bluuebunny/crossref_metadata_2025 huggingface dataset:
3,4‐Dihydro‐4‐hydroxy‐1,3‐benzoxazin‐2‐one derivatives
Authors: Strube R. E. , Mackellar F. A.
Published: September 2010

A general method is described for synthesizing compounds of structure exemplified by A, from methyl isocyanate and 2‐hydroxybenzaldehyde in the magnified imagepresence of a basic catalyst (triethylamine).

The reaction product of phenyl isocyanate and 2‐hydroxybenzaldehyde in the presence of triethylamine is 3,4‐dihydro‐3‐phenyl‐4(phenylcarbamoyloxy)‐2H‐1,3‐benzoxazin‐2‐one (structure B).

Evidence for the proposed structures is presented based on chemical and spectral properties.
A thermodynamic study of the dissociation of o‐chloroaniline hydrochloride
Authors: Aboul‐Seoud A. , El‐Hares M.
Published: September 2010

From the study of the distribution of o‐chloroaniline between petroleum ether and aqueous solutions of sodium chloride, at 5, 15, 25 and 35°, the activity coefficients of the free amine, under these conditions, were calculated.

The dissociation constant of o‐chloroaniline hydrochloride was determined under the same conditions using the distribution method. The ratio of the activity coefficients of hydrogen and o‐chloroanilinium ions was calculated for each case. The relationship between pK and salt molality was studied.
Mixed carboxylic acid anhydrides: II. Esterification of alcohols with the formic acid/acetic anhydride reaction mixture
Authors: Stevens W. , van Es A.
Published: September 2010

The investigations of Béhal and other authors (loc. cit.) have led to the generally accepted view that the esterification of alcohols with the formic acid/acetic anhydride reaction mixture leads to the exclusive formation of formates. A reinvestigation, however, has shown that under the conditions used by Béhal, acetates are also produced. Generally, the amounts of acetates formed decrease in the order primary, secondary, tertiary alcohols; in the last case acetates are formed to a negligible degree. This finding leads to a simple and convenient method for the preparation of pure tertiary alkyl formates in high yields. The results obtained are discussed in relation to conflicting literature data as regards the synthesis of formates.
Triethynyl‐phosphine, ‐arsine and ‐stibine
Authors: Voskuil W. , Arens J. F.
Published: September 2010

The compounds M(CCH)3, with MP, As and Sb, are prepared from the appropriate trichlorides and ethynylmagnesium bromide in tetrahydrofuran. All three compounds are relatively stable volatile solids at room temperature, but detonate violently by strong friction. Infrared and proton magnetic resonance data are given.
The system 2,6‐dichloro‐p‐benzoquinone‐N,N,N′,N′‐tetramethyl‐p‐phenylenediamine in acetonitrile: Short communication
Authors: Emslie P. H. , Foster R. , Thomson T. J.
Published: September 2010

The slow disappearance of the charge‐transfer complex and the slow increase in concentration of the Wurster free radical ion in solutions formed by dissolving 2,6‐dichloro‐p‐benzoquinone and N,N,N′,N′‐tetramethyl‐p‐phenylenediamine in acetonitrile have been shown to be the result of the upset of equilibria between these species due to the further reaction of the semiquinone ion formed from the quinone.
Thermodynamic functions of boron tri‐iodide
Authors: Finch Arthur
Published: September 2010

Free energy, enthalpy, entropy, and heat capacity data are calculated for B10I3 and B11I3 from 100 to 1000°K.
Spectroscopic investigations of olefinic compounds: Part I. Rehybridization as a concept for the counterbalance of sterical hindrance and ring strain
Authors: Rummens F. H. A.
Published: September 2010

Rehybridization as a possible means to alleviate the effects of sterical hindrance and ringstrain has been investigated. This concept, although general in nature, has been analysed in detail for ethylenic structures. It is shown that two out of the six fundamental distortions of a magnified image “molecule” can be counter‐balanced by rehybridization. One of these, the in‐plane rehybridization of the sp2 hybrid orbitals, seems to be the most useful mechanism. For small distortions the change in p character (as given by its mixing coefficient λk) for each of these sp2 orbits depends only on the change in bond angle (ΘY) opposite to the (k) hybrid orbital. It is shown that Δλk = √6ΔΘY.

The theory allows the prediction of infrared frequency shifts for the  C‐H stretching, C  C stretching, C  C‐H in‐plane deformation, and C  C‐H out‐of‐plane deformation vibrations as a function of sterical hindrance. A comparison of the infrared spectra of a large variety of ethylenic hydrocarbons reveals a very satisfactory agreement between observed and predicted shifts.
The synthesis of arylsulfonyl halides
Authors: Prinsen A. J. , Cerfontain H.
Published: September 2010

The synthesis of a series of arylsulfonyl chlorides by a modification of the Sandmeyer reaction as developed by Meerwein et al1 is described. This method seems applicable to the preparation of arylsulfonyl bromides, but not for arylsulfonyl fluorides. The characteristic IR vibrations of the SO2‐group are tabulated for the various arylsulfonyl halides.
Tetrakis(triphenylplumbyl)methane and two other triphenylplumbyl‐substituted methanes: (Preliminary communication)
Authors: Willemsens L. C. , van Der Kerk G. J. M.
Published: September 2010

The title products can be prepared readily from triphenylplumbyl‐lithium and carbon tetrachloride, chloroform or methylene chloride. The existence of (Ph3Pb)4C is remarkable from a stereochemical point of view.
Hetarynes IX: Reactions of some bromoethoxypyridines with lithium piperidide in piperidine
Authors: van Der Plas H. C. , Hijwegen T. , Den Hertog H. J.
Published: September 2010

Reactions of 3‐bromo‐4‐ethoxypyridine and 2‐bromo‐6‐ethoxypyridine with lithium piperidide in piperidine have been investigated.

It was found that in these compounds both substituents when occupying positions 2,4 or 6 are replaced by the piperidino group without rearrangements occurring. From 3‐bromo‐4‐ethoxypyridine some 2,4‐dipiperidinopyridine is formed as an additional product, probably via 4‐piperidino‐2,3‐pyridyne as an intermediate.
Volumetric estimation of chromium (VI) and vanadium (V) in mixtures
Authors: Rao K. Bhaskara , Rao Devaraj
Published: September 2010

A rapid and convenient volumetric method is reported for the estimation of chromium (VI) and vanadium (V) in mixtures. The procedure consists in the estimation of (1) chromium plus vanadium in the mixture by titration of the mixture in about 0.25 N sulfuric acid containing 5 ml of phosphoric acid and 1 ml of 0.1% barium diphenylamine sulfonate with ferrous ammonium sulfate to the exact end‐point; (2) vanadium in the mixture by titration of the solution, left after the first titration, with permanganate, using ferroin as indicator, and (3) chromium in the mixture by calculation from the difference of the two values.
An electron diffraction study of selenium trioxide
Authors: Mijlhoff F. C.
Published: September 2010

By electron diffraction it has been found that selenium trioxide vapour contains tetrameric ring molecules dissociated to the extent of about 30% into monomer at 120°. Principal distances are: in the monomer: Se‐O, 1.69 Å; in the tetramer: Se‐bridging O, 1.80 Å; Se‐non bridging O, 1.56 Å.
Vapour pressures and their estimation
Authors: Mcgowan J. C.
Published: September 2010

It is proposed that for liquid unassociated compounds well below their critical temperatures

Log p/pb) = Log Vg/VL)b

where p and pb are vapour pressures at the absolute temperature T and at the boiling point Tb respectively; Vg and VL are the molecular volumes of the compound in the vapour and liquid phases (the figures here referring to the boiling point); and n is a constant for a given compound. For monatomic gases n is one and for higher members of homologous series it is about two. For many substances, n can be taken as 1.7 and log10 (Vg/VL)b as 2.7: the equation with these values may be used to estimate vapour pressures of unassociated compounds. Moreover, for very similar compounds Tbn is proportional to the parachor.
The reaction of carbon suboxide with diazomethane
Authors: Schaafsma S. E. , Steinberg H. , De Boer T. H. J.
Published: September 2010

Methyl malonate (A), methyl succinate (B), methyl glutarate (C) and methyl 3‐oxocyclobutanecarboxylate (D) are formed from diazomethane and carbon suboxide in the presence of methanol. A mechanism is proposed for this reaction.
Chemistry of α‐diazosulfones: Part V. The synthesis of arylsulfonyldiazomethanes and alkylsulfonyldiazomethanes
Authors: van Leusen A. M. , Strating J.
Published: September 2010

N‐(Sulfonylmethyl)urethanes, described in the preceding paper1, are converted into N‐nitroso derivatives, RSO2CH2N(NO)CO2C2H5, which are transformed into α‐diazosulfones, RSO2CHN2, by a heterogeneous reaction on alumina. Reaction of α‐diazosulfones with hydrochloric acid leads to α‐chlorosulfones, and with triphenylphosphine to so‐called phosphazines, RSO2CH = N ‐ N = P(C6H5)3. The IR and NMR spectra of α‐diazosulfones are discussed.
Thermal decomposition of chloroform in the presence of olefins
Authors: Engelsma J. W.
Published: September 2010

The gas‐phase decomposition of chloroform at 400‐500°C in the presence of an alkene leads to a chlorodiene and hydrogen chloride.

Evidence is presented that the primary step is the decomposition of chloroform to dichlorocarbene, which adds to the alkene; the resulting dichlorocyclopropane rearranges, with loss of hydrogen chloride, to a chlorodiene.
The chemistry of cycloheptatriene: Part XI: A further study of transannular 1‐5 shifts of hydrogen in phenylcycloheptatrienes
Authors: Ter Borg A. P. , Kloosterziel H.
Published: September 2010

The rate of the interconversion of 2‐ and 1‐phenylcycloheptatriene upon heating has been measured. These 1‐5 shifts ‐ in which the phenyl group is attached to the non‐shifting double bond — are somewhat faster than in unsubstituted cycloheptatriene.
Spectroscopic investigations of thiobenzophenones: I. Electronic spectra
Authors: Korver O. , Veenland J. U. , de Boer Th. J.
Published: September 2010

The effect of substituents on the geometry of thiobenzophenones is derived from the arylthiocarbonyl U.V.‐absorption at 300‐375 nm.Hammettσ‐constants can be correlated with the energy of the n→π* transition of the thiocarbonyl group near 600 nm. Absorption at 230 nm can be ascribed partly to aryl‐aryl interaction by comparison with substituted diarylethylenes.
Fatty acid synthesis in dairy cattle with experimental ketosis
Authors: Elema J.
Published: September 2010

The incorporation of acetate‐α‐14C in the liver higher fatty acids of normal and ketotic cows has been studied.

In vitro incubations with liver slices, obtained by biopsy, showed an inhibited synthesis of these acids in ketotic livers compared with that in normal livers. The inhibition ranged from 18% to 72% in accordance with the intensity of the ketosis.
Studies in homogeneous catalysis: The competitive formation of alkyl nitrite and nitrosamine in the reaction of NO with diethylamine‐alcohol mixtures (II)
Authors: Brackman W. , Smit P. J.
Published: September 2010

The copper‐catalysed reaction of nitric oxide with diethylamine in alcoholic solvents at 30° and 1 atm yields nitrosamine as the sole nitrosation product. At lower reaction temperatures, e.g.−30° nitrosamine is formed only in low yields and alkyl nitrite, derived from the alcohol, is obtained instead.

The mechanism controlling the relative formations of the two products has been studied. It is demonstrated that the decisive factor is not primarily the temperature, but rather the NO‐concentration in solution. Arguments are presented for the view that the reductive splitting of the adduct R2N·N(NO)O− by cuprous ion is conditioned by the presence of a proton donor (here the alcohol) which must be coordinated with the cuprous ion (eq. 7‐10). The cupric alkoxide complex which is formed in this reaction and which is not in equilibrium with the amine‐alcohol system gives rise, at sufficiently high NO‐concentrations, to the formation of alkyl nitrite.
Pyridineboronic Acids
Authors: Fischer F. C. , Havinga E.
Published: September 2010

The synthesis of 3‐pyridineboronic acid and 4‐pyridineboronic acid is reported.
Paper chromatography of isomeric ureas and thioureas
Authors: Fishbein Lawrence
Published: September 2010

The separation, detection and identification of 67 isomeric linear and cyclic ureas and thiourea is described. The effects of various substituents on the chromatographic behavior of the isomeric urea and thiourea moiety are discussed.
A spiro Meisenheimer compound
Authors: Foster R. , Fyfe C. A. , Morris J. W.
Published: September 2010

A Meisenheimer compound has been prepared by the action of a base on 1‐(2′‐hydroxyethoxy)‐2,4,6‐trinitrobenzene. The structure contains a 1,3‐dioxolane ring linked to the six membered ring containing the pentadienate system by a common carbon atom.
Synthesis of β‐phenylethylamine derivatives IX: The enantiomers and diastereoisomers of N‐phenoxyalkyl‐β‐(4‐hydroxyphenyl)ethylamine derivatives
Authors: van Dijk J. , Keizer V. G. , Peelen J. F. , Moed H. D.
Published: September 2010

The investigation deals with the synthesis and configuration of the stereoisomers of a new class of sympathomimetic amines: magnified image
Aromatic sulfonation XII: Kinetics of the sulfonation of p‐ and o‐toluenesulfonic acid in aqueous and fuming sulfuric acid
Authors: Cerfontain H.
Published: September 2010

The kinetics of the sulfonation of p‐ and o‐toluenesulfonic acid have been measured at 25.0° in aqueous and fuming sulfuric acid, the concentrations varying from 93.3‐103.3 wt‐% H2SO4. The reaction is first order with respect to the sulfonic acid.

The observed variation in the apparent first order rate constants is of the order of 106. The sulfonation kinetics are shown to be consistent with the sulfonation mechanisms previously proposed for aqueous1 and fuming2 sulfuric acid. In aqueous sulfuric acid varying in composition from 93.3‐98.8 wt‐% H2SO4 isomerization was shown to be a reaction of minor importance.
Microbiological conversion of 19‐nortestosterone (VI) 1β‐hydroxylation
Authors: Bolt C. C. , Mijs W. J. , Zeelen F. J. , Szpilfogel S. A. , de Flines J. , van der Waard W. F.
Published: September 2010

The microbiological transformation of 19‐nortestosterone with Botryodiplodia malorum, leading to the 1β‐hydroxy‐derivative, is described.
The synthesis of 1‐arylisochromans and their use in the preparation of ortho‐substituted diphenylmethane derivatives
Authors: van der Stelt C. , Hofman P. S. , Nauta W. Th.
Published: September 2010

Several 1‐arylisochromans were prepared from 1‐bromoisochroman and 1‐bromo‐4,4‐dimethylisochroman by reaction with arylmagnesium bromides. Bromination and heating yielded, presumably via bromo‐1‐arylisochromans, o‐(bromoalkyl)benzophenones. Treatment with lithium aluminium hydride converted the ketones into the corresponding carbinols, the side‐chain being simultaneously debrominated if sufficient hydride was used.

Reactions of the bromoalkylbenzophenones with hydrazine derivatives yielded benzodiazepines.

Treatment with hydriodic acid and red phosphorus converted 1‐phenyl‐isochroman into o‐(2‐iodoethyl)diphenylmethane while 4,4‐dimethyl‐1‐phenyl‐isochroman yielded 10,11‐dihydro‐10,10‐dimethyl‐5H‐dibenzo[a,d]cycloheptene and a compound (C13H10)n of unknown structure.
A simple synthesis of α,α,α‐trifluoro‐p‐toluic acid
Authors: van der Stelt C. , Nauta W. Th.
Published: September 2010

The inexpensive p‐chloro‐α,α,α‐trifluorotoluene proved a useful intermediate for the preparation of p‐trifluoromethylphenyl compounds because of its easy conversion (with cuprous cyanide in 1‐methyl‐2‐pyrrolidone at 240° in a closed vessel) into α,α,α‐trifluoro‐p‐tolunitrile and, subsequently, into α,α,α‐trifluoro‐p‐toluic acid.
Validity of Martin's equation in reversed‐phase paper‐chromatography
Authors: Peereboom J. W. Copius
Published: September 2010

The properties of the paper‐chromatographic system paraffin oil/acetic acid‐water (84 + 16), applied to the analysis of sterols, have been investigated.

The variation of the cross sectional areas occupied by the stationary and mobile phases (AL/AS ratio) was studied. By inserting experimental values for AL/AS, RF and the partition coefficients of two sterols in the equation of Martin: α = AL/AS (1/RF ‐ 1), strong evidence was obtained as to the validity of this equation in the reversed‐phase system studied.
Preparation of silver sulfate from silver bromide
Authors: Krijt J. , Hofman P. S.
Published: September 2010

A simple method for the conversion of silver bromide into silver sulfate is described.
The pyrolysis of 2‐chloro‐1,3,2‐dioxaborolan
Authors: Finch Arthur , Hyams I. J.
Published: September 2010

The kinetics of liquid phase pyrolysis of 2‐chloro‐1,3,2‐dioxaborolan between 100° and 150° have been followed by spectrophotometric and titrimetric methods.
Photoconductivity spectra of stable and metastable single‐crystals of perylene
Authors: Mulder B. J.
Published: September 2010

A study was made of the photoconductive properties of plate‐shaped single crystals of perylene with aqueous electrodes applied to both sides of the crystal. Two modifications have been investigated, a stable modification (α‐perylene) and a metastable one (β‐perylene). Photoconductivity spectra have been measured by illuminating through the positive electrode. The spectra of α and β‐crystals show analogous systems of vibronic bands with a wavelength shift of about 200 cm−1 between the two band systems. In the case of α‐crystals the conductivity spectrum duplicates the optical absorption spectrum. For β‐crystals the agreement between the conductivity spectrum and the reported absorption spectrum is less satisfactory.

The shape of the photoconductivity spectra and various other evidence indicates that the origin of all observed photocurrents is at the surface of the crystal in contact with the positive electrode. Here excited perylene molecules react with the electrode to give a mobile charge carrier (hole). To account for the observed quantum yields of the photoconduction process it must be assumed that excitation energy can migrate (in the form of excitons) from the interior of the crystal to its surface (the same picture is generally accepted in the photoconduction of anthracene crystals). The quantum efficiencies obtained with β‐crystals were considerably higher than those for α‐crystals. This can be correlated with a difference in the mean diffusion paths of the excitons in the two modifications. The relatively short diffusion path in the dimeric α‐crystals is attributed to the formation of immobile charge‐transfer states.
On the impedance of galvanic cells: XII. The impedance and the admittance of a streaming mercury electrode; theoretical considerations
Authors: Ijzermans A. B. , Sluyters‐Rehbach M. , Sluyters J. H.
Published: September 2010

Expressions for the complex impedance and admittance of a streaming mercury electrode in the presence of either an irreversible or a reversible redox system are derived. An irreversible redox couple gives rise to complex plane diagrams identical with those formerly derived for other electrodes (part I1, part III2). However, complex plane diagrams characteristic for the streaming mercury electrode occur in the case of a reversible redox system.

Methods for obtaining information from the diagrams are indicated. The application of streaming mercury electrodes for the determination of kinetic parameters of electrode reactions does not seem very attractive.
Rearrangements in polyhedric foam
Authors: Schwarz H. W.
Published: September 2010

The process of rearrangement of lamellae in polyhedric foam is described, and rules for the course of these rearrangements are given.

It is shown that in polyhedric foam the lamellae and Plateau borders should be curved in general to fulfil the requirements that the angles between the lamellae are 120° and those between the Plateau borders 109°28′.
Untersuchungen über N‐Oxyde des 2‐Dimethylaminopyridins II
Authors: Wieczorek J. S. , PłLażek E.
Published: September 2010

Bei der Nitrierung des N2‐Oxydes des Dimethylaminopyridins (II) entsteht das 2‐Dimethylamino‐5‐nitropyridin; die gleiche Verbindung wurde bei Nitrosierungsversuchen erhalten. Durch eine weitere Oxydation des N1‐Oxydes (I) des 2‐Dimethylaminopyridins wurde das N1,N2‐Dioxyd erhalten (III). Es wurde gefunden das sich das N2‐Oxyd des Dimethylpyridins und das N‐Oxyd des Dimethylanilins, nicht aber das N1‐Oxyd des 2‐Dimethylaminopyridins in einfacher Weise mit CS2 desoxydieren lassen. Aus dem N1,N2‐Dioxyd des 2‐Dimethylaminopyridins entsteht mit CS2 das N1‐Oxyd. Bei der Nitrierung des N1,N2‐Dioxydes entsteht das N1‐Oxyd des 2‐Dimethylamino‐5‐nitropyridins.
Electronic spectra of nuclear methyl‐substituted 1,1‐diphenylethylenes
Authors: Korver O. , Veenland J. U. , de Boer Th. J.
Published: September 2010

The electronic spectra of nuclear methyl‐substituted 1,1‐diphenylethylenes in ethanol, cyclohexane and in 98% sulfuric acid are discussed.
Chemistry of acetylenic ethers: 78 Isomerization of some conjugated enyne compounds
Authors: van Boom J. H. , Montijn P. P. , Berg M. H. , Brandsma L. , Arens J. F.
Published: September 2010

Enyne‐hydrocarbons, ‐alcohols and ‐ethers with the systemcan be converted into the isomers with a terminal acetylenic group, by treating them with an excess of potassium amide in liquid ammonia and hydrolysing the reaction mixture thus formed. In most cases yields are excellent.

Enyne thioethers RCC‐CHCH‐SC2H5(R  alkyl) undergo an elimination of ethanethiol under these conditions. Hydrolysis affords the 1,3‐diynes RCC‐CCH in very good yields.
The constitution of the Grignard Reagent: Part V. On the possibility of an equilibrium between ethylmagnesium bromide and diethylmagnesium
Authors: Blomberg C. , Vreugdenhil A. D. , van Zanten B. , Vink P.
Published: September 2010

The possibility of the existence of an equilibrium in diethyl ether between ethylmagnesium bromide ‐ prepared from 14C‐labelled ethyl bromide and magnesium ‐ and diethylmagnesium was investigated. The result was inconclusive because complete exchange of ethyl groups was found which might be attributed either to the existence of an equilibrium or to a transmetallation reaction.
Phosphonate analogs of cephalin
Authors: Rosenthal Arthur F. , Pousada Manuel
Published: September 2010

Two ester‐phosphonate analogs of cephalin of the type

magnified image

have been synthesized in the L‐dipalmitoyl (R  C15H31) and DL‐distearoyl (R  C17H35) forms. 2‐Phthalimidoethylphosphonic acid was prepared by hydrogen bromide cleavage of its crude diethyl ester. Reaction of D‐αβ‐dipalmitin or DL‐αβ‐distearin with 2‐phthalimidoethylphosphonyl dichloride gave, after hydrazinolysis and purification of the product on a silicic acid column, the corresponding phosphono‐cephalins (I).

A diether‐phosphonate analog of cephalin,magnified image

was prepared in high yield by condensation ofmagnified image

with 2‐hydroxyethylphthalimide and trichloroacetonitrile, followed by hydrazinolysis of the phthalyl diether phosphonocephalin.
Investigations on sterols XXIV: Synthesis of some 6‐dehydro‐8α, 10α‐steroid hormone analogues and conversion of 8β, 10α‐ into 8α, 10α‐steroids
Authors: van Moorselaar R. , Halkes S. J. , Havinga E.
Published: September 2010

The synthesis of some 6‐dehydro‐8α,10α‐steroids from 10α‐ergosterol (pyrocalciferol) is described. 17β‐Hydroxy‐8α,10α‐androsta‐4,6‐dien‐3‐one (XI) has also been prepared from 17β‐hydroxy‐10α‐androst‐4‐en‐3‐one 17‐acetate (XIV).
Investigations on sterols XXVIII: Synthesis of 6‐methyl‐9β,10α‐steroids; conformation of ring B in 4‐en‐3‐one derivatives
Authors: van Kamp H. , Halkes S. J.
Published: September 2010

The synthesis is described of 6‐methyl‐9β,10α‐4‐en‐3‐ones, which were dehydrogenated to some of their 1‐dehydro, 6‐dehydro and 1,6‐bisdehydro derivatives. N.M.R. spectra reveal that ring B in 6α‐methyl‐9β,10α‐4‐en‐3‐ones has a boat conformation. The factors forcing ring B into a boat form are discussed. A summary of endocrinological data is given.
The copper‐catalysed oxidation of unsaturated carbonyl compounds: II. Base‐catalysed isomerization of isomesityl oxide and Δ5‐cholestenone
Authors: Volger H. C. , Brackman W.
Published: September 2010

The mechanism of the base‐catalysed isomerization of the βγ‐unsaturated ketones isomesityl oxide and Δ5‐cholestenone to their αβ‐unsaturated isomers was studied. The results are interpreted on the basis of a reaction scheme in which a dienolate anion, formed by deprotonation of the starting material, is an intermediate. The factors determining the rate of deprotonation of unsaturated ketones are discussed.

Methoxide ions were found to deprotonate both ketones studied, whereas triethylamine, which deprotonates isomesityl oxide directly, was found to react with Δ5‐cholestenone only via the intermediate formation of methoxide ions from the solvent methanol.
Gas hydrates of nitrogen and oxygen. II
Authors: van Cleeff A. , Diepen G. A. M.
Published: September 2010

p‐t relations of different three phase equilibria in the systems nitrogen‐water and oxygen‐water are given from ‐6 to 18° for pressures up to 1000 atm. From the data, the heats of formation of nitrogen‐ and oxygen‐hydrate and the composition of these hydrates were calculated.
Syntheses of amino and bromo derivatives of 4‐methyl‐, 4‐t‐butyl‐ and 4‐phenyl‐pyrimidine
Authors: van der Plas H. C.
Published: September 2010

A description is given of syntheses of 5‐amino, 6‐amino and 5‐bromo derivatives of 4‐methyl‐, 4‐t‐butyl‐ and 4‐phenyl‐pyrimidine, using 6‐hydroxy‐4‐methyl‐, 4‐t‐butyl‐6‐hydroxy‐ and 6‐hydroxy‐4‐phenyl‐pyrimidine as starting substances.
Structure of malic acid chloralide
Authors: Baron Maximo , Hollis Donald P.
Published: September 2010

The structure of malic acid chloralide was studied by N.M.R. and found to be a 1,3‐dioxolan‐4‐one.
Mesures de pH dans des Mélanges Eau‐éthanol
Authors: Gelsema W. J. , de Ligny C. L. , Visserman Melle G. F.
Published: September 2010

Suivant la méthode du National Bureau of Standards à Washington les valeurs pHs* ont été déterminées d'un tampon oxalique et d'un tampon succinique dans l'eau et quelques mélanges eau‐éthanol ainsi que celles d'un tampon salicylique et d'un tampon diéthylbarbiturique dans l'éthanol absolu. Par des mesures de f.é.m. de cellules à jonction saline il est possible de montrer que les potentiels de diffusion entre ces solutions‐tampons standard et une solution aqueuse saturée de chlorure de potassium dépendent uniquement de la teneur en éthanol du solvant et non pas de la nature du tampon, ce qui a permis la détermination des valeurs pHs* du tampon diéthylbarbiturique dans l'eau et quelques mélanges eau‐éthanol.

Utilisant les solutions‐tampons standard, les constantes de dissociation de plusieurs acides des types HA et BH+ont été mesurées dans l'eau et quelques mélanges eau‐éthanol. Il s'ensuit des résultats que les fonctions d'acidité H−et H0ne sont pas des mesures sans équivoque de l'acidité dans ces milieux. La faible basicité de la propylamine et de la butylamine par rapport aux autres amines primaires aliphatiques est expliquée par l'existence d'une liaison hydrogène intramoléculaire du type C‐H …. N. De même, une liaison hydrogène intramoléculaire du type C‐H …. O est responsable de la faible acidité de l'acide propionique par rapport aux autres acides carboxyliques. L'influence de substituants sur les valeurs pK*‐pK est attribuée principalement à un empêchement à la solvatation des ions organiques, croissant avec le nombre de molécules d'éthanol solvatées. Dans les cas de l'ammoniac et de l'aniline on peut démontrer que même le substituant méthyle exerce un tel effet stérique.
Hammett and Taft‐Ingold relations in heterocyclic compounds
Authors: ten Thije P. A. , Janssen M. J.
Published: September 2010

Acid and base catalysed hydrolysis rates were determined for the ethyl esters of 2‐ and 3‐furoic acids and 2‐ and 3‐thiophenecarboxylic acids. From the data, σ* values were derived for the 2‐ and 3‐furyl‐ and ‐thienyl grpups. The dissociation constants (pKa) of the acids are proportional to the σ* values of the appropriate groups and it appeared that benzoic acid fits the same relation.

From a study of the hydrolysis of 5‐substituted 2‐thiophenecarboxylic esters (methyl, chloro, bromo and nitro substituents were covered) it was found, that the alkaline hydrolysis rates could adequately be related by a set of substituent constants σth, which are rather similar to σm in the benzene series. However, both the acidic hydrolysis rates of the same esters, and the chemical shifts of the methyl protons of 5‐substituted 2‐methylthiophenes show large deviations from this relation.
Acid anilides: XII. The preparation of 4‐ and 5‐hydroxyalkananilides from γ‐ and δ‐lactones
Authors: de Jonge A. P. , van der Ven B.
Published: September 2010

The preparation of 4‐ and 5‐hydroxyalkananilides from minute amounts of lactones is discussed. In addition, the solubility of two 5‐hydroxyalkananilides in cyclohexane was determined.

The rate of hydrolysis of hydroxyalkananilides by hydrochloric acid has been determined spectrophotometrically.
Studies on imidazoles, part I: The action of phosphorus pentachloride on N‐butyl‐N′‐ethyloxamide
Authors: Trout G. E. , Levy P. R.
Published: September 2010

Two isomeric 5‐chloro‐1,2‐dialkylimidazoles, obtained by the action of phosphorus pentachloride on N‐butyl‐N′‐ethyloxamide, have been isolated and their structure determined.
Chemistry of acetylenic ethers 80 1‐acylthio‐1‐alkynes, a new class of compounds
Authors: Wijers H. E. , Montijn P. P. , Brandsma L. , Arens J. F.
Published: September 2010

1‐Acylthio‐1‐alkynes magnified image (R and R′ are alkyl) have been prepared in satisfactory yields from ethereal suspensions or solutions of alkynyllithium R′CLi, sulfur powder, and acyl bromides magnified image.

Addition of water at 60‐70° to magnified image proceeds smoothly with formation of magnified image. This product is identical with a sample prepared from magnified image.
Kinetic protium‐deuterium isotope effect in an intramolecular 1–5 shift of hydrogen
Authors: Kloosterziel H. , ter Borg A. P.
Published: September 2010

The thermal isomerization of 5,8‐dideuterocycloocta‐1,3,6‐triene to the 1,3,5‐isomer has been studied. From the rate, as compared with that of the unlabelled compound, and from the distribution of the label in the rearranged material, values were obtained for the primary and secondary kinetic isotope effects. The large value of 5.0 at 120° for the former tallies with a nearly symmetrical transition state.
Preparation of 1,3‐hexadiyne from 2,4‐hexadiyne
Authors: de Vries G.
Published: September 2010

2,4‐Hexadiyne in liquid ammonia is isomerized by an excess of sodamide. After hydrolysis 1,3‐hexadiyne results. This compound polymerizes very easily.
Racemisation during peptide synthesis with 1‐alkynylamines (ynamines)
Authors: van Mourik A. S. , Harryvan E. , Arens J. F.
Published: September 2010

The Anderson‐Young test was applied to peptide syntheses in which 1‐dialkylamino‐1‐alkynes (ynamines) were used as condensing agents. Considerable racemisation was observed.

PHT‐L‐phe anhydride could be obtained from PHT‐L‐phe and 1‐diethylamino‐1‐pentyne without racemisation, provided that no excess of reagent was used.
Energy data on the carbon‐carbon bond VII heats of dissociation of some symmetrical tetra‐arylethanes measured by electron spin resonance
Authors: Fleurke K. H. , de Jong J. , Nauta W. Th.
Published: September 2010

The heats of dissociation of some ortho alkyl‐substituted tetraphenylethanes which show reversible thermal dissociation in solution at room temperature, were measured by means of ESR. The values found are 22.0, 19.7 and 12.0 kcal/mole for symm.tetra(2,6‐dimethylphenyl)ethane, symm.tetra(2‐tert‐butyl‐phenyl)ethane and symm.tetra(2,6‐diethylphenyl)ethane, respectively.
Internal reactions in the Grignard‐complex containing compounds with alkoxy‐groups part III: Allyl phenyl ether
Authors: Blomberg C. , Vreugdenhil A. D. , Vink P.
Published: September 2010

The reaction of methylmagnesium iodide with allyl phenyl ether was investigated. Contrary to expectation2 1‐butene, the product of the ether cleavage reaction, was formed only to a small extent, the main gaseous product being methane. The mechanism proposed for the formation of this product is: Claisen rearrangement of allyl phenyl ether under the influence of magnesium iodide and reaction of methylmagnesium iodide with the rearrangement product, o‐allylphenol with formation of methane. The formation of methane as well as of 1‐butene indicates that two competitive reactions (rearrangement and ether cleavage reaction) take place.
Derivatives of benzo‐ and indolo‐quinolizines II. Synthesis of 2‐substituted hexahydro‐2h‐benzo[a]quinolizines and octahydroindolo[2,3‐a]quinolizines from substituted valerolactones
Authors: Gootjes J. , Nauta W. Th.
Published: September 2010

The preparation of a number of 2‐substituted 1,3,4,6,7,11b‐hexahydro‐9,10‐dimethoxy‐2H‐benzo[a]quinolizines and 1,2,3,4,6,7,12,12b‐octahydroindolo[2,3‐a]quinolizines is described. Starting from 3‐substituted valerolactones, the preparation required five stages (see Reaction Scheme I). A number of the 3‐substituted valerolactones used were conveniently prepared by reduction of the corresponding glutaric acid derivatives, e.g. the anhydrides, with sodium borohydride. The final stage is a stereoselective reduction, leading to cis or trans isomers. The synthesis and data of one of the end‐products, 1,3,4,6,7,11b‐hexahydro ‐9,10‐dimethoxy‐2‐phenyl‐2H‐benzo[a]quinolizine, are compared with those reported for this compound by Tomimatsu.
Experiments in the 5H‐dibenzo[a,d]cycloheptene series II. Synthesis of some esters and piperazine derivatives of 5H‐dibenzo[a,d]cycloheptene
Authors: van der Stelt C. , Haasjes A. , Tersteege H. M. , Nauta W. Th.
Published: September 2010

The synthesis of a number of acids in the 5H‐dibenzo[a,d]cycloheptene series is described including the 5‐carboxylic acid and its 10,11‐dihydro analogue, 5H‐dibenzo[a,d]cycloheptene‐5‐acetic acid and its 10,11‐dihydro derivative. The latter acid was prepared by several routes. Treatment of its acid chloride with stannic chloride yielded 2,6,7,1 1b‐tetrahydro‐1H‐dibenzo[c,d,h]azulen‐2‐one, which by reductive amination with methylamine, dimethylamine and 1‐methyl‐phenethylamine was converted into the corresponding amines. Several esters with aliphatic and heterocyclic amino alcohols were prepared from the carboxylic acids mentioned. The acids were likewise converted into 1‐substituted 4‐piperazides which were reduced to the corresponding piperazine derivatives. The acid derivatives were screened for biological activity.
The crystal structure of 6,6‐dibromo‐2,3:4,5‐dimethano‐2,4‐dinitrocyclohexanone
Authors: Stam C. H. , Evers H.
Published: September 2010

The crystal structure of 6,6‐dibromo‐2,3:4,5‐dimethano‐2,4‐dinitrocyclohexanone has been determined in order to find the positions of the two cyclopropyl rings relative to the carbonyl group.
The NMR spectrum of the cyclic trimer of glycidaldehyde
Authors: Jungnickel J. L. , Reilly C. A.
Published: September 2010

A sample of glycidaldehyde cyclic trimer, 2,4,6‐tris(epoxyethyl)‐1,3,5‐trioxane, yielded an NMR spectrum more complex than expected. From its method of preparation, it must be a cis‐cis isomer of the chair form, with all three epoxyethyl groups equatorial. The complexity of the spectrum has been explained in terms of asymmetric carbon atoms, the sample being a racemic mixture of ddl and lld forms. A second form, with a simpler spectrum, has been identified with the ddd + lll racemate. This interpretation is believed to explain also a complex spectrum of parabutylchloral obtained by Barón and Hollis.
The formylation of ketones
Authors: van der Zeeuw A. J. , Gersmann H. R.
Published: September 2010

Formylation of ketones with carbon monoxide to give α‐formyl ketones under the influence of alkali metal alkoxides in dimethoxyethane (DME) can occur in two ways. With primary alkoxides as bases, formylation takes place via alkyl formates. Addition of the corresponding alcohol favors the reaction. When potassium tert‐butoxide is used, besides this indirect reaction, a direct reaction of the ketone anion with CO occurs. In the absence of alcohols e.g. when the ketone is ionized by potassium naphthalene only the direct reaction occurs; its mechanism has been studied in more detail.
Changes in ultraviolet absorption of aldoses during thermal decomposition in dilute aqueous solution
Authors: Berrens L.
Published: September 2010

Heating of dilute aqueous solutions of simple aldoses at 50° induces marked alteration in the electronic absorption spectra of the sugars. Maxima at 230 mμ and 275 mμ, and low‐intensity peaks at 325 mμ and 350 mμ, appear as a function of the time of heating and of pH. These maxima are attributed to intermediates in the degradation of aldoses; the absorption peaks at 230 and 325 mμ in particular are concluded to represent the K‐ and R‐bands in the spectrum of the enolic forms of 3‐deoxyglycosuloses.
The photocurrent in anthracene crystals under illumination of the negative electrode
Authors: Mulder B. J. , de Jonge J. , Vermeulen G.
Published: September 2010

Photocurrents in anthracene crystals (with electrolytic electrodes) generated by strongly absorbed light (25000‐30000 cm−1) have their origin exclusively at the surface of the crystal in contact with the positive electrode. Photocurrents observed under illumination of the negative electrode arc the result of reabsorption of fluorescent light.
A new γ‐lactone found in butter
Authors: Lardelli G. , Dijkstra G. , Harkes P. D. , Bolding J.
Published: September 2010

A characteristic component of butter flavour is 2,3‐dimethyl‐2,4‐nonadien‐4‐olide, the enol lactone of 2,3‐dimethyl‐4‐oxo‐2‐nonenoic acid. Homologues have not been found. The substance which has a strong odour reminiscent of celery and occurs in an amount of about 0.5 mg/kg butter, was called “bovolide”.

The elucidation of its structure and its synthesis are described. Also several related compounds have been synthesized.
Energy data on the carbon‐carbon bond VIII activation energies of the dissociation of some symmetrical tetra‐arylethanes
Authors: Fleurke K. H. , Nauta W. Th.
Published: September 2010

The activation energies of the dissociation of some ortho‐alkyl‐substituted symmetrical tetraphenylethanes were determined by measuring the reaction rates of these compounds with oxygen in m‐xylene solutions. The values found are 25.3, 22.9 and 19.6 kcal/mole for symm.tetra(2‐tert‐butylphenyl)ethane, symm.‐tetra(2,6‐dimethylphenyl)ethane and symm.tetra(2,6‐diethylphenyl)ethane, respectively. The frequency factors and activation entropies of the dissociation reaction were obtained from the same measurements. Using the known data on the dissociation equilibria, we also calculated the relevant kinetic values for the recombination reactions.
On the structure of α‐UO3
Authors: Loopstra B. O. , Cordfunke E. H. P.
Published: September 2010

From the neutron diffraction pattern of a‐UO3 it was found that the generally accepted hexagonal structure is incorrect. Both chemical and structural arguments have led us to regard a‐UO3 as an imperfectly crystalline form of the orthorhombic modification generally called UO2.9. This substance has an unknown structure which is shown to be disordered.
Synthesis and physiological properties of some heterocyclic‐aromatic sulfides and sulfones. V: Synthesis of some ring‐substituted aromatic ethene thioethers and their corresponding sulfones
Authors: Trompen W. P. , Huisman H. O.
Published: September 2010

The synthesis of some ring‐substituted aromatic ethene thioethers and their corresponding sulfones is described. The acaricidal activity and ovicidal action on eggs of Tetranychus urticae, Koch are reported.
Studies in homogeneous catalysis: Copper‐phenanthroline complexes as catalysts for the oxidation of methanol
Authors: Brackman W. , Gaasbeek C. J.
Published: September 2010

Copper phenanthroline complexes are catalysts for the oxidation of methanol by oxygen at 30‐45 °.

A feature of the reaction is that it shows an induction period unless started with small amounts of H2O2 or cuprous ion. During the reaction the system contains a considerable amount of cuprous complex, the presence of which appears to be an essential condition for the continuation of the oxidation.

Hydrogen peroxide, in contrast to other hydroperoxides, rapidly forms cuprous complex when added to a cupric‐phenanthroline system. This reaction probably proceeds via formation of O2−. from HO2− ion and cupric complex. The radical ion \documentclass{article}\pagestyle{empty}\begin{document}\[{\rm O}_{\rm 2}^{-\bullet}\]\end{document} would then abstract a hydrogen atom from methanol (or methoxide) coordinated to cupric‐phenanthroline complex, while simultaneously the cupric ion would abstract an electron from the methanol ligand, thus giving rise to formaldehyde and a proton without the intervention of free methanol radicals. The HO2− ion formed in this reaction would either be reoxidized by cupric complex (chain propagation) or reductively split by a cuprous‐phenanthroline complex (termination).

The reactions leading to the hydrogen peroxide‐induced formation of cuprous complex probably constitute an essential part of the mechanism of the copper‐phenanthroline‐catalysed oxidation of methanol by oxygen. In this latter reaction \documentclass{article}\pagestyle{empty}\begin{document}\[{\rm O}_{\rm 2}^{-\bullet}\]\end{document} is supplied by the reaction of cuprous complex with oxygen.
ESR spectra of some diarylmethyl radicals
Authors: de Jong J. , Fleurke K. H. , van Hardeveld R.
Published: September 2010

The ESR spectra of four ortho‐alkyl‐substituted diphenylmethyl radicals have been measured in solutions of m‐xylene. The proton coupling constants were assigned experimentally such that the reconstructions of the spectra agreed with the recorded tracings. The spin densities were calculated assuming proportionality between proton coupling constant and spin density on the adjacent carbon atom. The relation between spin distribution and steric configuration of the radicals is considered on a qualitative basis.
Investigations into the prins reaction with 1‐dodecene
Authors: Heslinga L. , van Gorkom M.
Published: September 2010

Addition of protonated formaldehyde to 1‐dodecene in acetic acid solution yields 4‐decyl‐1,3‐dioxane and both cis‐ and trans‐4‐acetoxy‐3‐nonyltetrahydropyran as major products. The configuration of these reaction products was investigated by proton magnetic resonance. Their formation is explained by a recently reported reaction mechanism.
Syntheses of carotenoidal compounds. III: Condensation of polyene‐aldehydes with 1,4‐dicyano‐2‐butene
Authors: Haeck H. H. , Kralt T.
Published: September 2010

Preparation, reactions and spectra of condensation products of β15‐, β17‐, β20‐ and β22‐aldehyde with 1,4‐dicyano‐2‐butene are described.
Experiments in the 5H‐dibenzo[a,d]cycloheptene series. III. Synthesis of 10,11‐substituted 5H‐dibenzo[a,d]cycloheptene derivatives
Authors: Corts G. J. B. , Nauta W. Th.
Published: September 2010

The synthesis is described of a number of derivatives of 10,11‐dihydro‐5H‐dibenzo[a,d]cycloheptene, with basic substituents in the ethylene bridge. Moreover, a method is reported for the preparation of amino ethers of 5H‐dibenzo‐[a,d]cyclohepten‐10‐ol.
Photoreactions of aromatic compounds IX: Photo‐fries rearrangement of aryl sulfonates
Authors: Stratenus J. L. , Havinga E.
Published: September 2010

Phenyl and a‐naphthyl p‐toluenesulfonates as well as phenyl methanesulfonate were found to undergo photochemical rearrangement upon irradiation with light from a high pressure mercury arc lamp. In the case of phenyl p‐toluenesulfonate, o‐ and p‐hydroxyphenyl‐p‐tolylsulfone and phenol were identified as products originating from a photo‐Fries reaction.
Studies in homogeneous catalysis: mechanism of the oxidation of aliphatic aldehydes and ketones catalysed by copper‐pyridine complexes
Authors: Brackman W. , Volger H. C.
Published: September 2010

From kinetic and stoichiometric data the following mechanism is derived for the oxidative steps of the degradation of saturated aldehydes and ketones with oxygen, catalysed by copper‐pyridine complexes in the presence of triethylamine, described in the previous paper.

The aldehyde (ketone) is deprotonated by methoxide ions, formed from methanol and triethylamine. The enolate ion co‐ordinates with cupric ion and pyridine to a complex which does not decompose spontaneously. This complex, however, is reactive toward oxygen, yielding an a‐hydroperoxide anion of the carbonyl compound, which decomposes via ionic reactions. The complex is also reactive towards triphenylphosphine, yielding a cuprous phosphine complex and presumably an enolate radical. The dimers of such radicals have been isolated.

At high concentrations of oxygen the overall reaction rate is controlled by the rate of formation of the copper‐enolate complex or, if the copper concentration is sufficiently high, by the deprotonation step. In the absence of oxygen the same reactions control the rate of the reaction with triphenylphosphine.
Chemistry of acetylenic ethers 83: Acid‐catalyzed rearrangement of allenyl thioethers into thioethers with a conjugated diene system
Authors: Wijers H. E. , Brandsma L. , Arens J. F.
Published: September 2010

Allenyl thioethers RCHCC(SR″′ )CHR′R″ (R, R′, R″ are H or alkyl: R′″ = alkyl) have been isomerized under the influence of acids into the dienes RCHCHC(SR′″) = CR′R″.
The conformation of non‐aromatic ring compounds. XXIII: Some halogenated 1,4‐dithianes
Authors: Kalff H. T. , Havinga E.
Published: September 2010

Several 2,3‐ and 2,5‐disubstituted halogeno‐1,4‐dithianes have been prepared and their conformational features have been investigated by means of dipole moments and infrared spectra. The NMR spectra, described elsewhere2, support the results presented in this paper. The crystal structures of trans‐2,3‐dichloro‐1,4‐dithiane3 and trans‐2,5‐dibromo‐1,4‐dithiane1, determined by X‐ray analysis, provide us with a basis for the conformational analysis. In both compounds the halogen atoms are in axial positions.

For the 2,3‐compounds (dichloro‐, dibromo‐, and 2‐bromo‐3‐chloro‐) the dipole moments remain constant on changing the solvent; the infrared spectra in the solid state (KBr discs) and in solution (CS2) are practically identical. The 2,5‐compounds, however, show additional peaks in solution in carbon disulfide, indicating a shift from the conformation with two axial halogen atoms to that with two equatorial halogen atoms in solution. The tetrachloro‐1,4‐dithiane, described by Varvoglis and Tsatsaronis4, is proved to be 2,2,3,3‐tetrachloro‐1,4‐dithiane.

No trace of mono‐substituted, cis‐2,3‐ or cis‐2,5‐disubstituted products could be detected in our synthetic experiments.
On the oscilloscopic determination of rate constants of electrode reactions by means of square wave and sine wave current II: Scope of the method
Authors: Teppema P. , Sluyters‐Rehbach M. , Sluyters J. H.
Published: September 2010

The sources of error pertaining to the oscilloscopic determination of rate constants of electrode reactions are studied and the upper and lower limits of the methods are given. The former is mainly determined by the accuracy with which the moment of zero diffusion polarization can be adjusted.

It is shown that the extrapolation of cell responses to zero frequency does not eliminate the contribution of the double layer capacitance completely. The remaining contribution is a negative resistance,‐2 σ2 Cd, irrespective of waveform.
On the reactivity of organophosphorus compounds: II. The effects of structural variations in the alkyl and alkoxy groups on the values of ΔH* and ΔS* for the alkaline hydrolysis of a number of organophosphorus esters
Authors: Ginjaar L. , Blasse‐Vel S.
Published: September 2010

The second‐order rate constants of the alkaline hydrolysis at different temperatures of a number of nitrophenyl phosphorus esters and the values of the quantities ΔH* and ΔS* at 25°C are reported. The effect of structural changes on the values of ΔH* and ΔS* are considered and are compared with similar changes in other nucleophilic substitution reactions, on both phosphorus and carbon atoms.