bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant pigments in digestion trial studies
Authors: Deijs W. B. , Bosman Maria S. M. 
Published: September 2010

AbstractThe plant pigments (“chromogens”) in extracts of fresh grass and feces from cows in 85 per cent (by volume) acetone, applied as digestion trial markers, have been separated and determined chromatographically. In the extracts of fresh grass chlorophyll (converted into pheophytin by oxalic acid), carotene, xanthophyll, and a small amount of porphyrins could be determined. In feces pheophytin, carotene, xanthophyll, phylloerythrin, and other porphyrins not yet defined could be detected.The application of naturally occurring plant pigments as Indicators in the determination of the digestibility of feed by ruminants has been discussed.
Studies on tautomerism V: Some remarks on the tautomeric equilibrium, dimerization, and ionization of quinone monoximes (nitrosophenols)
Authors: Schors A. , Kraaijeveld A. , Havinga E. 
Published: September 2010

AbstractMeasurements of absorption spectra in the ultra‐violet as well as in the visible (red) region were used to study the tautomeric equilibria in the case of p‐benzoquinone monoxime, 3‐chlorobenzoquinone‐4‐monoxime, naphthoquinone monoxime, and anthraquinone monoxime.In die case of the benzoquinone monoxime ‐ and less easily also with the chloroquinone monoxime ‐ the presence of the nitrosophenol form could be traced and its amount could be estimated. This was not possible with the naphthoquinone monoxime and the anthraquinone monoxime, which in solution seem to consist almost completely of the quinonoid form. A short theoretical comment is given.Experimental results and conclusions concerning the spectra of nitroso‐benzenes in general are discussed. Complications that may be caused by dimerization phenomena and by electrolytic dissociation of the compounds investigated were studied.Some nitrosophenols were found to be rapidly etherified at room temperature in methanol (and less quickly also in other alcohols) which had been acidified by addition of a few per cent, of concentrated hydrochloric acid.
Eine genaue Methode zur Papierelektrophoretischen Auswertung von Proteinen
Authors: de Jong E. B. M. 
Published: September 2010

AbstractFür die Anfärbung der Eiweissfraktionen auf Filtrierpapier wird Amidoschwarz benutzt, weil dieser Farbstoff ein sehr gutes Bindungsvermögen mit Protein hat und unabhängig von der Auswaschmethode mit den verschiedenen Eiweissfraktionen ein konstantes Bindungsverhältnis aufweist.Der Nachteil der schweren Auswaschbarkeit des Amidoschwarz an der nicht mit Eiweiss beladenen Stelle, wird beseitigt indem man einen einfachen Apparat gebraucht, worin die Papierstreifen bei 65° C mit 1%‐iger Essigsäure ausgewaschen werden.Nach eingehenden Untersuchungen der photometrischen Auswertung, haben wir die Folgerung gezogen, dass diese Methode aus prinzipiellen Gründen verwerflich ist.Deshalb wird die Elutionsmethode benutzt. Die Ursache der Unbeständigkeit von Amidoschwarz in Lauge wird untersucht, weil diese Unbeständigkeit selbstverständlich eine genaue Bestimmungsmethode verhindert.Es wurde gefunden, dass die Unbeständigkeit ihre Ursache in der Anwesenheit von Schwermetall‐ionen in Lauge hat, was durch Zufügung von “Komplexon” völlig beseitigt werden kann.Eiweissmengen bis 0.75 mg auf 2 cm2 Filtrierpapier weisen ein genaues lineares Verhältnis auf mit der Menge gebundenem Farbstoff.Die verschiedenen Eiweissfraktionen können nach Papierelektrophoretischer Trennung mit einer sehr geringen Fehler bestimmt werden.Für Alb. ± 0.5; α1 ± 0.3; α2 ± 0.3; β ± 0.3 und γ ± 0.4 rel. Prozente.Mit unserer Methode konnten bei 45 gesunden Personen Normalwerte bestimmt werden.Albumin 69.8 ± 1.5; α1‐Glob. 3.3 ± 03; α2‐Glob. 6.3 ± 0.6; β‐Glob. 7.9 ± 0.8 und γ‐Glob. 12.9 ± 1.3.
Fibre‐forming polyalkylene ureas: I. General remarks on the chemical preparation and a study of the structure and the mechanism of formation
Authors: van der Kerk G. J. M. , Overmars H. G. J. , van der Want G. M. 
Published: September 2010

AbstractThe chemical preparation is described of linear polyalkene ureas from aliphatic α,ω‐diamines and carbon oxysulphide. Using chemical and physical methods, the mechanism of the poly‐condensation reaction is studied and a satisfactory picture of the structure and of the mode of formation is obtained.After melt‐spinning the products can be cold‐stretched to form strong and flexible fibres
Synthesis of di‐amino‐salicil and some of its derivatives
Authors: Berends W. , Waisvisz J. M. , Mulder A. K. J. 
Published: September 2010

AbstractFrom the work of R. Kuhn et al. it appeared that brominated derivatives of salicil have a high anti‐bacterial activity in vitro, but that in vivo they show only little activity as a result of serum‐binding. Base‐substituted phenols are usually bound by serum to a smaller extent. Therefore, an amino‐substituted bromo‐salicil was synthesized. A water soluble derivative of this compound was also prepared.
Dehydration of 17α‐hydroxy‐20‐ketopregnanes
Authors: Szpilfogel S. A. , Gerris V. 
Published: September 2010

AbstractDuring an investigation on compounds related to cortisone the dehydration of various 17α‐hydroxy‐20‐ketopregnanes was studied.In a recent paper Bernstein et al.1) reported on the elimination of 17α‐hydroxy groups adjacent to a 20‐ketal group. These hydroxy groups were known to be stable towards phosphorus oxychloride‐pyridine at room temperature2), but with thionyl chloride‐pyridine the desired Δ16‐steroids were formed. This publication covers part of the work carried on for some time in this laboratory and prompts us to give our additional results.
Über Glutamal‐5, Aspartal‐4 und einige hiervon Abgeleitete Peptide: Untersuchungen in Beziehung zu Eiweiss‐Problemen VII
Authors: Kög F. , Schopman W. 
Published: September 2010

AbstractDer γ‐Halbaldehyd von DL‐Glutaminsäure und der β‐Halbaldehyd von DL‐Asparaginsäure wurden durch Zerlegung der entsprechenden Mercaptale dargestellt. Letztere dienten weiterhin zur Synthese der Aldehydopeptide Glycyl‐DL‐glutamal‐5, Glycyl‐DL‐glutamal‐5‐yl‐glycin und Glycyl‐DL‐aspartal‐4. Aus dem Verhalten dieser Peptide bei der Hydrolyse mit Salzsäure ist zu folgern, dass die genannten Aldehyde ‐ falls sie als Baustein von Proteinen auftreten würden ‐ in den entsprechenden Hydrolysaten nicht ohne weiteres nachweisbar sind.
Synthesis of α‐phenacyl‐N‐methylpiperidine (“sedamine‐ketone”) under pseudo‐physiological conditions.(Short communication)
Authors: Beyerman H. C. , Enthoven P. H. 
Published: September 2010

AbstractThe condensation of N‐methyl‐α‐piperidol (I), which we consider to be a cyclic tautomer of 5‐methylaminopentanal (II), with benzoylacetic acid is reported to give α‐phenacyl‐N‐methylpiperidine (“Sedamine‐ketone”, IVa) in yields up to 50% depending on the pH of the reaction mixture.
The effect of long‐chain alcohols on the properties of sodium laurate solutions: Part I. Surface tension
Authors: Harva O. 
Published: September 2010

AbstractThe surface tensions of sodium laurate solutions containing aliphatic alcohols from hexanol up to decanol have been measured at pH 11. The occurrence of break points in the surface‐tension concentration curves for higher alcohol concentrations are explained by assuming complex formation to occur between the laurate anion and the alcohol molecule.
Reactions of ethyl bromide and aluminium bromide. I. Bromine exchange
Authors: Sixma F. L. J. , Hendriks H. , Holtzapffel D. 
Published: September 2010

AbstractThe kinetics of the exchange reaction of bromine atoms between ethyl bromide‐ [82Br] and aluminium bromide in carbon disulphide has been studied. The reaction rate is proportional to the ethyl bromide concentration and to the square of the aluminium bromide concentration. The energy of activation amounts to 11.7 kcal/mole (±7%).It is probable that no carbonium ions are involved in the reaction.The rate of the exchange reaction is very low in such solvents as nitrobenzene, nitromethane, ether and acetonitrile. This is ascribed to the formation of rather strong complexes between these solvents and aluminium bromide.
Synthèse de quelques nouveaux éthylpolyméthylphénols
Authors: Buu‐Hoï N. P. , Sy Michel , Lejeune Guy 
Published: September 2010

AbstractA l'aide d'une méthode de récurrence comprenant des formylations par la diméthylformiamide, des réductions d'aldéhydes par l'hydrate d'hydrazine, et des déméthylations des polyalkylanisoles obtenus par le chlorhydrate de pyridine, on a préparé le 3‐éthyl‐4,5‐diméthylphénol, le 3‐éthyl‐2,4,5,6‐tétra‐méthylphénol, et le 1,3‐diméthyl‐5,6,7,8‐tétrahydro‐2‐naphtol; le 2‐éthyl‐3,4,5‐triméthylphénol a été préparé à partir du 2‐acétyl‐3,4,5‐triméthylanisole.
Studies on vitamin D and related compounds V: Corroboration of the scheme proposed for the photochemical conversion of the provitamins D, in particular with regard to the place of the previtamins D
Authors: Havinga E. , Verloop A. , Koevoet A. L. 
Published: September 2010

AbstractIn continuation of the irradiation experiments with mixtures of labelled provitamin D and inactive lumisterol and tachysterol, which led to the rejection of the traditional reaction scheme and the introduction of a new scheme for the photochemical conversion of provitamin D 1) 2), mixtures of C14‐labelled ergosterol and inactive previtamin D2 were irradiated and the resulting products analysed. Moreover, complementary spectrophotometric investigations into the photochemical conversion of previtamin D2 were carried out. The results confirmed the non‐validity of the schemes which assign to one of the irradiation products of provitamin D the part of an essential intermediate for the formation of the other products. Particularly, the investigations confirmed that previtamin D2 does not function as an essential intermediate with respect to the formation of tachysterol2 from ergo‐sterol 4) 5). The possibility is mentioned that the unstable intermediate which holds a central position in the proposed scheme in its simplest form 1), might be a triplet state.
Microbiological preparation of substance U from cortisone
Authors: Szpilfogel S. A. , de Winter M. S. , Alsche W. J. 
Published: September 2010

AbstractAmong the many transformations of steroids by microorganisms reported in recent years were those using Fusarium strains1) 2). With progesterone as the substrate the main product isolated was Δ1,4‐androstadiene‐3,17‐dione. The same product has been found to be formed from Δ4‐androstene‐3,17‐dione, Δ5‐3β‐hydroxypregnene‐20‐one and Δ5‐3β‐hydroxyandrostene‐17‐one1). In contrast with the acetyl side‐chain of progesterone the dihydroxyacetone side‐chain of cortisone has not been attacked and cortisone was dehydrated to prednisone (1,2‐dehydrocortisone) 2).
Complex coacervation. III. Thermodynamic calculations on three‐component systems
Authors: Voorn M. J. 
Published: September 2010

AbstractUsing the model of complex coacervation, described in parts I and II, a phase diagram is calculated, giving the influence of electrolytes on complex coacervation in a mixture of two poly‐electrolytes in equivalent amounts. The suppressive action of salts is explained as a result of electrical interactions.
Electrophoresis of polyelectrolytes with partial drainage
Authors: Overbeek J. Th. G. , Stigter D. 
Published: September 2010

AbstractThe electrophoretic velocity of a uniformly charged porous sphere in a salt solution is considered to be composed of three contributions. These are:
a motion caused by that part of the charge which is exactly compensated by counter‐ions within the porous sphere.
a motion caused by the net charge of the porous sphere.
a motion caused by the counter‐ions outside the sphere.
The influence of relaxation is left out of consideration. The presence of the counter‐ions is shown to lead to a relatively high degree of draining. In solutions of high ionic strength, where the porous sphere model fails, polyelectrolyte coils are shown to be freely drained and the application of Henry's theory of electrophoresis of a cylindrical rod is discussed.
Thermodynamic changes associated with the formation of aminopolycarboxylate chelates
Authors: Martell Arthur E. 
Published: September 2010

AbstractBy emf. measurements of cells of the type Pt‐H2, H+, A− (buffer), KCl, Ag‐AgCl, and extrapolation of the data to infinite dilution, thermodynamic dissociation constants and metal chelate stability constants have been obtained for ethylenediaminetetraacetic and nitrilotriacetic acid. From measurements of this type made over a series of temperatures, the enthalpy and entropy changes associated with complex formation were calculated. In all cases the enthalpy changes were found to be relatively small, while the entropy contributions to the stability of the chelate compounds were found to be considerably greater. The results are interpreted on the basis of the structures of the compounds, and of present theories of chelate ring formation.
Collision complexes
Authors: Ketelaar J. A. A. 
Published: September 2010

AbstractThe observation of simultaneous vibrational transitions in mixtures of compressed gases: CO2 with N2, O2 and H2, as well as in liquids, such as CS2, with Br2, I2, CCl3SCl, PCl3, and S2Cl2, is explained as being due to the presence of collision complexes.The theory of these simultaneous vibrations and the intensity rules are given.
Complexes in coal
Authors: Schuyer J. 
Published: September 2010

AbstractA considerable portion of the coal is composed of aromatic structural units ‐ lamellae ‐ that contain 20 to 100 carbon atoms. These lamellae show a strong packing tendency resulting in the formation of crystallites. The interlamellar binding energy in these crystallites may be very high, higher even than that of the saturated CC bonds.By assuming that charge‐transfer may occur between the lamellae in the crystallites and that the lamellae may function both as electron donors and as electron acceptors, it will be understood why anthracite behaves as an intrinsic semi‐conductor.The influence of this charge‐transfer on the optical properties ‐ refraction and absorption of light ‐ is explained with the aid of strongly schematized models.
Structure and magnetic properties of Co3O4 and ZnCo2O4
Authors: Cossee P. 
Published: September 2010

AbstractMeasurements are described of the paramagnetic susceptibilities of Co3O4, ZnCo2O4, and mixed crystals of ZnAl2O4‐ZnCo2O4 and the results are given in a table of X‐values and two plots of 1/X against absolute temperature.To explain the very low value of the mean Bohr magneton number, found for these compounds, the assumption is made that Co3+ in these spinel structures is situated at octahedral interstices and covalently bonded as in the other complex compounds of CoIII, thus not contributing to the paramagnetism.This assumption gives the reasonable, although somewhat high value of 4.7 μB for the Co2+ ion in Co3O4. This high value of μ for Co2+ and the weak paramagnetism of ZnCo2O4 may be caused by a slight oxygen deficiency of the compounds or a small energy difference between the diamagnetic and paramagnetic states of Co3+ in octahedra.
Application of paper chromatography to the identification of accelerators and antioxidants: IV. Detection of antioxidants
Authors: Zijp J. W. H. 
Published: September 2010

AbstractIn this paper the paper‐chromatographic separation and identification of various antioxidants is described. Because only few antioxidants can be separated by paper chromatography after coupling with diazotized arylaminosulphonic acids, it is preferable to separate these compounds, which are generally insoluble in water, by means of acetylated filter paper.The identification of antioxidants, using acetylated filter paper, is described.
Polymerisation of p‐methoxy‐isopropenylbenzene (p‐methoxy‐α‐methyl‐styrene) under the influence of 43 % sulphuric acid
Authors: van der Zanden J. M. , Rix Th. R. 
Published: September 2010

AbstractFollowing up the publications concerning the polymerization of methyl‐chavicola) and of orthomethoxyallylbenzeneb), p‐methoxyisopropenyl‐benzene (I) has now been studied. The structure of the dimer obtained has been determined. Further the course of the reaction during dimerization is discussed.
Hydrocarbures polycycliques aromatiques. II. La formylation du pérylène et du 3‐méthylpérylène
Authors: Buu‐Hoï N. P. , Long C. T. 
Published: September 2010

AbstractIl est montré que le pérylène peut être formylé par la N‐méthylformanilide en présence d'oxychlorure de phosphore, et que le monoaldéhyde obtenu est le 3‐formylpérylène. Cette réaction constitue une voie d'accès vers de nombreux dérivés monosubstitués du pérylène, et s'applique également au 3‐méthylpérylène.
Synthesis of 5‐ and 5,8‐dimethoxy‐2‐methylchromones
Authors: Rao C. Ramachandra , Venkateswarlu V. 
Published: September 2010

AbstractA new method of synthesis of some derivatives of 2‐methylchromone with possible physiological activity similar to kellin and visnagin but not containing the furan ring has been reported. Starting from 2‐hydroxy‐6‐methoxy‐acetophenone, 5‐methoxy‐2‐methylchromone has been obtained by way of the intermediate, 2‐hydroxy‐6‐methoxy‐ω‐acetylacetophenone. By alkaline persulphate oxidation, 5‐hydroxy‐2‐methylchromone is converted into 5,8‐dihydroxy‐2‐methylchromone. Its acetate, partial and complete methyl ethers have been obtained. Demethylation of 5,8‐dimethoxy‐2‐methylchromone gave the isomeric 5,6‐dihydroxy‐2‐methylchromone, the constitution of which has been established by independent synthesis.
Chemistry of acetylenic ethers XX. Note on the preparation of secondary ethoxyethynylcarbinols
Authors: Postma J. C. W. , Arens J. F. 
Published: September 2010

AbstractSecondary ethoxyethynylcarbinols cannot be obtained from aldehydes and ethoxyethynylmagnesium bromide. The substances can be prepared, however, by interaction of the aldehydes with ethoxyethynyl‐lithium. The secondary carbinols are rearranged to α,β‐unsaturated esters by acids.
The stability constants of metal complexes of some N‐dialkyldithtocarbamic acids: Part. I. Copper complexes in 75 % (v/v) ethanol water
Authors: Janssen M. J. 
Published: September 2010

AbstractThe stability constants for the formation of copper complexes of N‐dimethyl‐, diethyl‐, di‐n‐propyl‐, di‐n‐butyl‐, cyclotetramethylene‐, and cyclopentamethylene‐dithiocarbamic acids were measured spectrophotometrically in a 75 % ethanol/water mixture by a competition method using 8‐hydroxyquinoline as the third component.This method was especially developed for the evaluation of stability constants in the presence of “mixed” complexes, containing both hydroxyquinoline and the dithiocarbamic acid.
Chemistry of acetylenic ethers XXI: Reactions of 1,1‐diazido‐1‐ethoxyethane with amines
Authors: Sinnema Y. A. , Arens J. F. 
Published: September 2010

AbstractBy the interaction of 1,1‐diazido‐1‐ethoxyethane, II, and ammonia, acetamidinium azide, III, was obtained. The same substance was formed by catalytic reduction of II. With n‐butylamine, II yielded N,N′‐di‐n‐butylacetamidinium azide, IV. The reaction of II with diethylamine was slow and yielded no identifiable derivatives of II. Triethylamine did not react with II.Diphenylamine and II yielded N‐acetyldiphenylamine, V, ethylazide, VI, and 1‐azido‐1‐ethoxyethane, VII, which was obtained also from ethyl vinyl ether and hydrazoic acid.
Investigations on pyrazine derivatives
Authors: Mager H. I. X. , Berends W. 
Published: September 2010

AbstractA simple method is given for the preparation of pyrazine tetracarboxylic acid from o‐diaminobenzene. A stable 1,4‐dihydro‐compound only is produced on hydrogenating tetraethyl pyrazine tetracarboxylate at relatively high pressures and temperatures. The cause of this stability must be sought in the presence of two, probably mutually independent, mesomeric systems.
Isomerisation of unsaturated fatty acid esters. Part II: Location of double bonds by oxidative degradation methods
Authors: Keppler J. G. 
Published: September 2010

AbstractFor the location of the double bonds in di‐ethenoid acids, ozonolysis is recommended in preference to degradation with KMnO4, as the former method leads to a higher yield of the primarily formed mono‐ and di‐carboxylic acids and the latter method may result in the formation of interfering secondary degradation products. By subjecting some pure dicarboxylic acids or their half‐esters to the action of the oxidising agents Ag2O or KMnO4, it was found that the latter causes a fairly considerable secondary degradation of the higher homologues.
Über Muscarin. III
Authors: Kögl F. , Salemink C. A. , Schouten H. , Jellinek F. 
Published: September 2010

AbstractDie in einer Untersuchung aus dem Jahre 1931 für Muscarin angenommene Konstitution eines quaternären Trimethylammoniumsalzes von α‐Amino‐β‐oxy‐valeraldehyd [C8H18O2N]+Cl− hat sich als unrichtig erwiesen. Die nunmehr mit Hilfe chromatographischer Methoden ausgeführte Isolierung dieses Alkaloids aus Fliegenpilzen führte in Übereinstimmung mit neueren Untersuchungen aus anderen Laboratorien zur Bruttoformel [C9H20O2N]+Cl−. Es zeigte sich, dass Fliegenpilze auch das beim pharmakologischen Test am Froschherzen noch aktivere Acetylcholin enthalten. Beim Hofmannschen Abbau des Muscarins konnte ausser Normuscarin nur Trimethylamin als Abbauprodukt identifiziert werden. Die beiden Sauerstoffatome liegen in einer Hydroxylgruppe und einem Tetrahydrofuranring vor. Letzteres ergab sich u.a. aus dem Infrarot‐Absorptionsspektrum. Durch Reduktion des Muscarins mit Jodwasserstoffsäure und nachfolgende Hydrierung entstand Trimethyl‐hexyl‐ammonium‐jodid. Diese Verbindung enthält ‐ abgesehen von den Sauerstoffatomen ‐ das gesamte Skelett des Muscarin‐kations. Schliesslich führte die Röntgenanalyse zur endgültigen Festlegung der Struktur und des räumlichen Baus. Muscarin ist das quaternäre Trimethylammoniumsalz von 2‐Methyl‐3‐oxy‐5‐(amino‐methyl)‐tetrahydrofuran.
Resorption of cholecalciferol from an intramuscular oil depot
Authors: Bots J. P. L. 
Published: September 2010

AbstractBy injecting chickens intramuscularly with radioactive cholecalciferol (vitamin‐D3) in oil and determinating the radioactivity still present after various times, it is shown that an intramuscular depot of vitamin‐D3 is only slowly absorbed in the course of at least seven months.
Quantitative determination of antioxidants, after a chromatographic separation on completely acetylated filter paper. I. Determination of phenyl‐1‐naphthylamine and of phenyl‐2‐naphthylamine
Authors: Zijp J. W. H. 
Published: September 2010

AbstractIn this paper a general method for the quantitative determination of antioxidants is described. After isolation from the rubber compound the antioxidants are separated by partition chromatography, using completely acetylated Whatmanpaper no. 1.A detailed procedure is given for the quantitative determination of phenyl‐1‐naphthylamine and of phenyl‐2‐naphthylamine. These antioxidants are coupled with diazotized sulphanilic acid and determined colorimetrically.
Quantitative determination of antioxidants, after a chromatographic separation on completely acetylated filter paper. II. Determination of some p‐phenylenediamine derivatives
Authors: Zijp J. W. H. 
Published: September 2010

AbstractIn this paper methods are given for the quantitative determination of three antioxidants, viz. N.N′‐diphenyl‐p‐phenylenediamine, N.N′‐di‐2‐naphthyl‐p‐phenylenediamine and N‐phenyl‐N′‐cyclohexyl‐p‐phenylenediamine.According to these methods the antioxidants are extracted from the rubber compound, separated by partition chromatography on completely acetylated filter paper and oxidised to the corresponding p‐quinonediimines, where after these oxidation products are determined colorimetrically.