bluuebunny/crossref_metadata_2025 huggingface dataset:
Aromatic sulphonation VII: Orientation in the homogeneous sulphonation of toluene in aqueous and fuming sulphuric acid
Authors: Cerfontain H. , Sixma F. L. J. , Vollbracht L.
Published: September 2010

The isomer distribution in the homogeneous monosulphonation of toluene in 77.6‐98.8 wt‐ % aqueous sulphuric acid has been determined at various temperatures between 5 and 65°. Sulphone formation and disulphonation are negligible. The isomer distribution is independent of toluene conversion. The degree of meta‐substitution is low under all conditions. At 25.0° the ratio of o‐ to p‐toluene‐sulphonic acid changes from 0.276 to 1.08 on varying the concentration of sulphuric acid from 77.6 to 98.8 wt‐%; the meta‐isomer shows only a small increase over this acid range. The decrease in the partial rate factor ratio, fp/fm, with increasing sulphuric acid concentration results mainly from an increase in the activation enthalpy difference between para‐ and meta‐substitution. This decrease in fp/fm, is taken as an indication of increasing reactivity of the sulphonating entity.

The entropy of activation is greater for para‐substitution than for ortho‐substitution. On varying the sulphuric acid concentration from 77.6 to 95.8 wt‐%, the entropy difference decreases from 8.8 ± 0.2 to 4.8 ± 0.7 cal · degree‐1 · mole‐1 probably because the solvation of the transition state leading to ortho‐substitution decreases with increasing acid concentration. The difference in activation enthalpy between para‐ and ortho‐substitution is 1.3 ± 0.2 kcal · mole‐1, whatever the acid concentration. This enthalpy difference is explained by an intramolecular hyperconjugative proximity effect in the transition state leading to ortho‐substitution.
The autoxidation of mercaptans in non‐aqueous alkaline media
Authors: Berger H.
Published: September 2010

The autoxidation of n‐octyl mercaptan and thiophenol in tert‐butanol containing varying amounts of potassium tert. butoxide, yields as the only products disulfide and/or acids (sulfinic and sulfonic). It appears that disulfide is formed from unionized mercaptan, whereas the acids originate in the mercaptide ion. A mechanism for the formation of the acids is presented, in which the sulfenate anion (RSO−) is an important intermediate. The primary species formed in the reaction of mercaptide ion with oxygen is thought to react preferentially with unionized mercaptan to give the disulfide.
The binary system sulphur trioxide‐selenium trioxide
Authors: Mijlhoff F. C. , Gerding H.
Published: September 2010

The solid‐liquid equilibria present in mixtures of sulphur trioxide and selenium trioxide have been investigated. Homogeneous mixed crystals exist in a wide range of SeO3‐ concentrations up to 100% SeO3. T he system has a eutectic at 15° with a composition of 0.03 mole % SeO3 and 99.97 mole % SO3.

The melting point (120.9 ± 0.5°) and the heat of fusion (1.7 kcal/mole SeO3) of pure SeO3 were determined.
Separation of unsaturated dinitrophenylhydrazones into classes
Authors: de Jong K. , Mostert K. , Sloot D.
Published: September 2010

Unsaturated dinitrophenylhydrazones with one or more isolated double bonds may, as a class, be separated from saturated, α‐β‐unsaturated or α‐β, γ‐δ‐unsaturated DNPHs by using silicagel impregnated with AgNO3 (column chromatography) or alumina impregnated with AgNO3 (thin layer chromatography).
Efficiency of chromatographic procedures. I. Theory
Authors: de Ligny C. L. , Schmidt H. M. , de Vries W.
Published: September 2010

Equations for the efficiency of chromatographic procedures are derived. In contrast to the equation, obtained by Haarhoff and Pretorius, these equations are not restricted to column chromatography and in the derivation the theoretical‐plate concept is not introduced.
Investigations into the conformation of non‐aromatic ring‐compounds IX: The crystal structure of trans‐2,3‐dichloro‐1,4‐dioxan at −145°
Authors: Altona C. , Romers C.
Published: September 2010

trans‐2,3‐Dichloro‐1,4‐dioxan crystallizes in the monoclinic system, space group P21/c, Z = 4, with cell dimensions:

a = 7.203 Å, b = 5.704 Å, c = 15.79 Å, β = 107.3° at −145°.

The structure was refined in two projections by means of reflexion data obtained at −145° using molybdenum radiation. The dioxan ring has the chair conformation; the chlorine atoms occupy axial positions.
Chemistry of acetylenic ethers 68: Preparation of enynes by elimination of alcohol from acetylenic ethers
Authors: Brandsma L. , Montijn P. P. , Arens J. F.
Published: September 2010

Acetylenic ethers of the types RCH2CCCH2OR′ and RCH2CH2CCOR′ have been converted into alkenynylides RCHCHCCNa and alkoxides R′ONa by treatment with two moles of sodamide in liquid ammonia.
Pesticides. I. the structure of dihydronicotyrine
Authors: Mechoulam Raphael , Gaoni Yehiel
Published: September 2010

Dihydronicotyrine, the reduction product of the alkaloid nicotyrine, has been shown to possess structure III.
Cardiolipin and derivatives: I. Synthesis of an acyl derivative of diphosphatidylglycerol
Authors: de Haas G. H. , van Deenen L. L. M.
Published: September 2010

This paper describes the synthesis of a long‐chain fatty acyl ester of diphosphatidylglycerol. The properties of this compound were compared with those of natural cardiolipin isolated from ox‐heart. Although both substances display a very similar behaviour, they are not identical.
On Criegee's mechanism of ozonisation: The isolation of the six possible ozonides from methyl oleate
Authors: Riezebos G. , Grimmelikhuysen J. C. , van Dorp D. A.
Published: September 2010

Ozonisation of methyl oleate in light petroleum at 10° yielded six ozonides. They were characterised as the three possible pairs of “cis‐” and “trans‐” isomers, which can be predicted on the basis of Criegee's theory. Our results indicate that a complete breakdown occurs of the oleate molecule into “zwitter‐ionic” and aldehydic fragments. Hence we exclude a mechanism proposed by Milas, where a complete breakdown of the molecule does not take place.
Polysubstituted monocyclic boroxazolidines
Authors: Zimmerman Howard K. , Jones David A.
Published: September 2010

Six new substituted aminoethyl esters of hydroxydiphenylborane are described.

In contrast to the behaviour of triptych boroxazolidines, in which subsituents in the amino‐alcohol carbon atoms are associated with increased resistance of the boroxazolidine towards acidic hydrolysis, increased substitution among the monocyclic boroxazolidines is associated with increased lability in acidic solutions.
Hydrazine derivatives of pyridylacetic acids
Authors: Bojarska‐Dahlig H. N.
Published: September 2010

A series of hydrazine derivatives of 2‐, 3‐ and 4‐pyridylacetic acids has been prepared by catalytic hydrogenation of aldehyde or ketone pyridylacetyl‐hydrazones and tested in vitro for MAO inhibition. Compounds derived from benzylhydrazine were the most active MAO inhibitors in vitro.
Nitration of α‐chloronaphthalene‐α‐sulphonic acids
Authors: Bassilios H. F. , Shawky M. , Salem A. Y. , Mohtasseb I. F.
Published: September 2010

Nitration of α‐chloronaphthalene‐α‐sulphonic acids using mixed acids or fuming nitric acid gives α‐substituted nitro derivatives. The deactivation of the aromatic nucleus by the two electrophilic groups is increased as the sulphonic group passes from the 4‐ to the 5‐ and finally to the 8‐position.
Phosphatidic acids and derivatives: XIII. Synthesis and alkaline hydrolysis of tris(2‐stearoyloxyethyl) phosphate
Authors: van Gijzen J. , Hoefnagel M. A. , Verkade P. E.
Published: September 2010

We describe the preparation of tris(2‐stearoyloxyethyl) phosphate, starting from monostearoylglycol (2‐stearoyloxyethanol) and phosphorus oxychloride and from silver bis(2‐stearoyloxyethyl) phosphate and stearoylglycol iodohydrin. The alkaline hydrolysis of the first‐mentioned compound is investigated.
Chemistry of acetylenic ethers 71: Acetylenic benzyl ethers and their rearrangement into 2‐indanones
Authors: Olsman H. , Graveland A. , Arens J. F.
Published: September 2010

Acetylenic benzyl ethers, IV, with R  CH3 or C2H5 and R′  H or CH3 have been prepared according to the scheme below. These compounds rearrange very easily into 1,3‐dialkyl‐2‐indanones, V, on refluxing in tetrachloromethane and into 1‐hydroxy‐1‐phenyl‐2‐alkynes with sodamide in liquid ammonia.
Chemistry of acetylenic ethers 72: Nucleophilic substitutions at sulphur and selenium in some alkynyl thioethers and alkynyl selenoethers
Authors: Brandsma L.
Published: September 2010

Under the catalytic influence of bases, such as sodamide and sodium acetylide dissolved in liquid ammonia, ethylselenoacetylene, HCC‐SeC2H5, disproportionates into bis(ethylseleno)acetylene, C2H5SeCCSeC2H5, while ethylthioacetylene remains unchanged under the same conditions. Bis(ethylseleno)acetylene and bis(ethylthio)acetylene react with phenyl‐lithium in ether. The selenoether gives lithium ethylselenoacetylide, LiCCSeC2H5 or dilithium acetylide LiCCLi and ethyl phenyl selenide, C6H5SeC2H5, while the thioether is converted into lithium ethylthioacetylide, LiCCSC2H5 or dilithium acetylide and ethyl phenyl sulphide, C6H5SC2H5, and some phenylacetylene. Ethers of the type RCCSC2H5, in which R represents a tertiary butyl group or a phenyl group, are smoothly cleaved by a solution of potassium amide in liquid ammonia, RCCK being produced.
Intensities in the raman effect and complex formation of CS2
Authors: Koningstein J. A.
Published: September 2010

From the data of the intensities of the symmetrical (v1) and forbidden vibration (v2) in the Raman Spectrum of CS2 it can be shown that complex formation of CS2 occurs as well in the liquid as in solution with cyclopentane.
A reversible nitrate electrode
Authors: Ketelaar J. A. A. , Dammers‐De Klerk A.
Published: September 2010

A reversible nitrate electrode is described consisting of a bristle of platinum wires through which a stream of NO2 and O2 is maintained. The behaviour of the nitrate electrode is tested with respect to stability and reversibility against a silver electrode in molten silver nitrate. The standard EMF at 600° K was found to be E° = 0.176 V against a calculated value of E° = 0.175 V.
Derivatives of amino‐acids and peptides VI: Reaction of ethoxyethyne with acylamino‐acids
Authors: Tadema G. , Harryvan E. , Panneman H. J. , Arens J. F.
Published: September 2010

Some ethoxyvinyl esters II were prepared by addition of acylamino‐acids to ethoxyethyne (see table I). These products react with amino‐acid or peptide esters to produce peptide esters or with hydrogen chloride to yield acid chlorides.

A sensitive reaction for ethoxyvinyl esters consists in treatment with bromine, where lachrymatory products (ethyl bromoacetate and acyl bromide) are formed.

The reaction of ethoxyethyne with two moles of acylamino‐acids yields anhydrides of acylamino‐acids (see table II).

Expectedly, anhydrides of acylamino‐acids react with aniline to produce anilides and with amino‐acid or peptide esters to produce peptide esters.

Anhydrides of benzyloxycarbonylamino‐acids are thermolabile. The decomposition of the anhydride of benzyloxycarbonylglycine has been shown to produce N,N′‐bisbenzyloxycarbonylglycylglycine.
A synthesis of curcumin and related compounds
Authors: Pabon H. J. J.
Published: September 2010

Curcumin has been prepared in 80% yield from vanillin and acetylacetone/B2O3 in the presence of tri‐sec. butyl borate and butylamine. The reaction was carried out in ethyl acetate at room temperature. Eight compounds related to curcumin have also been synthesized.
Bicyclanes III. The acid‐catalysed isomerization of perhydronaphthalene and perhydroindane
Authors: Knotnerus J. , Bickel A. F.
Published: September 2010

The formation of the bicyclo[3.3.0]octane ring system by isomerization of perhydronaphthalene and perhydroindane has been studied. Experiments were performed in the liquid phase under the influence of aluminium halides and in the gas phase at 300‐500° in the presence of a silica‐alumina catalyst. In both types of reaction a great number of compounds were formed.

From the liquid‐phase reaction product of perhydronaphthalene a hydrocarbon carrying two methyl groups per molecule could be separated by preparative GLC; its structure could not be determined.

In the liquid as well as in the gas‐phase experiments with perhydroindane the five isomeric methyl‐cis‐bicyclo[3.3.0]octanes were formed besides a large number of unidentified degradation products.

Experiments with the individual isomers revealed that under the conditions of the gas‐phase reactions their stabilities differ considerably; 1‐methyl‐cis‐bicyclo[3.3.0]octane is the most stable, the endo‐2‐methyl derivative the least stable isomer.
Bicyclanes IV. Preparation and properties of the methyl‐cis‐bicyclo[3.3.0]octanes
Authors: Knotnerus J. , Schilling H.
Published: September 2010

The syntheses of the five methyl‐cis‐bicyclo[3.3.0]octanes are described. The exo‐3 compound could only be obtained as a mixture with an equal amount of its endo‐3 isomer.
Analysis of the nondialyzable constituents in a sample of succus liquiritiae
Authors: Berrens L.
Published: September 2010

The nondialyzable components in a sample of succus liquiritiae have been separated into four fractions by ammonium sulphate fractionation and precipitation with organic solvents. The chemical composition and some properties of these fractions are given.

Succus liquiritiae contains a hemicellulose fraction, starch, and a fair amount of various brown peptide‐carbohydrate compounds (glycoproteins).

The inhalant allergen in succ. liq. is associated with one of the glycoprotein fractions. The relation of the allergenicity of succ. liq. to browning reactions is discussed.
Enamine chemistry II. Addition of thiophenols to enamines
Authors: Lawesson Sven‐Olov , Larsen Erik Holger , Jakobsen Hans Jørgen
Published: September 2010

In a few cases it has been shown that non‐cyclic enamines add thiophenols to give solid α‐amino‐sulfides.
Some physical constants of normal saturated fatty acids and their methyl esters
Authors: Adriaanse N. , Dekker H. , Coops J.
Published: September 2010

The series of the normal saturated fatty acids and their methyl esters with 5 to 20 carbon chain atoms was synthesized and careful purified, mainly by fractional distillation of the methyl esters in columns with up to 58 theoretical plates.

The purity was checked with the aid of melting curves determined in a microcalorimeter and proved to be 96.6% or better.

Refractive indices were determined and can be represented by

equation image

with an accuracy of 5 units in the fifth decimal place (c = number of carbon chain atoms).

Densities, accurate to 1 unit in the fourth decimal place, can be represented by

equation image

Boiling points can be given by

b.pt. 20 mmequation imagefor the methyl esters (c> 5), accurate to 0.1 °.

From our data, combined with literature values, the molecular refractivity of the CH2group in an aliphatic chain calculated according toLorentz‐Lorenz.was determined at 4.64 at room temperature.

In addition, melting and transition points, and heats of fusion and transition were determined.
Oscilloscopic determination of the double layer capacity of mercury in 1 M HClO4 at high potentials by means of sine wave current
Authors: Sluyters J. H. , de Leeuwe R.
Published: September 2010

A simple procedure is described by which the double layer capacity of mercury can be determined at potentials where the Hg/Hg2++ redox couple interferes with the direct mode of double layer capacity measurements. The results agree with those obtained recently with a different method

M. Sluyters‐Rehbach and J. H. Sluyters, Rec. Trav. Chim. 83, 217 (1964).

.
Chemistry of α‐diazosulfones: Part III. A simple preparation of N‐(sulfonylmethyl)urethanes by a Mannich condensation
Authors: Engberts J. B. F. N. , Strating J.
Published: September 2010

N‐(Sulfonylmethyl)urethanes, which are important intermediates in the synthesis of α‐diazosulfones, have been prepared in reasonable yields by a Mannich condensation of a sulfinic acid, formaldehyde and ethyl carbamate.
The influence of steric and electronic factors on acidity. II. Cis‐ and trans‐3‐endo‐arylsulfonylbicyclo [2,2,1]hept‐5‐ene‐2‐carboxylic acids. Intramolecular field effect
Authors: Hogeveen H.
Published: September 2010

The apparent acidity constants of cis‐ and trans‐3‐endo‐arylsulfonylbicyclo‐[2,2,1]hept‐5‐ene‐2‐carboxylic acids, with aryl = p‐CH3OC6H4‐‐, p‐CH3C6H4‐, C6H5‐, p‐ClC6H4‐, m‐NO2C6H4‐ and p‐NO2C6H4‐, have been measured in 50% (by vol.) aqueous ethanol at 25°. The acidities of cis‐compounds are much lower than those of trans‐isomers, which is most likely due to an intramolecular field effect between the sulfonyl‐oxygens and the carboxylic anion in the cis‐compounds. The data in both series follow the Hammett equation with excellent fit and the values for the reaction constant δ are 0.351 (trans‐series) and 0.418 (cis‐series. This indicates that the magnitude of the field effect is virtually independent of substitution in the phenyl ring.
Studies in IVth group organometallic chemistry XVII: The exchange of butyl groups and chlorine atoms between tin and germanium
Authors: Luijten J. G. A. , Rijkens F.
Published: September 2010

One butyl group is exchanged for chlorine when tetrabutyltin and germanium tetrachloride or tin tetrachloride and tetrabutylgermane, respectively, are heated at 200° without a catalyst. The first of these reactions may be used in the preparation of butyltrichlorogermane.
Saturated five membered heterocyclics, II: Preparation of 1,3,4‐oxadiazolidines
Authors: Zwanenburg B. , Weening W. E. , Strating J.
Published: September 2010

2,3,4,5‐Alkyl substituted 1,3,4‐oxadiazolidines are prepared in good yields by reaction of a symm.dialkylhydrazine and an aliphatic aldehyde. Two alternate mechanisms of the reaction are discussed. The N.M.R. spectra could be analysed taking into account the possible stereochemical configurations.
Reactivities of Csec‐H bonds towards chlorine in some alkanes and alkane carbochlorides
Authors: Smit P. , den Hertog H. J.
Published: September 2010

Photochlorinations of some alkanes (C5‐C7) and alkane carbochlorides (C3‐C6 and C8) in the liquid phase have been investigated, in the absence and in the presence of benzene, a solvent enhancing the selectivity of the reagent.

It was found that whereas the Cω‐1‐H bonds are the most reactive ones in nearly all photochlorinations, the Cω‐2‐H bonds are attacked preferentially when chlorinating octanoyl chloride and the alkanes C5‐C7 in benzene.
Acid anilides: X. The analysis of ω‐phenylalkanoic acids by chromatography of the free acids and their anilides
Authors: de Jonge A. P. , Verhage A. , van der Ven B.
Published: September 2010

Paper‐chromatographic separation of ω‐phenylalkanoic acid anilides is discussed and compared with the separation of free acids by other methods. Combination of both separation methods affords a means of identification which has been designated as pseudo two‐dimensional chromatography. Preparation of the anilides and the ultra‐violet spectra of both acids and anilides are described.
The constitution of the Grignard reagent: Part III, Conductivity of some ethylmagnesium compounds
Authors: Vreugdenhil A. D. , Blomberg C.
Published: September 2010

Electrical conductivities of the Grignard reagent ‐ prepared from ethyl bromide and magnesium ‐, diethylmagnesium and mixtures of diethylmagnesium and magnesium bromide, all dissolved in diethyl ether have been measured in the concentration range 0.05‐3.0 molar at 25°. Significant differences between the conductances of a solution of the Grignard reagent and an equivalent solution of a mixture of diethylmagnesium and magnesium bromide were found only at concentrations up to 0.4 molar.
Synthesis of 3‐tert‐aminothiophens and their tetrahydro derivatives via enamines
Authors: Buiter F. A. , Weiland J. H. Sperna , Wynberg Hans
Published: September 2010

Aromatization of 3‐ketotetrahydrothiophen enamines (II) furnishes 3‐dialkyl‐aminothiophens (III). Reduction of the enamines with formic acid yields the tetrahydro derivatives (V). These compounds represent the first examples of simple 3‐tert‐amino‐thiophens and ‐tetrahydrothiophens.
Studies on vitamin d and related compounds. XVIII: An investigation into the interconversion of precalciferol and calciferol and of analogous compounds
Authors: Schlatmann J. L. M. A. , Pot J. , Havinga E.
Published: September 2010

Two simple calciferol analogues (1) having no five‐membered (D) ring fused to the C ring, show the same smooth thermal isomerisation to the corresponding precalciferol analogues as calciferol itself. The kinetics of this reaction have been studied; the activation energy and entropy were found to be 21.6 (± 0.2) kcal/mole and −17.2 e.u., respectively. The insensitivity of the reaction towards even rather drastic changes in the conditions is striking and the reaction mechanism formerly given10, 15 for the vitamin D ⇆ previtamin D interconversion seems to remain an attractive working hypothesis.

There is one difference between the analogues and the calciferol system itself; in the former the equilibrium is far more on the “precalciferol” side. It is argued that this difference (and perhaps also the relative long wavelength ultra‐violet absorption of precalciferol) may be due to a strain in the precalciferol molecule originating from the presence of the C8‐C9 double bond in combination with the trans fused five‐membered ring. In agreement herewith, 13α‐precalciferol analogues having the five‐membered ring cis‐bonded and lacking this strain, are found to show a position of the equilibrium (and an ultra‐violet absorption) similar to that of the analogue II and different from that of precalciferol.
Chemistry of acetylenic ethers 74: 1‐(dialkylamino)‐1‐alkynes from 1‐alkoxy‐1‐alkynes
Authors: Montijn P. P. , Harryvan E. , Brandsma L.
Published: September 2010

1‐Alkynyl ethers, RCC‐O‐Alk (with R  alkyl), have been converted into the corresponding yneamines, RCC‐N‐(R′)2, in good yields (except when R  CH3) by means of lithium dialkylamides, LiN‐(R′)2.
The interaction of transition metal ions and hydroxymethyl radicals during the radiolysis of methanol
Authors: Brackman W. , van de Craats F. , Smit P. J.
Published: September 2010

Certain metal ions, in particular Co2+, Ni2+ and Cu2+ were found to increase the yield of formaldehyde at the expense of glycol during the radiolysis of methanol. The activities of the divalent first‐row transition metal ions correlate strikingly with the effect of these metal ions upon the quenching of triplet anthracene as measured by Linschitz and Pekkarinen.

Both effects are ascribed to rapid complex formation between the metal ions and the· CH2OH radicals or triplet anthracene.
Diuretics II: 3‐Amino‐6‐chloro‐7‐sulfamoyl‐1,2,4‐benzotriazine 1‐oxide
Authors: Dolman H. , Peperkamp H. A. , Moed H. D.
Published: September 2010

The synthesis of 3‐amino‐6‐chloro‐7‐sulfamoyl‐1,2,4‐benzotriazine 1‐oxide (IIc) is described. This structural congener of the diuretic chlorothiazide (I) did not exhibit any diuretic activity.
The relative thermal stabilities of some boron heterocycles
Authors: Finch Arthur , Gardner P. J. , Pearn E. Joy
Published: September 2010

The relative thermal stabilities of some ringsubstituted 2‐chloro ‐ and 2‐alkoxy ‐ five‐and sixmembered boron heterocycles are discussed.
Chemistry of acetylenic ethers 75: Isomerization of some 2‐alkynyl ethers into allenyl ethers with a note on the preparation of branched acetylenes
Authors: van Boom J. H. , Montijn P. P. , Brandsma L. , Arens J. F.
Published: September 2010

2‐Alkynyl ethers of the types R′R″CH‐CC‐CH2OC2H5and R′R″R″′C‐CC‐CH2OC2H5(in which R′, R″ and R″′ are alkyl groups) have been converted by means of sodamide in liquid ammonia, in 70‐95% yields, into the allenyl ethers R′R″CH  C  CH‐OC2H5and R′R″R″′C‐CH  C  CH‐OC2H5.

Acid hydrolysis of the allenyl ethers afforded thetrans‐α,β‐unsaturatedmagnified image.
The constitution of the Grignard Reagent: Part IV. The influence of oxygen on the number of individual particles in solutions of ethylmagnesium compounds
Authors: Vreugdenhil A. D. , Blomberg C.
Published: September 2010

The influence of oxygen on the number of individual particles in 10−3 · 10−2 molar diethyl ether solutions of ethylmagnesium bromide, diethylmagnesium, magnesium bromide and a mixture of diethylmagnesium and magnesium bromide was investigated. The ethoxide formed from the ethylmagnesium compounds is present as a trimer.
Titration of cerium (IV) sulfate with sodium oxalate at room temperature, using nitroferroin as indicator
Authors: Rao K. Bhaskara
Published: September 2010

A new convenient procedure is reported for the titration of ceric sulfate with sodium oxalate at room temperature. The procedure consists in the titration of ceric sulfate with sodium oxalate in about 0.5 N nitric, perchloric, or hydrochloric acid media, using nitroferroin as indicator.
Sur les Ethers β‐Diéthylaminoéthyliques des Derives du Biphényle et Leurs Propriétés Pharmacodynamiques
Authors: Petit M. L. , Gouot Mll E. J. , Luczak Mme J.
Published: September 2010

On a synthétisé un certain nombre d'éthers β‐diéthylaminoéthyliques des p‐hydroxybiphényle, chloro‐3 hydroxy‐2 biphényle, bromo‐5 hydroxy‐4 biphényle et dihydroxy‐2‐2′ biphényle, afin d'examiner certaines des propriétés pharmacodynamiques des substances ainsi obtenues. Les éthers possèdent une bonne activité spasmolytique et sont comparables à la quinidine et à la papavérine.
Racemization and bifunctional catalysts in peptide synthesis
Authors: Beyerman H. C. , van Den Brink W. Maassen , Weygand F. , Prox A. , König W. , Schmidhammer L. , Nintz E.
Published: September 2010

The influence was examined of representative bifunctional catalysts on racemization in peptide syntheses via aminolysis of cyanomethyl, p‐nitrophenyl, thiophenyl, and vinyl esters. Three different tests were used, based on gravimetric, polarimetric, and gas‐liquid chromatographic analysis, respectively. 1,2,4‐Triazole, which was investigated most extensively, did not cause racemization in any of the couplings.

Imidazole, which has also been recommended for acceleration of peptide syntheses, led to racemization in several cases.

The structure of N‐acyl derivatives of 1,2,3‐ and 1,2,4‐triazole was determined by proton resonance measurements.
The conformation of bicyclo[3.3.1]nonane
Authors: Laszlo Ilona
Published: September 2010

X‐ray powder diagrams of bicyclo[3.3.1]nonane I) showed that the pure compound crystallizes in the face centered cubic lattice with a cell parameter of 9.57 Å. Phase diagrams and X‐ray diagrams of binary mixtures of (I
) and adamantane indicate that the conformation of bicyclo[3.3.1]nonane is that of a slightly distorted chair‐chair form.
Interaction of electron acceptors with bases part 14: Solvent effect on the optical transition of organic charge‐transfer complexes
Authors: Emslie P. H. , Foster R.
Published: September 2010

The energies of the optical transitions for “non‐ionic” organic charge‐transfer complexes in a range of solvents have been measured. The solvents may be divided into those which can achieve an effective solvent cage and those which cannot. For the former class the Franck‐Condon principle applied to solvent re‐orientation results in a hypsochromic shift with increasing ionising ability of the solvent. For the latter class, which may be described as inert solvents, where there is no solvent cage, the dispersion forces and polarisation of the solvent cause bathochromic shifts as the ionising ability of the solvent increases.
Fluid phase equilibria in the system polyethene‐ethene
Authors: Swelheim T. , De Swaan Arons J. , Diepen G. A. M.
Published: September 2010

The system polyethene ‐ ethene has been investigated in a high‐pressure autoclave in a temperature region of 100‐140° up to pressures of 2000 kg/cm2. Pressure‐temperature (P‐T) data were taken for the curve separating the homogeneous fluid phase region from the fluid two‐phase region for mixtures with polyethene‐compositions up to 30% by weight.
The infrared spectra of dialkylphosphinic chlorides
Authors: Blasse G.
Published: September 2010

The infrared spectra of the dialkylphosphinic chlorides are given. The presence of two P‐Cl absorption bands is attributed to rotational isomerism.
Spectroscopic investigations of thiobenzophenones: II. Electronic spectra. Correlation of Substituent Effects on the Arylthiocarbonyl Absorption Maximum with substituent parameters
Authors: Korver O. , Veenland J. U. , de Boer Th. J.
Published: September 2010

In ortho‐methylthiobenzophenone the unsubstituted phenyl group is nearly coplanar with the thiocarbonyl group, whereas the o‐tolyl group is not.

The phenylthiocarbonyl absorption band shifts upon introduction of meta‐and para‐ substituents according to various σ‐values. A similar quantitative correlation exists for the intensities.
Spectroscopic investigations of thiobenzophenones: III. Infra‐red absorption and nuclear magnetic resonance spectra of thiobenzophenones
Authors: Korver O. , Veenland J. U. , de Boer Th. J.
Published: September 2010

The shifts in the CS stretching vibration caused by various substituents in thiobenzophenone are so small that no good correlations between substituent constants and absorption frequencies is found.

Differences between the n.m.r. spectra of thiobenzophenones and benzophenones can be explained with the aid of conformations deduced from the electronic spectra.
Investigations on pyrazine derivatives IX: On the effect of hydrogen peroxide on 5,6‐diphenyl‐2,3‐dihydropyrazine
Authors: Mager H. I. X. , Berends W.
Published: September 2010

The effect of hydrogen peroxide on 5,6‐diphenyl‐2,3‐dihydropyrazine has been studied. Several reactions take place which might be considered as models for some of the spontaneous conversions shown by partially reduced pyrazines on exposure to air. In no case was 5,6‐diphenyl‐2,3‐dihydropyrazine 1,4‐di‐N‐oxide formed, but products of ring‐opening: N/N′‐dibenzoylethylenediamine, and N‐benzoylethylenediamine, and a product of a most interesting ring‐contraction: 2‐phenyl‐2‐imidazoline. In addition some 2,3‐diphenylpyrazine could be isolated. Reaction mechanisms have been postulated; the primary product of oxidation has been formulated as 5,6‐diphenyl‐1,2,3,6‐tetrahydro‐pyrazine 6‐hydroperoxide.

Tetrahydropyrazine hydroperoxides may also be formed spontaneously, for example, after catalytical hydrogenation, if tetrahydropyrazines are exposed to air. The results described in this paper seem also to be of some importance in the fields of condensed pyrazines like quinoxalines, pteridines, iso‐alloxazines and, moreover, they contain principles for new syntheses of 2‐imidazolines.
Studies in homogeneous catalysis: Kinetics and mechanism of the copper‐catalysed reaction of nitric oxide and diethylamine (I)
Authors: Brackman W. , Smit P. J.
Published: September 2010

A study has been made of the copper‐catalysed reaction of NO with diethylamine, which at 30° yields nitrosodiethylamine and N2O. A mechanism is proposed in which the cupric ion in combination with NO functions as the nitrosating agent for the amine. The cuprous complex formed in this reaction is rapidly reoxidized by the adduct of diethylamine and NO, (C2H5)2NH2+ · (C2H5)2N · (NO)O−, which yields the fragments NO− (or NOH) and (C2H5)2N · NO−. The radical‐anion reacts with NO to regenerate the original adduct while NOH yields nitrous oxide and water.
Acid anilides: XI. synthesis, ultra‐violet spectra and paper chromatography of 2‐alkenanilides and 2,4‐alkadienanilides
Authors: de Jonge A. P. , Schogt J. C. M. , de Bruijn J. , Verhage A.
Published: September 2010

The anilides of some 2‐alkenoic and 2,4‐alkadienoic acids were prepared, their ultra‐violet spectra recorded, and their paper‐chromatographic behaviour compared to that of alkananilides.
A solvent‐extraction study of the dissociation of aniline sulfate
Authors: Aboul‐Seoud A. , Doheim M.
Published: September 2010

The distribution of aniline betweenn‐heptane and aqueous ammonium sulfate solutions was studied at different temperatures. The activity coefficients of aniline in aqueous ammonium sulfate solutions, were determined.

The effect of ammonium sulfate on the dissociation of aniline sulfate was studied, at different amine salt concentrations, and different temperatures, using a modified distribution method1. ΔH, ΔS and ΔF for the dissociation of the anilinium ion, were determined.
Investigations on sterols XXVI: Synthesis and properties of 6‐substituted 9β,10α‐steroids
Authors: Westerhof P. , Hartog J. , Halkes S. J.
Published: September 2010

The synthesis and properties are described of some 6‐halo‐9β,10α‐pregnane and 6‐halo‐9β,10α‐androstane derivatives containing the 4‐en‐3‐one system. Halogenation at position 6 is accomplished by reaction of the 3‐acetoxy‐3,5‐dienes with perchloryl fluoride, chlorine, bromine or N‐bromosuccinimide. At the fluorination 6‐hydroxy compounds are obtained as by‐products, the structures of which are proved by alternative synthesis and by conversion into related compounds. The spectral data are discussed in connection with the structural assignments of the 6‐substituents. The biological results are summarized.
Investigations on sterols XXIX: Synthesis and properties of some 6,7‐dehydro‐9β,10α‐steroids
Authors: Westerhof P. , Hartog J.
Published: September 2010

Alternative methods are described for the synthesis of a number of 6‐halo‐9β,10α‐pregnane and 6‐halo‐9β,10α‐androstane derivatives having a 4,6‐dien‐3‐one or a 1,4,6‐trien‐3‐one system. 4‐Halo and 6‐methoxy‐4,6‐dien‐3‐ones have been prepared, too. The endocrinological results are summarized.
Bromination of methylpyridines in fuming sulfuric acid
Authors: van der Does L. , den Hertog H. J.
Published: September 2010

Brominations of the isomeric methylpyridines and 2,6‐dimethylpyridine in fuming sulfuric acid have been studied.

It was found that in this medium at moderate temperatures bromo derivatives substituted in the pyridine nucleus are formed in excellent yields as sole reaction products.

Some of these bromination reactions are satisfactory as synthetic methods.
The synthesis of pentacyclic systems by the Diels‐Alder reaction of dicycloalkenyls with cinnamic acid and related compounds
Authors: Maoz N. , Vromen S.
Published: September 2010

The Diels‐Alder reaction between dicycloalkenyls and aromatic α‐β unsaturated acids and esters was investigated. Suitable conditions for the cyclization of the adducts leading to fluorenone conditions were found. The nature of the isomerization, observed in some cases, is discussed.
A colorimetric assay method for microquantities of quaternary ammonium detergents
Authors: van Steveninck J. , Maas M.
Published: September 2010

A sensitive and quick assay method was required for the determination of cationic detergents in aquous solution of biological origin. A number of assay methods for cationic detergents has been published (e.g.1,2,3,4). The best results were obtained with the colorimetric method, described by Auerbach2, the principle of which is the formation of a colored complex between bromophenol blue and the detergent. This colored complex can be extracted from aqueous solution, with an appropriate solvent, and measured colorimetrically.
On the liquid phase air oxidation of n‐heptane
Authors: Bigot J. A. , Kerkhoffs P. L. , Theeuwen H.
Published: September 2010

The amounts of isomeric heptanols and heptanones formed during liquidphase air oxidation of n‐heptane at 150‐160 °C were determined. It was found that the amounts of 2‐heptanone and 2‐heptanol were larger than could be expected statistically. This is explained by a slightly faster attack on the methylene groups near the chain ends during oxidation.
Base‐catalysed acylation of phenols in carbon tetrachloride
Authors: Bonner T. G. , Gabb E. G. , Mcnamara P.
Published: September 2010

Acetylation of phenols by acetyl trifluoroacetate is superseded by more rapid trifluoroacetylation in the presence of low concentrations of pyridine bases.
Doubling of the methyl doublet in some isopropyl compounds with an asymmetric centre
Authors: van der Vlies C.
Published: September 2010

The methyl resonance patterns of some isopropylcarbinols and isopropyl esters are described and discussed. The important influence of a phenyl nucleus on these patterns is obvious. The presence of such a nucleus as well as that of an asymmetric centre is a prerequisite for doubling of the methyl doublet in the case of the esters. It could not be established whether the doubling is due to intrinsic asymmetry, to preferential conformations, or to both factors.
Reactions of aliphatic halides with solutions of alkali metals in liquid ammonia v. Experiments with trans‐1‐chloro‐2‐butene and 3‐chloro‐1‐butene
Authors: Verkade P. E. , de Vries K. S. , Wepster B. M.
Published: September 2010

The reaction of trans‐1‐chloro‐2‐butene with solutions of lithium, sodium, or potassium in liquid ammonia yields mainly trans‐2‐butene, 2,6‐octadiene, and 3‐methyl‐1,5‐heptadiene. Under the same conditions 3‐chloro‐1‐butene yields mainly trans‐ and cis‐2‐butene (in a ratio of about 2 : 1), 3‐methyl‐1,5‐heptadiene, and 3,4‐dimethyl‐1,5‐hexadiene. The composition of the “bibutenyls” provides strong evidence that these products are formed in an SN2 reaction between carbanion and chloride.
Synthesis of all‐cis methyl 3,6,9,12‐octadeca‐tetraenoate, methyl 4,7,10,13‐nonadecatetraenoate and methyl 5,8,11,14,17‐eicosapentaenoate
Authors: Pabon H. J. J. , van der Steen D. , van Dorp D. A.
Published: September 2010

4,7,10,13‐Nonadecatetraynoic acid and 5,8,11,14,17‐eicosapentaynoic acid were synthesized via coupling of 1‐bromotetradecatriyne or ‐tetrayne with 4‐pentynoic or 5‐hexynoic acid respectively. 3,6,9,12‐Octadecatetraynoic acid could not be prepared in this way; it was obtained via the corresponding tetraynol. All poly‐ynoic acids were esterified and partially hydrogenated to the corresponding all cis‐enoic acids.

Difficulties in the partial hydrogenation of 4,7,10,13,16,19‐docosahexaynoic acid, described in a previous paper, were overcome.
Decarbonylation of α‐hydroxylaminocarboxylic acids
Authors: Duynstee E. F. J. , Hennekens J. L. J. P. , Mevis M. E. A. H.
Published: September 2010

Aliphatic and cycloaliphatic α‐hydroxylaminocarboxylic acids are smoothly decarbonylated in dilute oleum at room temperature. For example, α‐hydroxyl‐aminocyclohexanecarboxylic acid (II) gives a high yield of carbon monoxide and caprolactam. Other α‐hydroxylaminocarboxylic acids give CO and oxime, or CO and a product that may be considered to have formed from the oxime by Beckmann rearrangement.
Ring transformations in reactions of heterocyclic halogeno compounds with nucleophiles (iii) conversion of 2,6‐dibromopyridine by potassium amide in liquid ammonia into 4‐amino‐2‐methylpyrimidine
Authors: den Hertog H. J. , van der Plas H. C. , Pieterse M. J. , Streef J. W.
Published: September 2010

Reactions of 6‐substituted derivatives of 2‐halogenopyridines with potassium amide in liquid ammonia have been investigated.

Together with aminations leading to the formation of 2‐amino compounds, two unusual reactions were found to occur, i.e. reactions partially involving meta‐rearrangement and conversions involving a ring transformation.

The rearrangements took place in aminations of various substances (e.g. of 2‐bromo‐6‐methylpyridine, 2‐chloro‐6‐methylpyridine and 2‐bromo‐6‐ethoxypyridine). Ring transformations occurred in aminations of 2,6‐dibromo‐ and 2,6‐dichloro‐pyridine, 4‐amino‐2‐methylpyrimidine being formed.

The mechanism of the remarkable reaction last‐mentioned is discussed.
Stability constants of nickel (II), cobalt (II) and copper (II) complexes of some optically active and racemic amino‐acids
Authors: Ritsma J. H. , Wiegers G. A. , Jellinek F.
Published: September 2010

The stability constants of nickel (II), cobalt (II) and copper (II) complexes of glutamic acid, aspartic acid, asparagine, and glutamine have been determined in aqueous solutions, containing either the pure L‐form or both the D‐ and L‐forms of the ligands. No significant differences were found between the stabilities of corresponding ML2 and MDL complexes in solution.
Heterocyclic diazo compounds. Part I. Preliminary communication
Authors: Engberts J. B. F. N. , van Bruggen G. , Strating J. , Wynberg Hans
Published: September 2010

The preparation of 2‐thienyl‐ and 2‐furyldiazomethane is described. Evidence for a carbene intermediate on photolysis of 2‐thienyldiazomethane is given.
The reaction of acetone with hydrogen sulfide
Authors: van Dort H. M. , Mijs W. J.
Published: September 2010

A crystalline compound (“tetrathiopentone”, C15H28S4) has been isolated in high yield from the reaction of acetone with hydrogen sulfide in an acidic medium. Its structure was established as, 2,2,4,4,8,8,10,10‐octamethyl‐3,5,7,9‐tetrathiaspiro[5,5]undecane (I).
Studies in group IV organometallic chemistry. XXI. Mechanism of the hydrostannation of Isocyanates and Isothiocyanates
Authors: Leusink A. J. , Budding H. A. , Noltes J. G.
Published: September 2010

The mechanism of the addition of organotin mono‐hydrides across the CN bond of isocyanates and the C = S bond of isothiocyanates has been studied more closely. A polar mechanism is operative in both types of additions as appeared from the lack of activity of free radical generators and free radical scavengers and from the considerable influence of the polarity of the solvent on the rate of reaction. Kinetics, isotope effects and the influence of substituents attached to both the hydride and the unsaturated partner on the rate of addition, strongly point to a nucleophilic attack of the organotin hydride hydrogen on carbon as the first and rate‐determining step.
Synthesis and physiological properties of some heterocyclic‐aromatic sulfides and sulfones. VII: Determination of the stereochemical configurations by I.R.‐ and N.M.R.‐spectrometry
Authors: Trompen W. P. , Kruk C. , van der Haak P. J. , Huisman H. O.
Published: September 2010

The determination of the stereochemical configurations of a number of ringsubstituted aromatic and aromatic‐hetereocyclic ethene thioethers by I.R.‐ and N.M.R.‐spectrometry is reported.
Photoreactions of aromatic compounds VI: The mechanism of the photohydrolysis of m‐nitroanisole
Authors: de Jongh R. O. , Havinga E.
Published: September 2010

The photohydrolysis of m‐nitroanisole in alkaline media has been investigated by kinetic (quantum yield) measurements and by 18O‐tracer experiments. It is concluded that the reaction can be described as a bimolecular nucleophilic substitution reaction at the aromatic carbon bearing the methoxy group. Possibly, OH− is bound to the π→π* excited m‐nitroanisole to form a s‐complex that subsequently changes into either the starting material or the reaction products (m‐nitrophenol and methanol).
Electrophilic displacement of the formyl and acetyl group in 2,4,6‐trimethoxybenzaldehyde and 2,4,6‐trimethoxyacetophenone
Authors: Strating J. , Thijs L. , Zwanenburg B.
Published: September 2010

By reaction of 2,4,6‐trimethoxybenzaldehyde and 2,4,6‐trimethoxyacetophenone with sulfuryl chloride an electrophilic displacement of the formyl and acetyl groups takes place prior to chlorination in the 3 and 5 positions. 2,4,6‐Trimethoxybenzophenone gives the normal chlorination product.
Chemistry of α‐diazosulfones. VII: acid‐induced cyclization reactions of β′‐alkoxy‐α‐diazosulfones
Authors: van Leusen A. M. , Richters P. , Strating J.
Published: September 2010

The cyclization reaction of two new α‐diazosulfones [α‐methoxyphenyl‐sulfonyldiazomethane (I) and 2‐(benzyloxy)ethylsulfonyldiazomethane (II)], effected by hydroxyfluoroboric acid, afforded 1,3‐benzoxathiolane‐3,3‐dioxide (III) and 1,3‐oxathiolane‐3,3‐dioxide (IV) respectively. These hitherto unknown ring compounds have been prepared also by independent methods.
Complex formation and isomerization of propyl bromides with aluminium bromide investigated by microwave measurements
Authors: Adema E. H. , Teunissen A. J. J. M. , Tholen M. J. J.
Published: September 2010

The complex formation ofn‐propyl bromide and isopropyl bromide with aluminium bromide in carbon disulfide has been investigated by means of microwave measurements. The results are explained with the formation of 1: 1 complexes according to:

with the equilibrium constants K9= 1.3 1/mole and K3= 7.30 1/mole at 24.0°. The isomerization reaction goes to completion within the analytical errors of the techniques used. The reaction rate appeared to be a function of then‐C3H7Br concentration and the aluminium bromide concentration over a wide range of intake ratios:

with k = 0.71 1 · mole−1· min−1at 24°.

The reaction mechanism is discussed.
Thermochromic and solvochromic behaviour of cobalt (II) chloride solutions in various solvents
Authors: Nieuwpoort W. C. , Wesselink G. A. , van der Wee E. H. A. M.
Published: September 2010

In this paper the spectral behaviour at different temperatures of solutions of anhydrous CoCl2 in water, methanol, ethanol, 1‐propanol, 2‐propanol, and acetone is reported and discussed. The work was initiated by the striking colour changes observed in some of these solvents when the temperature is lowered well below room temperature. The effects are interpreted in terms of octahedral‐tetrahedral configurational changes of solvated Co2+ complexes. A number of earlier observations, which are relevant to the ones reported here and most of which support the interpretation given, are briefly reviewed and discussed.
Chemistry of α‐diazosulfones, VIII: Orthoformic acid derivatives from α‐diazosulfones and sulfenyl chlorides
Authors: Strating J. , Reitsema J.
Published: September 2010

An interesting group of compounds with the general formula R′SO2CH(Cl)SR, is formed by reaction of α‐diazosulfones (R′SO2CHN2) with sulfenyl chlorides (RSCl). Representatives with different kinds of R and R′ groups are described.
Investigations on pesticidal phosphorus compounds V: The structure of the products of the reaction of 3‐alkyl‐5‐anilino‐1,2,4‐triazoles with bis(dimethylamido)phosphoryl chloride
Authors: van den Bos B. G. , Schipperheyn A. , van Deursen F. W.
Published: September 2010

The reaction of bis(dimethylamido)phosphoryl chloride (Bisdi) with 5‐anilino‐1,2,4‐triazoles gave two series of isomers. Their structures were determined and can be characterized by formulae I and II.
Derivatives of benzo‐ and indolo‐quinolizines. III: The stereochemistry of 2‐substituted hexahydro‐2H‐benzo[a]quinolizines and octahydroindolo[2,3‐a]quinolizines
Authors: Gootjes J. , de Roos A. M. , Nauta W. Th.
Published: September 2010

To some of the quinolizine derivatives described earlier (1 and 2) we have been able to assign a cis or trans structure on the strength of a stereoselective synthesis. Infrared spectral data and differences in the rate of dehydrogenation, combined with a study of the conformations possible, allowed such assignment for other compounds in this series.
Fluid phase equilibria in the system polyethylene‐ethylene, II
Authors: Koningsveld R. , Chermin H. A. G. , Diepen G. A. M.
Published: September 2010

Experimental data on fluid phase equilibria in the system polyethylene‐supercritical ethylene have been analyzed thermodynamically. The behaviour of the system can be treated as a case of partial miscibility. A quantitative description of this behaviour can be given with the Flory‐Huggins polymer solution theory. A mathematical expression has been derived for the pressure‐temperature projections at constant polymer concentration. Its form resembles a reduced equation of state. An empirical relation was found for the cloud‐point curve, which accounts for its maximum and two inflexions. The expressions obtained permit of extrapolating the experimental data into temperature regions investigated by other authors. The comparison indicates that the different sets of data are consistent.