bluuebunny/crossref_metadata_2025 huggingface dataset:
The oxidation of phenols with copper‐amine catalysts and its relation to the mode of action of tyrosinase III. Kinetics of the oxidation of monohydric phenols with copper‐morpholine complex as a homogeneous catalyst
Authors: Brackman W. , Havinga E.
Published: September 2010

In this paper the kinetics of the direct conversion of phenol into dimorpholino‐orthobenzoquinone in systems containing phenol, morpholine, copper salt, oxygen and solvent, are described.

The reaction only proceeds, if the phenol concentration exceeds a certain critical value. An induction period is usually observed. The effect of concentrations, solvents and inhibitors upon the introduction period and the reaction rate has been studied.
Synthesis of four dipyridylamines
Authors: Zwart C. , Wibaut J. P.
Published: September 2010

The syntheses of the 2,3′‐, 2,4′‐, 3,3′‐, and 3,4′‐dipyridylamines are described.
Synthésé de quelques molecules fortement conjuguées pour les recherches cancérologiques
Authors: Buu‐Hoï N. G. Ph. , Eckert Bernard
Published: September 2010

Un certain nombre de composés dont la molécule présente un fort degré de conjugaison, et qui dérivent du pyrène, de l'acénaphthène, ou du 1,4‐distyrylbenzène, ont été synthétisés en vue de leur étude biologique. Malgré leur degré de conjugaison, tous ces composés sont inactifs au point de vue du pouvoir cancérogène sur la peau.
Studies on vitamin D and related compounds III. Short communication on the cis‐trans isomerization of calciferol and the properties of “trans”‐vitamin D2
Authors: Verloop A. , Koevoet A. L. , Havinga E.
Published: September 2010

Isomerization of vitamin D2 in apolar solvents at room temperature under the influence of small amounts of iodine in diffuse daylight yields a compound that could be isolated in the form of the crystalline phenylazobenzoate. Spectra of solutions of the free vitamin D isomer obtained upon saponification of the ester are presented. They support the view that the isomer should be considered as trans‐vitamin D2 having structure A (fig. 3).
The directive influence of the N‐oxide group during the nitration of derivatives of pyridine‐n‐oxide (III). The nitration of 2‐ and 3‐methoxypyridine‐N‐oxide
Authors: den Hertog H. J. , van Ammers M.
Published: September 2010

The nitration of 2‐hydroxypyridine‐N‐oxide, according to Lott and Shaw 3), has been repeated. The same nitration product as described by these authors was obtained; a new proof of its structure affirmed that the nitro group in this compound occupies the 5‐position.

Whereas thus in the nucleus the directive effect of the hydroxy group is not surpassed by that of the N‐oxide group, the influence of the methoxy group appears to be smaller, for during the nitration of both 2‐ and 3‐methoxy‐pyridine‐N‐oxide the 4‐nitro compounds are the sole reaction products isolated.
The directive influence of the N‐oxide group during the nitration of derivatives of pyridine N‐oxide (IV). Nitration of 3‐bromo‐5‐methoxy‐ and 3,5‐dimethoxypyridine‐N‐oxide
Authors: den Hertog H. J. , van Ammers M. , Schukking S.
Published: September 2010

Whereas the nitration of 3‐bromo‐, 3,5‐dibromo‐, as well as of 3‐methoxypyridine‐N‐oxide yields the 4‐nitro compound, from the mixture obtained in the nitration of 3‐bromo‐5‐methoxypyridine‐N‐oxide the 6‐nitro derivative has been isolated as the sole reaction product. Also from 3,5‐dimethoxypyridine‐N‐oxide the 2‐(=6‐) nitro, and not the 4‐nitro derivative is obtained.
On the physiological activity of diazo anhydrides. I: Diazotetronic anhydrides and related compounds
Authors: Pons L. , Veldstra H.
Published: September 2010

Diazotetronic anhydride, which contains the (N2)CHCO.O.CH2‐grouping ‐ characteristic for the antibiotic azaserine ‐ in a cyclic structure was assayed for inhibitory activity in a number of tests, together with a series of its γ‐substituted derivatives and some related compounds. The properties of diazotetronic anhydride parallel those of azaserine to a large extent. In some cases its antibacterial activity is higher than that of the antibiotic. The activity of the structurally related 3‐chlorobenzene‐6‐diazo oxide against Ebert. typhi practically equals that of chloramphenicol (in vitro).

The blastocoline activity (inhibition of seed‐germination) of diazotetronic anhydride is comparable with that of coumarine, while rootgrowth inhibition is of the same order as in the case of azaserine. Oxygen consumption by rat liver homogenate is reduced by addition of the compound.

At low concentrations filament formation in E. coli (inhibition of cell division) is observed.

Structural similarities between diazotetronic anhydride, benzenediazo oxides, diazouracil, the antibiotics azaserine and cycloserine (oxamycine) and the internal salt of 2,5‐bis‐ethylenimino‐hydroquinone (highly active against a number of transplantable tumors) are pointed out, also in connection with their activities.
Fatty acid oxidation in normal and neoplastic tissues: Octanoate oxidation by tumor mitochondria in relation to biochemical properties governing structural integrity
Authors: Emmelot P. , Bos C. J.
Published: September 2010

The fatty acid oxidation of normal liver mitochondria was found to be inhibited after the addition of mitochondria from many transplanted and spontaneous mouse tumors. This inhibitory effect was not an exclusive property of tumor mitochondria, it was also exhibited by rat brain mitochondria and by liver mitochondria pre‐incubated at 37° C in the absence of substrates. Addition of fluoride to the combined system of tumor and liver mitochondria counteracted the inhibitory effect of the former on the fatty add oxidation of the latter. These results, obtained with the Warburg technique, were confirmed and substantiated by experiments with radioactive substrates.

The conditions governing the inhibitory effect were studied, and it was found that those conditions which favoured the latency of the mitochondrial adenosine triphosphate‐splitting activities resulted in a disappearance of the inhibitory effect in many cases. It was concluded for the present that, by the splitting of adenosine triphosphate, the active adenosine triphosphatase of the tumor mitochondria prevented the ATP‐dependent formation of the acyl‐co‐enzyme A bond, which is a prerequisite for the fatty acid oxidation of the liver mitochondria.

The tumors studied could be listed in the order of an increasing tendency to show the inhibitory effect as a result of different treatment during preparation of the mitochondria.

During this investigation it was demonstrated for the first time that mitochondria from various transplanted tumors, if isolated in isotonic sucrose‐containing versene, are capable of oxidizing octanoate.

The osmotic behaviour of liver and tumor mitochondria was also studied, and some direct measurements of the inorganic phosphate liberated from ATP by the action of these mitochondria were made.
Equilibria in polyamide systems from ϵ‐caprolactam and water
Authors: van Velden P. F. , Heikens D. , Hermans P. H. , van der Want G. M. , Kruissink Ch. A. , Staverman A. J.
Published: September 2010

Nylon 6 type polyamide equilibrium products prepared from ε‐caprolactam and water in closed systems at temperatures of 222 and 254° C have been investigated. Unconverted caprolactam, higher membered cyclic compounds, chain fractions and end‐groups (−NH2 and −COOH) were determined quantitatively. Percentages of caprolactam and higher rings increase with increasing temperature and/or increasing water content (corresponding to decreasing DP) of equilibrium products. Number‐average DP of chain fractions varied from ∼ 100 → 10 in the range investigated. The results have been evaluated in terms of equilibrium constants on the basis of plausible theoretical considerations including the Flory‐Schulz distribution of chain lengths.

The equilibrium constant of the polycondensation reaction has been found to decrease with decreasing DP of products. This behaviour is in accordance with similar results obtained for different polyamide equilibrium products. Possible explanations are discussed. A comparison with some data available from the literature is included.
Raman spectra of aliphatic chlorine compounds: V. Chloroethers and chloroalcohols
Authors: Gerding H. , Haring H. G.
Published: September 2010

The Raman spectra of a number of chloroethers and chloroalcohols are communicated, several of which contain the grouping CCl3CHCl. CH2‐ or CHCl2CHCl. CH2‐. A comparative study of these spectra reveals that specific group frequencies deduced for the chloropropanes retain their values in the ethers and alcohols, and that additional characteristic frequencies may be distinguished for the configurations ‐OCH3 and ‐CH2O‐.

For a number of the compounds studied, structural formulae which had not yet been established with certainty could be confirmed by means of Raman analysis, i.e. on account of specific group frequencies and spectral analogies observed.

As a final conclusion from our Raman spectroscopic investigations on aliphatic chlorine compounds the “specific group frequencies” deduced are summarized.
Raman analysis of polychloro compounds from the condensation of chloral with 1,2‐dichloroethene
Authors: Haring H. G.
Published: September 2010

This paper describes the Raman spectroscopical investigations which contributed to the elucidation of the chemical structure of the compounds obtained by the condensation of chloral with 1,2‐dichloroethene. As has been pointed out in the chemical part of this study, decomposition (by the action of aluminium chloride) of 1,1,1,3,4,4‐hexachloro‐2‐methoxybutane yielded the same compounds, but in other proportions.

The Raman spectra are discussed of various fractions, obtained through distillation in vacuo. In several of these spectra “extra lines” indicated the presence of contaminations; these have been identified by their characteristic Raman lines.

“Group frequency analysis”, in addition to the chemical evidence obtained, allowed of a final conclusion concerning the structural formulae of some of the compounds.
The polarographic reduction of conjugated hydrocarbons: VI. Comparison of Hückel's and Wheland's m.o. approximation with experimental half‐wave potentials of various alternant and non‐alternant hydrocarbons
Authors: Hoijtink G. J.
Published: September 2010

On the basis of the results reported in the foregoing papers IV and V and the data obtained byBergman2) from the reduction of various aromatic hydrocarbons in ethylene glycol mono‐methyl ether Maccoll's relationship between the experimental halfwave potential and the root a of the m.o. secular equation corresponding to the lowest non‐occupied π‐electronic level has been investigated in more detail. It is shown that the half‐wave potentials of 38 alternant and non‐alternant hydrocarbons being reduced according to the mechanism inferred in paper IV satisfy the relationship:

The mean value of the resonance parameter γ in e.v. for various experimental:

magnified image

The half‐wave potentials of the univalent anions of various conjugated hydrocarbons determined by the equilibrium R′ + e ⇋ R″ in 96% dioxan‐water and the half‐wave potential of the radical triphenylmethyl fit the relationship.

In this case the mean value of γ following fromHückel's and Wheland'm.o. approximation becomes −2.82 ± 0.13 and −2.57 ± 0.11 e.V., respectivelly.

In accordance with the discussion given in paper V the half‐wave potentials of various l‐n‐diarylpolyenes show a slight departure from the linear relationship.

The addition of an electron to non‐planar hydrocarbons may involve a decrease in the mutual hindrance between the integral parts of the system, since the lenght of the carbons bonds in the negative ions formed, will be greater than in the original hydrocarbons. Owing to this “resonance stabilisation” the difference between the experimental half‐wave potential and the one computed with the aid of the linear relationship assuming a planar structure, is sometimes appreciably larger (dibiphenylene‐ethene) or smaller (cis1,2‐diphenylethene andcis, cis1,4‐diphenylbutadiene‐1,3) than we might expect from the non‐planarity of the reducible hydrocarbon.
The photochlorination of butyryl and valeryl chloride: (Preliminary communication)
Authors: den Hertog H. J. , de Vries B. , van Bragt J.
Published: September 2010

Some preliminary experiments on the photochlorination of butyryl and valeryl chloride in the liquid and the vapour phase are described.

The chlorination of butyryl chloride in the liquid phase yields about equal quantities of β‐ and γ‐chlorobutyryl chloride and only a small amount of the α‐chloro compound. In the gas phase somewhat more of the β‐chloro derivative is formed.

In the chlorination of valeryl chloride, too, the substitution preferentially occurs in positions remote from the carbochloride group. This result differs considerably from that obtained by Bruylants and collaborators'). These authors report that in the gas phase, together with a small amount of the a‐chloro compound, only β‐ and γ‐chlorovaleryl chloride are formed, whereas we have found that the reaction mixture contains, in addition to the above‐mentioned substances, 25‐30% of δ‐chlorovaleryl chloride. Our results do not support the hypothesis of Bruylants c.s. that the course of the chlorination depends on a cyclic conformation of the acid halides.
Ueber die Isolierung und Strukturaufklärung eines neuen Alkaloids aus Sedum acre L: (Vorläufige Mitteilung)
Authors: Beyerman H. C. , Muller Yvonne M. F.
Published: September 2010

Extracts of Sedum acre L. were analysed by chromatography on paper. Sedamine and nicotine reported to occur in S. acre could not be found, but several spots marked the presence of other alkaloids.

One of these alkaloids — was isolated and is shown to be the dextro‐rotatory component of the racemate with m.p. 75° of 1‐(2‐piperidyl)‐2‐propanol (III, “dihydroisopelletierine”, ( + )‐sedridine). Some (±)‐sedridine was also found.

Possible implications of these findings are indicated.
Potentiometric estimation of vanadium. I. Reduction of quinquevalent vanadium with quinquevalent tungsten or quadrivalent uranium
Authors: Tourky A. Riad , Issa I. M. , Daess A. M.
Published: September 2010

It has been found that V+5 can be potentiometrically estimated by titrating it with W+5 or U+4. The process is applicable to small quantities of vanadium as low as 30 γ the titration curves are smooth with sharp inflections. The most favourable results are obtained with W+5 in the presence of 7‐8 N HCl and 0.1‐8 N H3PO4, both at room temperature and at 60°C. With U+4 the best results are obtained in ∼ 2 N HCl.
On the synthesis and stereochemistry of sedamine
Authors: Beyerman H. C. , Eveleens W. , Muller Yvonne M. F.
Published: September 2010

A simple synthesis of the alkaloid (±)‐sedamine, which gives further proof of its assumed structure, is reported; some improvements on a known synthesis are also given.

From the mother liquors of the former syntheses a diastereoisomer of (±)‐sedamine, which is named (±)‐isosedamine, has been isolated.

(±)‐Sedamine was resolved and (−)‐sedamine is described. The various stereoisomers are discussed also in relation to their infrared spectra.
An adiabatic calorimeter for measuring heat of solution (short communication)
Authors: Coops J. , Balk A. N. , Tolk M. W.
Published: September 2010

An adiabatic calorimeter has been developed for the measurement of the heat of solution. By means of a thermistor temperature changes of about 0.04°C can be measured with a precision better than 4 × 10−5° C, hence only small amounts of solute are required. As a check of accuracy the integral heat of solution of KCl in H2O at 25°C up to a concentration of 2 × 10−4 molar was directly determined as 17.24±0.03 kj per mole

For the “uncertainty interval” is used twice the standard deviation of the mean, i.e.
equation image
, as recommended bij F. D. Rossini and W. E. Deming, J. Wash. Acad. Sci. 29, 416 (1939). The probability that the measured quantity lies within this limit is 96%.

).
The effect of long‐chain alcohols on the properties of sodium laurate solutions. Part II. Critical micelle concentration
Authors: Harva O.
Published: September 2010

The effect of monohydric alcohols from hexanol to decanol and of the dihydric alcohols, 1,2‐decanediol and 1,10‐decanediol, on the critical micelle concentration (CMC) of sodium laurate in aqueous solution at pH 11 has been investigated at 24°C.

Only up to a certain alcohol concentration was a linear relation found to apply between the CMC and the alcohol concentration. The break points in the CMC against alcohol concentration curves are attributed to complex formation between the laurate anion and the alcohol molecule. When, however, complex formation between the solutes does not occur, as is assumed to be the case for 1,10‐decanediol and sodium laurate, the CMC is found to be a linear function of the alcohol concentration up to the saturation concentration of the diol in aqueous solution, and no break point is observed in the CMC against alcohol concentration curve.
A new hydrate of sodium perborate
Authors: van Gelder D. W.
Published: September 2010

A new hydrate of sodium perborate having the composition NaBO3.3H2O, has been discovered. Above 15°C in contact with the saturated solution, it appears to be more stable than the normal commercial salt, NaBO3.4H2O. The preparation of the trihydrate and its most important properties are described.

It is indicated briefly how the formation of the trihydrate from the commercial salt is important for the stability of the latter product at slightly raised temperatures.
Esters derived from batyl alcohol
Authors: Stegerhoek L. J. , Verkade P. E.
Published: September 2010

An improved method for the preparation of batyl alcohol is described. Unambiguous methods are given for the synthesis of monoesters and of mono‐acid and di‐acid diesters of batyl alcohol.
Tautomerism of hydroxypyridines (I): The structure of 2,4‐dihydroxypyridine
Authors: den Hertog H. J. , Buurman D. J.
Published: September 2010

Syntheses of 2‐hydroxy‐4‐methoxypyridine, 4‐hydroxy‐2‐methoxypyridine, 4‐methoxy‐N‐methylpyridone‐2, and 2‐methoxy‐N‐methylpyridone‐4 are described.

The ultraviolet absorption spectra of 50% aqueous ethanolic solutions of the above‐mentioned compounds and of 2,4‐dihydroxypyridine and 2,4‐di‐methoxypyridine are measured. Comparison of these spectra enables the determination of the predominant tautomeric structures of 2,4‐dihydroxypyridine and its derivatives.

It appears that the chief structure of 2,4‐dihydroxypyridine in aqueous ethanol is that of 4‐hydroxypyridone‐2.

Finally it is shown that the methyl derivative of 2,4‐dihydroxypyridine, obtained by Maquenne and Philippe

a. L. Maquenne and L. Philippe, Compt. rend. 183, 506 (1904). b. Recently E. C. Taylor Jr., Aldo J. Crovetti, and Harvey M. Loux described an analogous synthesis of this substance from an isomer of ricinine ( J. Am. Chem. Soc. 77, 5445 (1955)).

) when heating ricinine with hydrochloric acid solution or by conversion of 4‐methoxy‐N‐methylpyridone‐2 with the same reagent according to Späth and Tschelnitz

E. Späth and E. Tschelnitz, Monatsh. 42, 251 (1921).

), is 4‐hydroxy‐N‐methylpyridone‐2.
The reaction between silver phosphate and substituted phenoxyacetyl chlorides
Authors: Klaassens K. H. , Schoot C. J.
Published: September 2010

The reaction between silver phosphate and a number of substituted phenoxyacetyl chlorides is described. In all cases liberation of carbon monoxide is observed. After reaction, it is possible in some cases to isolate a substance with the formula R‐O‐CH2‐O‐CO‐CH2‐O‐R (where R represents a substituted phenyl group). The remaining compounds form resins of the phenol‐formaldehyde type but under certain circumstances it is possible to identify an o‐hydroxybenzyl alcohol. A possible mechanism for the reaction is discussed.
Some photochemical properties of alkali salts of aryldiazosulphonic acids
Authors: de Jonge J. , Dijkstra R.
Published: September 2010

The structure of the labile form of an aryldiazosulphonate and the precise result of exposing a stable diazosulphonate to actinic light is considered to be still uncertain.

From experiments on the action of light it can be concluded that a stable diazosulphonate is transformed into a product which is in solution at least partly, but possibly completely, dissociated into diazonium ions and sulphite ions.

For a number of diazosulphonates the quantum yield for the photochemical reaction has been determined.
Complex coacervation. I. General theoretical considerations
Authors: Voorn M. J.
Published: September 2010

Some characteristics of complex coacervation are briefly discussed. A general phase diagram is given, showing the influence of electrolytes on the composition of the two‐phase system at constant charge density and mixing ratio of the two poly‐electrolytes. The applicability of the phase‐rule is discussed.

A model for calculations on complex coacervation is proposed, based on the interaction of oppositely charged coils in a sslt solution.
Photochemical acceleration of the hydrolysis of nitrophenyl phosphates and nitrophenyl sulphates
Authors: Havinga E. , de Jongh R. O. , Dorst W.
Published: September 2010

Neutral and alkaline solutions in water of the nitrophenyl phosphates are very stable in the dark. These compounds, however, and the meta derivative in particular were found to undergo a remarkable rapid hydrolysis when exposed to visible or ultra‐violet light. The reaction velocity is independent of the hydrogen ion concentration at pH's between 3 and 12 but increases strongly at higher pH's. Nitrophenol and phosphoric acid could be traced as the products of this photochemical reaction. The reaction proved to be zero order; the rate did not change upon varying of the temperature from 25° to 40° C. The nitrophenyl sulphates show an analogous behaviour but for the fact that the increase of reaction rate at higher pH's does not occur and that the difference in the rate of photochemical reaction between the meta compound on the one hand and the ortho and para derivatives on the other hand are even greater than with the phosphates. The experimental evidence points to a purely photochemical (non sensitized) reaction, the nature of which is tentatively discussed.
Méthode d'Obtention Rapide des Indices de Liaison des Hydrocarbures Alternants
Authors: Chalvet O.
Published: September 2010

En utilisant l'idée de classification géométrique des liaisons des hydro‐carbures alternants, on développe une méthode rapide d'obtention des indices de liaison.

La méthode est testée par comparaison avec des résultats tirés de la méthode L.C.A.O. dans son application rigoureuse; l'accord obtenu permet de penser que la méthode semble satisfaisante pour le calcul d'indice de liaison en vue d'étude de problèmes concernant la réactivité chimique des hydrocarbures.
Sur la Synthèse de Polyacides Ramifiés par Hydrogénolyse de Composés Thiophéniques
Authors: Buu‐Hoï N. P. , Sy Michel , Xuong N. D.
Published: September 2010

On décrit la synthèse de l'acide 5,5,10,10‐tétraméthyl‐n‐tétradécane‐1,14‐dicarbonique, de l'acide β,β‐diphényladipique, et de l'acide β,β'‐dicarboxyadipique par la méthode de réduction désulfurante de dérivés appropriés du thiophène au moyen de l'alliage de Raney. On montre l'intérêt de cette méthode pour la préparation de polyacides ramifiés difficilement accessibles par d'autres voies.
Synthesis of 1,2‐dehydroderivatives of adrenal cortical hormones
Authors: Szpilfogel S. A. , Posthumus T. A. P. , De Winter M. S. , van Dorp D. A.
Published: September 2010

Selenium dioxide dehydrogenation furnishes a method for the introduction of double bonds in ring A of saturated and unsaturated 3‐ketosteroids.
Inorganic complexes
Authors: van Arkel A. E.
Published: September 2010

A survey is given of different types of ionic and covalent complexes.
The structures of oxide and hydroxide salts of some tetrapositive ions
Authors: Lundgren Georg
Published: September 2010

The crystal structures of some oxide and hydroxide sulphates or chromates of tetravalent metal ions have been investigated by X‐ray methods. The results show that the crystals contain polynuclear complexes, either infinite or finite. The following types of infinite complexes occur in the crystals:

chains [Me (OH2)2+]n in Th(OH)2CrO4H2O, Th(OH)2SO4, and U(OH)2SO4

chains [MeO2+]n (type I) in TiOSO4H2O

chains [MeO2+]n (type II) in CeOSO4H2O

two‐dimensional, net‐like complexes in zirconium chromates.

Finite complexes, [Me6O4(OH)4]12+, are formed in the crystals of U6O4(OH)4(SO4)6 and Ce6O4(OH)4(SO4)6.

In VOSO4(H2O)5, the metal ions do not seem to be joined by oxide or hydroxide bridges, but form mononuclear V‐O6 octahedra.
Komplexbildung in Phosphoroxychlorid
Authors: Gutmann Viktor
Published: September 2010

Die geringe Eigenleitfähigkeit des Phosphoroxychlorids beruht auf Eigendissoziation: POCl3 ⇋ POCl2+ + Cl−. Eine Anzahl von Stoffen bildet mit dem Solvens definierte Verbindungen, die das POCl2 +‐Ion enthalten, z.B.: POCl2SbCl6, POCl2AlCl4, (POCl2)2TiCl6. Die Existenz des POCl2+‐Ions in den elektrolytisch dissoziierten Lösungen dieser Stoffe in Phosphoroxychlorid ergibt sich aus ihrem chemischen Verhalten, aus Überführungsmessungen und aus ramanspektrographischen Untersuchungen. Die dadurch ermöglichten Chloridionenübergänge zwischen POCl2+‐Ionen und POCl3‐Molekeln werden für die hohe Überführungszahl dieses Ions verantwortlich gemacht.

Säuren des Solvosystems Phosphoroxychlorid treten mit Basen (Chloridionendonoren) zu Chlorokomplexen zusammen, deren Nachweis teils auf präparativem und teils auf konduktometrischem Wege erfolgte. Beispiele hierfür sind: (R4N)2VCl6, (R4N)SbCl6, (R4N) (POCl2) (TiCl6), PCl4SbCl6, oder Al2SnCl10.2 POCl3. Die in den Lösungen vorliegenden Ionengleichgewichte, sowie die Eigenschaften der Chlorokomplexe werden besprochen.
Zur Frage der Bindung in den Cyclopentadienkomplexen mit Übergangselementen
Authors: Fischer E. O.
Published: September 2010

Im Zusammenhang mit der Vorstellung eines Eingreifens der gesamten π‐Elektronen der aromatisierten Cyclopentadienylringe in die Elektronenschale der zentralen Übergangsmetalle und des Vorliegens von Durchdringungskomplexen werden Ergebnisse von Hydrierungs‐ und Ozonisierungsversuchen mitgeteilt.

Eine Zusammenstellung magnetischer Daten der Verbindungsklasse unter Einbeziehung neu dargestellter, z.B. mit CO, NO, H substituierter Metallcyclopentadienyle wird gegeben und die Verträglichkeit mit der Bindungsauffassung dargetan. Ergebnisse röntgenographischer Untersuchungen werden mitgeteilt.

Zur Vorstellung einfach homöopolar gebundener Ringe wird von diesen experimentellen Befunden her Stellung genommen.
Über Interkombinationsspektren von Komplexionen der Übergangsmetalle
Authors: Hartmann H. , Schläfer H. L.
Published: September 2010

Nach einer kurzen Übersicht über die allgemeinen Gesichtspunkte zur theoretischen Behandlung der Termsysteme der Zentralionen von Komplexen der Übergangsmetalle werden die Ergebnisse quantenmechanischer Überlegungen für die Termsysteme von Ni2+ bei tetraedrischer und quadratisch planarer Anordnung der Liganden mitgeteilt.

Weiterhin wird über die Interkombinationsspektren von Mn2+ und Fe3+‐Aquokomplexen berichtet. Die theoretisch ermittelten Termsysteme der Komplexe werden angegeben.
Complexes between tributyl phosphate and inorganic nitrates
Authors: Healy T. V. , Mckay H. A. C.
Published: September 2010

Many inorganic nitrates dissolve freely in tributyl phosphate (TBP), forming complexes with the solvent. TBP saturated with uranyl nitrate, for example, corresponds exactly to the composition UO2(NO3)2. 2TBP and has a sharp melting‐point of −6°C; no other complex involving uranyl nitrate and TBP appears to be of any significance. There is only slight ionisation in the TBP phase.

A useful general method of determining the number of TBP molecules attached to the inorganic nitrate is by partition experiments between TBP and water. The aqueous phase is kept constant in composition while an inert diluent, e.g. benzene or kerosene, is added to the TBP; the partition of a trace of the inorganic nitrate in question is then measured at a series of dilutions. At high dilutions a limiting law of the form:

Partition coefficient ∼ (TBP Concentration)n

is obtained, in which the exponent n gives the number of TBP molecules in the complex. The following formulae have been established for different complexes:

magnified image

In all except the first the central atom is co‐ordinated with six groups (O, NO3 or TBP). However in other cases, e.g. the alkali metal nitrates, the co‐ordination number is probably lower.
Stabilities of complex compounds of metals in non‐aqueous solutions
Authors: Burkin A. R.
Published: September 2010

By defining the successive stability constants of metal complex compounds in terms of generalised equilibria it is possible to study metals which do not form simple hydrated metal ions and also non‐water soluble ligands and complexes.

If the equilibrium constants are to be interpreted in terms of bond energies etc. it is necessary that the system be defined. That is, the real compositions of the compounds in the equilibrium solution should be known. Some important types of interfering dissociations and reactions can be detected by means of electrical conductivity measurements and some results of such measurements are outlined.

The system [PdCl2 (n‐C8H17NH2)2] + PBu3n = [PdCl2 (n‐C8H17NH2) (PBu3n) ] +C8H17NH2 [PdCl2 (n‐C8H17NH2) (PBu3n)] + PBu3n = [PdCl2(PBu3n)2] + C8H17NH2 has been studied and the free energy changes for the replacement of n‐octylamine by tri‐n‐butylphosphine in the two stages are:

ΔG1 = −4.56 to −5.08 kcal.

ΔG2 =−5.30 to −5.92 kcal.
Some comments on the Benesi‐Hildebrand equation
Authors: Scott Robert L.
Published: September 2010

A modification is given of the Benesi‐Hildebrand equation to determine the equilibrium constant for complex formation from spectrophotometric measurements. Difficulties arising from the use of either concentrations or mole fractions are discussed.
The exchange of [14C] ethylenediamine with metal‐ethylenediamine complexes
Authors: Wilkins R. G. , Popplewell D. S.
Published: September 2010

The exchange of [14C] ethylenediamine with various metal‐ethylenediamine complexes was studied in aqueous solution. As would be expected from a consideration of the properties of the ions, [Co en3]3+ exchanged very slowly even at 95° C (no exchange in 6 hours at pH = 7 or 12) whereas (Zn en3)2+, [Cu en2]2+ and [Hg en2]2+ exchanged very rapidly at 0° C (within 5 seconds at pH ∼ 11). Although [Ni en3]2+ exchanged rapidly at 0° C (t½ ∼ 5 seconds at pH ∼ 11) the general features of the kinetics were studied. The [Au en2]3+ ion exchanged measurably slowly at 25° C [t½ ∼ 2 hours at pH ∼ 1] and the kinetics of this exchange are being investigated.
Proton affinities
Authors: Longuet‐Higgins H. C.
Published: September 2010

A theoretical definition and interpretation of proton affinities is given. The theory is applied to the aromatic hydrocarbons.
Optical and paramagnetic resonance spectra of some coordination compounds
Authors: Weissman S. I.
Published: September 2010

The applications are discussed of optical and paramagnetic resonance spectroscopy to the study of coordination compounds e.g. of chelate compounds of beryllium with dibenzoylmethane and benzoylacetone.
The proton complexes of pyrene
Authors: Mackor E. L. , Hofstra A.
Published: September 2010

The basicity constant of an aromatic is one of the main factors determining its partition coefficient over anhydrous HF and n‐heptane.

The composition of the conjugate acid formed by the addition of a proton to an aromatic was derived from measurements of the partition coefficient of the aromatic over solutions of NaF in HF and n‐heptane.

Pyrene and a few other compounds behave in an exceptional fashion and the mechanism of the reactions involved has been investigated. It was found that this peculiar behaviour is due to the formation of a more complicated ion containing six pyrene molecules and two protons.
Clathrate compounds
Authors: Powell H. M.
Published: September 2010

Clathrate compounds are those in which two (or more) components are associated without ordinary chemical union through complete enclosure of one molecular kind by a suitable structure formed by the other. There are various related types of molecular compounds frequently referred to as inclusion compounds or by similar names. A limited number of such kinds of molecular compounds has so far been found although the total number of members of the series is very great. Many more are to be expected. Some problems requiring further study include the following:

Conditions of formation. Work on related compounds of phenols and on gas hydrates is helpful. In the case of the quinol clathrates there are some difficulties in attaining equilibrium conditions. Some observations on vapour pressures will be discussed.

State of the enclosed molecules. Various grades of restriction on motion may arise from their enclosure. Experiments on the electrical, magnetic and other physical properties will be mentioned.

Which molecules will form clathrates? Although for a given enclosing structure it is possible by space considerations to predict, within limits, the molecules that can be present as enclosed component, it is more difficult to foresee what is capable of enclosing. Some suggestions will be considered.

New structural types of clathrates. A brief mention will be made.
Thermodynamic properties of quinol clathrates
Authors: van der Waals J. H. , Platteeuw J. C.
Published: September 2010

The statistical‐mechanical description of clathrate compounds of quinol with non‐polar gases is discussed on the basis of the Lennard‐Jones and Devonshire model. Formulae are given for the equilibrium vapour pressure of the gaseous component and for the chemical potential of the quinol in the clathrate. From the formulae it appears that the concentration of the gas in a quinol clathrate, which is simultaneously in equilibrium with solid α‐quinol and a gas phase, is independent of the nature of the gas.

An experimental method is described for determining the vapour pressure and the composition of the clathrate at the above three‐phase equilibrium. Results are given for the compound with argon. The limited number of experimental data on vapour pressures and heats of mixing at present available seems to support the theory.
Complex coacervation: IV. Thermodynamic calculations on four‐component systems
Authors: Voorn M. J.
Published: September 2010

The Donnan equations in complex coacervation, are derived and discussed for a simple case. Calculations are given on the influence of the mixing proportion of two poly‐electrolytes on complex coacervation.
A new method of expression of electrokinetic data
Authors: O'Connor D. J.
Published: September 2010

The usefulness of the fundamental electrokinetic ratio ζD/4πη for expression of double layer properties in terms of experimentally measured quantities is discussed and, when electrostatic units are used, the ratio ζD/4πη is shown to have dimensions equivalent to the reciprocal of the e.s.u. magnetic induction or magnetic flux/cm2. It is proposed that the ratio ζD/4πη be assigned the symbol G, and the unit of one (e.s.u. magnetic flux/cm2)−1 be called the Gouy.
A multiple gaschromatographic apparatus for use at temperatures up to 250 °C
Authors: Keppler J. G. , Schols J. A. , Dijkstra G.
Published: September 2010

A description is given of an apparatus for the separation of high‐boiling mixtures by means of vapour‐phase chromatography at temperatures up to 250° C. The immobile phase consists of either silicone grease or silicone rubber; the detector is a catharometer working at the same temperatures.
Synthesis and properties of the chlorination products of methyl 4‐amino‐2‐hydroxy‐benzoate. III
Authors: van Der Stelt C. , Nauta W. Th.
Published: September 2010

Both the isomeric chlorination products of methyl 4‐amino‐2‐hydroxy‐benzoate (XIII, P.A.S. methyl ester) with the structure of methyl 1,3,3,5,5,6‐hexachloro‐4‐chlorimino‐cyclohexanone‐2‐carboxylate‐1 (XXIII and XXIV) reacted with an aqueous potassium iodide solution to yield methyl 1,3,5,5,6‐pentachloro‐4‐amino‐cyclohexene‐3‐one‐2‐carboxylate‐1 (XXX). Further reduction converted XXX into methyl 3,5‐dichloro‐4‐amino‐2‐hydroxy‐benzoate (XV). In 2 N sodium hydroxide, one molecule of hydrogen chloride was eliminated from XXX, yielding the yellow product: methyl 1,3,5,6‐tetrachloro‐4‐amino‐cyclohexadiene‐3,5‐one‐2‐carboxylate‐1 (XXXI). Reduction with stannous chloride converted XXXI into methyl 3,5,6‐trichloro‐4‐amino‐2‐hydroxy‐benzoate (XXXII).

When reacted with methanolic hydrogen chloride, both the isomers XXIII and XXIV gave an identical reaction product. In view of the fact that the compound did not liberate iodine from a potassium iodide solution, the structure of a dimethyl α‐(1,2,2,4,4,4‐hexachloro‐3‐imino‐butyl)‐α‐chloro‐malonate (XXXIII) was made plausible for this reaction product. Treatment of XXXIII with 2 N sodium hydroxide resulted in the elimination of a molecule of hydrogen chloride. Reduction with stannous chloride converted XXXIII into a pyridine derivative, which is supposed to be a dichloro substitution product of methyl 2‐hydroxy‐6‐methyl‐nicotinate (XXXV) in which the positions of the two chlorine atoms are still unknown.

The reaction of XXIV with ethanolic hydrogen chloride led to the formation of two reaction products. One of them is formulated as the diethyl ester homologue of XXXIII (XXXVI), the other one being the methyl ethyl ester homologue (XXXVII). XXXVI was likewise reduced to a 2‐hydroxy‐nicotinic acid derivative.
Total synthesis in the steroid series. I. An tricyclic intermediate to 18‐oxygenated steroids. d,l‐Δ8a‐4bβ‐Methyl‐2β‐formyl‐2α‐(3′‐oxopropyl)‐7‐ethylenedioxy‐4aα,10aβ‐dodecahydrophenanthrene‐4β‐ol‐l‐one)
Authors: Szpilfogelw S. A. , van Der Burg J. , Siegmann C. M. , van Dorp D. A.
Published: September 2010

The total synthesis of racemic aldosterone (I) was achieved recently by J. Schmidlin, G. Anner, J.‐R. Billeter and A. Wettstein

A. Wettstein at the XIVth International Congres of Pure and Applied Chemistry, July 1955, Zürich. Experientia 11, 365 (1955).

. Our own efforts in the field of the total synthesis of adrenal cortical hormones and derivatives will be described in the present and forthcoming papers

See Experientia 11, 365 (1955), footnote 2.
Changes in the light‐absorption of intact and killed algal cells upon illumination (Preliminary Communication)
Authors: Spruit C. J. P.
Published: September 2010

A comparison of the effects of illumination on the changes in the absorption spectra of intact and killed Chlorella cells between 420 and 600 mμ indicates that several pigment systems contribute to these changes. Some appear to be closely connected with the primary steps of light‐energy conversion, whereas others are more indirectly involved.
Preparation of p,p′‐substituted tetraphenyl‐N,N′‐dimethyl‐thiourea derivatives and investigation into their physiological activity in two fields
Authors: van der Zanden J. M. , de Vries G. , Handelé M. J.
Published: September 2010

Preparation of p,p′‐substituted tetraphenyl‐N,N′‐dimethyl‐thiourea derivatives is described.
Acid anilides: IV. The infra‐red absorption spectra of fatty acid anilides
Authors: Dijkstra G. , de Jonge A. P.
Published: September 2010

In continuation of the work on fatty acid anilides the infra‐red spectra of a number of these anilides are described.
Studies on vitamin D and related compounds VI: The synthesis and properties of dihydrotachysterol3
Authors: van De Vliervoet J. L. J. , Westerhof P. , Buisman J. A. Keverling , Havinga E.
Published: September 2010

Whereas dihydrovitamin D3 I and dihydrovitamin D3 II can be isolated from the mixtures obtained on reduction of cholecalciferol with sodium and alcohols, attempts to obtain dihydrotachysterol3 in a crystalline state from such mixtures were unsuccessful. Pure dihydrotachysterol3, however, could be obtained by reducing tachysterol3 with an excess of lithium in liquid ammonia, concentrating by chromatography on alumina, esterification with phenylazobenzoyl chloride and saponification of the ester. Ultra‐violet and infra‐red absorption spectra are given. The capacity of dihydrotachysterol3 to raise the calcium level of the blood (plasma) proved to be about twice as large as that of dihydrotachysterol2.
Evidence for free radicals as intermediates in the oxidation of phloroglucinol
Authors: Stein H. N. , Tendeloo H. J. C.
Published: September 2010

The existence of free radicals in the oxidation of phloroglucinol could be proved by initiating the polymerization of styrene.
The action of p‐toluenesulphonyl chloride on pyridine‐N‐oxide : Preliminary communication
Authors: de Villiers P. A. , den Hertog H. J.
Published: September 2010

It is shown that during the reaction between p‐toluenesulphonyl chloride and pyridine‐N‐oxide, among other substances, N‐(2′‐pyridyl)‐5‐chloropyridone‐2 is formed in a fair yield.
Preparation and constitution of a number of derivatives ofMeta‐di‐Tert. butylbenzene
Authors: Burgers J. , van Hartingsveldt W. , van Keulen J. , Verkade P. E. , Visser H. , Wepster B. M.
Published: September 2010

The synthesis of a number of derivatives ofmeta‐di‐tert.. butylbenzene is described. Wherever the constitution of the compounds obtained did not follow from the method of preparation, it is proved.
Chemistry of acetylenic ethers XVII: The reactions of some ethoxyethynylcarbinols with mercaptans and thio‐acids
Authors: Weiland J. H. Sperna , Arens J. F.
Published: September 2010

The addition of ethyl mercaptan to 1‐ethoxy‐3‐methylbut‐1‐yn‐3‐ol (V) under the influence of peroxides yielded 1‐ethoxy‐2‐ethylmercaptobut‐1‐ene‐3‐ol (VI) in high yield (reaction scheme A). This substance could be rearranged to 2‐ethylmercapto‐3‐methylcrotonaldehyde (VII) (reaction scheme B). The same reaction took place with other mercaptans.

The addition of ethyl mercaptan to 1‐(1‐hydroxycyclohexyl)‐2‐ethoxyethyne (XV) and 1‐(1‐hydroxycyclopentyl)‐2‐ethoxyethyne (XVI) under the same conditions yielded 2‐cyclohexylidene‐2‐ethylmercaptoacetaldehyde (XVIII) and 2‐cyclopentylidene‐2‐ethylmercaptoacetaldehyde (XXII) after rearrangement (reaction scheme D).

Other thioenol ether compounds were prepared (reaction schemes C and D) starting from the aldehydes VII, XVIII and XXII.

Addition of thiobenzoic acid to 1‐ethoxy‐3‐methylbut‐1‐yn‐3‐ol (V) proceeded by a different (probably ionic) mechanism and yielded ‐ after rearrangement and saponification ‐ β,β‐dimethylacrylic acid (reaction scheme E).
Dosage Rapide de L'Aluminium dans les Alliages Cuivreux
Authors: Detmar D. A. , van Aller H. C.
Published: September 2010

Un mode opératoire pour le dosage gravimétrique de l'aluminium applicable ã tous les alliages cuivreux dont la teneur en aluminium est supérieure ou égale à 0.5 %, est décrit.

L'aluminium est précipité par la 8‐hydroxyquinoléine dans une solution ammoniacale, contenant du cyanure de potassium, de l'acide tartrique et du complexone‐III.

Les éléments, qui se trouvent normalement dans ces alliages, c.à.d. Cu, Zn, Sn, Fe, Mn, Pb, Ni et Co ne gênent pas et ne sont pas séparés.
The sterical structure of tropinol and pseudo‐tropinol
Authors: Beyerman H. C. , Siegmann C. M. , Sixma F. L. J. , Wisse J. H.
Published: September 2010

In a preliminary communication

F. L. J. Sixma, C. M. Siegmann and H. C. Beyerman, Proc. Koninkl. Nederl. Akad. Wetenschap. B 54, 452 (1951).

some of us have reported on the rates of alkaline hydrolysis of the benzoic and p‐nitrobenzoic esters of tropinol and ψ‐tropinol and of their methiodides in aqueous ethanol.

It is shown in the present investigation, that in the afore‐mentioned solvent mixture a rapid trans‐esterification of the methiodides takes place. This caused the assignment of wrong structures to tropinol and ψ‐tropinol.

Our measurements have been repeated therefore in aqueous dioxan. The reaction rates are now in complete accordance with the expectations based on the configurations and conformations deduced for the tropane alkaloids by other means.
Chemistry of acetylenic ethers. XXIII. Some reactions of acetylenic thioethers
Authors: Arens J. F. , Volger H. C. , Doornbos T. , Bonnema J. , Greidanus J. W. , van den Hende J. H.
Published: September 2010

From acetylenic thioethers, Grignard or lithium derivatives can be obtained, which react with carbonyl compounds to yield the expected carbinols. The reactions with carbon dioxide and ethyl chlorocarbonate also are normal. By oxidative “dimerisations” of the thioethers the diacetylenic bis‐thioethers are obtained. Hydration of acetylenic thioethers is much less easy then for oxygen ethers. Piperidine is added in an anti‐Markownikow way as is also the case for thiols and thiol acids.

Rearrangement of carbinols derived from acetylenic thioethers by acids yields the expected thiol esters. This is a method for the preparation of α,β‐unsaturated thioesters.

Partial reduction of the carbinols and hydrolysis of the products yields α,β‐unsaturated aldehydes.
Phenoxyacetic acid
Authors: van Essen H. , Beets M. G. J.
Published: September 2010

In a recent paper by Brettle a synthesis of phenoxyacetic acid in two steps giving an overall yield of 56% of the theoretical is recorded.

This method is described as a favorable alternative for the single step process because, as the author of the above mentioned paper observes “the condensation of phenol and chloroacetic acid in aqueous alkali gave poor yields of phenoxyacetic acid”.

Several years ago, however, we developed a process which gives reproducible yields of about 82% in one step. As the literature gives little information on the single step process, we describe our method in some detail.
Investigations on agricultural fungicides. I. Trichloromethyl thiolsulphonates
Authors: Uhlenbroek J. H. , Koopmans M. J. , Huisman H. O.
Published: September 2010

The preparation and the biological properties of a number of strongly fungitoxic compounds of the general type RSO2SCCl3 (trichloromethyl thiolsulphonates) are described in this paper. The phytotoxic character of these compounds may be lowered considerably by suitable substitution in the group R.
Theoretical interpretation of the temperature‐viscosity equation of slotte in connection with vitrification
Authors: Bêlehrádek Jan
Published: September 2010

Slotte's equation fits the viscosimetric data on water (‐10 to 140° C) and various watery solutions; it is applicable also to the rate of diffusion in water and to the electric conductivity of weak electrolyte solutions. The term ‐a is identified as the temperature at which a supercooled liquid ceases to flow under the force applied; it is suitable as a specific characteristic of the vitreous state.
Free radical reactions involving sulphur compounds: II. The relative reactivities of substituted thiophenols with respect to hydrogen abstraction by a free trivalent carbon radical
Authors: Schaafsma Y. , Bickel A. F. , Kooyman E. C.
Published: September 2010

In continuation of previous work on aliphatic thiols, a quantitative comparison has been made of the relative reactivities of substituted thiophenols with respect to hydrogen abstraction by a free trivalent carbon radical.

A competition method was employed involving reactions of 1‐cyano‐1‐cyclohexyl radicals with a mixture of two thiophenols in toluene solution at 110° C; 1‐cyano‐1‐cyclohexyl radicals were generated by thermal dissociation of 1,1′‐azo‐bis‐1‐cyclohexane nitrile. Relative reactivities were determined by measuring the residual amounts of thiophenols.

In agreement with theoretical expectations the effects of the substituents appeared to be small, electron‐withdrawing groups decreasing the rate of the hydrogen abstraction reaction and electron‐repelling substituents increasing it; results were roughly in accordance with a Hammett ϱσ‐relationship, the value of ϱ amounting to about −0.4.
New musk odorants: Aldehydes derived from polyalkylindans. IV
Authors: Spoelstra D. B. , Weber S. H. , Kleipool R. J. C.
Published: September 2010

In previous communications, the preparation of acetylpolyalkylindans possessing musk type odours has been described. The present paper describes the preparation of several of the corresponding aldehydes that have a similar type of odour. These aldehydes were obtained by chloromethylation of the polyalkylindan followed by conversion of the chloro‐compound to the aldehyde.