bluuebunny/crossref_metadata_2025 huggingface dataset:
Bromo‐derivatives of 3,5‐diethoxypyridine
Authors: den Hertog H. J. , Mulder B.
Published: September 2010

Two dibromo‐diethoxypyridines of undetermined structure are described in the literature, viz. a compound melting at 142° bySelland an isomer with m.p. 165°, byKönigs, GerdesandSirot.We have shown that the bromine atoms occupy the 2 and 6 positions in the bromo‐derivative melting at 142°. The compound melting at 165°, prepared according to the directions ofKönigsand his co‐workers, appears to be 2‐bromo‐3,5‐diethoxy‐6‐nitro‐pyridine instead of a dibromo‐diethoxypyridine.

2,6‐Dibromo‐3,5‐diethoxypyridine was isolated bySellas the sole reaction product from the bromination of 3,5‐diethoxypyridine in an acid medium. By carrying out the bromination in pyridine as solvent, we have obtained 2‐bromo‐3,5‐diethoxypyridine along with the dibromo‐compound. The further bromination of this mono‐bromo‐compound is a reversible process; the dibromo‐derivative is converted into mono‐bromo‐diethoxypyridine by heating with a solution of hydrobromic acid in glacial acetic acid.

Finally we have examined the action of cuprous cyanide, sodium ethylate and nitric acid on the 2‐bromo‐ and the 2,6‐dibromo‐derivative of 3,5‐diethoxypyridine.

In proving the structure of derivatives of 3,5‐diethoxypyridine, the possibility of the occurrence of various abnormal substitution reactions with these substances must be taken into account.
The carbohydrates in grass. I. The soluble carbohydrates
Authors: de Man Th. J. , de Heus J. G.
Published: September 2010

A method is worked out according to which a separate determination of aldoses, fructose, sucrose and fructosan in grass is possible.

The contents of these substances in relation to the age of the grass are determined; the fructosan content passed through a peak.

Evidence was obtained that the sucrose content was highest on bright sunny days.

Sucrose appeared to be the only carbohydrate which showed a distinct diurnal variation.
The heat of mixing in the system n‐heptane‐n‐hexadecane: Preliminary communication)
Authors: van der Waals J. H. , Hermans J. J.
Published: September 2010

The heat of mixing in the system n‐heptane‐n‐hexadecane is measured. When this heat of mixing is subtracted from the excess free energy determined by Brønsted and Koefoed an excess entropy is obtained which is in good agreement with the theoretical formula developed by Guggenheim.
Oxidative phenomena in dilute solutions of substances with a system of conjugated double bonds. I. Vitamin‐A Acetate
Authors: Groot E. H.
Published: September 2010

In measuring absorption spectra of substances containing a system of conjugated double bonds, in very dilute solutions with the aid of a Beckman spectrophotometer, typical abnormalities in the spectra are sometimes found which in all probability have their origin in autoxidative phenomena of the substance in solution.
Syntheses of polychloro compounds with aluminium chloride VII: The auto‐condensation of 1,2,3,3‐tetrachloropropene‐1
Authors: Prins H. J.
Published: September 2010

The synthesis of polychloro compounds by the catalytic action of aluminium chloride has been extended to the auto‐condensation of 1,2,3,3‐tetrachloropropene‐1 giving 1,2,3,4,5,5,6,6‐octochlorohexene‐1.

This octochlorohexene gives hexachlorohexadienes when treated with alcoholic potash solution.
Absorption spectra of quinones. I. Naphthoquinones and naphthohydroquinones
Authors: Spruit C. J. P.
Published: September 2010

This paper reports the ultraviolet and visible absorption spectra of a number of derivatives of 1,4‐naphthoquinone and 1,4‐naphthohydroquinone. A statistical analysis of the spectra shows that the absorption bands of the quinones may be divided into three groups. Two of these groups contain absorption bands, the position of which is only slightly dependent upon the nature of the substituents, and which are characteristic of the class of the naphthoquinones. The bands of the third group, situated mainly in the visible and near ultraviolet, are determined by the structure of the molecule as a whole. It is shown by several examples that the wavelengths of bands from the last group increase when negative charge is introduced into the nucleus by the attachment of substituents able to donate electrons, such as hydroxy groups. The reverse holds for electron‐attracting groups such as the carbonyl group.
The preparation of the two hexachlorocyclopentenones
Authors: Prins H. J.
Published: September 2010

Details are given on the preparation of these substances from catechol.
Synthese von L‐ und D‐glutaminsäure‐1,2‐C14 13. Mitteilung über die Chemie der Tumoren
Authors: Kögl F. , Halberstadt J. , Barendregt T. J.
Published: September 2010

Ausgehend von radioaktivem Bariumcarbonat wurde über Natriumbicarbonat, Natriumformiat, Natriumoxalat und Silberoxalat radioaktiver Oxalsäuredimethylester gewonnen. Durch Kondensation mit Bernsteinsäuredimethylester und Spaltung mit Salzsäure entstand α‐Ketoglutarsäure, die durch reduktive Aminierung in DL‐Glutaminsäure‐1,2‐C14 umgesetzt wurde. Die Gewinnung der radioaktiven Antipoden erfolgte in der bei Glutaminsäure leicht durchführbaren Weise durch fraktionierte Kristallisation nach Zusatz des betreffenden „leichten”︁ Antipoden

Vgl. hierzu die Bemerkungen am Schluss der Arbeit

).

Die zur Bestimmung der Radioaktivität angewandte Methodik wird kurz beschrieben.

) Vgl. hierzu die Bemerkungen am Schluss der Arbeit.
Contribution to the knowledge of metanethole II
Authors: van der Zanden J. M. , de Vries G.
Published: September 2010

Synthesis of 1‐p‐methoxyphenyl‐2‐methyl‐3‐ethyl‐6‐methoxy‐hydrindene:

magnified image

of β‐ethyl‐p‐methoxycinnamic acid:

magnified image

and of 2‐methyl‐3‐p‐methoxyphenyl‐5‐methoxyindenone:

magnified image
The thermal decomposition of O‐hydroxy‐diazonium compounds
Authors: de Jonge J. , Dijkstra R. , Braun P. B.
Published: September 2010

Experimental evidence has been found that the thermal decomposition of o‐hydroxy‐diazonium salts may be identical with the photo‐decomposition.
General considerations concerning the number of virtual phases
Authors: Zernike J.
Published: September 2010

A formula is deduced showing that ρ phases becoming critically identical should be counted as 2ρ‐1 virtual phases. Again no more than two phases having the same composition can be in equilibrium, whatever the number of components. Finally two phases having the same composition cannot be in equilibrium with a third phase with which one of these phases becomes critically identical. A few examples from the literature found to be at variance with these rules are discussed.
Einfluss Mittlerer Ionenkonzentrationen auf die Elektrostatische Energie von Fadenmolekülionen in Lösung
Authors: Künzle O.
Published: September 2010

Using polymethacrylic acid as example it is shown that the electric charges cause the chain molecules to become expanded. The expansion decreases when the concentration is increased or when salts are added. This contraction is ascribed to an increase of ionic strength.

A general expression is developed for the electrical free energy of statistically coiled, electrically charged chain molecules. In this the end‐to‐end distancehof the polymer molecule is used as characteristic parameter for the shape.

The distribution of ions with opposite charge and the variations of potential inside and outside of a coiled molecule are computed in accordance with the method ofDebijeandHückel.

In special cases, i.e. various concentrations and different amounts of added salt, the electrical free energy is calculated as a function ofh(the distribution of the oppositely charged ions being taken into account).

Using the free energy‐hfunction so found,h2and the specific viscosity are calculated and compared with experiments on polymethacrylic acid.
Polymérisation et copolymérisation du m‐nitrostyrène
Authors: Smets G. , Reckers A.
Published: September 2010

La polymérisation du méta‐nitrostyrène est caractérisé par une vitesse de polymérisation proportionelle à la concentration en intiateur utilisée; ce comportement s'interprête par un transfert de chaïne désactivant, dû à la présence d'un groupe nitré dans le noyau benzénique.

De même que les polymères, les copolymères, obtenus au départ de m‐nitrostyrène et de styrène, méthacrylate de méthyle ou chlorostyrène, ont toujours un poids moléculaire très bas; la validité du schéma habituel de la copolymérisation dans ce cas particulier est discutée. Les valeurs apparentes de r1 et de r2 sont indiquées pour les différents systèmes de monomères étudiés.
The hydrolysis and polycondensation of tetra alkoxysilanes
Authors: Aelion R. , Loebel A. , Eirich F.
Published: September 2010

A comparative study of the hydrolysis of the symmetrical orthosilicates, tetra‐ethyl,‐ tetra‐butyl, tetra‐hexyl, tetra‐2,6‐dimethyl‐heptyl‐4‐silicate, and of the unsymmetrical orthosilicates, diethyl‐dihexyl, diethyl‐di‐2‐methylpentyl‐4, diethyl‐diheptyl‐2, diethyl‐di‐2,6‐dimethyl‐heptyl‐4‐silicate, has been undertaken. A mechanism of the hydrolysis and of the polycondensation reaction of the silicols formed is proposed. Methods of preparation of some polyalkoxysiloxanes are described and the boiling points, melting points and densities determined. The higher polymers obtained by hydrolysis of alkoxy silicates are always highly cross‐linked siloxane networks. Attempts to obtain linear polyalkoxysiloxanes of high molecular weights by the hydrolysis of unsymmetrical esters have been found impracticable.
Velocity of hydrolysis of sodium chloroacetate in alkaline medium and concentrated solutions)
Authors: Nanninga L. B.
Published: September 2010

The reaction velocity of the hydrolysis of sodium monochloroacetate was determined in concentrated solutions and alkaline medium at 40° and 50°.

It was found that the reaction follows the bimolecular equation. However, the reaction constant increases considerably with the normality of the hydroxide, which was explained by an effect of the total electrolyte concentration. The temperature coëfficient of the reaction was calculated to be 3.0 per 10°.
Kinetic analysis of organic halides. Part I. Analysis of low molecular monohalides
Authors: Salomon G. , Ultée A. J.
Published: September 2010

A new kinetic test has been applied to the estimation of mixtures of two or more organic halides. The reactivity of a halide group with an organic base is a characteristic property of the group and can therefore be used for its identification.

The rate of these halide‐base reactions increases with the strength of the base and the dielectric constant of the medium. The latter factor becomes preponderant in the dissociation of tertiary halides to olefins. The dependence of the rate of halogen ion formation on the concentration of the base is higher than second order.

As the chain length and branching of the halide chain have little influence on the reaction rate, group reactivity decreases therefore in the usual series: allyl > primary > secondary > cyclohexyl >> vinyl.

Tertiary halides are distinguished by their high rate of dissociation in pure aniline.

A system of analysis has been drawn up and examples of application are given. The kinetic analysis of macromolecular halides (part II) is based on these model experiments.
Size, viscosity and precipitation of polymer molecules in solution
Authors: Kunst E. D.
Published: September 2010

Les viscosités intrinsèques de fractions de polystyrène et de polyisobutylène ont été déterminées, ainsi que leurs poids et dimensions moléculaires par diffusion de la lumière.

Les relations entre viscosité et dimensions d'une part et entre viscosité et poids moléculaire de l'autre, ont été analysées à l'aide des théories récentes de la viscosité des solutions macromoléculaires. L'accord avec la théorie est qualitatif et non quantitatif.

D'autre part, on a étudié la relation entre les dimensions, le solvant et la température. Pour le polystyrène les dimensions sont uniquement fonction de la pente A2 de la courbe de (Hc/τ) en f(c), quelle que soit la température; on en conclue que la barrière de potentiel s'opposant à la rotation libre est très raide.

Pour le polyisobutylène les dimensions augmentent avec la température pour une valeur constante de A2. Ici il y aurait donc deux barrières de potentiel, dont l'une empêche la réalisation des configurations très enroulées, et dont l'autre, moins raide, empêche la réalisation des configurations étendues. Finalement, l'adsorption préférentielle du solvant dans un mélange solvant—précipitant est discutée. Pour des raisons encore inconnues l'adsorption se présente si l'éthanol est le précipitant et non si l'hexane est est le précipitant.
New syntheses of purines
Authors: Cook A. H. , Heilbron Ian
Published: September 2010

New general methods by which easily accessible 5‐amino‐4‐carbethoxyiminazoles may be smoothly converted into purines, including adenine and guanine analogues, are described.
Etude sur le Mécanisme de la Réaction Rubrénique: Le bis(p‐diméthylaminophényl)phényléthynylcarbinol, ses propriétés halochromiques: Un colorant vert à fonction acétylénique
Authors: Dufraisse M. Charles , Lefrancq Jean , Barbieri Pierre
Published: September 2010

Le bis‐(p‐diméthylaminophényl)phényléthynylcarbinol, décrit dans le mémoire, se rapproche étroitement, par ses propriétés halochromiques, du bis (p‐diméthylaminophényl)phénylcarbinol, base du vert malachite, si ce n'est que la teinte des sels est plus profonde. Toutefois, à la différence du second, le premier s'isomérise en cétone éthylénique, ce qui bouleverse le caractére halochrome de la molécule. Les propriétés tinctoriales ont été examinées. L'impossibilité de passer par la méthode usuelle du carbinol, ou de ses sels colorés, au rubrène correspondant suggère l'idée que le premier temps de la réaction rubrénique ne doit pas être un décrochage d'ion négatif.
Studies in the reductone series
Authors: v. Euler Hans , Hasselquist Hans
Published: September 2010

This communication concerns derivatives of the triose reductone. C3H4O3. In the first part we describe some new reductone esters. The second part contains new data on the reactions of reductone with aminobenzoic acid and with two aminosalicylic acids.
The anomalous rotatory power of cystine
Authors: Fieser Louis F.
Published: September 2010

A hitherto unexplained anomaly in optical rotations pointed out by van 't Hoff prompted the present suggestion regarding the structure of the cystine unit in proteins.
Remarks on a paper by Ishikawa and sakurai on the synthesis of α‐pentyl‐2‐hydroxycinnamaldehyde and α‐pentyl‐3‐methoxy‐4‐hydroxycinnamaldehyde
Authors: Verkade P. E. , Meerburg W.
Published: September 2010

It is shown that α‐pentyl‐2‐hydroxycinnamaldehyde and α‐pentyl‐3‐methoxy‐4‐hydroxycinnamaldehyde cannot be obtained in the way indicated by the above‐mentioned authors.
The structure of the thiosulphate ion in aqueous solution
Authors: Gerding H. , Eriks K.
Published: September 2010

The Raman frequencies of the S2O3″ ion in aqueous solution were redetermined and the depolarization ratios of the Raman lines of this ion are given here for the first time. The experimental material available makes it very probable that the S2O3″ion has the symmetry C3v. The force constants f(S.O), f(S.S), d(S.O) are calculated. Some remarks are made with regard to another structure proposed for S2O3″ and to some calculations of the theoretical frequency spectrum given in the literature.
The influence of SiO2 on the activity of nickel catalysts
Authors: van Eijk van Voorthuijsen J. J. B. , Franzen P.
Published: September 2010

Under appropriate conditions Ni(OH)2 and silica gel can form two compounds: Ni3(OH)4Si2O5 nickel antigorite and Ni3(OH)2(Si2O5)2 nickel montmorillonite. These two compounds, together with Ni(OH)2, are present in the pre‐reduction stage of Ni‐on‐SiO2 catalysts depending on the Ni/Si ratio. Their properties are a determining factor for the activity of the catalysts prepared from them by reduction.
The chloropyridines
Authors: den Hertog H. J. , Schogt J. C. M. , de Bruyn J. , de Klerk A.
Published: September 2010

The synthesis and some chemical properties are described of 2,4,5‐trichloropyridine, the only chloropyridine which has as yet not been mentioned in the literature.

Six other chloropyridines, which have only been prepared once previously, have been examined more closely.

It has been shown that a compound, which Königs, Mields and Gurlt obtained by heating 4‐nitraminopyridine with hydrochloric acid, is not 3,4‐dichloropyridine as stated by these investigators, but 4‐amino‐3,5‐dichloropyridine. 3,4‐Dichloropyridine has been prepared from 4‐hydroxypyridine via the well known 4‐chloro‐3‐nitropyridine.

Further it appeared that a solid, m.p. 74°‐75°, which Sell and Dootson obtained by chlorination of pyridine and which they assumed to be 2,3,4,6‐tetrachloropyridine, must have been a mixture of chlorinated pyridines. We have synthesised 2,3,4,6‐tetrachloropyridine from 2,4‐dihydroxypyridine via 2,4‐dichloro‐3‐nitropyridine and from 4‐amino‐2,6‐dichloropyridine.

The structure has been established of twenty five compounds discussed in connection with the chloropyridines mentioned above.

Finally, the melting points and boiling points of the nineteen chloropyridines have been determined or verified.
Some derivatives of methacrylic acid
Authors: Heyboer J. , Staverman A. J.
Published: September 2010

The following substances, not yet described in the literature, were prepared:

N‐tert‐butyl methacrylamide, m.p. 59° C, b.p. 111°° C/42 mm.

tert‐butyl methacrylate, b.p. 136° C, fr.p. −48° C.

N‐methacrylyl‐benzenesulphonamide, m.p. 128–129° C.

N‐methacrylyl‐p‐toluenesulphonamide, m.p. 153–154° C.

An improved method of preparation for methacrylic acid and methacrylyl chloride is described.

Densities and refractions of several of these compounds are given.

Some of these compounds have been polymerised and the solubility of the polymers in various solvents has been determined.
Investigations in the vitamin‐A series. I. A new synthesis of vitamin‐A acid and vitamin‐A: (Preliminary communication)
Authors: Huisman H. O.
Published: September 2010

The chemical and physical properties of β‐ionylidene acetaldehyde, the important key intermediate for the synthesis of vitamin‐A, are given.

Starting from β‐ionylidene acetaldehyde a new synthesis of vitamin‐A acid and vitamin‐A is described.
Thermodynamic properties of mixtures of alkanes differing in chain length. I. Heats of mixing
Authors: van der Waals J. H. , Hermans J. J.
Published: September 2010

The construction is given of an isothermal twin calorimeter in which the small heat absorption on mixing two alkanes is compensated by electric heating. Results are given for the systems n‐hexane‐n‐hexadecane (20° C), n‐heptane‐n‐hexadecane (20°, 25° C), n‐octane‐n‐hexadecane (20°, 30°, 50° C), n‐decane‐n‐hexadecane (20°, 30°, 73° C), n‐decane‐n‐dotriacontane (73° C) and 2,2,4‐trimethyl pentane‐n‐hexadecane (25° C). A recent theory of Tompa s is compared with the observed dependence of the heat of mixing on the difference in chain lengths of the constituent molecules. The strong temperature dependence of the heat of mixing found is discussed in its relation to the entropy of mixing.
4‐Hydroxy‐6‐amino‐isophthalic acid, A byproduct in the synthesis of p‐aminosalicylic acid from m‐aminophenol)
Authors: Beyerman H. C. , Alberda G.
Published: September 2010

Carboxylation of m‐aminophenol under carbon dioxide pressure may yield not only p‐aminosalicylic acid (PAS), but also a dicarboxylic acid as a by‐product. For this by‐product the structure of the unknown 4‐hydroxy‐6‐amino‐isophthalic acid is proved.

The possibility of the occurrence of 4‐hydroxy‐6‐amino‐isophthalic acid in commercial PAS for clinical use and of resulting implications is stressed.

Preliminary data concerning toxicity and tuberculostatic activity are given.
The preparation of some 3‐hydroxy‐4‐pyridones substituted on the nitrogen atom
Authors: Kleipool R. J. C. , Wibaut J. P.
Published: September 2010

N‐Methyl‐3‐hydroxy‐4‐pyridone‐6‐carboxylic acid is produced by the action of methylamine on meconic acid and, by splitting off carbon dioxide, N‐methyl‐3‐hydroxy‐4‐pyridone is obtained. Similar reactions occur with ethylamine and isopropylamine.

By the action of these amines on 3‐hydroxy‐y‐pyrone the corresponding N‐alkyl‐3‐hydroxy‐4‐pyridones are obtained. A pyridone carrying a substituent on the nitrogen atom is obtained by the action of aminoacetal on the above mentioned pyrone derivative. The reaction between glycine and meconic acid is described.
Discrepancies in the literature IX AND X
Authors: van Alphen J. , Drost G.
Published: September 2010

The melting point of 2‐benzal‐1‐tetralone is 106‐7°.
Biphenyl derivatives II. Basic 4‐Biphenyl compounds
Authors: Goldschmidt  , Modderman P.
Published: September 2010

Continuing investigations described in a preceding paper 1) N‐alkylated biphenyl‐4 and 4‐cyclohexyl phenyl‐substituted amines have been prepared and tested for pharmacological activities. N‐derivatives of (biphenyl‐4)‐methylamine, β‐(biphenyl‐4)‐ethylamine, 4‐(2′‐methoxy biphenyl)‐ethyl‐amine, 4‐(cyclohexyl phenyl)‐methylamine and β‐4‐(cyclohexyl phenyl)‐ethylamine are described.
The dielectric constants of some hexanes, heptanes and octanes
Authors: de Vos F. C.
Published: September 2010

An apparatus is described for the determination of the dielectric constants of small amounts of liquid, with an accuracy of 1—2 units in the fourth decimal place.

With this apparatus some pure hexanes, heptanes and octanes were studied at temperatures between 20° and 50° C.

The results of the measurements are used for the computation of the polarisability of the molecules with the aid of Böttcher's method.
Optical rotation and atomic dimension
Authors: Brauns D. H.
Published: September 2010

From measurements of the optical rotations of F, Cl, Br, I substitutes of acetyl sugars and of optically active alcohols two rules are derived connecting the differences in optical rotation with the differences of atomic diameter.
Stabilisation of montmorillonite sols by chemical treatment. Part I. Properties of sodium and calcium montmorillonite sols
Authors: van Olphen H.
Published: September 2010

According to ultramicroscopical counting and relative viscosity data the micelles of Na and Ca montmorillonite sols are minute flat crystal plates with an average thickness corresponding to that of a packet of about five crystal lattice layers only with an average diameter‐thickness ratio of the order of a few hundred. This is corroborated by electronmicrographs and X‐ray studies.

The average thickness of the micelles decreases with decreasing sol concentration, indicating a concentration‐dependent association‐dissociation equilibruim of the crystal lattice layers.

Montmorillonite is a peculiar colloid in the sense that the platy micelles may be assumed to bear two basically different double layers, one on the surface of the lattice and a second at the broken lattice edges. The two double layer potentials may even have a different sign.
Monobromocyclohexadiene and dibromocyclohexadiene
Authors: Wibaut J. P. , Haak F. A.
Published: September 2010

The substitution of bromine in cyclohexadiene‐1,4 with N‐bromosuccinimide has been investigated more closely. Monobromocyclohexadiene was isolated in a slightly impure form as an almost colourless liquid; this substance decomposes violently on warming to 100°. The action of two molecules of N‐bromosuccinimide on 1 mol. of cyclohexadiene‐1,4, furnishes, amongst other things, dibromocyclohexadiene, which has been proved by isolation of bromobenzene from the decomposition products of this compound. Alongside substitution, a considerable amount of bromine addition took place to give dibromocyclohexene.
Steric effects on mesomerism. V.) steric effects on mesomerism in derivatives ofpara‐nitro‐acetanilide
Authors: Wepster B. M. , Verkade P. E.
Published: September 2010

This paper contains data on the (pseudo) catalytic deacylation of a number of derivatives ofpara‐nitro‐acetanilide in which steric effects on mesomerism are to be expected. The rate of deacylation found for each compound is discussed in some detail on the basis of current electronic theory.

Special attention is paid to a valency deflection hypothesis relating to thesemi‐cyclic bonds of the benzene nucleus.

Finally, a general remark is made on the magnitude of the steric effects on mesomerism, which we have found in derivatives ofortho‐ andpara‐nitro‐acetanilide (part IV of this series and this paper).
The antitubercular activity of azo dyes. II. Monazo dyes derived from diazotized sulfa drugs and bis (4‐aminophenyl)‐sulfone and bisazo dyes from tetrazotized bis (4‐aminophenyl)‐sulfone and sulfa drugs
Authors: Sah Peter P. T. , Oneto John F.
Published: September 2010

With the aim of obtaining azo dyes with high chemotherapeutic properties, two groups of azo dyes were prepared for studies, namely, (1) monazo dyes by the diazotization of sulfa drugs and related amines and then coupling with bis(4‐aminophenyl)‐sulfone, and (2) bisazo dyes by the tetrazotization of bis(4‐aminophenyl)‐sulfone and then coupling with sulfa drugs.

Biological tests seemed to indicate that the monazo dyes are in general more active than the corresponding bisazo dyes, which in turn are more active than the bisazo dyes described previously and prepared from tetrazotized bis(4‐aminophenyl)‐sulfone and various common coupling components.

In this paper, the relationship between chemical structure and biological properties (notable antitubercular in vitro) has been again discussed.
The decomposition of aliphatic azo‐compounds: II
Authors: Bickel A. F. , Waters W. A.
Published: September 2010

The thermal decomposition of 2,2′‐azo‐isobutyronitrile, which yields the radical (CH3)2Ċ‐CN, has been investigated with a view to establishing the nature of the termination process of the polymerization of methacrylonitrile.

The results of these experiments may indicate that the chain termination in the above polymerization occurs mainly by combination and only to a small extent by disproportionation of the polymer radicals.
The electrokinetic behaviour of freshly prepared γ‐ and α‐FeOOH
Authors: van Schuylenborgh J. , Arens P. L.
Published: September 2010

α‐FeOOH and γ‐FeOOH have been prepared in different ways and their electrokinetic behaviour was investigated.

Dilution of the solution containing the components from which the minerals were synthesized led to a decrease of the isoelectric point (pH) of these substances. Drying of the moist preparations had the same effect.

These results have been correlated with those from Röntgenographic and differential thermal analysis of the preparations.
Derivatives of oxazolidinedione‐2,4: I. Alkylation of the oxazolidinedione ring
Authors: Rekker R. F. , Verleur H. , Nauta W. Th.
Published: September 2010

Depending on the method of working, alkylation of 5,5‐dimethyl‐oxazolidinedione‐2,4 leads to 3‐alkyl‐5,5‐dimethyl‐oxazolidinedione‐2,4 or an alkyl derivative of a lactim form of 5,5‐dimethyl‐oxazolidinedione‐2,4.

It could be shown that the compound obtained by Spielman, by methylating 5,5‐dimethyl‐oxazolidinedione‐2,4 with dimethyl sulphate, had indeed the structure of 3,5,5,‐trimethyl‐oxazolidinedione‐2,4.

Methylation of the silver salt of 5,5‐dimethyl‐oxazolidinedione‐2,4 with methyl iodide on the other hand, leads to the formation of an oxygen‐methylated compound.

In connection with this matter, several syntheses, which might lead to the formation of 3,5,5‐trimethyl‐oxazolidinedione‐2,4 were submitted to a closer examination.
The synthesis of kawaïn
Authors: Kostermans D. G. F. R.
Published: September 2010

Kawaïn, one of the pyronones occurring in the kawa kawa‐plant (Piper methysticum), has been synthesised. The melting point of the synthetic substance is not identical with the melting point of kawaïn given by Borsche. Probably this is due to the fact, that Borsche did not obtain kawaïn in a pure state.
Aminolyse des 1,1,1‐trisulfones substituées: (Propriétés du groupe sulfonyle XV
Authors: Backer H. J.
Published: September 2010

Les sulfones qui sont susceptibles de subir une hydrolyse se scindent généralement en acide sulfinique et composé hydroxylé (ou oléfinique). Soumises à l'action décomposante d'amines, ces sulfones peuvent engendrer également un acide sulfinique, le second produit étant une amine substituée.

Par contre, les dérivés substitutées du tris‐méthylsulfonyl‐méthane ZC(SO2CH3)3 donnent, par hydrolyse, l'acide méthane‐sulfonique et des disulfones substituées.

L'aminolyse de ces trisulfones a lieu dans la plupart des cas selon le même principe; d'acide méthanesulfonique se présente à l'état d'amide substitué.

Cependant les thioaryl‐tris‐méthylsulfonyl‐méthanes font exception; tandis que l'hydrolyse alcaline suit le schéma des autres trisulfones, les amines attaquent le groupe thioaryle, au lieu d'un groupe méthylsulfonyle.

Le mécanisme électronique des scissions observées est discuté.
Preparation of esters of gallic acid with higher primary alcohols
Authors: van der Kerk G. J. M. , Verbeek J. H. , Cleton J. C. F.
Published: September 2010

The esters of gallic acid and higher primary alcohols, especially fatty alcohols, have recently gained considerable interest as possible antioxidants for fats.

Two independent methods for the preparation of these esters are described.

In the first method the hitherto unknown compound galloyl chloride is converted into an ester of gallic acid by reaction with the appropriate alcohol.

A new type of molecular addition compound between galloyl chloride and dioxane is described.

The second method deals with the direct esterification of gallic acid with higher alcohols, which, until now, had not been successfully achieved.
The synthesis of 2‐mercapto‐4‐aminobenzoic acid
Authors: van Der Stelt C. , van Der Lugt W. , Nauta W. Th.
Published: September 2010

The synthesis of 2‐mercapto‐4‐aminobenzoic acid, a compound which is the sulphur analogue of p‐amino‐salicylic acid (2‐hydroxy‐4‐aminobenzoic acid), is described.
Biochemical production of dihydroxyacetone from glycerol
Authors: Rutten A. M. G.
Published: September 2010

Dihydroxyacetone (propanediolone) has been prepared from glycerol by the action of Acetobacter suboxydans var. biourgianum, nov. var. Kluyver and de Leeuw.

It was found that the high values in the production of the ketose, obtained by several investigators, are not due to a hypothetical reducing impurity, present in the medium, but to erroneous data appearing in the literature concerning the reducing power of the dihydroxyacetone. Moreover, it was shown that during the conversion of the glycerol, some pyruvic acid and a fluorescing substance were formed. The latter displayed absorption bands at 273 mμ and 450 mμ.
Inhibition of photogalvanic phenomena
Authors: Weber K. , Matijević E.
Published: September 2010

Solutions of thionine give in presence either of thiosine‐amine or diethyl‐thiosine‐amine pronounced photogalvanic effects, the numerical values of which amount to over 400 mV. Under the influence of light, the redox‐potential of the system becomes more negative. These effects are closely related to the photochemical bleaching of thionine. In regard to the rate of increase, as well as to the influence of light, the photogalvanic effect may be interpreted by means of the general kinetic equation of photochemical kinetics.

The photogalvanic effects of thionine are strongly inhibited by various inorganic salts and polyphenols. Reducing agents stabilise these systems in such a way that the initial redox‐potential of the electrode becomes negative, while for oxidizing agents the stabilization potential takes much more positive values. Apart from inhibition, the addition of foreign substances brings about electrolytic as well as other effects which increase numerical values of photogalvanic effects.

Other thiazinic and azinic dyes show also photogalvanic effects. It is probable that there is a close connection between their normal redox‐potentials and the magnitude of photogalvanic effect.
Spectrophotometric study of the solvation of iodine in dioxan solution
Authors: Ketelaar J. A. A. , van de Stolpe C. , Gersmann H. R.
Published: September 2010

The solvation of iodine in dioxan‐carbon tetrachloride solutions was studied by determining a large number of absorption spectra at different compositions and different temperatures. The concentration of the iodine‐dioxan complex was derived from the extinction at 4515 Å (at 17° C), the wavelength of maximal absorption of iodine in pure dioxan, as compared with the extinction of iodine in pure dioxan and in pure carbon tetrachloride, respectively. Application of the mass law resulted in equilibrium constants essentially independent of concentration. However, this was only the case when based on the assumption of a ratio of 1:1 for the composition of the complex. From the dependance on temperature the heat of formation of the complex was found to be 2700 cal/mol.
The behaviour of membranes between electrolyte solutions: I. The relation between pH and the membrane potential across cellophane
Authors: Hirsch P.
Published: September 2010

The behaviour of membranes in contact with electrolyte solutions has been studied as regards both electrical potential differences between the two sides of the membranes and the movement of dissolved substances as well as solvent (water) through the membrane. This first communication deals with potential measurements on “cellophane” membranes through which KCl and NaCl solutions diffused towards solutions of ten times smaller concentrations of the same salt. The pH was maintained the same on both sides of the membrane. It was found that pH had a great influence on the measured membrane diffusion potential (MP) (table III).

The difference Δ between MP and the liquid junction potential (LJP) was the same in KCl and in NaCl experiments. Δ increases with the pH according to a curve (fig. 1) which is very similar to the dissociation curve of a monobasic acid. There is apparently a close correlation between MP (or Δ) and the dissociation of acid groups in the membrane substance.
The nitrosation of methallylchloride
Authors: Kooyman E. C. , Farenhorst E. , Werner E. G. G.
Published: September 2010

The action of aqueous nitrous acid on 2‐chloromethylpropene‐1 (methallylchloride) results in the formation of an unstable addition product which is converted into 1‐chloro‐2‐methyl‐3‐nitropropene‐1 upon treatment with alkali. For this new compound, the name nitro isocrotyl chloride is proposed. Its structure was established by ozonolysis, which yielded nitroacetone and hydrogen chloride.

Dinitrogen tetroxide acts upon methallyl chloride to give a nitronitrite, which may be converted into a nitroalcohol upon treatment with methanol. This nitroalcohol has the probable structure formula 2‐chloromethyl‐1‐nitro‐propanol‐2.
Vapour pressures of saturated ammonium bicarbonate solutions
Authors: Zernike J. , Haider S. Z. , Jaheruddin Md. , Rahman F.
Published: September 2010

Critical survey of literature. The system ammonium bicarbonate‐water is ternary. Measurements of the vapour pressures of the solutions as function of the volume of the gaseous phase, down to zero volume, at different temperatures. The vapour phase is found to contain no weighable amounts of ammonia.
The benzoyl peroxide initiated addition of carbon tetrachloride to olefins
Authors: Kooyman E. C. , Farenhorst E.
Published: September 2010

The initiation, propagation and termination steps of the benzoyl perioxide initiated additon of carbon tetrachloride to olefins are described.

Initiation follows two main routes, viz. a) addition of benzoate and of phenyl radicals to the olefinic double bond, followed by chlorine abstraction from carbon tetrachloride by the new radicals and b) formation of trichloromethyl radicals from carbon tetrachloride and phenyl radicals.

The propagation mechanism proposed by Kharasch et al.2) is confirmed and the extent of telomer *) formation estimated for the case of cetene.

Chain termination consists in the formation of stable allyl‐type radicals, which are incapable of starting a new chain; in the case of cyclohexene, these radicals were found in the form of their dimer 3,3′‐dicyclohexenyl.

Supporting evidence is based on detailed analyses of the reaction mixtures, peroxide decomposition products and other by‐products being isolated and identified. Further arguments follow from the influence of retarders and the results obtained with olefins of a special structure.
The constitution of dihydro‐nicotyrine (“N‐methyl‐myosmine”)
Authors: Wibaut J. P. , Beyerman H. C.
Published: September 2010

The structure of the dihydronicotyrine obtained by zinc‐hydrochloric acid reduction of 3,2′‐nicotyrine (I) has for some time been established by chemical means as N‐methyl‐myosmine (II). Recently spectroscopic and chemical evidence has been published which is contrary to this opinion.

These spectroscopic findings have been confirmed and extended by the inclusion of 3‐allyl‐pyridine in this investigation.

Oxidative degradation of dihydronicotyrine hydrochloride with ozone gave nicotinic acid hydrochloride in approximately 85% yield. This is in accordance with the structure of N‐methyl‐myosmine (II), if a “normal” degradation is assumed. In view of other investigations on “abnormal fission” of double bonds with ozone, we are inclined to regard this evidence as inconclusive.

Therefore structures III and IV have to be considered as representing dihydronicotyrine, and from these III seems most probable.

A new and convenient synthesis of (pyridyl‐3)‐acetic acid is reported.
Kinetical experiments on ozonisation reactions: II. The ozonisation of benzene
Authors: Sixma F. L. J. , Boer H. , Wibaut J. P. , Pel H. J. , de Bruyn J.
Published: September 2010

The velocity of the ozonisation of benzene in chloroform is proportional to the concentration of benzene and that of ozone. The reaction constant was determined at eight temperatures between −25 and −40° C.

The reaction takes place about three times more rapidly in nitromethane than in chloroform.

Aluminium chloride and ferric chloride catalyse the reaction; the velocity increases directly with the concentration of aluminium chloride.

The results of our measurements are in agreement with the reaction mechanism suggested in a previous publication.
Syntheses with the aid of lithiopyridines: Preparation of di‐pyridyl ketones, pyridyl‐phenyl‐carbinols and tri‐pyridyl‐carbinols
Authors: Wibaut J. P. , de Jonge A. P. , van der Voort H. G. P. , Otto P. Ph. H. L.
Published: September 2010

The preparation of phenyl pyridyl ketones by the action of 2‐lithiopyridine or 3‐lithiopyridine on benzoic anhydride, ethyl benzoate or benzonitrile is described: di‐pyridyl‐phenyl‐carbinols are produced by the further action of lithiopyridine on the ketones so obtained.

The action of 2‐lithiopyridine on 2‐cyanopyridine or ethyl picolinate gives bis‐(pyridyl‐2) ketone; in a similar way bis‐(pyridyl‐3) ketone is prepared and some other di‐pyridyl ketones.

By the action of 2‐lithiopyridine on bis‐(pyridyl‐2) ketone there is obtained tris‐(pyridyl‐2)‐carbinol; tris‐(pyridyl‐3)‐carbinol has been synthesised in a similar way.
Reaction products of primary β‐hydroxy‐amines with carbonyl compounds. IX. Etude magnétochimique
Authors: Metzger J. , Pacault A.
Published: September 2010

Malgré quelques difficultés rencontrées dans le calcul des susceptibilités magnétiques, les résultats obtenus dans l'étude magnétochimique de plusieurs des substances examinées dans le précédent mémoire (VIII) corroborent pleinement les conclusions de ce dernier.
The synthesis of N‐(ϵ‐aminocaproy L‐) ϵ‐aminocaproic acid. „Di‐ϵ‐aminocaproic acid”︁.
Authors: van der Want G. M. , Staverman A. J.
Published: September 2010

The possibility of synthesizing ω‐peptides by condensation of a ω‐phthalimido acid chloride with a ω‐amino acid and subsequent treatment with hydrazine has been investigated.

The synthesis of N‐(ϵ‐aminocaproyl‐) ϵ‐aminocaproic acid is described.
Polypeptides. I. N.‐Carbonic anhydrides, (NCA) of some amino acids. (4 substituted oxazolid‐2,5 diones)
Authors: Petri E. M. , Staverman A. J.
Published: September 2010

The preparation of the N‐carbonic anhydrides and the carbomethoxy compounds of the following amino acids is described: glycine, valine, leucine, norleucine, phenylalanine, proline and cystine.
The addition of ozone to aromatic bonds
Authors: Badger G. M.
Published: September 2010

Some properties of “double bond reagents” are discussed, and the mechanism of the reaction between ozone and aromatic compounds as proposed by Wibaut and his co‐workers, is criticised. It is suggested that the initial stage in the reaction is the formation of a π‐bond between the carbon‐carbon bond having the highest double bond character and the ozone molecule.
Time‐dependence of boundary tensions of solutions: IV. Kinetics of adsorption at liquid‐liquid interfaces
Authors: Ward A. F. H. , Tordai L.
Published: September 2010

Various mechanisms are considered which might explain the variation of interfacial tensions with time, when fatty acids are adsorbed from hexane on to a hexane water interface. In these solutions there are both single and associated molecules of the fatty acids. Although the single molecules are the adsorbable species, it is shown that the slow adsorption cannot be attributed to their relative scarcity. The Langmuir adsorption isotherm is found not to apply accurately at equilibrium, and a new isotherm is proposed. A mechanism is suggested to explain the kinetics of adsorption and desorption and is found to be in accordance with the experimental variation of interfacial tension with time. Velocity constants for adsorption (kt) and desorption (k2) are evaluated. The resulting equilibrium constants (k1/k2) are found to agree well with equilibrium constants deduced thermodynamically by an entirely independent process. The effect of temperature on the processes of adsorption and desorption is also discussed.
Arenicochrome: Degradation to arenicochromine, a sulphur‐free pigment
Authors: van Duijn P.
Published: September 2010

This paper contains a description of the hydrolysis of arenicochrome in acid milieu. This leads to the splitting off of all the sulphur in the arenicochrome molecule in the form of sulphuric acid and results in the preparation of a sulphur‐free crystalline derivative of arenicochrome. The name arenicochromine is proposed for this violet pigment. The composition of arenicochromine accords with the formulae C42H34O16 or C42H34O16.

The absorption spectra as well as some other properties of arenicochromine are reported.
Titration curves of dialysed clay minerals
Authors: van Schuylenborgh J. , Vervelde G. J.
Published: September 2010

Titration experiments were carried out on dilute suspensions of dialysed samples of three clay minerals, viz. kaolinite, illite and bentonite. Sodium and potassium hydroxide solutions were used as titration liquid. Both the hydrogen and the sodium or potassium ion activities were measured by means of glass electrodes. The titration curves were analysed on the basis of a theory, describing the clay suspensions as a system of two solutions, one containing the clay acid and the other being responsible for the activities measured. The interrelation of the composition of these solutions can be expressed by the laws of the Donnan equilibrium. There is reason to reconsider the traditional view, that the properties of clay acids cannot be described by one or a few dissociation constants.
Apparent osmotic pressure of solutions of heterodisperse polymers
Authors: Staverman A. J.
Published: September 2010

The theory of apparent osmotic pressure obtained with membranes which are partially permeable to the solute is applied to solutions of heterodisperse polymers. An expression for the relation between the measured osmotic pressure and the permeability of the membrane is derived and it is shown how molecular distributions of polymers can be obtained from simultaneous measurements of permeability and osmotic pressure with a given polymer‐solvent‐system and different membranes.
Amides X: The use of tertiary amides in the perkin reaction
Authors: Parkes E. A. , Polya J. B. , Spotswood T. M.
Published: September 2010

The effects of basic catalysts and temperature on the condensations of benzaldehyde with N‐methyldiacetimide, N‐phenyldiacetimide, N,N‐dimethylacetamide and N,N‐diphenylacetamide respectively have been studied. These condensations have little practical value but the isolation of N‐cinnamoyl acetanilide from the reaction between benzaldehyde and N‐phenyldiacetimide proves that dehydration precedes deacylation during the Perkin reaction involving tertiary amides.
Synthèse de Provitamines D À Chaînes Latérales Variées
Authors: de Vries Harmen , Backer H. J.
Published: September 2010

Après avoir synthétisé quelques Δ5‐stérols ayant des chaïnes latérales différentes

Mémoires antérieurs: Rec. trav. chim. 69, 759. 1252 (1950).

), les auteurs y ont introduit une seconde liaison double en position 7. Ainsi ils ont obtenu cinq Δ5,7‐stérols nouveaux (provitamines D). dont, après irradiation, l'activité a été examinée.

Plusieurs tentatives pour préparer de tels composés aux dépens d'ergostérol n'ont pas conduit au résultat désiré, par suite de la difficulté de protéger réversiblement la double liaison conjuguée.
Méthylation du Bis‐Méthylsulfonyl‐Nitrométhane au Moyen de Iodure de Méthyle: (Propriétés du groupe sulfonyle XXVII))
Authors: Backer H. J.
Published: September 2010

L'iodure de méthyle réagissant sur le dérivé argentique du bis‐méthylsulfonyl‐nitrométhane fixe un groupe méthyle sur l'atome de carbone central. La structure du produit résulte de l'hydrolyse et de la pipéridinolyse, qui s'accomplissent sans retard à la température ambiante et qui, en expulsant un groupe méthylsulfonyle, conduisent au 1‐méthylsulfonyl‐1‐nitro‐éthane; la synthèse de ce dernier composé à partir du 1‐bromo‐1‐nitro‐éthane confirme la structure donnée:
Une nouvelle preparation des pyridylaldehydes
Authors: Wibaut J. P. , Huls R.
Published: September 2010

Le diéthylacétal du pyridyl‐3‐méthanal, obtenu à partir de 3‐bromopyridine, selon la méthode de Wibaut et van der Voort, a été transformé, avec un rendement de 84%, en pyridyl‐3‐méthanal.

Le pyridyl‐2‐méthanal a été de même préparé, avec un rendement de 78%, à partir de l'acétal correspondant, obtenu par condensation de l'orthoformiate d'éthyle avec le bromure de pyridyl‐2‐magnésium.
The thermal decomposition of (—)∼menthyl esters
Authors: Wibaut J. P. , Beyerman H. C. , van Leeuwen H. B.
Published: September 2010

It has been reported in the literature by various investigators that the pyrolysis of (—)‐menthyl acetate (in the gas phase) results in the formation of (+)‐p‐menthene‐3 only.

We investigated the thermal decomposition of (—)‐menthyl acetate in the gas phase and of (—)‐menthyl stearate in the liquid state. It was found that the two methods give about the same yield of terpene. This terpene is a mixture essentially consisting of (+)‐trans‐p‐menthene‐2 (33—36%) and of (+)‐p‐menthene‐3 (67—64%)

The infrared spectra of these mixtures agree with the spectrum given in the literature for “(+)‐p‐menthene‐3”. A statement in the literature with regard to characteristic infrared absorption of unsaturated hydrocarbons seems to have no application to this case
Electrophoretic determination of the equivalent weight of β‐lactoglobulin from the changes in concentration at the δ or ϵ boundary
Authors: Wegelin E. , de Wael J.
Published: September 2010

The equivalent weight of β‐lactoglobulin at pH = 6.8 and μ = 0.15 has been calculated from a Tiselius experiment by the method given in a previous paper and elaborated in this paper. The result: E = 2.710, agrees reasonably well with the value E = 3.130 calculated from the dissociation curve. The agreement between the two results would be better, if an accurate calculation of the Donnan equilibrium were possible
Preparation of 2‐ethoxy‐4‐diethylaminobenzene‐1‐diazoniumborofluoride
Authors: Klaassens K. H. , Schoot C. J.
Published: September 2010

The preparation of 2‐ethoxy‐4‐diethylaminobenzene‐1‐diazoniumborofluoride is described. A stable diacetyl derivative is formed by treating 2‐ethoxy‐4‐diethylamino‐1‐aminobenzene with acetic anhydride.