bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untersuchungen über Indolderivate VI.: Die Reaktion Zwischen Monobromaceton und Primären und Sekundären Aromatischen Aminen
Authors: Janetzky E. F. J. , Verkade P. E. , Lieste J. 
Published: September 2010

AbstractDie Reaktion zwischen Monobromaceton und primären aromatischen Aminen verläuft abnormal; es bilden sich nicht die zu erwartenden α‐Arylaminoketone, sondern Produkte von doppeltem Molekulargewicht.Mit sekundären aromatischen Aminen verläuft die Reaktion in üblicher Weise. Untersucht wurde besonders die Einwirkung von Monomethyl‐ und Monoäthylanilin, wobei mit sehr guter Ausbeute Phenylmethylamino‐propanon bzw. Phenyläthylamino‐propanon erhalten wurde. Durch Erhitzen mit 11/2% ihres Gewichtes an Zinkchlorid gingen diese Substanzen glatt in 1,3‐Dimethylindol bzw. 1‐Äthyl‐3‐methylindol über. Es handelt sich bei diesen Reaktionen um wahre Ringschliessung.Ausgehend von N‐Methyl‐p‐anisidin und Monomethylanilinhydrochlorid konnte mit sehr befriedigender Ausbeute 1,3‐Dimethyl‐5‐methoxyindol (Physostigmolmethyläther) erhalten werden.
The determination of uranium with o‐oxyquinoline
Authors: Claassen A. , Visser J. 
Published: September 2010

AbstractHecht and Reich‐Rohrwig's method for the determination of uranium by means of o‐oxyquinoline was subjected to a critical investigation. It was found that washing the precipitate with hot water, as prescribed in the original procedure, leads to heavy losses, which can be prevented by washing with a hot 0.04% oxine solution. Precipitation is complete at a pH between 5.0 and 9.0. The proposed procedure gives results which are about 0.2% too low when calculated with the theoretical conversion factor. Ignition of the oxinate to U3O8 gives results accurate within 0.1%. Tartrates do not prevent quantitative precipitation. The separation of U from magnesium, the alkaline earths and from alkali metals is complete.
Über Die Konfiguration des Glutathions aus Tumoren: II. Mitteilung über die Chemie der Tumoren
Authors: Kögl F. , Akkerman A. M. 
Published: September 2010

AbstractEs wurde festgestellt, dass Epi‐g‐glutathion als Aktivator der Glyoxalase fungieren kann; es besitzt etwa 65% der Aktivität des natürlichen Glutathions.Bei der Bestimmung des Glutathion‐Gehalts von Tumoren gibt das manometrische Verfahren von Woodward niedrigere Werte als die jodometrische Methode von Waelsch und Rittenberg; bei normalen Geweben wurde dieser Unterschied nicht gefunden.Lösungen von Cupro‐glutathion in 1.4 n Salzsäure zeigen eine konstante Drehung; die in der Literatur beschriebene Mutarotation beruht auf der bei Luftzutritt erfolgenden Oxydation zum Disulfid.Das aus 14 malignen Tumoren und aus 2 Uterusmyomen als Cuproverbindung isolierte Glutathion zeigte praktisch die gleiche spezifische Drehung wie die aus normalem Gewebe erhaltenen Präparate. An Tumorbrei zugefügtes Epi‐g‐glutathion liess sich durch die Depression der Drehung des isolierten Cupro‐merkaptids nachweisen.
Sur la synthèse et les propriétés de certaines aryl‐benzyl‐cétones
Authors: Buu‐Hoï N. G. Ph. , Royer René 
Published: September 2010

AbstractDans le présent travail, on décrit toute une série de réactions de Friedel‐Crafts entre le chlorure de phénylacétyle d'une part, et d'autre part, de nombreux composés aromatiques appartenant aux noyaux benzénique et naphtalénique. Plusieurs aryl‐benzyl‐cétones nouvelles ont été ainsi préparées, leur constitution établie, et leurs principales propriétés chimiques indiquées. Subsidiairement, la structure d'un corps obtenu autrefois par Mac Kenzie et Tattersall à partir de l'acide phényl‐a‐naphtyl‐acétique a pu être éclaircie.
The basic amino acids, purine bases and pyrimidines of protein‐free grass extracts
Authors: de Man Th. J. 
Published: September 2010

AbstractThe nitrogen compounds of low molecular weight of protein‐free extracts from one of the most important pasture grasses, Lolium perenne, were investigated. Adenine could be isolated as a picrate and arginine as a flavianate from a fraction obtained by a treatment with mercuric acetate and sodium carbonate and a subsequent precipitation with phosphotungstic acid.After hydrolysing the protein‐free extract in order to split the peptides present, in addition to the above mentioned compounds lysine could be isolated as a picrate and a flavianate from the histidine fraction.This flavianate proved not to be a histidine diflavianate, but micro‐analysis showed that it had the composition of cytosine flavianate. The occurrence of cytosine in Lolium perenne was proved and the occurrence of lysine as a building stone of peptides is discussed.The purine fraction obtained with the aid of ammoniacal silver nitrate was investigated; besides adenine, we were not able to isolate other purine bases from this fraction.
Researches on the alkoxy‐amino‐nitrobenzenes II. Synthesis and taste of the ten possible ethoxy and n‐propoxy compounds. Some remarks concerning the problem of the relation between taste and constitution
Authors: Verkade P. E. , Witjens P. H. 
Published: September 2010

AbstractThe preparation of the ethoxy and n‐propoxy compounds of the types III‐X (see below) is described. The aqueous solutions of the substances of type IV taste faintly bitter; the substances of the other seven types possess no appreciable taste.In communication I of this series it was shown that the corresponding compounds of type I have a very pronounced sweet taste, whereas those of type II are tasteless.On the basis of these facts some problems concerning the relation between taste and constitution of organic compounds are discussed.
On the reactions of acid chlorides and acid anhydrides with the lithium compounds of 2‐methylpyridine and 2,6‐dimethylpyridine
Authors: Kloppenburg C. C. , Wibaut J. P. 
Published: September 2010

AbstractIn the action of acetic anhydride on picolyl lithium (I) the by‐product 1,3‐bis‐(2‐pyridyl)‐2‐methylpropanol‐2 (III) is formed in addition to α‐picolylmethylketone (II); in the action of acetyl chloride on I it depends upon the conditions of the experiment whether the main product will be II or III. In the action of benzoic anhydride on I α‐picolylphenylketone (IV) is formed and a small amount of (2‐pyridyl)‐dibenzoylmethane (V). According to the conditions of the experiment the action of benzoylchloride on I gives mainly IV or a base containing no oxygen: 1,3‐bis‐(2‐pyridyl)‐2‐phenylpropene (IX). In the action of phenyl lithium and benzoic anhydride on lutidine 6‐(2‐picolyl)‐dibenzoylmethane (XVII) is formed.
The ozonization of 2,3‐dimethylnaphthalene; and of 1,4‐dimethylnaphthalene. a contribution to the problem of the bond structure of naphthalene
Authors: Wibaut J. P. , van Dijk J. 
Published: September 2010

AbstractBy the ozonization of 2,3‐dimethylnaphthalene are formed glyoxal, methylglyoxal and dimethylglyoxal; these compounds have been identified by means of the oximes.The relative amounts of these oxidation products have been determined, the molecular ratio of dimethylglyoxal to methylglyoxal is about 1 : 0.1. By the ozonization of 1,4‐dimethylnaphthalene are formed glyoxal and methylglyoxal; the relative amounts of these oxidation products have been determined, the total yields are low.The experimental evidence obtained does not support the assumption made by Marckwald, Fries, Fieser and other chemists, that naphthalene and its derivatives have the symmetrical structure (Erlenmeyer‐Graebe structure) and that the single and double bonds between the carbon atoms of the bicyclic system are incapable of migrating.The experimental results can be interpreted in the simplest way by the assumption that 2,3‐dimethylnaphthalene can react according to the three mesomeric forms and that 1,4‐dimethylnaphthalene can react according to an unsymmetrical structure (Erdmann structure). It remains undecided whether 1,4‐dimethylnaphthalene can also react according to the symmetrical structure; however, the assumption that 1,4‐dimethylnaphthalene can react according to the three mesomeric forms is not contradictory to the observed facts.
The carbon‐chlorine bond in the chloronaphthalenes
Authors: Ketelaar J. A. A. , van Oosterhout G. W. 
Published: September 2010

AbstractThe dipole moments of 1 and 2‐chloronaphthalene are discussed by the method of molecular orbitals. If an “effective” electron charge is assumed in agreement with the dipole moment of 1‐chloronaphthalene, the moment of 2‐chloronaphthalene can be calculated in complete agreement with the experimental value.The calculated energy levels are in nearly quantitative agreement with the long‐wave limits of U.V. absorption of the two compounds. From the calculation follow the values 14.2% and 13% for the double‐bond character of the C‐Cl bond in 1 and 2‐chloronaphthalene, respectively. Starting from this result the acid and basic strengths of the naphtholes and the naphthylamines are discussed by consideration of a very simple valence bond scheme.
Electrochemical behaviour of ion‐exchanging substances: II. Potential measurements on plant roots and their bearing on ion uptake by plants
Authors: Tendeloo H. J. C. , Vervelde G. J. , Voorspuy A. J. Zwart 
Published: September 2010

Abstract
Assuming that the non‐diffusible ion in the theory of the Donnan equilibrium originates from a substance which behaves as a weak acid, the concentration of its anion being therefore not constant but depending on the pH, a fairly good agreement could be detected between the calculated and the experimentally found figures for the potentials of plant roots.
Some considerations based on the Donnan principle, concerning the intake of ions by plants from different solutions are in agreement with practical results on plants grown in the field and in culture solutions. It seems likely that the first stage of the intake of ions by living plants, viz. the passage of ions through the root wall, may be understood with this theory of the Donnan equilibrium.
Movement of uncharged particles and molecules in the electric field
Authors: Janssen L. W. 
Published: September 2010

AbstractThe movement of molecules of sugar in the electric field in different solutions of electrolytes is studied in the electrophoresis apparatus of Tiselius and with a modified optical arrangement according to Philpot‐Svensson. It is found that under such conditions uncharged molecules move.The velocity of the sugar molecules is dependent on the strength of the field and on the nature of the ions which are present. The new effect is not due to electroendosmosis, transport of water or electrode phenomena; but originates actually from the kinetic energy of the ions transporting the current. Often the influence of the anions predominates causing an anodic movement of the sugar.Especially in the case of stronger fields the ions crossing the boundaries produce well defined distortions of the boundaries clearly visible with the used optical technique.If uncharged particles can in fact move in the electric field, the results of the investigation of the movement of charged particles, the electrophoresis, ought to be corrected for this new electrokinetic phenomenon.
Étude des solutions colloïdales par des mesures de viscosité et de densité optique
Authors: Boutaric Augustin 
Published: September 2010

AbstractSous diverses influences ou même spontanément les solutions colloïdales sont le siège de transformations se traduisant par une variation de volume de leurs particules. Nous voudrions dans cet exposé appeler l'attention sur les renseignements que permettent d'obtenir les mesures de viscosité et de densité optique et indiquer les résultats ainsi obtenus dans l'étude des solutions colloïdales.
Relaxation effects in stretched cellulose model filaments. I. Relaxation of Retractive Force
Authors: Hermans J. J. 
Published: September 2010

AbstractIf cellulose model filaments are stretched at a moderate rate and then kept at constant length, the retractive force relaxes to a finite value, which is roughly 1/2 of the initial force at the moment relaxation sets in. Both this initial force before and the final force after relaxation are independent of whether the fibre is stretched to the elongation studied in subsequent stages or directly.
Relaxation effects in stretched cellulose model filaments II. Relaxation of double refraction
Authors: Vermaas D. 
Published: September 2010

AbstractHighly swollen fresh cellulose model filaments, when kept at constant length after having been stretched, show an increase in double refraction and a decrease in degree of swelling with time. Reswollen filaments exhibit a decrease in double refraction at relatively low stretch and an increase at high elongation, the degree of swelling remaining constant in the former case and decreasing in the latter. A tentative explanation is given for these variations in double refraction.
X‐ray investigation of d‐α‐Br, Cl and CN‐camphor . A direct determination of a molecular structure by comparison of isomorphous crystal structures
Authors: Wiebenga E. H. , Krom C. J. 
Published: September 2010

AbstractThe structure of the camphor molecule was determined by comparison of the X‐ray diagrams of the isomorphous α‐Br, Cl and CN derivatives. This rather general procedure, avoiding the usual difficulty of Fourier synthesis by a direct determination of the signs of the Fourier components, is described in the introduction of part I. The structure thus found has been checked in part II by comparison of calculated and observed intensities.
The determination of different sugars in aqueous extracts of rye milling products in connection with amylolysis. I. Pre‐existing reducing sugars
Authors: Hintzer H. M. R. 
Published: September 2010

AbstractExact knowledge of the carbohydrate system of the cereal grain is important with regard to the distinction between the kinds of cereals, and especially in the case of rye for the sake of information about its baking value.A method by which the soluble carbohydrates of the cereal grain can be determined side by side with sufficient accuracy cannot be found in the literature up to the present moment. In the following paper a method is indicated by which the reducing sugars in rye flour may be determined biochemically.
The interaction of 1‐chloro‐2‐cyano‐4‐nitrobenzene and 1‐chloro‐4‐nitrobenzene with sodium glycolate and sodium glycerolate
Authors: Blanksma J. J. , Fohr P. G. 
Published: September 2010

AbstractThe chlorine atom in 1‐chloro‐2‐cyano‐4‐nitrobenzene can be replaced by the OCH2. CH2OH and the OCH2. CHOH. CH2OH groups, respectively, by treatment with sodium glycolate and sodium glycerolate. With an anhydrous solution of sodium glycolate in glycol at 150°, 1‐chloro‐4‐nitrobenzene gives 4‐nitrophenyl β‐hydroxy‐ethyl ether. No crystalline compound could be obtained by the interaction of sodium glycolerate and 1‐chloro‐4‐nitrobenzene.
Substitution of mobile halogen atoms in some halogenonitrobenzenes with glycol and glycerol
Authors: Blanksma J. J. , Fohr P. G. 
Published: September 2010

AbstractThe mobile halogen atom in 1‐chloro‐2:4‐dinitrobenzene and other halogenonitrobenzenes can be replaced, by interaction with sodium glycolate or sodium glycerolate, by the β‐hydroxyethyl‐, OCH2.CH2OH and βγ‐dihydroxypropyl, OCH2.CHOH.CH2OH group, respectively. Glycol and glycerol are sweet but 2: 4‐dinitrophenyl β‐hydroxy‐ethyl ether and 2: 4‐dinitrophenyl βγ‐dihydroxypropyl ether, obtained from them, are bitter and these compounds on partial reduction with sodium disulphide afford 2‐amino‐4‐nitrophenyl β‐hydroxyethyl ether, which is twenty times as sweet as cane sugar and 2‐amino‐4‐nitrophenyl‐βγ‐dihydroxypropyl ether, which is thirteen times as sweet as cane sugar. Since 2‐amino‐4‐nitrophenyl ethyl ether is 1,400 times and 2‐amino‐4‐nitro‐phenyl n‐propyl ether, 5.000 times as sweet as sugar, the replacement of the ethoxy group by a β‐hydroxy‐ethoxy group and the replacement of n‐propoxy‐by a dihydroxypropoxy group leads to a very considerable decrease in the intensity of the sweet taste. For the development of the sweet taste, in the compounds mentioned, a free amino group is necessary, since the corresponding acylated derivatives are tasteless, which is in agreement with the observations made previously with 1‐alkoxy‐2‐amino‐4‐nitrobenzenes ) J. J. Blanksma and P. W. M. van der Weyden, Rec. trav. chim. 59, 629 (1940).
.
The reaction between ethyl chlorocarbonate and pyridine compounds
Authors: Arens J. F. , van Dorp D. A. 
Published: September 2010

AbstractBy the action of ethyl chlorocarbonate upon 2‐ and 4‐alkyl pyridines high‐boiling substances are formed from 2 molecules of the pyridine compound and 1 molecule of the chloro‐ester minus hydrochloric acid. It is highly probable that these substances contain an unsaturated chain, formed by the opening of one pyridine ring, attached to the nitrogen atom of a 1,2‐dihydropyridine ring (formula V). By the action of acids and alkalies the substances decompose into the original pyridine compound and carbon dioxide.
Application de la theorie de l'hyperconjugaison a l'etude de la reactivite des molecules organiques
Authors: Buu‐Hoï Ng. Ph. , Daudel Raymond 
Published: September 2010

AbstractIl est montré que la théorie de l'hyperconjugaison permet d'expliquer les règles de substitution expérimentalement trouvées, non seulement pour le noyau benzénique, mais également pour le noyau du naphtalène. La généralisation du concept de l'hyperconjugaison à des combinaisons non aromatiques permet de rendre compte de nombreuses propriétés physiques et chimiques importantes de ces corps.
Derivatives of hydrazine‐N. N′‐dicarboxylic acid
Authors: Vogelesang C. 
Published: September 2010

AbstractHydrazine‐N, N′‐dicarboxylic acid is not known in the free state, but the methyl and ethyl esters are of some importance because they form the starting materials for the preparation of the corresponding azo‐esters. Various other derivatives of hydrazine‐N,N′‐dicarboxylic acid are known, such as the amide, the azide and the hydrazide. These have been studied further.In the hope of being able to prepare nitrohydrazines their behaviour towards absolute nitric acid was investigated; both the esters and the methylamides were completely oxidized. This occurred also with dimethyl methylhydrazine‐N,N′dicarboxylate and methylhydrazine‐ N,N′‐dicarbomethylamide, compounds in which three of the four hydrogen atoms in hydrazine are replaced by protecting groups; nevertheless the stability towards absolute nitric acid appears to be insufficient and these substances differ from compounds like acetanilide and methylaniline, which afford nitramines.The dimethyl ester of (hydrazine‐N,N′‐dicarbohydrazide)‐ωω′‐dicarboxylic acid still gives a visible coloration with 1 part of copper in 4 × 106 parts of water.
On the use of the rotating step sector in combination with intermittent light sources in spectrochemical analysis II
Authors: Schmidt R. 
Published: September 2010

AbstractIn a previous communication ) R. Schmidt, Rec. trav. chim. 62, 437 (1943).
) it was shown that it is possible to apply the combination of an interrupted are, as used by the author) R. Schmidt, A. Schuringa, Rec. trav. chim. 64, 349 (1945). R. Schmidt, thesis Amsterdam 1942.
), and a slowly rotating step sector to the determination of a function of the relative intensities of two spectral lines, which may be used in quantitative spectrochemical analysis as a measure of concentration.To this end the sector speed must be adjusted so that one flash ‐ or an integral multiple ‐ passes the smallest aperture of the sector during one revolution.Arguments are now put forward toward the conclusion that true relative intensities may be measured in this way if the sector speed exceeds a certain critical value, which depends on the photographic emulsion and the illumination (energy/cm2‐sec).Several photographic emulsions were tested with respect to this point.
Untersuchungen über Indolderivate. IX . Die reaktion zwischen methyl‐α‐brompropylketon und primären und sekundären aromatischen aminen
Authors: Janetzky E. F. J. , Verkade P. E. 
Published: September 2010

AbstractIn Anschluss an früheren Untersuchungen wird die Reaktion zwischen Methyl‐α‐brompropylketon und Anilin bzw. Monomethylanilin untersucht.
Organic analysis of hevea latex. IX. Some details of the mainfractions
Authors: Altman R. F. A. 
Published: September 2010

AbstractSome details of the preparation, properties and chemical composition of the main fractions separated from Hevea latex are outlined. The results, which relate exclusively to fresh unammoniated latex of Hevea clone “Tjirandji 1”, are summarized in the table on page 923.
The preparation of peroxides by the oxidation of propane
Authors: Kooijman P. L. 
Published: September 2010

AbstractThe following is a description of an investigation into the optimum conditions for the preparation of peroxides by incomplete oxidation of propane. Special attention has been paid to the optimum formation of hydrogen peroxide.In connection with the removal of heat, it is probably only possible to use a 90/10 propane‐oxygen mixture in a technical apparatus. With this mixture the optimum production of hydrogen peroxide was found at an average reaction temperature of 465°C and a contact time of 4 sec.Under these conditions 15 moles of peroxides (9 moles of which was free hydrogen peroxide) was formed per 100 moles of propane used. At the same time 83 moles of propene was formed, in addition to 87 moles of water, 34 moles of carbon oxides, 12 moles of aldehydes, 1 mole of alcohol and 1 mole of hydrogen.
Some properties of the ecgonines and their esters V: Conversion of 1‐ecgonine in aqueous solutions
Authors: de Jong A. W. K. 
Published: September 2010

AbstractBy heating l‐ecgonine in weakly acidified aqueous solution and also in strong hydrochloric acid solution, l‐ecgonine is converted to the extent of 10.5‐12.5% into d‐φ‐ecgonine, an equilibrium mixture of ecgonines being formed.Both l‐ and d‐φ‐ecgonine give black crystals like l‐ecgonidine with hydriodic acid solution containing iodine; these crystals, when boiled with water, give solutions which show respectively leavo‐ and dextro‐gyratory rotations.On boiling l‐ecgonine as an alkali‐salt in saturated alkali chloride solution, another equilibrium is reached between the ecgonines; the sodium salt gave a 86.9% conversion into d‐φ‐ecgonine, the potassium salt one of 69% and the calcium salt one of 78.5%.
Researches on heat of combustion I: Method and apparatus for the accurate determination of heats of combustion
Authors: Coops J. , van Nes K. , Kentie A. , Dienske J. W. 
Published: September 2010

AbstractAfter a brief description of a new apparatus for the determination of heats of combustion, the theory of an isothermally jacketed calorimeter is discussed. Several factors which require attention in accurate determinations are dealt with, viz.: purity of reagents, completeness of the combustion reaction, determination of time, determination of weight and corrections of the second order. A description is then given of some details of the apparatus and method. The accuracy attained, 0.01‐0.02%, is demonstrated in a series of experiments. Finally, it is shown that the heat of combusiton of our sample of benzoic acid is in excellent agreement with that of preparation 39b of the National Bureau of Standards, Washington.
Researches on heat of combustion III: The use of the Beckmann thermometer as a very accurate instrument for use in isothermally jacketed calorimeters
Authors: Coops J. , van Nes K. 
Published: September 2010

AbstractFor measuring a rise in temperature the ordinary Beckmann thermometer is in no way inferior to the resistance thermometer if the measurements are carried out in a definite way and if at the same time a number of precautions (with regard to vibrator, manostat and water jacket around the scale) are taken, in order to obviate the effects of possible errors in the instrument. In an example it is shown that by taking these things into consideration it is possible to obtain a (relative) temperature reading, which is accurate to 5 × 10−5°. Thus it is possible, by using the Beckmann thermometer, to carry out heat measurements reproducible to 0.01%.