bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and physiological properties of some heterocyclic‐aromatic sulphides and sulphones. I. Synthesis of some aryl‐pyridyl sulphides
Authors: van Zwieten P. A. , van Velthuijsen J. A. , Huisman H. O. 
Published: September 2010

AbstractThe preparation of some aryl‐pyridyl sulphides with potential acaricidal properties is described. In the compounds synthesized the benzene nucleus is substituted with a para‐chlorine atom or with three chlorine atoms in positions 2, 4 and 5. Position 5 in the pyridine nucleus is either unsubstituted or carries a chlorine substituent. From a few aryl‐pyridyl sulphides the corresponding N‐oxides have been prepared.
A polarographic study of the oxidation of some polyhydroxybenzenes with atmospheric oxygen: (Preliminary communication)
Authors: van Dijk H. , Ter Haar H. E. 
Published: September 2010

AbstractAs a contribution to the study of the formation of humic acids in soil, a polarographic investigation has been made of the oxidation of some poly‐hydroxybenzenes in aqueous solution under different conditions. The formation of hydroxyquinone as an intermediate in the oxidation of hydroquinone was confirmed. Indications were obtained for the identity of some other intermediate reaction products. The important conclusion is drawn that the presence of tyrosinase or certain clay‐minerals frequently not only influences the reaction velocity, as is sometimes supposed, but also may alter the course of the oxidation reaction.
Use of carbonylditriazole in peptide synthesis
Authors: Beyerman H. C. , van Den Brink W. Maassen 
Published: September 2010

AbstractN,N′‐Carbonyldi‐s‐triazole is shown to be a useful peptide‐forming reagent. Advantages over other reagents are: (1) low degree of racemization, (2) applicability in dimethylformamide, a solvent for both small and large peptides.
Thermodynamic properties of transition metal compounds and coordination complexes: I. The heats of hydration of divalent cations in the series Ca2+ ‐ Zn2+
Authors: Schuit G. C. A. 
Published: September 2010

AbstractAccording to the ligand‐field theory the heat of hydration of a transition‐metal ion is the sum of an electrostatic interaction and a ligand‐field stabilization.An estimate of the latter can be deduced from the spectroscopic Δ‐value. If the experimental heats are corrected for the ligand‐field effects, a steady rise for the residual heats is observed going from Ti2+ to Zn2+ which is considered an argument for the validity of the theory.However, in the m.o. approximation the metal d‐electrons are either in the t2g state (non‐bonding in the absence of π‐interaction) or in the antibonding eg state. Hence formally the transition‐metal hydrates can be considered as destabilized with respect to a hypothetical standard state which can be calculated, by making suitable corrections, with help of the spectroscopic Δ‐values. It is shown here that the values so obtained are numerically equal to those given by an empirical equation for cations with the inert gas configuration— (ΔHn) = I + constant(I is the ionization energy for the formation of divalent cations).
Studies in IVth group organometallic chemistry VIII: Synthesis of linear organotin polymers from organotin dihydrides and acetylenic compounds
Authors: Noltes J. G. , van der Kerk G. J. M. 
Published: September 2010

AbstractLinear organotin polymers with molecular weights (Mw)in the range of 45 000 to 100 000 have been obtained by poly‐addition reactions involving organotin dihydrides and α,ω‐diynes, such as 1,5‐hexadiyne, 1,8‐nonadiyne, and 1,4‐diethynylbenzene. A number of 1‐stanna‐2,6‐cycloheptadiene derivatives (cyclic monomers derived from 1,5‐hexadiyne) have been isolated.
The chemistry of propadiene: Some investigations on the addition of Br2, BrCl, and Cl2
Authors: Peer H. G. 
Published: September 2010

AbstractThe reaction of propadiene with Br2, BrCl, and Cl2 is studied in various solvents and at different temperatures. It is shown that only partial addition takes place, and further that the initial attack of the Hal+ ion takes place at the central C atom. The findings are interpreted as the result of the formation of the intermediary carbonium ion, stabilized by resonance: magnified image.In the reaction with Cl2, propargyl chloride is formed besides 2,3‐dichloro‐propene. The way in which the former product is formed, is discussed.
Heterocyclic compounds IV: Synthesis and reactions of some 2,3‐pyrrolidinedione derivatives
Authors: Merchant J. R. , Srinivasan V. 
Published: September 2010

AbstractA number of 2,3‐pyrrolidinediones have been synthesised by the condensation of oxalacetic and oxalpropionic esters with different aldehydes and ketones. Typical reactions and properties of the diones have been studied by the preparation of suitable derivatives.
Some new reaction products of divinylsulphone with primary amines
Authors: Bellaart A. C. 
Published: September 2010

AbstractThe preparation is described of some substituted 1,4‐thiazane‐1,1‐dioxides containing respectively propargyl, allyl, cyclohexyl, benzyl, octyl, dodecyl and cetyl groups in the 4‐position.Also some quaternary compounds derived from the first four substances are described.
A convenient synthesis of 2,2‐disubstituted‐1‐cyclopentanones
Authors: Conley Robert T. 
Published: September 2010

AbstractThe synthesis of 2,2‐dimethyl‐ and 2,2‐diphenylcyclopentanone in high yield is reported by the ring expansion of the corresponding 1‐(disubstituted carbinol)‐1‐hydroxycyclobutane in polyphosphoric acid. Modifications of the general synthetic route using reported reactions offers a general route to 2,2‐disubstituted‐1‐cyclopentanones.
Di‐ and tri‐nitro derivatives of 1‐chloronaphthalene
Authors: Bassilios H. F. , Salem A. Y. , Shawky M. 
Published: September 2010

AbstractNitration of 1‐chloronaphthalene with excess of fuming nitric acid at a relatively high temperature provided a mixture of 1‐chloro‐4,5‐ and 1‐chloro‐4,8‐dinitronaphthalenes. The same dinitro derivatives can be obtained by further nitration of 1‐chloro‐4‐nitronaphthalene. The nitration of 1‐chloro‐4,5‐dinitronaphthalene with either fuming nitric acid or mixed acids provides the known 1‐chloro‐2,4,5‐trinitronaphthalene, while that of 1‐chloro‐4,8‐dinitronaphthalene with fuming nitric acid yields a new trinitro derivative melting with decomposition at 270° which is confirmed as being 1‐chloro‐4,5,8‐trinitronaphthalene.
Triazine isocyanates: Part II: Reaction of 2,4‐diamino‐s‐triazines with ethyl chlorocarbonate
Authors: Duynstee E. F. J. , Veerkamp Th. 
Published: September 2010

AbstractBenzoguanamine (2,4‐diamino‐6‐phenyl‐s‐triazine) and acetoguanamine (2,4‐diamino‐6‐methyl‐s‐triazine) both react with an excess of ethyl chlorocarbonate; in this reaction two hydrogen atoms from the guanamines are replaced by two carbethoxy groups. The I.R. spectrum reveals that this double substitution takes place on one amino group; in consequence, the resulting compounds are derivatives of iminodicarboxylic acid diethyl ester. Upon heating above the melting point, the compounds decompose, during which process a very short occurrence of isocyanate absorption can be observed in the I.R. spectrum.
The structure of AuCl.PCl3
Authors: Arai Gerda J. 
Published: September 2010

AbstractSo far no members of the group of coordination compounds in which PCl3 acts as a donor molecule have been investigated crystallographically, although many such compounds are known to exist. We have studied the structure of a relatively simple representative of this group, AuCl·PCl3. Univalent gold is always found to have a linear coordination, even when the analogous copper and silver complexes show a tetrahedral coordination of the metal atom. AuCl·PCl3 is no exception and also shows a linear configuration at the gold atom.
Mechanism of reactions of unsaturated ethers and thioethers. V: Dipole moments of acetylenic ethers and thioethers
Authors: Drenth W. , Hekkert G. L. , Zwanenburg B. G. 
Published: September 2010

AbstractElectric dipole moments of the following compounds have been measured in benzene solution:HC≡COCH(CH3)2, HC≡COC(CH3)3, H3CC≡COC(CH3)3H5C2C≡COC(CH3)3, (H3CC≡C)2S, (H5C2C≡C)2S, H3CC≡CSC2H5HC≡CSC2H5 and H2C≡CHSC2H5.Probably, hyperconjugation between R′ and the triple bond occurs in R′C≡COR. The charge shift due to the resonance structure R′C−=C=S⊕R, is smaller in the sulphur compounds than in the analogous oxygen compounds, but its quantitative value could not be estimated.
Über Aromaten‐Komplexe mit Titan‐Auminiumchloriden
Authors: de Vries Harmen 
Published: September 2010

AbstractMartin und Vohwinkel1 haben gezeigt, dass sich die von Natta und Mitarbb.2 als Al2T1IICl8·C6H5 angesprochene Verbindung aus TiCl2, 2 AlCl3 und C6H6 zusammensetzt. Es werden noch zwei Argumente zur Unterstützung dieser Formulierung angeführt.
Hydrolysis of 2‐substituted 4,6 dichloro‐1,3,5‐triazines
Authors: Koopman H. 
Published: September 2010

AbstractThe hydrolysis of the 2‐substituted 4,6‐dichloro‐1,3,5‐triazines was investigated in a mixture of water and acetone. The reaction constant of the hydrolysis of the first chlorine atom was determined, and is discussed in relation to the structure of the triazine derivatives.
Chemistry of acetylenic ethers LVI Di‐(alk‐1‐ynyl) ethers and thioethers
Authors: Brandsma L. , Arens J. F. 
Published: September 2010

AbstractA number of di‐(alk‐1‐ynyl) thioethers VIII have been synthesized using reaction scheme 1. Except for diethynyl ether VI the compounds are relatively stable.Reaction scheme 2 has been used to synthesize di‐(prop‐1‐ynyl) ether, a substance exploding at room temperature. An attempt to prepare (HC≡C)2O failed; this substance seems to be unstable even at −70°.
Chemistry of acetylenic ethers LVIII: Alkylthiolation of chloroethyne and ethoxyethyne (with a note on alkylthiolations in liquid ammonia)
Authors: Nooi J. R. , Arens J. F. 
Published: September 2010

AbstractConversions of chloroethynyllithium into 1‐chloro‐2‐(ethylthio)ethyne and of ethoxyethynyllithium into 1‐ethoxy‐2‐(ethylthio)ethyne have been effected with the thiolsulphonate C2H5SSO2C2H5 in liquid ammonia. 1‐Ethoxy‐2‐(ethylthio)ethyne is unstable and decomposes even at 0°. Attention is drawn to the fact that ammonia can also be alkylthiolated.
Chemistry of acetylenic ethers. LIX: Alk‐1‐enyl alk‐1‐ynyl ethers, thioethers and selenoethers
Authors: Brandsma L. , Arens J. F. 
Published: September 2010

AbstractThe compounds listed in tables I and II have been prepared by the reaction schemes A, B and C.Acid hydrolysis of vinyloxyethyne produces vinyl acetate. Rearrangement of 3‐hydroxy‐3‐methyl‐1‐vinyloxy‐1‐butyne XIV by acid gives the vinyl ester of 2,2‐dimethylacrylic acid XV.
Practical notes on the preparation of p‐anisyltrithione
Authors: Rekker R. F. , Reiding D. J. , Mulder D. , Nauta W. Th. 
Published: September 2010

AbstractWhen large quantities of p‐anisyltrithione are to be synthesized, the purification of the product presents great difficulties and consequently the yield of purified product is very disappointing. The present article suggests a few changes which can easily be incorporated into the original method of Böttcher and Lüttringhaus.
Mechanism of reactions of unsaturated ethers and thioethers.: VI. Nuclear magnetic resonance studies of acetylenic ethers and thioethers
Authors: Drenth W. , Loewenstein A. 
Published: September 2010

AbstractThe position of the acetylenic hydrogen in the n.m.r. spectra of several acetylenic ethers and thioethers was measured in carbon tetrachloride, benzene and dioxan. 1‐Hexyne and 1,5‐hexadiyne were taken as reference compounds. The results prove the existence of a large charge shift in acetylenic ethers, due to resonance. There is no appreciable charge shift in acetylenic thioethers.The rates of acetylenic hydrogen exchange in some of these compounds and in tert. butylacetylene, were also measured as a function of base concentration. The rates are highest in the sulphur compounds and lowest in tert. butylacetylene. They decrease with increasing dielectric constant of the solvent. The results are interpreted in terms of inductive effects and resonance structures of the anions.
Acetylation of anthracene by the Friedel‐crafts reaction using chloroform as the solvent
Authors: Bassilios H. F. , Shawky M. , Salem A. Y. 
Published: September 2010

AbstractAcetylation of anthracene by the Friedel‐Crafts Reaction using chloroform as the solvent leads to a high yield of 9‐acetyl or 1,5‐diacetylanthracene.
The resolution of DL‐4‐oxalysine
Authors: Tesser G. I. , Nivard R. J. F. , Gruber M. 
Published: September 2010

AbstractBoth enantiomorphs have been isolated from racemic Nα, Nδ‐diphthaloyl‐4‐oxalysine in optically pure form via brucine salts and converted into (+)‐and (‐)‐4‐oxalysine by acid hydrolysis.(‐)‐4‐Oxalysine has a negative Cotton‐effect from which we conclude that this stereoisomer possesses the D‐configuration. This conclusion is corroborated by the formation of a quasi‐racemic compound between (+)‐Nα, Nδ‐diphthaloyl‐4‐oxalysine, stereochemically corresponding to (‐)‐oxalysine, and Nα, Nδ‐diphthaloyl‐L‐4‐thialysine.
Syntheses of 2,6‐DI‐t‐Butylpyridine‐3‐and −4–sulphonic acids
Authors: van der Plas H. C. , den Hertog H. J. 
Published: September 2010

AbstractSyntheses of 2,6‐di‐t‐butylpyridine‐3‐ and −4‐sulphonic acids proving the structure of these compounds are described. They were carried out in order to confirm that during the sulphonation of 2,6‐di‐t‐butylpyridine at low temperature the sulphonic acid group enters the 3‐position.
Binary systems with water as second component. I. The system calcium cyclamate (cyclohexylsulphamate)‐ water
Authors: Broers P. M. A. , van Oeveren W. J. 
Published: September 2010

AbstractA large part of the phase diagram of this system has been determined, and the following compounds occur: Calcium cyclamate 5 aq, 2 aq and 2/3 aq.The dihydrate occurs in two modifications, α‐ and β‐, which change into one another at 79.6 ± 0.2°.
The lowering of the three‐phase equilibrium temperature in a binary system upon addition of a third component
Authors: Pieroen A. P. , Korvezee A. E. 
Published: September 2010

AbstractIn a binary system A‐B, wherein a solid compound ABn occurs beside a liquid phase consisting mainly of B and a gaseous phase consisting mainly of A, the three‐phase equilibrium temperature and pressure are interdependent. At a given pressure the addition of a third component C causes a lowering of the equilibrium temperature, already discussed in a previous article on gas hydrates1 and for which the general equation (VI) is now derived. Under specified conditions this equation may be simplified. The calculation of the standard heat of formation ΔH° to be used in this general equation is given in another previous paper 2. When the compound is formed from two immiscible liquid layers, instead of from a gaseous phase and a liquid one, similar considerations are valid.
X‐Ray diffraction studies on the structure of water
Authors: Heemskerk J. 
Published: September 2010

AbstractThe X‐ray diffraction of water was measured at 0°, 25° and 45°. An improved method has been used for the calculation of the distribution functions from the experimental data. This method was checked on the data for vitreous SiO2The interpretation of the distribution curves for water leads to a model for the “structure” of water in which the average configuration around the molecules is described in terms of a short‐range octahedral arrangement.
The thermal decarboxylation of alkali trichloroacetates in aprotic solvents VThe decarboxylation and its catalytic effect on the decomposition of trichloroacetic anhydride
Authors: Wagner W. M. , Kloosterziel H. , van der Ven S. , Bickel A. F. 
Published: September 2010

AbstractThermal decarboxylation of sodium trichloroacetate in 1,2‐dimethoxyethane yields NaCl, CO2, CO, CCl4, perchloroisopropenyl acetate (I) and perchloro‐1,2‐dimethylenecyclobutane (II). Strong evidence is presented for the intermediate formation of trichloroacetic anhydride. This compound was found to be decomposed to CO2, CCl4, I and II by heating with CCl3COONa in 1,2‐dimethoxyethane.The mechanisms of these reactions are discussed.
Crystallization chromatography of glycerides
Authors: van den Tempel M. , de Bruyne P. , Mank A. P. J. 
Published: September 2010

AbstractMixtures of high‐melting glycerides can be separated into their constituents by means of a chromatographic process resembling repeated fractional crystallization. Use is made of a column in which a temperature gradient is established, and of solvent mixtures with gradually increasing solvent power. The principle of the method is briefly discussed, and examples are given of the analysis and purification of synthetic glycerides, and the isolation of “pure” triglycerides from natural products.
A study of some biphenylamines: Part I. The electronic spectra in acidic solvents of some biphenylamines
Authors: Dieteren H. M. L. , Koningsberger C. 
Published: September 2010

AbstractThe K‐bands in the ultraviolet absorption spectra of meta and para substituted biphenylamines, dissolved in acidic media, appear to be essentially identical with each other and with that of their parent compound, biphenyl. Apparently the electronic interaction of the two aromatic rings is not markedly disturbed by the mere presence of positively charged ammonium groups, provided the molecules are able to assume a planar structure. As can be expected, however, appreciable hypsochromic shifts of the K‐bands become manifest when one or more of these groups are located at the ortho positions. Moreover, a buttressing effect is observed in the case where ammonium groups are present simultaneously in adjoining meta positions.A discussion of results takes into account both steric and electrostatic factors operating between the groups involved.
Über die basischen Inhaltsstoffe des Fliegenpilzes: XI. Mitteilung über das Muscaridin und Seine Stereoisomeren
Authors: Salemink C. A. , Schuller P. L. 
Published: September 2010

AbstractThis communication contains a description of the isolation of muscaridine from Amanita muscaria L. The constitution of muscaridin is established as erythro‐4,5‐dihydroxy‐n‐hexyltrimethylammoniumchloride. The synthesis, starting from 2,3‐dihydropyran, leads to racemic muscaridine. The resolution of racemic muscaridine succeeded with di‐p. toluyl‐L‐ tartaric acid and with di‐p. toluyl‐D‐tartaric acid. The synthetic product has the same RF‐value, a fully identical infrared spectrum and equal optical rotation as the natural base. The syntheses of threo‐4,5‐dihydroxy‐n‐hexyltrimethylammoniumchloride and of 5‐hydroxy‐n‐hexyltrimethylammoniumchloride are described as well.
Microbiological conversion of 19‐nortestosterone: (V) 6β‐ and 14α‐hydroxylation
Authors: de Flines J. , van der Waard W. F. , Mijs W. J. , van Dijck L. A. , Szpilfogel S. A. 
Published: September 2010

AbstractThe microbiological reactions of 19‐nortestosterone with Helminthosporium kusanoi leading to the 6β‐hydroxy‐derivative and with Helminthosporium buchloes leading to the 14α‐hydroxy‐derivative are described.
Acetylation of anthracene by the Friedel‐crafts reaction using ethylene chloride as the solvent
Authors: Bassilios H. F. , Shawky M. , Salem A. Y. 
Published: September 2010

AbstractAcetylation of anthracene by the Friedel‐Crafts Reaction using ethylene chloride as the solvent leads to a high yield of 1‐acetylanthracene. Diacetylation gives a mixture of 1,5‐ and 1,8‐diacetylanthtacene. Oxidation to the corresponding acetylanthraquinones and carboxylic acids is described.
The conversion of acylglycol‐iodohydrins into monoacylglycols with the aid of metal salts in a mixture of acetone and water
Authors: Boeree C. H. , Hoefnagel M. A. , Verkade P. E. 
Published: September 2010

AbstractIt was already known that monoacylglycols can be obtained readily and in very good yields by boiling a solution of the corresponding acylglycol‐iodohydrin and an appropriate silver salt (nitrite or nitrate) in a mixture of ethanol and water. We have now found that mercury(II) salts and palladium(II) salts are equally suitable for this purpose. When salts were used of a great many other metals, distributed as widely as possible over the whole periodic table, under identical experimental conditions the reaction did not take place, or at least not to an extent that could be clearly demonstrated by us. A discussion is devoted to these facts.
Preparation of adipic acid by oxidation of cyclohexanol and cyclohexanone with nitric acid: Part II. Reaction kinetics of the decomposition of 6‐hydroxyimino‐6‐nitro hexanoic acid
Authors: van Asselt W. J. , van Krevelen D. W. 
Published: September 2010

AbstractThe stablest intermediate product formed in the oxidation of cyclohexanol and cyclohexanone is 6‐hydroxyimino‐6‐nitro hexanoic acid (nitrolic acid). In the temperature range investigated it yields over 90% of adipic acid and N2O. In addition, a small amount of a still unidentified by‐product is formed at low temperatures; upon heating, the latter gives also adipic acid.The decomposition reaction appeared to be first‐order in nitrolic acid. Nitric acid greatly influences the reaction rate; in the range of concentrations up to 50% HNO3, the first‐order rate constant was found to be linearly dependent on the hydrogen‐ion activity. The activation energy of the reaction amounts about 24,000 cal/gmol.
Preparation of some 3‐benzylthiophenes from alkylbenzenes
Authors: Kooyman E. C. , Kroon J. B. H. 
Published: September 2010

Abstract3‐Benzyl, 3‐α‐methylbenzyl, and 3‐α‐dimethylbenzylthiophene were prepared from the sodium salts of the corresponding benzylsuccinic acids and phosphorus trisulphide in 20–40% yields. The succinic acids were obtained through side‐chain addition of toluene, ethylbenzene, and isopropylbenzene, respectively to maleic anhydride.
The chemistry of sulfenyl halides: Part II: Photochlorination of alkanes with trichloromethylsulfenyl chloride
Authors: Kloosterziel H. 
Published: September 2010

AbstractWhen solutions of trichloromethylsulfenyl chloride, Cl3CSCl, in alkanes are exposed to sunlight, alkyl chlorides, hydrogen chloride and hexachlorodimethyl disulfide are formed:

An advantage of this novel chlorination method is the high selectivity, which is even further increased in the presence of benzene. The disulfide may be reconverted to the sulfenyl chloride by molecular chlorine in a separate step.A radical chain mechanism is proposed for the reaction in which trichloromethylthiyl and alkyl are the chain‐carrying radicals.
Spiranes: II. The synthesis of carbocyclic polyspiranes with six‐membered rings. Preliminary communication
Authors: de Jongh H. A. P. , Wynberg Hans 
Published: September 2010

AbstractUsing the double Michael condensation technique with divinyl ketone recently described1, as well as the dialkylation method2, we have prepared the compounds I, II and III. No syntheses of linear dispiro‐ and trispiro‐hydrocarbons embodying the 6‐membered carbocyclic ring only, have yet been reported 3, 4, 5.
Reactions of ortho‐esters of germanium: Part IV Reactions of alkyl orthogermanates with acetyl chloride
Authors: Mehrotra R. C. , Chandra G. 
Published: September 2010

AbstractReacting alkyl orthogermanates with acetyl chloride in different stoichiometric ratios results in almost quantitative yields of compounds of the type (RO)xGeCl4‐X, where x is 2 or 3 and R=C2H5‐, iso‐C3H7‐ or n‐C4H9‐. Monoalkoxy trichloro derivatives, (RO)GeCl3 can be conveniently prepared by refluxing appropriate alkyl orthogermanates with excess germanium tetrachloride.