bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemistry of acetylenic ethers. LI: Introduction of alkylthio groups into acetylenic compounds and into other compounds with reactive hydrogen atoms by means of disulphides
Authors: Nooi J. R. , Arens J. F. 
Published: September 2010

AbstractAcetylenic compounds RC ≡ CH can be converted into acetylenic thioethers by treatment of the sodium or lithium alkynide with diethyl disulphide in liquid ammonia. This constitutes the easiest route to 1‐ethylthio‐1‐alkynes I.Other compounds with “acidic” CH3, CH2 or CH groups can likewise be alkylthiolated; generally the product containing two geminal ethylthio groups is formed in excess.
The action of p‐toluenesulphonyl chloride on pyridine‐n‐oxide (III)
Authors: den Hertog H. J. , Buurman D. J. , de Villiers P. A. 
Published: September 2010

AbstractThe reaction mixture formed during the heating of pyridine‐N‐oxide with p‐toluenesulphonyl chloride contains, together with pyridine, 2,3′‐dipyridyl ether, 3‐pyridyl p‐toluenesulphonate and N‐(2Prime;‐pyridyl)‐pyridone‐2 two chloro compounds, viz. N‐(2′‐pyridyl)‐5‐chloro‐pyridone‐2, which is the chief product, and N‐(2′‐pyridyl)‐3‐chloro‐pyridone‐2.In this connection the formation of brominated derivatives of N‐(2′‐pyridyl)‐pyridone‐2 during the reaction of pyridine‐N‐oxide and 2‐bromopyridine, as described by Ramirez and von Ostwalden is discussed.
On the impedance of galvanic cells: III. Applications to alternating current polarography
Authors: Rehbach M. , Sluyters J. H. 
Published: September 2010

AbstractThe theory described in part I of this series J. H. Sluyters, Rec. trav. chim. 79, 1092 (1960).
is applied to alternating current polarography by treating the complex cell impedance and cell admittance as functions of d.c. voltage.It is proposed to plot a.c. polarograms in the complex impedance or admittance plane. By this method it is possible to reduce the uncertainty in the height of the peak caused by the base current. An exactly linear relationship between the quantity measured and concentration can be obtained over a large range of concentrations by means of a simple construction.The measurements can be performed over a wide range of frequencies. Consequently, in some cases, a higher sensitivity can be obtained, because the most favourable frequency can be chosen.The method is not only suitable for analytical purposes, but also for the determination of the fundamental constants of electrode processes (rate constants, diffusion constants and double layer capacities).
γ‐Coniceine of conium maculatum L., a revision of the generally accepted structure
Authors: Beyerman H. C. , van Leeuwen M. , Smidt J. , van Veen A. 
Published: September 2010

AbstractThe commonly accepted structure of γ‐coniceine, the major alkaloid of Conium maculatum L., is revised on the basis of results obtained in the present study with “active hydrogen” determinations and with regard to nuclear magnetic resonance spectra. Infra‐red spectra also support this revision.γ‐Coniceine is 2‐n‐propyl‐3,4,5,6‐tetrahydropyridine.The revised structure of γ‐coniceine (a Δ1 ‐ piperideine) seems of interest with a view to the biogenesis of the piperidine alkaloids and related amino‐acids.
Über 2‐Propyl‐1‐ und 2‐Propyl‐3‐desaza‐adenin (4. Mitteilung über Desaza‐purin‐Derivate)
Authors: Salemink C. A. 
Published: September 2010

AbstractDie vorliegende Arbeit beschreibt die Synthesen von 2‐Propyl‐1‐desaza‐adenin und von 2‐Propyl‐3‐desaza‐adenin, nach Analogie der Synthesen von in der 1. und 3. Mitteilung dieser Reihe beschriebenen Strukturanalogen von Adenin.
Triazine isocyanates: Part I: 2,4‐diphenyl‐s‐triazine‐6‐isocyanate
Authors: Duynstee E. F. J. 
Published: September 2010

AbstractThe synthesis of the azide of 2,4‐diphenyl‐s‐triazine‐6‐carboxylic acid is described. Decomposition of this azide yields a product in which 2,4‐diphenyl‐s‐triazine‐6‐isocyanate has been spectroscopically detected. This very reactive isocyanate is the first example of a compound in which an isocyanate group is directly bound to a s‐triazine ring.
The resolution of DL‐muscarine
Authors: Salemink C. A. , Cox H. C. 
Published: September 2010

AbstractThe Debije‐Scherrer diagram of “natural” L(+)‐muscarine‐di‐p‐toluyl‐hydrogen‐D(−)‐tartrate‐hemihydrate is compared with the diagrams of muscarine‐di‐p‐toluyl‐hydrogen‐D(−)‐tartrates resulting from the resolution of two DL‐muscarine preparations. One of the latter diagrams proved to be identical with the diagram of “natural” L(+)‐muscarine‐di‐p‐toluyl‐hydrogen‐D(−)‐tartrate‐hemihydrate whereas the other was entirely different.
The P‐T‐x space model of the system ethylene naphthalene (I)
Authors: van Welie G. S. A. , Diepen G. A. M. 
Published: September 2010

AbstractIn a Cailletet apparatus the solubility of naphthalene in supercritical ethylene has been determined quantitatively up to pressures of 200 atm, by visually measuring P‐T sections at constant composition.
The P‐T‐x space model of the system ethylene‐naphthalene (II)
Authors: van Welie G. S. A. , Diepen G. A. M. 
Published: September 2010

AbstractAn apparatus is described by means of which quantitative P‐T measurements can be carried out visually, at constant composition, up to pressures of 1000 atmospheres. This apparatus is used for measuring the solubility of naphthalene in supercritical ethylene.
The P‐T‐x space model of the system ethylene‐naphthalene (III)
Authors: van Welie G. S. A. , Diepen G. A. M. 
Published: September 2010

AbstractOur two previous articlesG. S. A. van Welie and G. A. M. Diepen, Rec. trav. chim. 80, 659 (1961).
Idem, ibid., 80, 666 (1961).
and some supplementary observations enabled us to derive a number of sections and projections of the P‐T‐x space model of the ethylene‐naphthalene system, within the following limits of measurement: 0 to 1000 atm, 0 to 100 moles % naphthalene and 20° to 115°. An important result of our discovery is that the critical conditions of the second critical point are: P = 174.0 atm, T = 52.1° and x = 17 moles % ± 0.5.On the L2 = G curve we have found a pressure maximum at 244 atm and 195°.
Steric effects on the electronic spectra of substituted benzophenones. V. Some alkyl‐substituted benzophenones
Authors: Rekker R. F. , Nauta W. Th. 
Published: September 2010

AbstractThis article gives the experimental results of UV measurements made on a number of benzophenones with ethyl, isopropyl and tert.butyl groups as substituents. The results are compared with the previously published data on the corresponding methyl‐substituted benzophenones1,2,3,4. Our investigation showed that there is no significant difference between the effects of introduction of ortho‐methyl, ortho‐ethyl or ortho‐isopropyl groups into a benzophenone. With a tert.‐butyl group, however, the result is somewhat different: in this case a steric effect is observed on the electronic spectra, which is only slightly smaller than that encountered in 2,6‐dimethylbenzophenone. When plotting the λC differences between meta/para‐substituted derivatives and the unsubstituted benzophenone against the Hammett σ‐values the result is a straight line, the Hammett σ‐constant being −0.061 for ethanol and −0.050 for isooctane solutions.
Chemistry of the silylamines: IV. Condensation of N,N‐diethylamino‐trimethylsilane with the triphenylhydroxides of carbon, silicon, and germanium
Authors: Pike R. M. 
Published: September 2010

AbstractDerivatives of the type (C6H5)3M‐OH, where M  C, Si and Ge, were condensed with N,N‐diethylamino‐trimethylsilane in xylene solvent at 50°. The rates of the condensation reaction for this series (C, Si,Ge) were found to be in the ratio of approximately 1 : 3 : 1, respectively.
The reactivities of the tyrosine residues in insulin with respect to iodine I
Authors: de Zoeten L. W. , de Bruin O. A. , Everse J. 
Published: September 2010

AbstractWith the aim of studying the reactivities of the tyrosine residues in insulin, this protein was brought together with varying amounts of radioactive iodine under such conditions that the tyrosine residues were the only groups to react. The total uptake of iodine was measured. The A and the B chains were then separated and the iodine content of each chain was determined.The amounts of iodine present as mono‐ and as di‐iodinated tyrosine residues were established.
The reactivity of the tyrosine residues in insulin with respect to iodine II
Authors: de Zoeten L. W. , Havinga E. , Everse J. 
Published: September 2010

AbstractThis paper deals with the enzymatic hydrolysis of the A and the B chain of 131I‐iodinated insulin to yield four fragments each containing one tyrosine residue. The iodine content of the fragments obtained from samples of insulin that had reacted with varying amounts of iodine, are given. Residue A19 seems to take up only one iodine atom at a rapid rate. A comparison is made with the amount taken up by glycyltyrosine under the same conditions. The relative initial rates of reaction of glycyltyrosine and the four tyrosine residues A14, A19, B16, B26 are 1, 1, 1.6, 0.2, 0.2 respectively. In 8 molar urea the reactivities found are 1, 1, 1.5, 0.8, 0.6. A discussion is given.
Reserpine analogues IV. Hydroxy‐β‐phenylethylamine derivatives
Authors: Kralt T. , Asma W. J. , Moed H. D. 
Published: September 2010

AbstractThe synthesis of a series of compounds resembling in some respects the reserpine alkaloid and containing a β‐phenylethylamine configuration substituted at the phenylgroup with hydroxyl groups is described.
Photo‐oxidation, sensitised by proflavine, of furfuryl alcohol, N‐allyl thiourea and histidine
Authors: Sluyterman L. A. Æ 
Published: September 2010

AbstractThe photo‐oxidations, sensitised by proflavine, of furfuryl alcohol, N‐allyl thiourea and histidine as a function of pH and substrate concentration have been investigated.The rate of oxidation of the neutral compound furfuryl alcohol is constant over the pH range of 9–3 and decreases below pH 3. This decrease corresponds to a change in the fluorescence spectrum of proflavine (fig. 4).A similar decrease in the oxidation rate of N‐allyl thiourea at low pH is preceded by an unexpected increase in rate from pH 5 to pH 2 (fig. 5).The oxidation rate of histidine is constant from pH 9 to pH 7, drops below pH 7 and is virtually zero at pH 4 (fig. 6). This can be interpreted quantitatively to indicate that free imidazole groups and not positively charged imidazole groups are oxidized, provided the actual dependence of the oxidation rate on substrate concentration is taken into account (fig. 8).This dependence of the oxidation rate on the concentration of the three substrates can be described in terms of simple reaction kinetics (equation 8).
The antirachitic activity of previtamin D3
Authors: Hanewald K. H. , Rappoldt M. P. , Roborgh J. R. 
Published: September 2010

AbstractA prophylactic test (chick assay) was carried out with pure pre‐vitamin D3. The apparent antirachitic activity was found to be 35% of that of pure vitamin D3. This result is discussed in connection with the kinetics of the interconversion of previtamin D3⇆ vitamin D3. The observed activity may be interpreted as originating exclusively from vitamin D3 formed in the test animal.
Investigations on pesticidal phosphorus compounds IV: N‐bis(dimethylamido)phosphoryl heterocycli
Authors: van den Bos B. G. , Schoot C. J. , Koopmans M. J. , Meltzer J. 
Published: September 2010

AbstractIn view of their pesticidal properties a number of bis (dimethylamido)phosphoryl heterocyclic compounds was prepared. The fungicidal, insecticidal and acaricidal activities as well as the phyto‐toxicity and the toxicity for mice are given in table II.
Plant growth‐regulating activity of S‐carboxymethyl‐N,N‐dimethyldithiocarbamate and related compounds
Authors: Pluijgers C. W. , van der Kerk G. J. M. 
Published: September 2010

AbstractThe plant growth‐regulating activity on tomato plants of S‐carboxymethyl‐N,N‐dimethyldithiocarbamate and of structurally related compounds has been investigated. Activity is connected with the electronic configuration of the molecules, viz. with a distinct degree of double‐bond character of the NC bond. In addition, however, sterical factors seem to be of decisive significance for presence or absence of growth‐regulating activity.
Acid anilides: IX. Application to the determination of free and esterified lower fatty acids in dairy products and in fats
Authors: De Jonge A. P. , van Der Ven B. , Verhage A. 
Published: September 2010

AbstractIn this paper some applications of the qualitative and quantitative paper chromatography of fatty acid anilides are described, viz.:
detection of esterified acetic acid in butterfat;
demonstration of esterified lower fatty acids in palm oil and cocoa‐butter;
determination of free lower fatty acids in fresh and heated butter, ghee, and soured skim milk.
The quantitative conversion of small amounts of fatty acids into their anilides and the quantitative isolation of the acids concerned from the raw materials were investigated and procedures developed.
The chemistry of cycloheptatriene: Part I. Synthesis of benzocyclobutene
Authors: Ter Borg A. P. , Bickel A. F. 
Published: September 2010

AbstractAddition of dichlorocarbene to cyclopentadiene yields chlorobenzene. The addition of dichlorocarbene to cycloheptatriene yields 8,8‐dichloro‐bicyclo [5.1.0] octadiene‐2,4 (II). When (II) is heated at 140° a rearrangement to 1‐chlorobenzocyclobutene (III) occurs with evolution of HCl. Reduction of (III) with hydrogen in the presence of palladium gives benzocyclobutene (V).
Mechanism of reactions of unsaturated ethers and thioethers IV: Acid catalyzed rearrangement of ethoxyethynyl‐ and ethylthioethynyl‐carbinols
Authors: Hekkert G. L. , Drenth W. 
Published: September 2010

AbstractThe rearrangement of ethoxyethynyl‐carbinols into unsaturated esters was investigated in acidic aqueous solution. The reaction is general acid catalyzed and β‐hydroxy esters are by‐products. There exists a simple relation between the ratio of β‐hydroxy ester to unsaturated ester and the concentration of hydroxyl and acetate ions. The two products are formed in a common rate determining step, which is a proton addition to the β‐carbon atom of the carbinol. It is suggested, that the hydroxyl group participates and that a four‐membered ring intermediate is formed in this slow step: magnified image Ethylthioethynyl‐carbinols behave similary.
Synthesis of a series of alkyl‐substituted benzophenones, benzhydrols and benzhydryl chlorides
Authors: Fleurke K. H. , van der Stelt C. , Nauta W. Th. 
Published: September 2010

AbstractIn the course of an investigation into the properties of substituted tetraphenylethanes, benzhydryl chlorides and basic benzhydryl ethers we have prepared 2‐ethyl‐, 2,6‐ and 2,2′‐diethyl‐, 2,6,2′‐triethyl‐, 2,6,2′,6′‐tetraethyl‐, 2‐isopropyl‐, 2,6‐ and 2,2′‐diisopropyl‐, 2,6,2′‐triisopropyl‐ and 2,6,2′,6′‐tetraisopropyl‐benzophenone as well as the corresponding benzhydrols and benzhydryl chlorides.
The mercuration of pyridine‐N‐oxide (ii)
Authors: van Ammers M. , den Hertog H. J. 
Published: September 2010

AbstractPyridine‐N‐oxide has been mercurated with different reagents, i.e. mercuric acetate in acetic acid, mercuric sulphate, mercuric sulphate in sulphuric acid, mercuric chloride and mercuric bromide.Mercuration with mercuric acetate in acetic acid yields mainly derivatives substituted at positions 2 or 2 and 6, together with the compound substituted at the 3‐position. It is shown that the supposition of Ukai, Yamamoto and Hirano4 that the compound substituted at position 4 is formed in this reaction as the chief product, is incorrect.The 3‐ and 4‐isomers are obtained together with the 2‐isomer as chief product, however, when pyridine‐N‐oxide is heated with mercuric sulphate. Addition of sulphuric acid lowers the yield of this mercuration and changes the substitution pattern. Together with the derivative substituted at position 2 a considerable amount of the 3‐isomer is formed. Also in mercuration with mercuric chloride and mercuric bromide the nucleus is attacked at the 3‐ and 4‐positions, but here the reaction mixture consists preponderately of the 2‐isomer again.
Distribution of radio activity in trismethylene‐trinitrobenzene obtained from 14C‐labelled 1,3,5‐trinitrobenzene: Nucleophilic aromatic addition V
Authors: de Boer Th. J. , van Velzen J. C. 
Published: September 2010

AbstractThe previously suggested mechanism for the formation and the stepwise degradation of “trismethylene‐trinitrobenzene” (I) is confirmed by application of a 14C tracer technique. It is shown that all transformations occur without hydrogen shift.In this paper besides compound II a stereoisomer was considered, with a different position of the two cyclopropyl‐groups towards one another. Further investigation in collaboration with Mr. H. P. Venker has shown that formula II is most likely. However this may be, it is of no consequence for the conclusions reached in the present paper.
The chemistry of cycloheptatriene: Part IV: Synthesis of tropone, 2‐chlorotropone and tropolone
Authors: ter Borg A. P. , van Helden R. , Bickel A. F. 
Published: September 2010

AbstractAcid‐catalysed decomposition of tropyl ether gives tropone and cycloheptatriene in 83.5 and 90 % yields, respectively.Chlorination of tropone in carbon tetrachloride solution yields tropone dichloride, which can be made to isomerize to the hydrochloride of 2‐chlorotropone; 2‐chlorotropone is obtained in a 83.5 % yield.Hydrolysis of the latter compound in refluxing 80 % aqueous formic acid gives tropolone in 85 % yield.
Studies on cyclohexane derivatives: III. A chemical proof of the configurations of the two 1‐isopropyl‐4‐methylcyclohexanes (para‐menthanes)
Authors: van Bekkum H. , Medema D. , Verkade P. E. , Wepster B. M. 
Published: September 2010

AbstractThe configurations of the two 1‐isopropyl‐4‐methylcyclohexanes (para‐menthanes) were determined by means of syntheses starting from pure cis‐and pure trans‐4‐methylcyclohexanecarboxylic acid.
The reaction of dialkylaminosilanes with carbon dioxide and with carbon disulphide
Authors: Breederveld H. 
Published: September 2010

AbstractDialkylaminosilanes react at room temperature with carbon dioxide and with carbon disulphide to give silyl dialkylcarbamates and silyl dialkyldithiocarbamates, respectively. These reactions proceed by an ionic chain mechanism, which requires the presence of catalytic amounts of free amine.
The kinetics of the reaction of phenol and formaldehyde
Authors: Dijkstra R. , de Jonge J. , Lammers M. F. 
Published: September 2010

AbstractThe hydroxymethylation of phenol has been re‐investigated in the pH range 8.5‐12.5 at 30° in dilute aqueous solutions.The following rate equation covers the results quantitatively:

in which [F], [P] and [P−] denote the concentrations of the formaldehyde molecules, phenol molecules and phenoxide‐ions.In solutions with pH < 9, and phenol concentrations ⩾ 0.1 g‐mole · 1−1 this equation simplifies tov=6.9·10−5[P]−[F]·g‐mole·1−1sec−1which represents the bimolecular reaction found earlier1.The following two step mechanism is proposed:magnified imageX− denotes some 1: 1 complex between a phenoxide‐ion and a formaldehyde molecule, k1 = 6.9 · 10−5 1 · gmole−1 sec−1 and k−1/k2 = 0.006 gmole · 1−1.
Reactions of 1‐bromo‐2‐phenylethane and aluminium bromide: Part I. Isomerisation of 1‐bromo‐2‐phenylethane‐1‐14C
Authors: Adema E. H. , Sixma F. L. J. 
Published: September 2010

AbstractThe kinetics of the reaction involving the isomerisation of 1‐bromo‐2‐phenylethane‐1‐14C into 1‐bromo‐2‐phenylethane‐2‐14C under the influence of aluminium bromide in carbon disulphide has been studied in the temperature range of −70° to −100°. The energy of activation is 9.8 kcals/mole.The kinetic results can be explained if nearly all aluminium bromide is assumed to be bound as the complex C8H9Br: AlBr3. The reaction of C8H9Br: AlBr3 with one of the ions formed in the ionisation of the complex C8H9Br: Al2Br6 is represented as the rate determining step of the isomerisation reaction.
Synthesis of 1‐pentene‐4‐14C and 1‐pentene‐5‐14C
Authors: Otto P. Ph. H. L. , van Zanten B. 
Published: September 2010

Abstract1‐Pentene‐4‐14C and 1‐pentene‐5‐14C were obtained in one single step from iodoethane‐1‐14C and iodoethane‐2‐14C, respectively, by reaction with allylmagnesium chloride in tetrahydrofurfuroxytetrahydropyran (TFTP) as solvent. The synthesis was carried out on a twenty mmoles scale in a completely closed apparatus. The pentenes were formed in 80 % yield. After final purification by means of gas‐liquid chromatography the radio‐chemical purity was 99.7 %.
The relationship between the gas production and the current in the oxygen‐hydrogen coulometer
Authors: van Soestbergen A. A. 
Published: September 2010

AbstractThe oxygen‐hydrogen coulometer, using a 2 M solution of NaOH as electrolyte, yields a negative error at small currents. The magnitude of this error in ml gas at N.T.P./hr has been estimated at different currents and an empirical expression relating gas volumes to coulombs developed. The gas production can be calculated from: ml gas at N.T.P./coulomb = [b ‐ k1/(k2 · i + 1)] [1000/3600], where b = the theoretical gas production in ml gas at N.T.P./mA. hr; i = the current in mA; k1 and k2 are constants.Using a coulometer containing two platinum electrodes each 1 × 1 cm, k1 = 0.1938 and k2 = 0.6200. A maximum gas production of 0.1742 ml gas at N.T.P./coulomb is obtained at about 3000 mA and a minimum value of 0.1204 ml gas at N.T.P./coulomb at about 0.001 mA.Using a coulometer containing small platinum‐wire electrodes (anode 0.5 cm, ø 0.1 mm; cathode 0.5 cm, ø 0.5 mm), k1 = 0.0041 and k2 = 0.0132. A maximum gas production of 0.1742 ml gas at N.T.P./coulomb is obtained at about 1650 mA and a minimum value of 0.1731 ml gas at N.T.P./coulomb at about 0.001 mA.
The chemistry of the N‐alkylaldimines: III. The origin of the bands at 1400 cm−1 in the infrared spectra of N(1‐alkenyl)‐N‐propylamides
Authors: Breederveld H. , Rummens F. H. A. 
Published: September 2010

AbstractThe band at about 1400 cm−1 in the infrared spectra of N(1‐alkenyl)‐N‐propylamides is assigned to the N‐C‐stretching vibration of the systemmagnified image
2‐Vinyl‐ and 4‐vinyl‐1,3‐dioxan
Authors: Bellaart A. C. 
Published: September 2010

AbstractIt is shown that 2‐vinyl‐1,3‐dioxan can be synthesized by the methods of Faass and Hilgert1 and of Fisher and Smith2. From 2‐vinyl‐1,3‐dioxan we obtained 2‐ethyl‐1,3‐dioxan and 2‐(1′,2′‐dibromoethyl)‐1,3‐dioxan. 4‐Vinyl‐1,3‐dioxan and 2‐vinyl‐1,3‐dioxan have the same boiling point and refractive index; infrared spectra, however, are different.
Alkoxychlorogermanes
Authors: Pike R. M. , Fournier A. F. 
Published: September 2010

AbstractThe synthesis of alkoxychlorogermanes of the type (RO)xGeCl4‐x, where x may be 1, 2 or 3 and R = C2H5‐, iso‐C3H7‐, or tert‐C4H9‐ is reported. Diethoxydichlorogermane on treatment with n‐butanol and n‐hexanol gave di‐n‐butoxydichlorogermane and dichloro‐di‐n‐hexoxygermane, respectively.
Chemistry of acetylenic ethers LVII: Bifunctional acetylenic ethers
Authors: Nooi J. R. , Arens J. F. 
Published: September 2010

AbstractBifunctional acetylenic ethers ROC≡C(CH2)nC≡COR can be prepared by alkylation of alkoxyethynyl‐sodium or ‐lithium with α,ω‐dihalides in liquid ammonia. The compounds obtained, and other acetylenic ethers synthesized by alkylation of alkoxyethynes, are listed in table I.The bifunctional ether CH3C≡C·O·CH2CH2·O·C≡CC;H3 was prepared as outlined in the reaction scheme on page 520.
Chemistry of acetylenic ethers LX: Synthesis of cyclobutenone ethers from ketene and 1‐alkoxy‐1‐alkynes
Authors: Rosebeek B. , Arens J. F. 
Published: September 2010

AbstractThe cyclobutenone ethers V listed in table I have been prepared from 1‐alkoxy‐1‐alkynes and ketene.