bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of β‐phenylethylamine derivatives VII: The enantiomers of erythro‐1‐(4′‐hydroxyphenyl)‐2‐(1″‐methyl‐2″‐phenoxyethylamino)‐propanol‐1
Authors: van Dijk J. , Moed H. D. 
Published: September 2010

AbstractThe resolution of racemic erythro‐i‐(4′‐hydroxyphenyl)‐2‐(1″‐methyl‐2″‐phenoxyethylamino)propanol‐1 (Caa 40Name used in the pharmacological tests. Commercial name “Duvadilan”, N.V. Philips‐Duphar.
) is described. The absolute configuration of the three asymmetric centres of the enantiomers is established.
Syntheses, infrared spectra and molecular refractions of some sterically hindered p,p′‐dimethoxystilbenes: The influence of non‐planarity in styrene and stilbene derivatives IV
Authors: Laarhoven W. H. , Nivard R. J. F. , Havinga E. 
Published: September 2010

AbstractSyntheses of a series of 4,4′‐dimethoxystilbenes, substituted with methyl or ethyl groups in ortho and α‐positions, including the new compounds 2,2′,6,6′‐tetramethyl‐ ; α,2‐dimethyl‐ ; α,2′‐dimethyl‐ ; α,2,2′‐trimethyl‐ and α,α′,2‐trimethyl‐4,4′‐dimethoxystilbene, are described.In most cases demethylation with pyridine hydrochloride gave the 4,4′‐dihydroxystilbenes in good yield.Attempts to synthesize 2,2′,6,6′,α,α′‐hexamethyl‐4,4′‐dimethoxystilbene in reasonable amount were unsuccessful.The infrared absorption spectra of the dimethoxystilbenes were measured. An increase in the out‐of‐plane Cα‐H frequency was observed in the series: 4,4′‐dimethoxystilbene, 2,2′‐dimethyl‐, 2,2′‐diethyl‐, 2,2′,6,6′‐tetramethyl‐4,4′‐dimethoxystilbene. This increase, seemingly, parallels the increase in steric inhibition of molecular coplanarity, the same sequence being observed in the positions of the ultraviolet N → V absorption bands.For the α‐substituted stilbenes, the Cα‐H frequencies are located in the same region as the absorptions due to the substituted benzene rings and conclusions are uncertain.The molecular refractions of the compounds, corrected for the alkyl substituents, decrease with increasing steric hindrance. For most compounds the decrements in molecular refraction are linearly related with the oscillator strengths of the N → V transition in the stilbene chromophore.
Chemistry of the silylamines. III. Condensation of silylamines with silylesters
Authors: Pike R. M. 
Published: September 2010

AbstractThe conditions under which a series of trimethylsilylesters of the type magnified image, where R=H, CH3, CF3, and C6H5, condense with a number of trimethylsilylamines to form hexamethyl‐disiloxane and an organic amide were investigated. The nature of the R group in the silylester appreciably affected the relative ease of condensation. Addition of an acid catalyst to the reaction system was observed to increase the relative rate of the reaction.
A study of the biological activity of iodinated insulin
Authors: de Zoeten L. W. , van Strik R. 
Published: September 2010

AbstractBioassays were carried out with two iodinated insulin preparations containing 0.8 and 3.0 atoms of iodine per molecule of insulin. In these preparations 80% and 30% of the original biological activity was retained.With the help of the experimentally found reactivities of the tyrosine residues of insulin a statistical calculation is made of the iodine distribution over the insulin molecules at a certain (average) incorporation. On account of these distribution data it is reasonably certain that the substitution of one atom of iodine has no effect upon the biological activity. It seems likely that insulin molecules which contain two atoms of iodine also possess biological activity.
A study of the “david” reaction
Authors: Axelson Eeva , Diczfalusy Egon 
Published: September 2010

Abstract
Some of the variables influencing the David reaction have been studied. An improved method is described.
Among the oestrogens studied only compounds with a 17β and a 16α, or 16β‐hydroxyl group gave a positive David reaction; the approximate relative chromogenicities were oestriol:100, 16‐epioestriol: 60, 6‐hydroxyoestriol: 16 and 2‐hydroxyoestriol: 7%.
The presence of highly purified methylated and chromatographed urinary residues greatly diminished the David chromogenicity of oestriol. This decrease was linearly related to log concentration of urinary residue.
Determination of molecular weights with a semi‐micro‐ebulliometer
Authors: van Pelt J. G. 
Published: September 2010

AbstractThe semi‐micro‐ebulliometer consists of two units in a solvent vapour thermostat. The temperature difference is measured by two thermistors (readings of 3.10−4°. accurate to 1%). One determination takes 20 minutes. Light‐sensitive compounds are protected by a clear varnish. Decomposition, if not completed within 2 minutes, is indicated by a bent curve.
Acylation of aromatic ring systems with mixed anhydrides of phosphoric acid
Authors: Schoot C. J. , Ponjee J. J. , Klaassens K. H. 
Published: September 2010

AbstractThe reactions between a number of orthophosphates, especially silver orthophosphate, and acid chlorides are described as well as a synthesis and the properties of tribenzoyl phosphate. Nucleophilic aromatic ring systems are acylated by triacyl phosphates.
Study of the reactions between titanium tetrachloride and ethylaluminium compounds in hydrocarbon solution: III. Solid reaction products and the formantion of catalyst systems for olefin polymerization
Authors: Arlman E. J. , de Jong J. R. , Beintema J. , van Reijen L. L. 
Published: September 2010

AbstractThe brown precipitate obtained at 80°C, and the purple precipitate prepared at 170°C from AlEt3 and TiCl4 at an Al/Ti ratio 1/3, both consist essentially of TiCl3 in which about one sixth of the Ti is replaced by Al and a few percent of the chlorine by ethyl. The brown precipitate gives the X‐ray diagram of β‐TiCl3, whereas the purple one gives that of γ‐TiCl3.Magnetic measurements showed that already at ambient temperature precipitates of the β‐TiCl3 structure gradually change into products with the γ‐TiCl3 structure.On treating the brown precipitates with AlEt3 they change into nearly amorphous black products with an atom ratio of chlorine to (Al + Ti) considerably lower than two. The composition and structure of the purple precipitates are much less affected by this treatment, the effect of AlEt3 being stronger than that of AlEt2Cl.It seems that the catalyst systems so obtained only polymerize propene to a highly isotactic polymer if the crystalline substrate is not more than slightly converted at its surface.
A direct determination of nitrogen in sulphuric acid digestion mixtures
Authors: Böttcher C. J. F. , van Gent C. M. , Pries C. 
Published: September 2010

AbstractThe micro‐determination of nitrogen described is based on a preliminary digestion with sulphuric acid, potassium sulphate and selenium, followed by a direct assay of ammonia in the resultant solution by a phenol‐hypochlorite colorimetric method, without previous liberation and distillation of the ammonia.
Acid anilides: VIII. Determination of esterified acetic and butyric acids in butterfat
Authors: De Jonge A. P. , Verhage A. , van Der Ven B. 
Published: September 2010

AbstractIn this paper some applications of the qualitative and quantitative paper chromatography of fatty acid anilides are described, viz.:
identification of a very small sample of an unknown fat as butter‐fat;
determination of esterified acetic acid in butterfat and in fats containing aceto‐fats.
The 4‐(p‐phenylazophenyl)semicarbazones of some carbonylic pyridine derivatives
Authors: Allan F. J. , Allan G. G. 
Published: September 2010

AbstractThe preparation and characterisation of the 4‐(p‐phenylazophenyl)‐semicarbazones of pyridine‐2,3 and 4‐aldehyde, 2,3 and 4‐acetylpyridine, 6‐methylpyridine‐2‐aldehyde and pyridine‐2,6‐dialdehyde are described. These semicarbazones proved most useful for the isolation and characterisation of carbonylic pyridines. The preparation of the semicarbazones was carried out in dry ethanol and crystalline coloured products were obtained in good yield.
Investigations on chemical kinetics by means of absorption spectroscopy and calculations of immeasurable spectra by this method
Authors: van Senden K. G. , Koning H. N. 
Published: September 2010

AbstractThe determination of reaction‐rate constants of unimolecular, pseudo‐unimolecular and bimolecular reactions by means of absorption spectroscopy is described. The calculation of immeasurable absorption spectra by this method is given.
Studies in organosilicon chemistry. XLII. Reactions of certain silylbenzaldehydes in concentrated base
Authors: Maass Thomas J. , Post Howard W. 
Published: September 2010

AbstractA crossed Cannizzaro reaction using formaldehyde with m‐trimethylsilylbenzaldehyde and p‐trimethylsilylbenzaldehyde yields mostly the benzyl alcohol derivative. No formic acid was detectable but a small amount of the substituted benzoic acid was isolated. The corresponding triphenylsilylbenzaldehydes, meta and para, without formaldehyde gave good yields of hexaphenyldisiloxane or triphenylsilanol along with the substituted benzoic acid.
The isolation of citronin from the peel of argentine oranges (naranja dulce),: citrus sinensis, Linn
Authors: Rahman Aziz‐Ur , Khan Ausat A. 
Published: September 2010

AbstractThe isolation of ‘citronin’ from the peel of Argentine oranges, Citrus sinensis, Linn. has been described and its structure established as a 7‐rhamnoglucoside of 5,7‐dihydroxy‐2′‐methoxyflavanone. A higher m.p. (240–241°) as against 235° reported in the literature for the glycoside, and 225–226° as against 204° reported in the literature for the natural product, for the aglycone viz. citronetin, have been confirmed. The acetyl derivative of the glycoside and the acetyl and the methyl derivatives of the aglycone — have been prepared. The ultra‐violet and infra‐red spectra of the glycoside are discussed.
The iodination of monohydroxypyridines to monohydroxyiodopyridines
Authors: Broekman F. W. , Tendeloo H. J. C. 
Published: September 2010

AbstractThe method of Schickh, Binz and Schulz for the iodination of 3‐hydroxypyridine to give a hydroxymonoiodopyridine is also suitable for iodinating 2‐ and 4‐hydroxypyridine; 2‐ (or 4‐)hydroxy‐3,5‐diiodopyridine is produced as a by‐product from 2‐ and 4‐hydroxypyridine, respectively.Above ˜ 255° 4‐hydroxy‐3‐iodopyridine is converted into a mixture containing 4‐hydroxy‐3,5‐diiodopyridine.
The halogenation of aromatics: Part VII. Isomerizations, disproportionations and transbrominations involving bromobenzenes in the presence of aluminium bromide
Authors: Kooyman E. C. , Louw R. 
Published: September 2010

AbstractThe dibromobenzenes isomerize under the influence of aluminium bromide at room temperature to form an equilibrium mixture of dibromo compounds (60 % meta, 35 % para, 5 % ortho), bromobenzene and tribromobenzenes. p‐Dibromobenzene first forms ortho‐isomer, meta‐isomer being formed at a later stage. Small amounts of water have an accelerating effect (formation of HBr); carbon disulphide or naphthalene are inhibitors, probably as a result of complex formation involving aluminium bromide.The intermolecular nature of these reactions is demonstrated by the fact that in the presence of an excess of acceptors such as chlorobenzene or toluene, transbromination (ArBr + ArZ → ArH + ArZBr) is the main reaction observed.This phenomenon is used for the determination of relative rates of debromination of bromobenzenes (PhZBr) in competition runs: (Z = H unity), p‐Cl 0.6, p‐Br 0.4 (x2), m‐Br 0.03 (x2), 3,5‐diBr<0.01. Equilibrium constants are presented for several processes of the type ArBrZ + ArY ⇌ ArZ + ArYBr.Results are discussed in terms of an intermediate š‐complex ArBrH+, which may lose either a proton or a bromine cation. Equilibria may be correlated with data on bond strengths (Dc‐Br) in substituted bromobenzenes.
On the enthalpy change on formation of a solid compound from a gaseous and a liquid component
Authors: Korvezee A. E. , Pieroen A. P. 
Published: September 2010

AbstractFor the formation of a solid compound from a gaseous substance and a liquid at not too high pressures the relationship between the standard heat of formation of the compound, its actual heat of formation under equilibrium conditions and the heat quantity calculated from the slope of the three‐phase line gas‐liquid‐solid is discussed (equations XIV and XV). In sections 4 and 5 reference is made to the case of a solid compound formed from two partially miscible liquid substances as well as to the case of high pressure equilibria.
Studies in organosilicon chemistry: XLV. The addition of certain organosilicon compounds to ketene
Authors: Limburg William W. , Post Howard W. 
Published: September 2010

AbstractNine organosilicon compounds containing OH or NH have been found to add to ketene. Three carbon functional primary alcohols add to give acetates. Four primary amines and one secondary amine form N‐substituted acetamides while butyl‐trimethylsilyalmine yields N‐butyltrimethylsilylacetamide.
Electrochemical properties of a new glass‐electrode containing beryllium oxide
Authors: Tendeloo H. J. C. , Mans A. E. , Kateman I. , Voort F. H. V. D. 
Published: September 2010

AbstractA glass containing 73 mol % SiO2, 6 mol % BeO and 21 mol % K2O has been made and used as a glass‐electrode. This electrode responds rather well to potassium‐ and sodium‐ions, but not to calcium‐ions, and has a rather poor response to hydrogen‐ions.
Studies in IVth group organometallic chemistry. IX: Synthesis of organosilicon compounds and polymers containing the p‐Phenylene Group
Authors: Noltes J. G. , van der Kerk G. J. M. 
Published: September 2010

AbstractA number of oligomeric p‐phenylenesilanes containing 2‐6 silicon atoms per molecule and a series of low molecular weight poly‐p‐phenylenesilanes (n = 10‐30) have been prepared by Wurtz‐type condensation reactions involving appropriate combinations of p‐chlorophenyl‐ and chloro‐silanes. The polymeric products have been characterized by infrared spectroscopy, analytical and thermogravimetric data, and number‐average molecular weights, the low value of which is presumably caused by participation of the solvent (toluene) in the reaction. The polymers started to lose weight at temperatures varying from 310 to 485°.
Synthesis and physiological properties of some heterocyclic‐aromatic sulphides and sulphones: III Synthesis of some heterocyclic‐aromatic sulphones
Authors: van Zwieten P. A. , Gerstenfeld M. , Huisman H. O. 
Published: September 2010

AbstractThe synthesis of some heterocyclic‐aromatic sulphones with potential acaricidal properties is described. The benzene nucleus in these sulphones is substituted either with a para‐chlorine atom or with three chlorine atoms in positions 2, 4 and 5. The heterocyclic nuclei used are pyridine, pyrimidine, thiazole or thiophen. Apart from the sulphonyl substituent, these nuclei are unsubstituted or carry a halogen substituent; only in the thiophen series a nitro group is substituted in the heterocyclic nucleus. From the aryl‐pyridyl sulphones the corresponding N‐oxydes have been prepared.
Synthesis and reactions of esters of N‐hydroxyphthalimide and N‐protected amino acids
Authors: Nefkens G. H. L. , Tesser G. I. , Nivard R. J. F. 
Published: September 2010

AbstractEsters can be prepared from N‐hydroxyphthalimide and N‐carbobenzoxy‐ or N‐phthaloyl‐amino acids using dicyclohexylcarbodi‐imide as condensing agent. The compounds are suitable for the stepwise synthesis of peptides without racemization. With methanol the N‐hydroxyphthalimide ester of N‐phthaloylglycine can be converted into the methyl ester of N‐phthaloylglycine.
Synthesis of the C‐terminal tetrapeptide sequence derived from glucagon
Authors: Beyerman H. C. , Bontekoe J. S. 
Published: September 2010

AbstractA synthesis is described of the partially protected carboxyl‐terminal tetrapeptide sequence, L‐leucyl‐L‐methionyl‐L‐asparaginyl‐O‐t‐butyl‐L‐threonine t‐butyl ester, which is derived from the pancreatic hormone glucagon.In this synthesis we used successfully a novel combination of blocking groups, the t‐butoxy group and t‐butyl ester, together with N‐phthaloyl protection.
A novel synthesis of the diastereomeric 5‐phenylprolines
Authors: de Graaff G. B. R. , Melger W. Ch. , van de Kolk G. 
Published: September 2010

AbstractAs a preliminary to a synthesis of the diastereomeric 5‐(3′‐pyridyl)‐prolines, which will be reported in a subsequent paper, a preparation of the analogous 5‐phenyl‐prolines is described. As a result of the reaction sequence, a mixture of the two dl‐diastereomers was obtained, which were isolated and characterised.
The interaction of free radicals and aromatics: III The kinetics of the addition of cyanoisopropyl and trichloromethyl radicals on to anthracene derivatives
Authors: Farenhorst E. , Kooyman E. C. 
Published: September 2010

AbstractThe addition of cyanoisopropyl radicals to anthracenes obeys simple kinetics at high dilution and in the presence of a large excess of azoisobutyronitrile.The actual mechanism is shown to be rather complex, owing to transient formation of compounds containing the thermally unstable ketenimine structure. The simple kinetics observed apparently result from mutual compensation of anthracene‐consuming and ‐producing reactions.This would make the significance of relative cyanoisopropyl reactivities of different anthracenes rather doubtful. Nevertheless, these reactivities agree with those of trichloromethyl radicals towards anthracenes, found from the retardation by these anthracenes of the benzoyl‐peroxide‐initiated addition of bromo‐trichloromethane to styrene.
Aminations of bromo‐derivatives of 4‐ethoxy‐ and 2,4‐diethoxy‐pyridine, probably involving a 2,3‐pyridyne as intermediate
Authors: Pieterse M. J. , den Hertog H. J. 
Published: September 2010

AbstractThe amination of 3‐bromo‐4‐ethoxypyridine with potassium amide in liquid ammonia yielding 2‐amino‐4‐ethoxypyridine as chief product has been reinvestigated. It is shown that 2‐amino‐5‐bromo‐4‐ethoxypyridine is formed as a byproduct, probably via 3,5‐dibromo‐4‐ethoxypyridine and 5‐bromo‐4‐ethoxy‐2,3‐pyridyne as intermediates.In order to check the mechanism proposed for the process described above, aminations of 3‐ and 5‐bromo‐2,4‐diethoxypyridine were studied. Both reactions yield 6‐amino‐2,4‐diethoxypyridine as chief product. It was found that 3‐bromo‐2,4‐diethoxypyridine was converted first into the 5‐bromo‐isomer. It seems likely that in both aminations 2,4‐diethoxy‐5,6‐pyridyne is an intermediate.
Microbiological conversion of 19‐nortestosterone: (I) 16‐hydroxylation
Authors: de Flines J. , van der Waard W. F. , Mijs W. J. , Szpilfogel S. A. 
Published: September 2010

AbstractThe microbiological transformation of 19‐nortestosterone with Mycosphaerella latebrosa and with Hypomyces aurantius, leading to the 16β‐ and 16α‐hydroxy‐derivatives, respectively, is described.
Microbiological conversion of 19‐nortestosterone: (III) 12‐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 reaction of 19‐nortestosterone with Colletotrichum derridis yielding mainly 12β‐hydroxy‐19‐nortestosterone, is described.
Chemistry of acetylenic ethers 63: The synthesis of α,β‐unsaturated thiolesters from carbonyl compounds, acetylenic thioethers, and boron trifluoride
Authors: Bos L. B. , Arens J. F. 
Published: September 2010

AbstractThe α,β‐unsaturated thiolesters listed in Table I have been prepared by treating a mixture of a carbonyl compound and boron trifluoride with an acetylenic thioether (see reaction scheme 2). Good yields are obtained when ethers are used as solvents. The configuration of the esters prepared from aldehydes is trans. From unsymmetrical ketones mixtures of cis and trans isomers are formed.
Thermal substitution reactions of cupric benzoate II
Authors: Schoo W. , Veenland J. U. , de Boer Boer Th. J. , Sixma F. L. J. 
Published: September 2010

AbstractAfter thermal decomposition of cupric benzoate in the presence of deuterium oxide 43% of ortho‐deutero‐benzoic acid can be obtained beside phenol. A radical mechanism for the air oxidation of benzoic acid to phenol under the catalytic influence of copper oxide should therefore be reasonable.
Synthesis of β‐Phenylethylamine derivatives VIII: Four diastereoisomers of 1‐(4′‐hydroxyphenyl)‐2‐(1″‐methyl‐3″‐phenylpropylamino)propanol
Authors: van Dijk J. , Keizer V. G. , Moed H. D. 
Published: September 2010

AbstractThe two racemic‐ and the four diastereoisomeric erythro forms of the aminoalcohol II were prepared and characterizedmagnified imageThe relative configurations were established by synthesizing the diastereoisomers of II from the enantiomers oferythro‐p‐hydroxynorephedrine and from those of 1 ‐methyl‐3‐phenylpropylamine.The absolute configurations of the enantiomers of 1 ‐methyl‐3‐phenylpropylamine were determined by correlation with those of 2‐amino‐4‐phenylbutyric acid, of which the confuguration was known.On the basis of these experiments the configurations of the four erythro forms can be given as follows:(+)‐erythro‐II = αS : βR : γR(−)‐erythro‐II = αR : βS : γS(+)‐alloerythro‐II = αS : βR:γS(−)‐alloerythro‐II = αR : βS : γRBiological experiments confirmed these configurations.
Separation of amino acids on ion exchange paper
Authors: Hartel J. , Copper J. A. , van Bochove C. 
Published: September 2010

AbstractIt is very useful to employ ion‐exchanging chromatography papers for a rapid separation of a mixture of amino acids. Various separations are described, in some cases taking only one hour. Special papers were developed for this purpose based on chemical modification of cellulose and containing basic or acid groups. The possibilities for using these papers in a quantitative determination are discussed.
Chemistry of acetylenic ethers 65: 4‐Hydroxyalkynyl ethers, their synthesis and conversion into γ‐lactones
Authors: Vollema G. , Arens J. F. 
Published: September 2010

Abstract4‐Hydroxyalkynyl ethers can be prepared from epoxides and ethoxyethynyllithium in liquid ammonia or bis‐ethoxyethynylmagnesium in ether‐tetrahydrofuran.Under other conditions, notably in the presence of metal halides other products are obtained, including halohydrins and 3‐hydroxyalkynyl ethers, the latter arising from carbonyl compounds formed by isomerisation of the epoxides. For propylene oxide two types of isomerisation into carbonyl compounds have been described in the literature. Lewis acids like magnesium bromide convert the substance into propionaldehyde or into acetone. We found that the same change can also be caused by lithium iodide. For the preparation of pure 4‐hydroxyalkynyl ethers from epoxides it is therefore desirable to employ solutions of metallated acetylenic ethers devoid of salts.The reaction of epichlorohydrin with metallated ethoxyethyne or metallated ethylthioethyne leads to three and four successive products, respectively, depending on the reaction conditions and the solvent. The primary product is a 5‐chloro‐4‐hydroxyalkynyl (thio)ether which under alkaline conditions is converted into a 4,5‐epoxyalkynyl (thio)ether and, when sodamide is present, into a 5‐hydroxy‐Δ3,4 alkynyl (thio)ether. The thio compound (but not the oxygen analogue) finally undergoes ring closure to 2‐(alkylthiomethyl)furan.Hydrolysis and also pyrolysis of 4‐hydroxyalkynyl ethers gives γ‐lactones in good yields.
1‐(2‐Dialkylaminoethyl)‐methoxybenzimidazoles
Authors: Foster R. , Hanson P. 
Published: September 2010

AbstractA series of l‐(2‐dialkylaminoethyl)‐x‐methoxy‐benzimidazoles has been synthesised. Two of these compounds are the O‐methylated benzimidazole analogues of psilocine and of bufotenine.
Chemistry of acetylenic ethers 66: Thermal decomposition of l‐ethoxyvinyl esters
Authors: Zwanenburg B. 
Published: September 2010

AbstractThe thermal decomposition of some 1‐ethoxyvinyl esters is described. The first step of the decomposition is rearrangement to a β‐keto ester, the enolic form of which is subsequently acylated by the 1‐ethoxyvinyl ester.