bluuebunny/crossref_metadata_2025_split huggingface dataset:
The condensation of rhodanine and derivatives with trialdehydes containing a 1,3,5‐triazine ring
Authors: Allan F. J. , Allan G. G. 
Published: September 2010

AbstractThe condensation products of rhodanine, 3‐ethylrhodanine and 3‐phenylrhodanine with various trialdehydes containing a 1,3,5‐triazine ring have been prepared for bacterial and fungicidal evaluation. The condensation of rhodanine and its derivatives with aldehydes, previously described for mono and dialdehydes, has thus been extended to the trialdehydes. The 1,3,5‐triazine ring is itself the basis of compounds of known fungicidal properties and may therefore enhance the already known fungicidal character of the substituted rhodanines. The trialdehydes are novel compounds which were prepared by the interaction of the hydroxybenzaldehydes and 2,4,6‐trichloro‐1,3,5‐triazine. Condensations between the rhodanines and the trialdehydes were carried out in acid medium and crystalline coloured condensation products were obtained in good yield.
Investigations on nematicides: II. Structure of a second nematicidal principle isolated from Tagetes roots
Authors: Uhlenbroek J. H. , Bijloo J. D. 
Published: September 2010

AbstractA second nematicidal principle isolated from Tagetes roots has been identified as 5‐(3‐buten‐1‐ynyl)‐2.2′‐bithienyl. Upon catalytic hydrogenation 5‐butyl‐2.2′‐bithienyl was obtained which by comparison of infrared spectra proved to be identical with a synthetically prepared sample. The 5‐(3‐buten‐1‐ynyl)‐2,2′‐bithienyl was further characterized by its infrared absorption.
The sodium potassium‐selectivity of complexes of bovine serum albumin with positively or negatively charged detergents, measured by ultrafiltration
Authors: van Oss C. J. , Simonnet H. , Annicolas D. 
Published: September 2010

AbstractPure bovine serum albumin, which has no Na•/K•‐selectivity, may become strongly selective for Na• or for K• if it is associated with positive or negative detergents.A strong influence of the salt anion is observed: if Br′ is used instead of Cl′, the negative charge of the albumin grows considerably in most cases. The Na•/K•‐selectivity is highest when the negative charge of the albumin is low.
Osmotic pressures of aqueous poly‐(acrylic acid) solutions
Authors: Orofino T. A. 
Published: September 2010

AbstractOsmotic pressure measurements over a range of polymer concentration are reported for a high molecular weight sodium polyacrylate fraction of one‐third and full neutralization in 0.1 M‐sodium chloride solutions. From data on solutions sufficiently concentrated in polymer to justify representation as uniform dispersions of segments in solvent, values of an effective charge parameter are calculated. These are compared with charge parameters deduced indirectly, although in an equivalent manner, from previous dilute solution studies on related systems.
Preparation of diphenylpyridylmethanes and phenyldipyridylmethanes from the corresponding trisubstituted methanols by reduction
Authors: Otto P. Ph. H. L. , Wibaut J. P. , Groenendaal G. W. J. M. 
Published: September 2010

AbstractThe corresponding diphenylpyridylmethanes and phenyldipyridylmethanes are produced from diphenylpyridylcarbinols and phenyldipyridyl carbinols, respectively, by reduction with hydriodic acid in glacial acetic acid or with phosphorus triiodide and hydriodic acid. Tripyridylcarbinols are not reduced under these conditions.Diphenyl(β‐pyridyl) acetic acid is obtained from diphenyl(β‐pyridyl) methane by the action of phenyllithium‐phenylsodium and subsequent carboxylation.
The reaction of alkylmagnesium halides with thiophosphoryl chloride: II. Formation of dialkylphosphinic chlorides
Authors: Christen P. J. , van der Linde L. M. 
Published: September 2010

AbstractThe preparation of dimethyl‐, diethyl‐, dipropyl‐, dibutyl‐, and di‐isobutylphosphinic chlorides from bi(dialkylphosphinothioyl) compounds, mentioned in the first part of this paper1, is described (Table I).In the reactions of alkylmagnesium halides with PSCl3, where several phosphinic acidic reaction products are formed [for instance (R2PS)2, R2PSCl, and R2P(S)SH], the combined reaction products from each Grignard reaction are oxidized and the crude phosphinic acids converted into the phosphinic chlorides. In this way dipropyl‐, di‐isopropyl‐, dibutyl‐, di‐isobutyl, di‐s‐butyl‐, and dipentylphosphinic chlorides are obtained in good yield (Table II).
The reaction of N,N‐dimethyl‐ and N,N‐diethylaniline with silicon tetrabromide
Authors: Breederveld H. 
Published: September 2010

AbstractN‐methylanilino‐tribromosilane, N‐ethylanilino‐tribromosilane, and di(N‐ethylanilino)‐dibromosilane have been prepared from the corresponding N,N‐dialkylaniline and silicon tetrabromide at about 180°.
The halochromism of benzophenone oximes.
Authors: Rekker R. F. , Veenland J. U. 
Published: September 2010

AbstractA comparison of spectral data on benzophenone oximes in concentrated sulphuric acid and those of benzophenones in ethanol or iso‐octane suggests phenyl‐phenyl interaction as absorption mechanism for benzophenone oximes in concentrated sulphuric acid.
The reaction of phenol with formaldehyde: II. The ratio of ortho‐ and para‐hydroxymethylphenol in the base‐catalyzed hydroxymethylation of phenol.
Authors: Peer H. G. 
Published: September 2010

AbstractA kinetic study of the first step in the reaction of phenol and formaldehyde, the formation of ortho‐ and para‐hydroxymethylphenol, is described.It is found that when using NaOH or KOH as a catalyst under weakly alkaline conditions (pH = 8.5‐10.5) at 30° C, the para‐position in the phenolic nucleus is nearly twice as reactive as the ortho‐position (the ortho/para ratio being 1.10). Interesting effects are observed in more strongly alkaline media (pH = 10.5‐13.5), inter alia a sharp decrease in the ortho/para ratio with increasing value of pH.When other hydroxides are used, an increasing value of the ortho/para ratio is found with the hydroxides of K, Na, Li, Ba, Sr, Ca and Mg, respectively. Probably chelate formation occurs in the transition state for ortho substitution.
The effect of U.V.‐light on some components of the nucleic acids. IV. The influence of oxygen on the extent of the first irreversible reaction, shown by uracil and orotic acid
Authors: Beukers R. , Ijlstra J. , Berends W. 
Published: September 2010

AbstractThe percentage of orotic acid, sensitive to ultraviolet light, has been found to depend on the concentration of oxygen in solution. Diminishing this concentration by bubbling through nitrogen or hydrogen, the sensitivity increases from 14 % to 37 %. Saturation of the solution with oxygen leads to protection (instead of 14 % an irreversible loss of 7%). One of the reactions, shown by uracil on irradiation (“the first irreversible reaction”) also exhibits this relationship. The possibility of an intermediate triplet state is proposed.
Square wave electrolysis. I. The cyclic potential‐step method
Authors: Smit W. M. , Wijnen M. D. 
Published: September 2010

AbstractDrawbacks of the well‐known potential‐step method are briefly mentioned. A new method called the cyclic potential‐step method is introduced, the essential of which is that a square wave voltage is applied to a polarisable electrode. It is shown mathematically that the current response approaches rapidly to a constant pattern. The derivations presented are free from restrictions concerning the reversibility of the system and the magnitude of the amplitude of the square wave.It is shown that the cyclic potential‐step method offers easy means for the determination of the transfer‐coefficient (α) and the standard exchange current density (j00).
Synthesis of isocoumarin‐3‐carboxylic acids
Authors: Ribbens C. , van der Stelt C. , Nauta W. Th. 
Published: September 2010

Abstract2‐Carboxyphenylpyruvic acid and its derivatives with substituents in the phenyl nucleus can be prepared via a modified azlactone synthesis. These phenylpyruvic acids display a spontaneous ring closure into the corresponding isocoumarin carboxylic acids.
The effect of ultraviolet light on some components of the nucleic acids. VI The origin of the U.V. sensitivity of deoxyribonucleic acid
Authors: Beukers R. , Ijlstra J. , Berends W. 
Published: September 2010

AbstractThe rapid decrease in extinction of deoxyribonucleic acid in the first moments of irradiation with U.V. light (2537 Å) is due to the conversion of the pyrimidines into low‐absorbing substances. Thymine in this natural polymer reacts according to the so‐called “first irreversible reaction” shown by the free bases in solution. This could be demonstrated by means of a peculiar property of the irradiation product of thymine. Cytosine is supposed to react in the same way. The importance of this finding with respect to the lethal action of U.V. light on micro‐organisms is discussed.
Paper chromatography of derivatives of ethylenebis (dithiocarbamic acid)
Authors: Thorn G. D. , Ludwig R. A. 
Published: September 2010

AbstractDisodium ethylenebisdithiocarbamate and its products of oxidation by air (ethylenethiuram monosulphide, ethylenethiourea and sulphur) have been separated by ascending paper chromatographic techniques. Several commercial preparations derived from the dithiocarbamate have been analyzed for the presence of these oxidation products.
Studies on vitamin D and related compounds X. Preparation and properties of cis‐isotachysterol2
Authors: Verloop A. , Corts G. J. B. , Havinga E. 
Published: September 2010

AbstractThe photochemical conversion of isotachysterol2 (in ether) has been studied; the effects of wave‐length and time of irradiation on the composition of the irradiation mixture are discussed. On chromatography of the crude irradiation product a compound was obtained in a pure, non‐crystalline form. The compound did not show antirachitic activity. The ultra‐violet and infra‐red absorption spectra, the iodine‐catalysed quantitative conversion to isotachysterol2, the behaviour on heating in solution and the very low reactivity towards maleic anhydride led to the conclusion that the compound is the Δ6,7‐cis isomer of isotachysterol2, i.e. 9,10‐secoergosta‐5(10),6‐cis, 8(14), 22‐tetraen‐3β‐ol.
Über Verwendungsmöglichkeiten von 2‐chlor‐3,5‐dinitropyridin bei Untersuchungen über Eiweissabbau und Aminosäuren
Authors: Talik Zofia , Plaźek Edwin 
Published: September 2010

AbstractEs wurde festgestellt, dass das 2‐Chlor‐3,5‐dinitropyridin äusserst leicht kristallinische Derivate mit den wichtigsten aliphatischen Aminosäuren gibt. Auch mit einigen Polypeptiden und Eiweisstoffen wurden unlösliche gelbe Kondensationsprodukte erhalten.Es wird darauf hingewiesen, dass das 2‐Chlor‐3,5‐dinitropyridin vollwertig das Fluor‐2,4‐dinitrobenzen bei Eiweissuntersuchungen zu ersetzen vermag, und dabei manche Vorteile bietet.
Telomerization and prins reaction of styrene and formaldehyde in acetic acid. The role of cyclic formal in the reaction mechanism
Authors: Heslinga A. 
Published: September 2010

AbstractThe effect of variations in the reaction conditions on the composition of the end product was studied in the reaction of styrene with formaldehyde in acetic acid. Initially a relatively large amount of 4‐phenyl‐1,3‐dioxan is formed along with telomer homologues. This cyclic formal is cleaved by protolysis in a comparatively slow secondary reaction with styrene; it thus acts as an intermediate formaldehyde donor.The results are interpreted in terms of a carbonium‐ion mechanism.
On toxoflavin, the yellow poison of pseudomonas cocovenenans
Authors: van Damme P. A. , Johannes A. G. , Cox H. C. , Berends W. 
Published: September 2010

AbstractAbout 1933 a bacterium, now called Pseudomonas cocovenenans, was discovered by van Veen et al. as being responsible for the well known bongkrek‐poisonings in Java. Two toxic principles are produced by this microorganism. One of these is identical with the yellow pigment of this bacterium. The isolation of this substance, toxoflavin, was worked out and the elucidation of its structure was described. However, in our opinion the conclusions as to the structure were very improbable and for this reason we started a new investigation of this problem. The result of this work, leading to an entirely different structure, is described. Simultaneously the isolation of toxoflavin has been simplified.
The standard potential of the silver bromide‐silver electrode in anhydrous methanol at 25°
Authors: de Ligny C. L. , Wieneke A. A. 
Published: September 2010

AbstractIn the determination of pH values of standard buffer solutions in anhydrous methanol by the method of the National Bureau of Standards, it appeared that the pH values found by using a cell with a silver chloride electrode differed from the pH values found by using a cell with a silver bromide electrode. The assumption that this difference was caused by the use of an incorrect literature value for the standard potential of the silver bromide electrode, was checked by an experimental determination of this potential, viz. by determining the difference between the standard potential of the silver chloride electrode (which is supposed to be correct) and the silver bromide electrode.The new value found for the standard potential of the silver bromide electrode in anhydrous methanol is ‐0.1375 volt against the normal hydrogen electrode.
Infrared spectra of some methacrylic esters and their polymers
Authors: Salomon G. , Schooneveldt‐van der Kloes C. J. , Zwiers J. H. L. 
Published: September 2010

AbstractSpectra of 10 monomers and polymers of methacrylate esters and of methyl chloroacrylate have been studied between 6000‐450 cm−1.A number of known regularities are confirmed. The CH2 and CH3 deformation vibrations in the 1500‐1350 cm−1 region of the polymer unit can be distinguished from absorptions due to the substituents. Some absorptions typical for the substituents have been confirmed between 800‐450 cm−1.Absorptions due to deformation and stretching vibrations of the =CH2 group are readily determined in the corresponding first overtone region. An application of quantitative monomer estimation in the near infrared is reported.
The chemistry of the N‐alkylaldimines. I. The reaction of N‐alkylaldimines with acetic anhydride
Authors: Breederveld H. 
Published: September 2010

AbstractN‐Alkylaldimines add on acetic anhydride with the formation of the corresponding N‐alkyl‐N(1‐acetoxyalkyl)‐acetamides, which readily split off acetic acid to yield N‐alkyl‐N(1‐alkenyl)‐acetamides as the final products.N‐Propyl‐N‐vinyl‐, N‐propyl‐N(1‐propenyl)‐ and N‐propyl‐N(1‐butenyl)‐acetamide have been prepared by this method; the infrared spectra are discussed.
The structural proof of trismethylene‐trinitrobenzene: Nucleophilic aromatic addition III
Authors: de Boer Th. J. , van Velzen J. C. 
Published: September 2010

Abstract“Trismethylene‐trinitrobenzene” has structure IV and not VI (chart 1) as shown by ozonolysis, yielding an aldehydic acid VIII, a dicarboxylic acid IX and, on decarboxylation, a monocarboxylic acid X (chart 2). Ozonolysis in methanol leads to products which are consistent with the mechanism put forward by Criegee (chart 3). Oxidation of “trismethylene‐trinitrobenzene” with chromium trioxide results in a ketone XVIII, which can be cleaved by alkali into a carboxylic acid XIX (chart 4), the structure of which is again explicable only with structure IV for the parent compound.
Physical properties of organic thiones. Part I. Electronic absorption spectra of nitrogen‐containing thione compounds
Authors: Janssen M. J. 
Published: September 2010

AbstractThe electronic absorption spectra of some thioamides, dithiocarbamic esters, thioureas and one thioncarbamic ester are recorded in a hydrocarbon, diethyl ether, ethanol and concentrated sulphuric acid as solvents. The bands are classified according to their intensities and solvent effects. It is shown that the assignment of Koch must be reversed. The spectra of substituted thioureas are discussed in relation to their spatial structures.
Über Muscaridin. II
Authors: Salemink C. A. , Schuller P. L. , Demel R. A. 
Published: September 2010

A recent investigation of Kögl, Salemink and Schuller established the constitution of muscaridin as the quaternary trimethylammonium salt of 6‐amino‐2,3‐dihydroxyhexane.The present communication gives a preliminary description of a synthesis which started from 2,3‐dihydropyran, leading to racemic muscaridin. The synthetic product gives the same RF‐value and a fully similar infrared spectrum as the natural base.
Electrochemical methods of ultramicroanalysis
Authors: Alimarin I. P. , Petrikova M. N. 
Published: September 2010

AbstractFor a long time the attention of many analytical chemists in various countries has been attracted by the problem of studying the composition of small amounts of matter.The development of this interesting and practically important field of analytical chemistry is much indebted to the investigations, carried out by a number of outstanding chemists of our time.Emich, Pregl, Hechtin Austria, and the Russian analystsKorenman, Komarovsky, Tananaev, Malyarovand others, might be mentioned in this connection. The development of microchemistry owes much tovan Nieuwenburg, who, as long ago as 1937, wrote, that microanalysis, as he was firmly convinced, might be and would be the chemical analysis of the futureC. J. van Nieuwenburg, Mikrochemie21, 184 (1937).. A great propagandist of microchemistryIdem., Bull. soc. chim. France No. 11–12, c.63 (1953).Idem., Chim. Anal.38, (12), 423 (1956).Idem., Analyst81, 450 (1956).he considered the future development of micromethods and mentioned ultramicroanalysis.In this paper a short description of some of our investigations on electrochemical methods of ultramicroanalysis is given.
Dosage du Plomb dans les Alliages Techniques. Précipitation à l'état de PbSO4 dans les solutions homogènes
Authors: Burriel‐Marti F. , Gárate M. T. 
Published: September 2010

AbstractOn précipite le plomb à l'état de PbSO4, dans les solutions provenant de l'attaque du plomb pur par HNO3 et de ses alliages par un mélange des acides nitrique et fluorhydrique dilués.' La précipitation est effectuée, en presence d'alcool éthylique, par l'acide sulfamique comme générateur de l'ion sulfate.
The microchemistry of the platinum metals. Separation and determination of micro amounts of rhutenium, rhodium and palladium
Authors: Jasim Fadhil , Magee Robert J. , Wilson Cecil L. 
Published: September 2010

AbstractA method is outlined for the separation and determination of small amounts of ruthenium, rhodium and palladium individually as well as in combinations of two or even all three elements mentioned. It is based principally upon reactions of these elements with 8‐hydroxyquinoline. Determinations are carried out spectrophotometrically on the metal oxinate extract in chloroform. The procedure gives reproducible results and provides a. rapid method for the determination of each of the three elements even in their mixtures.
Polarography of copper (II) thiocyanate solutions
Authors: Kolthoff I. M. , Okinaka Y. 
Published: September 2010

AbstractConflicting interpretations are found in the literature of polarograms of copper (II) in thiocyanate solutions. In the present study it is shown that the polarograms change with concentration of thiocyanate and time of aging of the solutions when the thiocyanate concentration is greater than about 0.1 M. A wave appearing at the most negative potential (half‐wave potential −1.5 V vs. SCE), which is attributed in the literature to the reduction of copper (I) to copper metal or to a catalytic reaction, is actually due to the reduction of hydrogen ions produced as a result of reduction of copper (II) by thiocyanate ions.
Etude Analytique des Acides Sébacique Et Tétrachlorophtalique en Vue du Dosage du Thorium
Authors: Wenger Paul E. , Kapétanidis I. 
Published: September 2010

AbstractAu cours du prèsent travail, nous avons établi les constantes de dissociation thermodynamiques des acides sébacique (pk1 = 4,40, pk2 = 5,22) et tétrachlorophtalique (pk1 = fort, pk2 = 2,94). De même, nous avons déterminé les solubilités des sébacates et des tétrachlorophtalates du thorium et des terres cériques, ce qui nous a permis de calculer les produits de solubilité théoriques correspondants.
Metabolism and functions of phosphatides: The preparation of a series of L‐α‐lecithins
Authors: Kögl F. , de Haas G. H. , van Deenen L. L. M. 
Published: September 2010

AbstractTen L‐α‐lecithins have been prepared by acylation of L‐α‐glyceryl‐phosphorylcholine. Solubilities, RF‐values and other physical data are reported of L‐α‐[diacetyl]‐lecithin, L‐α‐[dibutyryl]‐lecithin, L‐α‐[diheptanoyl]‐lecithin, L‐α‐[didecanoyl]‐lecithin, L‐α‐[di‐10‐methyl‐undecanoyl]‐lecithin, L‐α‐[dipentadecanoyl]‐lecithin, L‐α‐[dioctadecanoyl]‐lecithin, L‐α‐[di‐undecenoyl]‐lecithin and L‐α‐[dioctadecenoyl]‐lecithin.
A simple preparation of phthaloyl amino acids via a mild phthaloylation
Authors: Nefkens G. H. L. , Tesser G. I. , Nivard R. J. F. 
Published: September 2010

AbstractPhthaloyl amino acids can be synthesized from N‐carboethoxy phthalimide and amino acid salts under very mild conditions in water. The preparation of 11 of these phthaloyl derivatives is described, some of which are new. Up to the present the method has only failed with tryptophane. Retention of the optical configuration during the reaction is shown.
The dissociation constants of some aliphatic amines in water and methanol‐water mixtures at 25°
Authors: de Ligny C. L. 
Published: September 2010

AbstractThe dissociation constants of some primary aliphatic amines were measured in water and in methanol‐water mixtures at 25°. These dissociation constants (K* = a*Ha*B/a*HB ) show a maximum at 60‐80% methanol. This maximum is ascribed to the unequal influence of the methanol content of the solvent on γ0,H and γ0,HB.
Acid anilides: VII. Quantitative analysis of fatty acids by paper chromatography of their anilides
Authors: de Jonge A. P. , Verhage A. 
Published: September 2010

AbstractThis report deals with the results of a detailed investigation into the accuracy of a quantitative analysis of mixtures of lower fatty acids (C2‐C12) by means of paper chromatography.To this end, mixtures of 2, 3, 4 or 5 fatty acids were weighed‐in, and by means of the methods described in previous reports, converted into the anilides and subjected to paper chromatography. From the results the compositions of the fatty acid mixtures were calculated and compared with the actual compositions. The differences were statistically evaluated to a mean deviation and a standard deviation. The values clearly demonstrate the reliability of the method. The recovery of the fatty acids was 81‐88%.The values obtained do not differ appreciably from these obtained in the analysis of pure anilides (the latter investigation had a more limited scope). It may, therefore, be concluded that the limitations of the method are connected with the paper chromatography.No indications have been obtained that the analytical data are dependent on the percentage or on the Rf‐value.
Synthesis of ortho‐substituted benzophenones by way of benzophenones carrying A t‐butyl group as a blocking group
Authors: Hofman P. S. , Reiding D. J. , Nauta W. Th. 
Published: September 2010

AbstractWhereas benzoylation of toluene or m‐xylene is known to lead to a mixture of 2‐ and 4‐methylbenzophenone and to 2,4‐dimethylbenzophenone respectively, the presence of a blocking t.butyl group in the 4‐ and the 5‐positions respectively leads to products which on debutylation yield benzophenones with substituents in the ortho position only.