potentiostatic conditions, time‐symmetry of the applied square wave and deviations from coulomb‐symmetry.
The condensation of rhodanine and derivatives with benzaldehyde sulphonic acids
Authors: Allan F. J. , Allan G. G. , Crank G. , Jack J.
Published: September 2010

The condensation products of rhodanine and some of its derivatives with benzaldehyde sulphonic acids have been prepared with a view to obtaining compounds of increased fungicidal properties. The products differ from the majority of previously prepared rhodanine‐aldehyde condensation products in that they are appreciably soluble in water. From a fungitoxicological standpoint this increased solubility may well increase the activity of such fungicides as their availability in aqueous media is greatly increased. The condensation products formed relatively insoluble and often crystalline salts with many metallic ions. The precipitation of these salts was briefly considered from the analytical point of view. The condensations between the rhodanines and the benzaldehyde sulphonic acids were carried out in acid media and crystalline coloured products were obtained in good yield.
Investigations on pyrazine derivatives. VI. The reduction of 2,3,5,6‐tetraethoxycarbonylpyrazine with alkaline sodium dithionite
Authors: Mager H. I. X. , Berends W.
Published: September 2010

A new convenient method is given for the preparation of 2,3,5,6‐tetraethoxycarbonyl‐1,4‐dihydropyrazine.
The infrared spectra of benzenoid and heteroaromatic nitro‐compounds
Authors: Katritzky A. R. , Simmons P.
Published: September 2010

The frequencies and apparent extinction coefficients for bands in the 1550, 1350, 1300, and 850 cm−1 regions for 11 ortho, 18 meta, and 29 para nitro‐benzenes and for 7 heteroaromatic nitro‐compounds are recorded.
Studies on vitamin D and related compounds XI investigations on sterols XIII the photoisomerisation of ergosterol
Authors: Rappoldt M. P. , Havinga E.
Published: September 2010

Kinetic experiments on the photoisomerisation of ergosterol were carried out using different sources of light. New methods of analysis for pre‐ergocalciferol and tachysterol2 had to be developed. The quantum yield of the photoisomerisation of ergosterol with ultraviolet light of 2537 Å was found to be 0.31 at 20°. This value was obtained when ether, ethanol and petroleum ether were used as solvents. Tachysterol2 is not formed from ergosterol during irradiation, but originates exclusively from pre‐ergocalciferol. Excited ergosterol falls back to its ground state (69%) or transforms to pre‐ergocalciferol (26%) and to unidentified products (5%).
L'Analyse par les Radioéléments de L'Aluminium de Très Haute Pureté Obtenu par la Technique de la Zone Fondue
Authors: Chaudron G.
Published: September 2010

L'auteur met en évidence le grand intérêt de la technique des radioéléments lorsqu'il s'agit d'identifier des traces d'impuretés dans un métal très pur. La méthode s'applique particulièrement à l'aluminium purifié par la technique de la zone fondue. Les analyses permettent actuellement de doser plus de 40 éléments, parmi lesquels les terres rares.
Essai de la Détermination, par Spectrographie Infrarouge, de la Structure de L'Anhydride Iodique I2O5
Authors: Duval Clement , Lecomte Jean
Published: September 2010

Jusqu'à présent, on possède relativement peu de renseignements sur les positions des bandes infrarouges qui mettent en jeu des liaisons entre l'iode et l'oxygène. Dans la littérature, on trouve les fréquences propres des iodates métalliques de l'ion periodique, et de l'acide iodique, déterminées par le spectre de diffusion et, au moins partiellement, par le spectre d'absorption. Ces données nous serviront à interpréter le spectre d'absorption de l'anhydride iodique, que nous avons obtenu pour la première fois, à notre connaissance.
Studien über analytisch verwertbare Umsetzungen von Dämpfen niedrig siedender organischer Lösungsmittel in der Tüpfelanalyse
Authors: Feigl F. , Goldstein D. , Haguenauer‐Castro D.
Published: September 2010

Es wurden in der Arbeitsweise der Tüpfelanalyse Versuche über den Eintritt von Dämpfen einiger niedrig siedender Lösungsmittel in Pyrolysenreaktionen angestellt. Es wurde gefunden:

Pyrolytische Oxydationen unter Bildung von Halogen erfolgen bei Erhitzung von halogenhaltigen Lösungsmitteln mit höheren Metalloxyden auf 240°. Bei Erhitzung mit Kupferoxyd, Wolframsäure oder Chromsäure unterscheiden sich die Dämpfe von Chloroform und Tetrachlorkohlenstoff in charakteristischer Weise.

Pyrolytische Reduktionen unter Bildung von Chlorwasserstoff erfolgen bei Erhitzung von Chloroform oder Tetrachlorkohlenstoff mit Benzoin auf 220°.

Pyrolytische Hydrolysen unter Bildung von Halogenwasserstoff erfolgen bei Erhitzung von Tetrachlorkohlenstoff oder Chloroform mit Mangansulfatmonohydrat auf 240°. Bei Schwefelkohlenstoff erfolgt bei 270‐280° eine Pyrohydrolyse unter Bildung von Schwefelwasserstoff.

Pyrolytische Ammonolyse unter Bildung von Cyanwasserstoff erfolgt bei Erhitzung von Chloroform mit Guanidinkarbonat auf 190°.

Pyrolytische Disproportionierung unter Bildung von Chlor und Chlorwasserstoff erfolgt bei Erhitzung von Dämpfen halogenhaltiger Lösungsmittel mit katalytisch wirksamen Oxyden, Kieselsäure, Chromaten, Sulfaten und Kohlenstoff auf 250°.

Über das Ausmass der pyrolytischen Reaktionen, denen plausible Umsetzungsgleichungen zugrundegelegt werden, können noch keine Aussagen gemacht werden. Sie sind indessen so weitgehend, um eine Reihe analytischer Anwendungen zu ermöglichen. Von diesen ist besonders die Unterscheidung von Tetrachlorkohlenstoff und Chloroform, deren Siedepunkte nahe beieinander liegen, von Interesse.
The determination of tungsten in high alloy steels by isotope dilution
Authors: Leliaert G. , Hoste J. , Eeckhaut Z.
Published: September 2010

An isotope dilution procedure using 185W has been developed for the determination of tungsten in high alloy steels. Tungsten is determined spectrophotometrically with hydroquinone in sulphuric acid medium, after homogeneous precipitation from a nitric acid‐hydrogen peroxide solution.

For molybdenum‐vanadium‐tungsten alloy steels no further chemical separations are required. The radiometric correction is applied to the residual tungsten so as to minimize counting errors. Analyses carried out on N.B.S. samples showed good accuracy and precision.

For high alloy steels containing niobium, tantalum and titanium a chemical separation of tungsten is necessary to avoid interference in the subsequent spectrophotometric determination. Although the recovery of tungsten is quite low, the magnesia method is entirely satisfactory.

The method was succesfully tested on a number N.B.S. high alloy steels to which varying amounts of tantalum and titanum were added.
Recovery of nickel and cobalt from lateritic iron ores
Authors: Heertjes P. M. , van Nes C. L.
Published: September 2010

It was desired to increase the ratio of the amounts of nickel and cobalt with respect to iron, as found in lateritic iron ores and to recover almost all the nickel and cobalt in these ores.

This was realised by converting nickel oxide and cobalt oxide almost selectively and completely into the corresponding chlorides. A stepwise process was used in which a gaseous mixture of steam and hydrogen chloride was passed through a fluidised bed of the granulated ore under proper conditions of temperature and concentration. The chlorides were recovered by extracting the chloridised ore with hot water.
A method for the determination of amyloid in plant seeds
Authors: Kooiman P.
Published: September 2010

1) A colorimetric method has been elaborated for the determination of amyloids in plant seeds, based on the blue colour of the iodine complex in concentrated sodium sulphate solution.

2) Details of the method are given and its possibilities and limitations are outlined.

3) Three procedures for removing interfering starch are recommended.
The hydrogen‐deuterium exchange reaction of the t‐butyl group substituted in aromatic hydrocarbons
Authors: Dallinga G. , ter Maten G.
Published: September 2010

A new type of hydrogen‐deuterium exchange reaction in acid media, viz. the exchange of hydrogen atoms of the t‐butyl group, substituted in benzene rings, has been found. The reaction is first‐order in the concentration of the hydrocarbon. There is no simple relation between the rate constant, k, and either the acidity function H0, or the concentration, ca, of the acid. Log k is, however, linearly related with (‐ H0 + log ca). The activation energy is 20.2 ± 0.3 kcal/mole.

The results indicate that the exchange reaction of the t‐butyl group proceeds via an ionic intermediate in which the carbon‐carbon bond between the t‐butyl group and the aromatic ring is probably weakened. The rate‐determining step of the reaction is the formation of this intermediate.

The exchange reaction seems to be closely related to isomerization and transalkylation reactions; the formation of the ionic intermediate may be a common step for all three reactions.
Latent heat of vaporisation and composition
Authors: Wright Franklin J.
Published: September 2010

The variation of vapor pressure and density with temperature up to the normal boiling point has been obtained for 32 homopolar liquids. From these measurements, the latent heats at the boiling point and the normal and true lyoparachors have been calculated. In keeping with Bowden and Jones's findings, the lyoparachors were found to be additive properties determined by the composition and molecular constitution of the compound. New bond and atom constants for the lyoparachors have been obtained.
Investigations on pesticidal phosphorus compounds II. On the structure of phosphorus compounds derived from 3‐amino‐1,2,4‐triazole
Authors: van den Bos B. G.
Published: September 2010

It is shown that in the compounds formed by reaction of 3‐amino‐1,2,4‐triazole or a 5‐substituted derivative thereof with a phosphoryl chloride the phosphoryl group is attached to the triazole ring.
Infra‐red absorption spectra of alkylthio compounds
Authors: Boonstra H. J. , Rinzema L. C.
Published: September 2010

A survey is given of the characteristic frequencies of a number of alkylthio groups. The infra‐red absorption spectra of a few groups of unsaturated thioethers are discussed in detail, attention being drawn, among other things, to their resemblance to infra‐red absorption spectra of analogous chlorine compounds.
Preparation of some 4‐dimethylamino‐azobenzene derivatives with substituents in the 3‐ or in the 3‐ and the 5‐position
Authors: van Loon A. , Verkade P. E. , Wepster B. M.
Published: September 2010

The preparation of a number of dimethylamino‐azobenzene derivatives of the types I‐IV (see formulae below) is described. The choice of the methods of preparation depends on considerations about steric effects on mesomerism.
Physical properties of organic thiones: Part III. The evaluation of transition energies, resonance energies and charge diagrams of organic thiones and dithioates
Authors: Janssen M. J.
Published: September 2010

An empirical LCAO MO method, in which self‐consistency was introduced, was applied to molecules of the general structure ABCS and ACS2−, in which A and B are saturated radicals bonded to the thione or dithioate group by carbon, sulphur, oxygen or nitrogen.

The transition energies for n → π* and π →π* transitions, the resonance energies and the charge diagrams are evaluated. The calculated transition energies proved to be related to the measured absorption frequencies for both transitions. A discrepancy is encountered between the experimental and theoretical assignment of the π → π* transition for the nitrogen‐containing thiones.
Phosphatidic acids and derivatives: XI. Infra‐red spectra of glycerol‐α‐kephalins and glycolkephalins
Authors: van Veen A. , Verkade P. E.
Published: September 2010

In the present paper we are publishing the infra‐red spectra of glycerol‐α‐kephalins and glycolkephalins synthesized in our laboratory. These spectra are discussed in relation with spectra of glycerol‐α‐kephalins already available in the literature.
On the impedance of galvanic cells: I. Theory
Authors: Sluyters J. H.
Published: September 2010

Impedances of galvanic cells are treated as complex quantities and graphical methods for the determination of reaction rate constants of the redox reactions, double layer capacities, ohmic resistances and diffusion constants are proposed.
Spectrophotometric investigations of the mechanism of complex formation: Part II. Complex formation of β‐phenylethyl bromide with aluminium bromide
Authors: Adema E. H. , Arnoldy H. , Visser R. , Sixma F. L. J.
Published: September 2010

Spectrophotometric titration curves of β‐phenylethyl bromide and aluminium bromide at −80° in carbon disulphide and heptane at 430 and 250 mμ respectively show the formation of a 1 : 1 complex by a fast reaction, which goes to completion.
The Fries rearrangement of p‐tolyl and o‐tolyl acetate catalysed by aluminium chloride
Authors: Cullinane N. M. , Edwards B. F. R. , Bailey‐Wood V. V.
Published: September 2010

The rearrangement of p‐tolyl acetate in nitrobenzene solution catalysed by aluminium chloride gives the o‐hydroxyketone only as rearrangement product. o‐Tolyl acetate under the same treatment yields mainly the para‐substituted hydroxyketone together with a small amount only of the ortho‐substituted compound. Both of these rearrangements appear to be intramolecular and the interpretation proposed for the titanium tetrachloride catalysed transformations of these esters may also be applied in the present case.
Study of the reactions between titanium tetrachloride and ethylaluminium compounds in hydrocarbon solution: II. Gaseous reaction products
Authors: Arlman E. J. , de Jong J. R.
Published: September 2010

Gaseous reaction products from the systems AlEt3/TiCl4, AlEt2Cl/TiCl4 and AlEtCl2/TiCl4 in isooctane solution at 80°C have been studied. A set of reactions explaining the formation of the observed products H2, C2H6, C2H5Cl, n‐C4H10 and n‐C6H14 is given. It is possible to account nearly quantitatively for the conversion of the ethyl groups and for the extent of reduction of TiCl4.

It appeared that the formation of ethane is partly due to dis‐proportionation of ethyl groups, and partly to ethyl groups abstracting hydrogen from the isooctane. In the system AlMe3/TiCl4 the methyl groups quantitatively react in the latter way to form CH4. The isooctane to a small extent decomposes into isobutane and isobutene or into isopentane and propene. It is supposed that the brown precipitates formed in the reduction of TiCl4 act as catalysts for this decomposition.
Investigations on sterols XIX: 6‐Dehydro‐9β, 10α‐progesterone from pregnenolone
Authors: Rappoldt M. P. , Westerhof P.
Published: September 2010

Pregna‐5, 7‐dien‐3β‐ol‐20‐one was irradiated with ultraviolet light to obtain the corresponding 9β, 10α compound. Oppenauer oxidation, followed by isomerization of 9β, 10α‐pregna‐5, 7‐dien‐3α‐ol‐20‐one, yielded 6‐dehydro‐9α, 10α‐progesterone.
U.V. spectra of derivatives of 1,3,5‐triazine
Authors: Koopman H.
Published: September 2010

The synthesis of four 2,4‐dichloro‐6‐(p substituted phenyl) 1,3,5‐triazines is described. The U.V. spectra of these compounds and those of the derivatives mentioned in the preceding papers 1,2,3 are dealt with and discussed.
Investigations in the vitamin B6‐series: II. Synthesis of 4,5‐dihydroxymethyl‐6‐hydroxy‐2‐methylpyridine, an isomer of vitamin B6
Authors: van der Wal B. , de Boer Th. J. , Huisman H. O.
Published: September 2010

The synthesis of 4,5‐dihydroxymethyl‐6‐hydroxy‐2‐methylpyridine, an isomer of vitamin B6, is described.

This isomer is biologically inactive on the growth of Saccharomyces carlsbergensis.
Investigations in the vitamin B6−series: III. Reductions of an intermediate of the vitamin b6 synthesis with lithium aluminium hydride
Authors: van der Wal B. , de Boer Th. J. , Huisman H. O.
Published: September 2010

Attempts are described to simplify the synthesis of vitamin B6 by a simultaneous reduction of the ester groups and reductive elimination of the chlorine atom in dimethyl 3‐amino‐6‐chloro‐2‐methylpyridine‐4,5‐dicarboxylate (III) with lithium aluminium hydride. After prolonged refluxing with a large excess of the reagent the chlorine free compound 3‐amino‐4,5‐dihydroxymethyl‐2‐methylpyridine (IV) could be isolated in low yield.
Ultraviolet absorption spectra of 1‐furfural and of 5‐hydroxymethyl‐furfural in aqueous buffers
Authors: Psarras Theodore , Tefteller J. Wilburn , Zimmerman Howard K.
Published: September 2010

The extinction coefficients in buffered aqueous solutions for furfural and for 5‐hydroxymethyl‐furfural (HMF) at their ultraviolet absorption maxima are respectively 16 800 ± 420 at 277 mμ for furfural and 17 900 ± 250 at 284 mμ for HMF. For both compounds, both the extinction and the maximum wavelength are unaffected by changes in pH over the range 3–10, in buffer capacity, or by a change from a phosphate‐citrate to a borate buffer. The extinction does diminish somewhat as the solution ages for each substance. This fact emphasizes the importance of determining the spectrum as soon as possible after the solution is prepared.
Chemistry of acetylenic ethers. LI: Introduction of alkylthio groups into acetylenic compounds and into other compounds with reactive hydrogen atoms by means of disulphides
Authors: Nooi J. R. , Arens J. F.
Published: September 2010

Acetylenic compounds RC ≡ CH can be converted into acetylenic thioethers by treatment of the sodium or lithium alkynide with diethyl disulphide in liquid ammonia. This constitutes the easiest route to 1‐ethylthio‐1‐alkynes I.

Other compounds with “acidic” CH3, CH2 or CH groups can likewise be alkylthiolated; generally the product containing two geminal ethylthio groups is formed in excess.
The action of p‐toluenesulphonyl chloride on pyridine‐n‐oxide (III)
Authors: den Hertog H. J. , Buurman D. J. , de Villiers P. A.
Published: September 2010

The reaction mixture formed during the heating of pyridine‐N‐oxide with p‐toluenesulphonyl chloride contains, together with pyridine, 2,3′‐dipyridyl ether, 3‐pyridyl p‐toluenesulphonate and N‐(2Prime;‐pyridyl)‐pyridone‐2 two chloro compounds, viz. N‐(2′‐pyridyl)‐5‐chloro‐pyridone‐2, which is the chief product, and N‐(2′‐pyridyl)‐3‐chloro‐pyridone‐2.

In this connection the formation of brominated derivatives of N‐(2′‐pyridyl)‐pyridone‐2 during the reaction of pyridine‐N‐oxide and 2‐bromopyridine, as described by Ramirez and von Ostwalden is discussed.
On the impedance of galvanic cells: III. Applications to alternating current polarography
Authors: Rehbach M. , Sluyters J. H.
Published: September 2010

The theory described in part I of this series

J. H. Sluyters, Rec. trav. chim. 79, 1092 (1960).

is applied to alternating current polarography by treating the complex cell impedance and cell admittance as functions of d.c. voltage.

It is proposed to plot a.c. polarograms in the complex impedance or admittance plane. By this method it is possible to reduce the uncertainty in the height of the peak caused by the base current. An exactly linear relationship between the quantity measured and concentration can be obtained over a large range of concentrations by means of a simple construction.

The measurements can be performed over a wide range of frequencies. Consequently, in some cases, a higher sensitivity can be obtained, because the most favourable frequency can be chosen.

The method is not only suitable for analytical purposes, but also for the determination of the fundamental constants of electrode processes (rate constants, diffusion constants and double layer capacities).
γ‐Coniceine of conium maculatum L., a revision of the generally accepted structure
Authors: Beyerman H. C. , van Leeuwen M. , Smidt J. , van Veen A.
Published: September 2010

The commonly accepted structure of γ‐coniceine, the major alkaloid of Conium maculatum L., is revised on the basis of results obtained in the present study with “active hydrogen” determinations and with regard to nuclear magnetic resonance spectra. Infra‐red spectra also support this revision.

γ‐Coniceine is 2‐n‐propyl‐3,4,5,6‐tetrahydropyridine.

The revised structure of γ‐coniceine (a Δ1 ‐ piperideine) seems of interest with a view to the biogenesis of the piperidine alkaloids and related amino‐acids.
Über 2‐Propyl‐1‐ und 2‐Propyl‐3‐desaza‐adenin (4. Mitteilung über Desaza‐purin‐Derivate)
Authors: Salemink C. A.
Published: September 2010

Die vorliegende Arbeit beschreibt die Synthesen von 2‐Propyl‐1‐desaza‐adenin und von 2‐Propyl‐3‐desaza‐adenin, nach Analogie der Synthesen von in der 1. und 3. Mitteilung dieser Reihe beschriebenen Strukturanalogen von Adenin.
Triazine isocyanates: Part I: 2,4‐diphenyl‐s‐triazine‐6‐isocyanate
Authors: Duynstee E. F. J.
Published: September 2010

The synthesis of the azide of 2,4‐diphenyl‐s‐triazine‐6‐carboxylic acid is described. Decomposition of this azide yields a product in which 2,4‐diphenyl‐s‐triazine‐6‐isocyanate has been spectroscopically detected. This very reactive isocyanate is the first example of a compound in which an isocyanate group is directly bound to a s‐triazine ring.
The resolution of DL‐muscarine
Authors: Salemink C. A. , Cox H. C.
Published: September 2010

The Debije‐Scherrer diagram of “natural” L(+)‐muscarine‐di‐p‐toluyl‐hydrogen‐D(−)‐tartrate‐hemihydrate is compared with the diagrams of muscarine‐di‐p‐toluyl‐hydrogen‐D(−)‐tartrates resulting from the resolution of two DL‐muscarine preparations. One of the latter diagrams proved to be identical with the diagram of “natural” L(+)‐muscarine‐di‐p‐toluyl‐hydrogen‐D(−)‐tartrate‐hemihydrate whereas the other was entirely different.
The P‐T‐x space model of the system ethylene naphthalene (I)
Authors: van Welie G. S. A. , Diepen G. A. M.
Published: September 2010

In a Cailletet apparatus the solubility of naphthalene in supercritical ethylene has been determined quantitatively up to pressures of 200 atm, by visually measuring P‐T sections at constant composition.
The P‐T‐x space model of the system ethylene‐naphthalene (II)
Authors: van Welie G. S. A. , Diepen G. A. M.
Published: September 2010

An apparatus is described by means of which quantitative P‐T measurements can be carried out visually, at constant composition, up to pressures of 1000 atmospheres. This apparatus is used for measuring the solubility of naphthalene in supercritical ethylene.
The P‐T‐x space model of the system ethylene‐naphthalene (III)
Authors: van Welie G. S. A. , Diepen G. A. M.
Published: September 2010

Our two previous articles

G. S. A. van Welie and G. A. M. Diepen, Rec. trav. chim. 80, 659 (1961).

Idem, ibid., 80, 666 (1961).

and some supplementary observations enabled us to derive a number of sections and projections of the P‐T‐x space model of the ethylene‐naphthalene system, within the following limits of measurement: 0 to 1000 atm, 0 to 100 moles % naphthalene and 20° to 115°. An important result of our discovery is that the critical conditions of the second critical point are: P = 174.0 atm, T = 52.1° and x = 17 moles % ± 0.5.

On the L2 = G curve we have found a pressure maximum at 244 atm and 195°.
Steric effects on the electronic spectra of substituted benzophenones. V. Some alkyl‐substituted benzophenones
Authors: Rekker R. F. , Nauta W. Th.
Published: September 2010

This article gives the experimental results of UV measurements made on a number of benzophenones with ethyl, isopropyl and tert.butyl groups as substituents. The results are compared with the previously published data on the corresponding methyl‐substituted benzophenones1,2,3,4. Our investigation showed that there is no significant difference between the effects of introduction of ortho‐methyl, ortho‐ethyl or ortho‐isopropyl groups into a benzophenone. With a tert.‐butyl group, however, the result is somewhat different: in this case a steric effect is observed on the electronic spectra, which is only slightly smaller than that encountered in 2,6‐dimethylbenzophenone. When plotting the λC differences between meta/para‐substituted derivatives and the unsubstituted benzophenone against the Hammett σ‐values the result is a straight line, the Hammett σ‐constant being −0.061 for ethanol and −0.050 for isooctane solutions.
Chemistry of the silylamines: IV. Condensation of N,N‐diethylamino‐trimethylsilane with the triphenylhydroxides of carbon, silicon, and germanium
Authors: Pike R. M.
Published: September 2010

Derivatives of the type (C6H5)3M‐OH, where M  C, Si and Ge, were condensed with N,N‐diethylamino‐trimethylsilane in xylene solvent at 50°. The rates of the condensation reaction for this series (C, Si,Ge) were found to be in the ratio of approximately 1 : 3 : 1, respectively.
The reactivities of the tyrosine residues in insulin with respect to iodine I
Authors: de Zoeten L. W. , de Bruin O. A. , Everse J.
Published: September 2010

With the aim of studying the reactivities of the tyrosine residues in insulin, this protein was brought together with varying amounts of radioactive iodine under such conditions that the tyrosine residues were the only groups to react. The total uptake of iodine was measured. The A and the B chains were then separated and the iodine content of each chain was determined.

The amounts of iodine present as mono‐ and as di‐iodinated tyrosine residues were established.
The reactivity of the tyrosine residues in insulin with respect to iodine II
Authors: de Zoeten L. W. , Havinga E. , Everse J.
Published: September 2010

This paper deals with the enzymatic hydrolysis of the A and the B chain of 131I‐iodinated insulin to yield four fragments each containing one tyrosine residue. The iodine content of the fragments obtained from samples of insulin that had reacted with varying amounts of iodine, are given. Residue A19 seems to take up only one iodine atom at a rapid rate. A comparison is made with the amount taken up by glycyltyrosine under the same conditions. The relative initial rates of reaction of glycyltyrosine and the four tyrosine residues A14, A19, B16, B26 are 1, 1, 1.6, 0.2, 0.2 respectively. In 8 molar urea the reactivities found are 1, 1, 1.5, 0.8, 0.6. A discussion is given.
Reserpine analogues IV. Hydroxy‐β‐phenylethylamine derivatives
Authors: Kralt T. , Asma W. J. , Moed H. D.
Published: September 2010

The synthesis of a series of compounds resembling in some respects the reserpine alkaloid and containing a β‐phenylethylamine configuration substituted at the phenylgroup with hydroxyl groups is described.
Photo‐oxidation, sensitised by proflavine, of furfuryl alcohol, N‐allyl thiourea and histidine
Authors: Sluyterman L. A. Æ
Published: September 2010

The photo‐oxidations, sensitised by proflavine, of furfuryl alcohol, N‐allyl thiourea and histidine as a function of pH and substrate concentration have been investigated.

The rate of oxidation of the neutral compound furfuryl alcohol is constant over the pH range of 9–3 and decreases below pH 3. This decrease corresponds to a change in the fluorescence spectrum of proflavine (fig. 4).

A similar decrease in the oxidation rate of N‐allyl thiourea at low pH is preceded by an unexpected increase in rate from pH 5 to pH 2 (fig. 5).

The oxidation rate of histidine is constant from pH 9 to pH 7, drops below pH 7 and is virtually zero at pH 4 (fig. 6). This can be interpreted quantitatively to indicate that free imidazole groups and not positively charged imidazole groups are oxidized, provided the actual dependence of the oxidation rate on substrate concentration is taken into account (fig. 8).

This dependence of the oxidation rate on the concentration of the three substrates can be described in terms of simple reaction kinetics (equation 8).
The antirachitic activity of previtamin D3
Authors: Hanewald K. H. , Rappoldt M. P. , Roborgh J. R.
Published: September 2010

A prophylactic test (chick assay) was carried out with pure pre‐vitamin D3. The apparent antirachitic activity was found to be 35% of that of pure vitamin D3. This result is discussed in connection with the kinetics of the interconversion of previtamin D3⇆ vitamin D3. The observed activity may be interpreted as originating exclusively from vitamin D3 formed in the test animal.
Investigations on pesticidal phosphorus compounds IV: N‐bis(dimethylamido)phosphoryl heterocycli
Authors: van den Bos B. G. , Schoot C. J. , Koopmans M. J. , Meltzer J.
Published: September 2010

In view of their pesticidal properties a number of bis (dimethylamido)phosphoryl heterocyclic compounds was prepared. The fungicidal, insecticidal and acaricidal activities as well as the phyto‐toxicity and the toxicity for mice are given in table II.
Plant growth‐regulating activity of S‐carboxymethyl‐N,N‐dimethyldithiocarbamate and related compounds
Authors: Pluijgers C. W. , van der Kerk G. J. M.
Published: September 2010

The plant growth‐regulating activity on tomato plants of S‐carboxymethyl‐N,N‐dimethyldithiocarbamate and of structurally related compounds has been investigated. Activity is connected with the electronic configuration of the molecules, viz. with a distinct degree of double‐bond character of the NC bond. In addition, however, sterical factors seem to be of decisive significance for presence or absence of growth‐regulating activity.
Acid anilides: IX. Application to the determination of free and esterified lower fatty acids in dairy products and in fats
Authors: De Jonge A. P. , van Der Ven B. , Verhage A.
Published: September 2010

In this paper some applications of the qualitative and quantitative paper chromatography of fatty acid anilides are described, viz.:

detection of esterified acetic acid in butterfat;

demonstration of esterified lower fatty acids in palm oil and cocoa‐butter;

determination of free lower fatty acids in fresh and heated butter, ghee, and soured skim milk.

The quantitative conversion of small amounts of fatty acids into their anilides and the quantitative isolation of the acids concerned from the raw materials were investigated and procedures developed.
The chemistry of cycloheptatriene: Part I. Synthesis of benzocyclobutene
Authors: Ter Borg A. P. , Bickel A. F.
Published: September 2010

Addition of dichlorocarbene to cyclopentadiene yields chlorobenzene. The addition of dichlorocarbene to cycloheptatriene yields 8,8‐dichloro‐bicyclo [5.1.0] octadiene‐2,4 (II). When (II) is heated at 140° a rearrangement to 1‐chlorobenzocyclobutene (III) occurs with evolution of HCl. Reduction of (III) with hydrogen in the presence of palladium gives benzocyclobutene (V).
Mechanism of reactions of unsaturated ethers and thioethers IV: Acid catalyzed rearrangement of ethoxyethynyl‐ and ethylthioethynyl‐carbinols
Authors: Hekkert G. L. , Drenth W.
Published: September 2010

The rearrangement of ethoxyethynyl‐carbinols into unsaturated esters was investigated in acidic aqueous solution. The reaction is general acid catalyzed and β‐hydroxy esters are by‐products. There exists a simple relation between the ratio of β‐hydroxy ester to unsaturated ester and the concentration of hydroxyl and acetate ions. The two products are formed in a common rate determining step, which is a proton addition to the β‐carbon atom of the carbinol. It is suggested, that the hydroxyl group participates and that a four‐membered ring intermediate is formed in this slow step: magnified image Ethylthioethynyl‐carbinols behave similary.
Synthesis of a series of alkyl‐substituted benzophenones, benzhydrols and benzhydryl chlorides
Authors: Fleurke K. H. , van der Stelt C. , Nauta W. Th.
Published: September 2010

In the course of an investigation into the properties of substituted tetraphenylethanes, benzhydryl chlorides and basic benzhydryl ethers we have prepared 2‐ethyl‐, 2,6‐ and 2,2′‐diethyl‐, 2,6,2′‐triethyl‐, 2,6,2′,6′‐tetraethyl‐, 2‐isopropyl‐, 2,6‐ and 2,2′‐diisopropyl‐, 2,6,2′‐triisopropyl‐ and 2,6,2′,6′‐tetraisopropyl‐benzophenone as well as the corresponding benzhydrols and benzhydryl chlorides.
The mercuration of pyridine‐N‐oxide (ii)
Authors: van Ammers M. , den Hertog H. J.
Published: September 2010

Pyridine‐N‐oxide has been mercurated with different reagents, i.e. mercuric acetate in acetic acid, mercuric sulphate, mercuric sulphate in sulphuric acid, mercuric chloride and mercuric bromide.

Mercuration with mercuric acetate in acetic acid yields mainly derivatives substituted at positions 2 or 2 and 6, together with the compound substituted at the 3‐position. It is shown that the supposition of Ukai, Yamamoto and Hirano4 that the compound substituted at position 4 is formed in this reaction as the chief product, is incorrect.

The 3‐ and 4‐isomers are obtained together with the 2‐isomer as chief product, however, when pyridine‐N‐oxide is heated with mercuric sulphate. Addition of sulphuric acid lowers the yield of this mercuration and changes the substitution pattern. Together with the derivative substituted at position 2 a considerable amount of the 3‐isomer is formed. Also in mercuration with mercuric chloride and mercuric bromide the nucleus is attacked at the 3‐ and 4‐positions, but here the reaction mixture consists preponderately of the 2‐isomer again.
Distribution of radio activity in trismethylene‐trinitrobenzene obtained from 14C‐labelled 1,3,5‐trinitrobenzene: Nucleophilic aromatic addition V
Authors: de Boer Th. J. , van Velzen J. C.
Published: September 2010

The previously suggested mechanism for the formation and the stepwise degradation of “trismethylene‐trinitrobenzene” (I) is confirmed by application of a 14C tracer technique. It is shown that all transformations occur without hydrogen shift.

In this paper besides compound II a stereoisomer was considered, with a different position of the two cyclopropyl‐groups towards one another. Further investigation in collaboration with Mr. H. P. Venker has shown that formula II is most likely. However this may be, it is of no consequence for the conclusions reached in the present paper.
The chemistry of cycloheptatriene: Part IV: Synthesis of tropone, 2‐chlorotropone and tropolone
Authors: ter Borg A. P. , van Helden R. , Bickel A. F.
Published: September 2010

Acid‐catalysed decomposition of tropyl ether gives tropone and cycloheptatriene in 83.5 and 90 % yields, respectively.

Chlorination of tropone in carbon tetrachloride solution yields tropone dichloride, which can be made to isomerize to the hydrochloride of 2‐chlorotropone; 2‐chlorotropone is obtained in a 83.5 % yield.

Hydrolysis of the latter compound in refluxing 80 % aqueous formic acid gives tropolone in 85 % yield.
Synthesis of N‐phthaloyl‐L‐serine‐t. butyl ester
Authors: de Haas G. H. , van Deenen L. L. M.
Published: September 2010

In this paper the synthesis and some properties of N‐phthaloyl‐L‐serine‐t.butylester are described.
Internal reactions in the Grignard‐complex containing compounds with alkoxy‐groups: Part I. Acetals
Authors: Blomberg C. , Vreugdenhil A. D.
Published: September 2010

The preparation of ethers by the reaction of a Grignard‐reagent with an acetal has been simplified by preparing the reagent in the acetal.
Studies on cyclohexane derivatives: III. A chemical proof of the configurations of the two 1‐isopropyl‐4‐methylcyclohexanes (para‐menthanes)
Authors: van Bekkum H. , Medema D. , Verkade P. E. , Wepster B. M.
Published: September 2010

The configurations of the two 1‐isopropyl‐4‐methylcyclohexanes (para‐menthanes) were determined by means of syntheses starting from pure cis‐and pure trans‐4‐methylcyclohexanecarboxylic acid.
The reaction of dialkylaminosilanes with carbon dioxide and with carbon disulphide
Authors: Breederveld H.
Published: September 2010

Dialkylaminosilanes react at room temperature with carbon dioxide and with carbon disulphide to give silyl dialkylcarbamates and silyl dialkyldithiocarbamates, respectively. These reactions proceed by an ionic chain mechanism, which requires the presence of catalytic amounts of free amine.
The kinetics of the reaction of phenol and formaldehyde
Authors: Dijkstra R. , de Jonge J. , Lammers M. F.
Published: September 2010

The hydroxymethylation of phenol has been re‐investigated in the pH range 8.5‐12.5 at 30° in dilute aqueous solutions.

The following rate equation covers the results quantitatively:

in which [F], [P] and [P−] denote the concentrations of the formaldehyde molecules, phenol molecules and phenoxide‐ions.

In solutions with pH < 9, and phenol concentrations ⩾ 0.1 g‐mole · 1−1 this equation simplifies to

v=6.9·10−5[P]−[F]·g‐mole·1−1sec−1

which represents the bimolecular reaction found earlier1.

The following two step mechanism is proposed:

magnified image

X− denotes some 1: 1 complex between a phenoxide‐ion and a formaldehyde molecule, k1 = 6.9 · 10−5 1 · gmole−1 sec−1 and k−1/k2 = 0.006 gmole · 1−1.
Reactions of 1‐bromo‐2‐phenylethane and aluminium bromide: Part I. Isomerisation of 1‐bromo‐2‐phenylethane‐1‐14C
Authors: Adema E. H. , Sixma F. L. J.
Published: September 2010

The kinetics of the reaction involving the isomerisation of 1‐bromo‐2‐phenylethane‐1‐14C into 1‐bromo‐2‐phenylethane‐2‐14C under the influence of aluminium bromide in carbon disulphide has been studied in the temperature range of −70° to −100°. The energy of activation is 9.8 kcals/mole.

The kinetic results can be explained if nearly all aluminium bromide is assumed to be bound as the complex C8H9Br: AlBr3. The reaction of C8H9Br: AlBr3 with one of the ions formed in the ionisation of the complex C8H9Br: Al2Br6 is represented as the rate determining step of the isomerisation reaction.
Synthesis of 1‐pentene‐4‐14C and 1‐pentene‐5‐14C
Authors: Otto P. Ph. H. L. , van Zanten B.
Published: September 2010

1‐Pentene‐4‐14C and 1‐pentene‐5‐14C were obtained in one single step from iodoethane‐1‐14C and iodoethane‐2‐14C, respectively, by reaction with allylmagnesium chloride in tetrahydrofurfuroxytetrahydropyran (TFTP) as solvent. The synthesis was carried out on a twenty mmoles scale in a completely closed apparatus. The pentenes were formed in 80 % yield. After final purification by means of gas‐liquid chromatography the radio‐chemical purity was 99.7 %.
The relationship between the gas production and the current in the oxygen‐hydrogen coulometer
Authors: van Soestbergen A. A.
Published: September 2010

The oxygen‐hydrogen coulometer, using a 2 M solution of NaOH as electrolyte, yields a negative error at small currents. The magnitude of this error in ml gas at N.T.P./hr has been estimated at different currents and an empirical expression relating gas volumes to coulombs developed. The gas production can be calculated from: ml gas at N.T.P./coulomb = [b ‐ k1/(k2 · i + 1)] [1000/3600], where b = the theoretical gas production in ml gas at N.T.P./mA. hr; i = the current in mA; k1 and k2 are constants.

Using a coulometer containing two platinum electrodes each 1 × 1 cm, k1 = 0.1938 and k2 = 0.6200. A maximum gas production of 0.1742 ml gas at N.T.P./coulomb is obtained at about 3000 mA and a minimum value of 0.1204 ml gas at N.T.P./coulomb at about 0.001 mA.

Using a coulometer containing small platinum‐wire electrodes (anode 0.5 cm, ø 0.1 mm; cathode 0.5 cm, ø 0.5 mm), k1 = 0.0041 and k2 = 0.0132. A maximum gas production of 0.1742 ml gas at N.T.P./coulomb is obtained at about 1650 mA and a minimum value of 0.1731 ml gas at N.T.P./coulomb at about 0.001 mA.