bluuebunny/crossref_metadata_2025_split huggingface dataset:
The reaction between ethyl diazoacetate and 1‐butoxybutane
Authors: de Graaff G. B. R. , van de Kolk G. 
Published: September 2010

AbstractIn continuation of a previously published investigation on the reaction between ethyl diazoacetate and ethers of different typesG. B. R. de Graaff, Mrs. J. H. van Dijck‐Rothuis and G. van de Kolk, Rec. trav. chim. 74, 143 (1955).
, the reaction mentioned in the title has been examined more completely.It has been found that several esters of butoxy derivatives of normal and branched caproic acids are formed together with ethyl butoxyacetate and butene‐1.Thus, two reactions appear to occur simultaneously viz.:
an addition reaction of the radical, formed from the reagent, to the oxygen atom of the ether;
direct attack by the radical of the various carbon atoms of the alkyl groups.
The structure of the reaction products has been proved and a discussion on the results obtained is given.
Investigations on sterols. X: The conversion of ergosterol and pre‐ergocalciferol by U.V. light of 254 mμ
Authors: Rappoldt M. P. , Westerhof P. , Hanewald K. H. , Buisman J. A. Keverling 
Published: September 2010

AbstractA study is presented of the conversion of ergosterol and pre‐ergocalciferol by U.V. light of 254 mμ From the experiments certain conclusions are drawn regarding the formation of tachysterol2 from ergosterol and on the quantum‐efficiency of the interconversion of pre‐ergocalciferol and tachysterol2.
A simple recording balance
Authors: Scholten P. C. , Smit W. M. , Wijnen M. D. 
Published: September 2010

AbstractA recording balance, consisting of a simple analytical balance, an electronic part and a recorder, is described.In a normal balance any deflection causes a compensating force due to gravity.The present balance has been made mechanically indifferent and an electrical zero‐point has been introduced, which may be shifted at will. The compensating force (which is free from any gravity component at any deflection) is directed by the deflection of the balance with the aid of a simple electro‐optical system. The electrical system, which contains no servo‐motor, also provides damping. Equilibrium is attained without restoring the balance to an initial position.The sensivity of the balance may be changed easily from 25 mg to 200 mg full scale deflection of the recorder.The accuracy, which is mainly determined by the accuracy of the recorder, amounts to 0.3% of full scale deflection.The use of the present balance as a thermobalance is described.But for the recorder the apparatus is simple and inexpensive.
The mercuration of pyridine‐N‐oxide
Authors: van Ammers M. , den Hertog H. J. 
Published: September 2010

AbstractBy heating pyridine‐N‐oxide with mercuric acetate in acetic acid solution at 130°, a reaction product was obtained, which afforded, after reacting successively with sodium chloride solution and bromine, a mixture containing 2‐bromo‐ and 2,6‐dibromopyridine‐N‐oxide. The structure of the dibromo‐compound was proved by converting it via 2,6‐dibromo‐4‐nitro‐pyridine‐N‐oxide into the known 4‐amino‐2,6‐dibromopyridine. Our result differs from that obtained by Ukai, Yamamoto and Hirano who record the 4‐monosubstituted derivative as the sole product of reaction under the same conditions 2).2,6‐Dibromopyridine‐N‐oxide is an excellent intermediate for the preparation of derivatives of pyridine and its N‐oxide, especially for those substituted in positions 2, 4 and 6.
Selective reduction by calcium hexammine: Part I. Aromatic hydrocarbons
Authors: Boer H. , Duinker P. M. 
Published: September 2010

AbstractFollowing up an investigation by Kazanskii B. A. Kazanskii and N. V. Smirnova, Bull. Acad. Sci. U.S.S.R., class. Sci. math. nat. 1937, 547; B. A. Kazanskii and N. F. Glushnev, J. Gen. Chem. U.S.S.R. 8, 642 (1937).
), the authors have investigated fne use of calcium hexammine, Ca(NH3)6. as an agent for laboratory‐scale selective reductions of aromatic hydrocarbons.Under carefully adjusted reaction conditions it proved to be possible to reduce polynuclear aromatic hydrocarbons to compounds containing only one isolated benzene ring. Under somewhat different conditions alkyl‐benzenes could be reduced to the corresponding cycloalkadienes or cyclo‐alkenes. It is assumed that reduction by metalammonia reagents requires a conjugated system of double bonds.The method described opens up possibilities for the preparation of compounds which are difficult to synthesize in other ways. Thus, cyclohexadiene‐1,4, as‐octahydrophenanthrene and some alkyltetralins were synthesized in fair yields.Some remarks are made on the mechanism of the reaction.A convenient method for the preparation of calcium hexammine is described.
Thermodynamic properties of quinol clathrates II. Vapour pressures of argon clathrates
Authors: Platteeuw J. C. 
Published: September 2010

AbstractThe equilibrium clathrate‐gas has been studied for the quinol‐argon compound at 60° C. It was found that the argon pressure is related to the composition of the clathrate according to a Langmuir isotherm, as predicted on theoretical grounds.
Foam stability: Part V. Mechanism of film rupture
Authors: de Vries A. J. 
Published: September 2010

AbstractLamellae of pure liquid and low‐molecular solutions are unstable because of the absence of a limiting thickness. Rapid collapse of these lamellae may start at relatively large thickness (∼ 500 Å) under influence of the London‐van der Waals attractive forces. Small quantities of surface active ions will prevent this collapse mechanism to occur in aqueous lamellae. A sufficient amount of activation energy for rupturing a “stable” lamella may be supplied by a local depression of surface tension in a small volume element of the film. The minimum surface area of such an element is calculated as a function of the film thickness, and its dependence on the rheological properties of the superficial layers of liquid (plasticity, viscosity and elasticity) is explained.Some results are given of an experimental investigation of the influence of a local rise in temperature on the lifetime of isolated lamellae of a Tee‐pol solution. The destabilizing effect of local heating is interpreted as a result of the decrease of surface tension in the warmer portion of the film. The importance of local temperature variations for the instability of foams is discussed. A calculation is given of the magnitude, frequency and average lifetime of spontaneous temperature fluctuations in liquid lamellae under adiabatic conditions. It is shown that these fluctuations are able to affect the stability of very thin lamellae only (thickness of the order of some tens of Å).A general explanation of the action of anti‐foaming agents is given, based on the occurrence of local depressions in surface tension. Finally the effect of mechanical disturbances on the probability of film rupture is considered.
Hydrocarbures Polycycliques Aromatiques. VIII. Sur deux homologues monométhylés du naphto[2,3‐a]pyrène
Authors: Buu‐Hoï N. P. , Lavit Denise , Jacquignon Pierre , Chalvet Odilon 
Published: September 2010

AbstractOn décrit la synthèse de deux homologues monométhylés du naphto [2,3‐a] pyrène. Le 10‐méthylnaphto[ 2,3‐a] pyrène a été préparé par la réaction d'Elbs à partir du 3‐(2,5‐diméthylbenzoyl)pyrène; d'autre part, la formylation du naphto [2,3‐a] pyrène conduit principalement à un aldéhyde qui, d'après le calcul des indices de valence libre effectué selon la méthode des combinaisons linéaires d'orbitales atomiques, doit étre le 6‐formylnaphto‐[2,3‐a] pyrène; comme sous‐produit de la réaction, on obtient un peu de 7‐formylnaphto[2,3‐a]pyrène. La réduction du dérivé 6‐formylé fournit le 6‐méthylnaphto[2,3‐a]pyrène, lequel peut être formylé à son tour pour donner le 7‐formyl‐6‐méthylnaphto[2,3‐a]pyrène.
Hydrocarbures Polycycliques Aromatiques. IX. Synthèse des 1,2‐ et 2,3‐cyclopenténoanthracènes, du 1,2‐benzanthracène et du naphtacène par la réaction d'Elbs
Authors: Buu‐Hoï N. P. , Lavit Denise 
Published: September 2010

AbstractIl est montré que la réaction d'Elbs, pratiquée sur le 5‐o‐toluoylindane, conduit principalement au 2,3‐cyclopenténoanthracène, le 1,2‐cyclopenténoanthracène étant obtenu en petites quantités comme sous‐produit de la réaction; la pyrolyse de la 2‐o‐toluoyltétraline, suivie de la déshydrogénation du produit de la réaction, conduit au 1,2‐benzanthracène et au naphtacène. Le 2,3‐cyclopenténoanthracène peut être formylé en position méso pour donner le 9‐formyl‐2,3‐cyclopenténoanthracène, lequel est réduit par la méthode de Kishner‐Wolff en 9‐méthyl‐2,3‐cyclopenténoanthracène.
Steric effects on mesomerism. XVII. Some properties of aromatic nitro‐, amino‐, and acylamino compounds with bulky ortho‐substituents
Authors: Burgers J. , Hoefnagel M. A. , Verkade P. E. , Visser H. , Wepster B. M. 
Published: September 2010

AbstractFollowing up earlier work, this paper discusses the influence of 2‐methyl‐6‐tert.butyl substitution and/or 2,6‐di‐tert.butyl substitution on certain properties of compounds such as nitrobenzene, aniline, N‐methylaniline, N,N‐dimethylaniline, acetanilide, 4‐nitro‐aniline, and 4‐nitro‐acetanilide.For the derivatives of nitrobenzene, N,N‐dimethylaniline, and acetanilide the electronic absorption spectra indicate a complete or almost complete elimination of the mesomeric interaction. In contrast with this it has to be concluded for all the primary amines investigated that the mesomerism is fully developed; in the relevant discussion the vectorial treatment of absorption Intensities has been of decisive importance. The secondary amines take up an intermediate position; in these cases, owing to the pyramidal configuration of the nitrogen atom, the angle of twist cannot be forced to values exceeding about 60°.The basic strength of 2,6‐di‐tert.butyl‐substituted primary amines is lower by a factor of about 108 than might be expected on the basis of the electrical effects of the alkyl groups; the basic strength of 2‐methyl‐6‐tert.butyl‐substituted N,N‐dimethylanilines is lower by a factor of about 106 than might be expected on the basis of the electrical effects of the alkyl groups and the steric inhibition of the mesomerism present in these compounds. These reductions of the basic strength have been ascribed to steric hindrance to solvation.The basic strength of 3,5‐di‐tert.butyl‐4‐nitroaniline confirms previously obtained information on the quantitative significance of the inductive and the mesomeric effect of the nitro group in 4‐nitroaniline as well as on the meta/para ratio of the inductive effect.
A new factor involved in amino acid incorporation and nucleic aced synthesis
Authors: Gale E. F. 
Published: September 2010

AbstractTable II summarises the present situation concerning the activities of the incorporation factor preparation. If disrupted staphylococcal cells are treated so that the greater part of their nucleic acid is removed, then the incorporation of a single amino acid such as glycine or glutamic acid can be promoted by the IF preparation to the same extent as by nucleic acid. The synthesis of RNA, as measured by the incorporation of adenine into the RNA fraction, requires the presence of a complete mixture of amino acids, the natural purines and pyrimidines, DNA and the IF preparation. The synthesis of protein, as judged by the development of catalase and β‐galactosidase, requires a complete mixture of amino acids, DNA and, in the case of catalase, RNA or in the case of β‐galactosidase, the synthesis of RNA; in neither case does IF have any effect over and above that involved in the nucleic acid or its synthesis. This may mean that the factor is concerned in the synthesis of ribonucleic acid and the role of amino acids in that synthesis rather than in the formation of protein per se.
Steric effects in the electronic spectra of substituted benzophenones III: Duryl ketones
Authors: Rekker R. F. , Nauta W. Th. 
Published: September 2010

AbstractThe U.V.‐absorption spectra of diduryl ketone, diisoduryl ketone and durylisoduryl ketone have been measured and mutually compared.A ketone previously described by Coops et al. as diduryl ketone was definitely established as durylisoduryl ketone.
Hydrocarbures Polycycliques Aromatiques. X: La formylation de l'acénaphtylène et du fluoranthène
Authors: Buu‐Hoï N. P. , Lavit Denise 
Published: September 2010

AbstractDans le cadre d'une étude sur le comportement des hydrocarbures polycycliques péri‐condensés dans la réaction de formylation par les formiamides N,N‐disubstitués, il est montré que l'acénaphtylène conduit au 1‐formylacénaphtylène, alors que, dans les mêmes conditions, le fluoranthène ne réagit pas. On discute également de la corrélation entre la facilité de formylation et les valeurs des indices de valence libre chez les hydrocarbures polycycliques péri‐condensés.
Chemistry of acetylenic ethers XXXII. Formation of 1,3‐dialkyl‐2‐ethoxy‐cyclobut‐2‐ene‐4‐ones from ethyl 1‐alkynyl ethers
Authors: Nieuwenhuis J. , Arens J. F. 
Published: September 2010

AbstractOn heating, ethylene is eliminated from an ethyl 1‐alkynyl ether; the product formed in good yield is a 1,3‐dialkyl‐2‐ethoxy‐cyclobut‐2‐ene‐4‐one. The ethoxy group can easily be saponified and the resulting product is a dimer of an alkyl ketene. Other reactions are summarised in scheme B.
1,3,5‐Triacetylbenzene as a base material for the preparation of symmetrical trialkylbenzenes
Authors: Wibaut J. P. , Paulis B. 
Published: September 2010

AbstractThe Grignard reaction of 1,3,5‐triacetylbenzene with CH3MgX has been studied; the synthesis is described and physical constants are given of four symmetrical trialkylbenzenes:1,3,5‐triisopropylbenzene,1,3‐diisopropyl‐5‐ethylbenzene,1‐isopropyl‐3,5‐diethylbenzene and1,3,5‐triethylbenzene.
Synthesis and some physical constants of three 5‐alkylindanes and two 6‐alkyltetralins
Authors: Wibaut J. P. , Paulis B. 
Published: September 2010

AbstractThe synthesis is described and physical constants are given of some 5‐alkylindanes and 6‐alkyltetralins, all containing fifteen carbon atoms: 5‐n‐hexylindane, 5‐(2‐methylpentyl)indane. 5‐(2‐ethylbutyl)indane. 6‐n‐pentyltetralin and 6‐(1‐ethylpropyl)tetralin.
The temperature variation of orthobaric density difference in liquid‐vapour systems. IV. Fatty acids
Authors: Costello J. M. , Bowden S. T. 
Published: September 2010

AbstractThe density of a series of fatty acids has been determined over ranges of temperature below and above the boiling point. It is shown that the variation of orthobaric density difference with temperature is well represented by the Verschaffelt equation. In general the exponent does not depart greatly from the standard value for non‐associated systems and its variability with temperature is not so marked as that found for water and the aliphatic alcohols. The equation applies with considerable precision to acetic acid from 0° to 280°C. The mean deviation between observed and calculated values of the orthobaric density difference for the higher acids generally does not exceed 0.3%.
The application of ion‐exchangers in detergent analysis
Authors: Voogt P. 
Published: September 2010

AbstractA method is described for the separation of mixtures of the sodium salts of some alkylsulphuric or sulphonic acids, fatty acids and non‐ionic material into three fractions containing strong acid, weak acid, and non‐ionic constituents respectively. To this end, the mixtures are successively passed over the ion‐exchangers Dowex‐50, X8, [H+], Dowex‐1, X2, [Ac−], and Dowex‐2, X8, [OH−]. The individual acids can be titrated potentiometrically. From the amount of titrant used and the weight of the salts formed as a result of the titration, both the contents and the molecular weights of the acids can be calculated. The content of non‐ionic constituents can be determined gravimetrically.
Assignment of the vibrational frequencies of S2X2 molecules
Authors: Hooge F. N. , Ketelaar J. A. A. 
Published: September 2010

AbstractA survey is given of the spectra of H2S2, S2(CH3)2, S2F2, S2Cl2 and S2Br2. The vibrational frequencies are calculated for a simplified planar cis model. This calculation leads to an assignment of the observed frequencies, which differs at some points from assignments given previously by other authors.
The assignment of the vibrational frequency of the P = S group
Authors: Hooge F. N. , Christen P. J. 
Published: September 2010

AbstractThe infrared spectra are given of (C2H5)3P, (C2H5),PO, (C2H5)3PS. (CH3)3PS and (C2H5)PSCl2.From these spectra and spectra of other P = S compounds published previously a useful correlation was found between the position of the P = S band and the different groups attached to the phosphorus atom in XYZP=S molecules. This correlation is supported by model calculations. A survey is given in fig. 10.
Some reactions of 1,1,1,3‐tetrachlorobutane
Authors: Kooyman E. C. , Wagner W. M. 
Published: September 2010

Abstract1,1,1,3‐Tetrachlorobutane reacts with an excess of many nucleophilic reagents to give good yields of products Cl2C = CH‐CHX‐CH3, in which X may be an OH, O‐alkyl, O‐aryl, aryl‐OH, NH2, alkylamino or dialkylamino group. Trichlorobutenes are probably intermediates, a mixture of 1,1,3‐trichlorobutene‐1 and 1,1,1‐trichlorobutene‐2 being formed when using a molecular proportion of alkali.The results are compared with those recently reported by Nesmeyanov et al.A. N. Nesmeyanov, R. Kh. Freidlina, L. I. Zakharkin and A. B. Belyavsky, Zhur. Obshchei. Khim. 26, 1070 (1956): Chem. Abstr. 50, 16658 (1956). Compare also A. N. Nesmeyanov et al., Quart. Revs. 10, 330 (1956).
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Etude Polarographique des Bishydroperoxydes Stéroïdes
Authors: Legrand Maurice , Delaroff Vladimir , Bimbad Madeleine 
Published: September 2010

AbstractEn milieu hydro‐alcoolique contenant du p‐toluéne sulfonate de sodium, les bishydroperoxydes stéroïdes fournissent, entre pH 5 et 8, des polarogrammes présentant en général quatre vagues. Les deux dernières permettent d'effectuer des dosages.La troisième vague correspondrait à la réduction du bishydroperoxyde qui redonnerait la cétone de départ et de l'eau oxygénée ensuite réduite au niveau de la dernière vague.
Researches on plant growth regulators, XXIV. Structure/activity, IX. Tetrazole derivatives
Authors: van de Westeringh C. , Veldstra H. 
Published: September 2010

AbstractTetrazole analogues of different types of carboxylic acids active as growth substances, were synthesized and analyzed as to their activity in the pea test and in the avena straight growth test.A large difference between the activities of indole and naphthalene derivatives, not normally found with growth substances, was observed.
Synthesis of β‐phenylethylamine derivatives VI Stereoisomers of 1‐(4′‐hydroxyphenyl)‐2‐(1″‐methyl‐2″‐phenoxyethylamino) propanol‐1
Authors: van Dijk J. , Moed H. D. 
Published: September 2010

AbstractThe synthesis is described of the four pairs of enantiomeric modifications of magnified imageThe stereochemical structures have been correlated with those of erythro‐ and threo‐ephedrine.Conformation analysis has been used to explain the configuration of the amino‐alcohols formed.
Studies on sedum alkaloids V. Synthesis and optical resolution of sedamine and sedridine
Authors: Beyerman H. C. , Eenshuistra J. , Eveleens W. , Zweistra A. 
Published: September 2010

AbstractThe synthesis of the racemates of the alkaloids sedamine and sedridine, the separation of the racemates, and their resolution into optical antipodes are described, with the exception of the resolution of (±)‐allosedridine and so far as no earlier information about these subjects has been given by us.The results are compared with data about the natural products obtained from Sedum acre and Lobelia inflata.
Hydrogenation of 2,6‐dimethyl‐4‐pyrone II
Authors: de Vrieze J. J. 
Published: September 2010

AbstractHydrogenation of 2,6‐dimethyl‐4‐pyrone affords pure 2,6‐dimethyltetrahydropyran‐4‐ol with a modified Raney‐nickel catalyst whereas with a palladium catalyst 2,6‐dimethyltetrahydro‐4‐pyrone is eventually obtained. Partial hydrogenation with a palladium catalyst affords a mixture of 2,6‐dimethyldihydro‐4‐pyrone and 2,6‐dimethyltetrahydro‐4‐pyrone. The latter is hydrogenated to 2,6‐dimethyltetrahydropyran‐4‐ol in presence of platinum.
Thermodynamic properties of gas hydrates II: Phase equilibria in the system H2S‐C3H3‐H2O AT −3°C
Authors: Platteeuw J. C. , van der Waals J. H. 
Published: September 2010

AbstractThe system H2S‐C3H8‐H2O was investigated at −3°C. It was found that the H2S/C3H8 ratio in the hydrate phase depends on the composition of the coexisting gas phase. In this respect it is similar to the system CH4‐C3H8‐H2O studied previously. Unlike the latter, the present system exhibits a minimum pressure (“azeotrope”). It is shown that the solution theory of clathrates can account for this phenomenon.Our investigation of hydrates in ternary systems leads us to the conclusion that von Stackelberg's distinction between double hydrates and mixed hydrates is not an essential one: both types of hydrates are solid solutions of two volatile solutes in a hydrate lattice.
The reaction of alkylmagnesium halides with thiophosphoryl chloride. I. Formation of bi(dialkylphosphinothioyl) compounds
Authors: Christen P. J. , van der Linde L. M. , Hooge F. N. 
Published: September 2010

AbstractThe reaction of PSCl3, with alkylmagnesium halides has been studied. In the case of methyl‐, ethyl‐, propyl‐, butyl‐ and isobutyl‐magnesium halides compounds with formula (R2PS)2, were formed. Their infrared spectra were recorded from 400 cm−1 to 3000 cm−1. From these spectra it was concluded that bi(dialkylphosphinothioyl) compounds were formed.In most cases a number of by‐products were isolated and some of these were identified.
An improved synthesis of vitamin B6 (pyridoxol)
Authors: Wuest H. M. , Bigot J. A. , de Boer Th. J. , Wal B. V. D. , Wibaut J. P. 
Published: September 2010

AbstractThe known synthesis of “Ichiba acid”, 2‐methyl‐3‐hydroxypyridine 4,5‐dicarboxylic acid (VII), starting from ethyl acetylpyruvate and cyanoacetamide, has been reinvestigated and simplified to a five step process.Several derivatives of Ichiba acid have been prepared including the tribenzyl derivative (XIV), with easily accessible dimethylphenylbenzylammonium hydroxide, and the 3‐acetoxy‐anhydride (XVI) with acetic anhydride.These derivatives are reduced with LiAlH4 to vitamin B6 (VIII) in yields of 72 and 53% respectively.Results have been compared with the reduction of related pyridine 4,5‐ dicarboxylic acid derivatives with LiAlH4.
Reaction products of primary β‐hydroxyamines with carbonyl compounds. XIII. Condensation of Primary β‐Mercaptoamines with Carbonyl Compounds
Authors: Bergmann Ernst D. , Kaluszyner A. 
Published: September 2010

Abstract2‐Mercaptoethylamine and 2‐amino‐3‐mercaptobutane have been condensed with various carbonyl compounds. The structure of 14 of these condensation products has been studied by physical methods (molecular refraction, infrared spectrum, ultraviolet spectrum). In all cases, the products formed were thiazolidines and not Schiff bases; in this respect, the 2‐mercaptoamines behave differently from their oxygen isologs.For comparison, the condensations of N‐substituted 2‐mercaptoethylamines with various carbonyl compounds have also been studied (22 examples). The thiazolidine ring causes a depression of the molecular refraction and is characterized by a series of infrared bands in the 1000–1380 cm−1 region. Contrary to the experience with N‐phenylethanolamine, N‐phenyl‐2‐mercaptoethylamine is capable of condensing not only with aldehydes, but also with ketones.
Synthesis and reactions of diphenyl (β‐pyridyl) chloromethane; Formation of a diphenyl‐(β‐pyridyl)methyl radical
Authors: Otto P. Ph. H. L. , Wibaut J. P. 
Published: September 2010

AbstractThe synthesis and properties of some new compounds connected with diphenyl (β‐pyridyl) carbinol, viz. diphenyl (β‐pyridyl) carbinol hydrochloride, diphenyl (β‐pyridyl) chloromethane and its hydrochloride, bis[diphenyl‐ (β‐pyridyl) methyl] peroxide and a compound C36H28N2, are described. The peroxide is very probably produced from the diphenyl (β‐pyridyl)‐methyl radical formed initially.