bluuebunny/crossref_metadata_2025 huggingface dataset:
The chemistry of the N‐alkylaldimines: III. The origin of the bands at 1400 cm−1 in the infrared spectra of N(1‐alkenyl)‐N‐propylamides
Authors: Breederveld H. , Rummens F. H. A.
Published: September 2010

The band at about 1400 cm−1 in the infrared spectra of N(1‐alkenyl)‐N‐propylamides is assigned to the N‐C‐stretching vibration of the system

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2‐Vinyl‐ and 4‐vinyl‐1,3‐dioxan
Authors: Bellaart A. C.
Published: September 2010

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

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

Bifunctional acetylenic ethers ROC≡C(CH2)nC≡COR can be prepared by alkylation of alkoxyethynyl‐sodium or ‐lithium with α,ω‐dihalides in liquid ammonia. The compounds obtained, and other acetylenic ethers synthesized by alkylation of alkoxyethynes, are listed in table I.

The bifunctional ether CH3C≡C·O·CH2CH2·O·C≡CC;H3 was prepared as outlined in the reaction scheme on page 520.
Chemistry of acetylenic ethers LX: Synthesis of cyclobutenone ethers from ketene and 1‐alkoxy‐1‐alkynes
Authors: Rosebeek B. , Arens J. F.
Published: September 2010

The cyclobutenone ethers V listed in table I have been prepared from 1‐alkoxy‐1‐alkynes and ketene.
The chemistry of cycloheptatriene Part VI: Interaction of 2,6‐dimethylphenol and tropylium salts
Authors: van Helden R. , ter Borg A. P. , Bickel A. F.
Published: September 2010

The interaction of 2,6‐dimethylphenol and tropylium salts has been investigated. When the reaction is conducted in acetic acid solution cycloheptatriene and (4‐hydroxy‐3,5‐dimethylphenyl)tropylium salts (III) are formed. The yield of the latter depends on the anion present; it increases in the order: ClO4− < BF4− < Cl− < CH3COO−. This reaction proceeds in two steps, viz. the primary formation of 2,6‐dimethyl‐4‐tropylphenol (IV) which then, by hydride ion transfer to tropylium ion, yields III. Isolation of the intermediate phenol was possible by the use of the heterogeneous system acetic acid ‐ water/hexane; upon reaction with tropylium salts it gave III.
The ultra‐violet absorption spectrum of iodides in dioxan‐water mixtures
Authors: Rummens F. H. A.
Published: September 2010

The influence of ion‐pairing on the U.V. absorption of the iodide ion is described. Lithium, potassium and tetra‐n‐butylammonium iodides were used along with mixtures of dioxan and water as solvents. It is shown that not only are effects attributable to ion‐pairing detectable, but that different effects can be associated with the presence or absence of solvent molecules between the ions of the ion pair.
Benzofuranquinone: (Absorption spectra of quinones, III)
Authors: Spruit C. J. P.
Published: September 2010

The preparation of benzofuran‐4,7‐quinone and some of its derivatives is described. The UV and visible absorption spectra are compared with those of analogous heterocyclic quinones.
Soap films as a tool for the study of colloidal stability
Authors: Lyklema J.
Published: September 2010

The same factors that govern the stability of hydrophobic colloidal systems influence the behaviour of thin detergent films. The study of soap films can therefore clarify many of the problems relating to colloidal stability, and vice versa. The advantages and limitations of the soap film approach are discussed. An interesting way of performing such experiments is to investigate the thickness of slowly formed soap films. Some results of this method are set forth.
A thermodynamic study of p‐chloroaniline
Authors: Aboul‐Seoud A. , El‐Hady A.
Published: September 2010

The distribution of p‐chloroaniline between heptane and aqueous sodium chloride solutions was studied at 15°, 25° and 35°. The data obtained was used to calculate the activity of the amine under the different conditions.

The hydrolysis of p‐chloroaniline hydrochloride was studied at different temperatures, different concentrations and in presence of different concentrations of sodium chloride, by the distribution method. The ratio of the activity coefficients of hydrogen and p‐chloroanilinium ions (γH/γAnil) was calculated for the different conditions. The relationship between the activity of the free amine in water, and salt concentration, was studied.
Chemistry of acetylenic ethers LXII: Tertiary phosphines with an acetylene‐phosphorus bond
Authors: Voskuil W. , Arens J. F.
Published: September 2010

A number of dialkylphosphinoethynes R2PC≡CH were prepared from chlorodialkylphosphines and ethynylmagnesium bromide. With di‐n‐butylphosphinoethyne the following experiments were performed.

From the lithium compound LiC≡CP(n•C4H9)2 it was possible to obtain 1‐dibutylphosphinoalkynes (n•C4H9)2PC≡CR and dibutylphosphinoethynylcarbinols (n•C4H9)2PC≡CC(OH)R′R″ in liquid ammonia.

With diethylamine and paraformaldehyde, dibutylphosphinoethyne gave no normal Mannich reaction, since acetylene separated off and the phosphine oxide (n•C4H9)2P(=O)CH2N(C2H5)2 was formed.

By free‐radical addition of ethanethiol, (n•C4H9)2PCH = CHSC2H5 was obtained.

During the reaction of organometallic compounds with dibutylphosphinoethyne we observed breaking of the P‐C ≡ bond. Further investigation proved that a nucleophilic substitution on phosphorus took place. On the strength of the reactions which are involved in this (see the scheme on p. 6) new methods could be developed for the replacement of acetylene‐hydrogen atoms by a dialkylphosphino group. These are based on reactions of the acetylene anion with RSPR2 or ROPR2. From phenyllithium and bis‐(dibutylphosphino)ethyne, mono(dibutylphosphino)ethyne and dibutyl‐phenylphosphine were obtained.
Reactions of aliphatic halides with solutions of alkali metals in liquid ammonia: I. Experiments with alkyl halides
Authors: Beverloo A. , Dieleman M. C. , Verkade P. E. , de Vries K. S. , Wepster B. M.
Published: September 2010

The reaction of alkyl halides with solutions of alkali metals in liquid ammonia leads to mixtures of alkane, alkene, bialkyl, and alkylamine in proportions depending upon the nature of the reactants and upon the reaction conditions.

Product compositions have been determined for eleven of the twelve butyl chlorides, bromides, and iodides. Rearrangement of the carbon skeleton does not occur. Sodium and lithium in liquid ammonia are especially useful for reducing chlorides almost quantitatively to the corresponding hydrocarbons with few or no by‐products.
Preparation of 2‐fluoroquinoline and 2,6‐difluoropyridine by halogen exchange
Authors: Hamer Jan , Link W. J. , Jurjevich A. , Vigo T. L.
Published: September 2010

The syntheses of 2‐fluoroquinoline and 2,6‐difluoropyridine in yields of respective 60% and 52% have been accomplished by treating the corresponding chloro‐compounds with anhydrous potassium fluoride in dimethyl sulfone. Under similar conditions, 2‐chloropyridine did not yield appreciable amounts of 2‐fluoropyridine.
Rates of decompositions of certain AZO compounds
Authors: McGowan J. C. , Powell T.
Published: September 2010

The rates of decompositions of a number of azo compounds have been measured and some relationships between these rates and the structures of the azo compounds have been noted.
Thermodynamic properties of quinol clathrates III
Authors: Helle J. N. , Kok D. , Platteeuw J. C. , van der Waals J. H.
Published: September 2010

The Gibbs free‐energy difference between β‐ and α‐quinol has been determined from the solubility of quinol in n‐propanol and the vapour pressure of the solutions. It was found that μQβ — μQα = 0.084 ± 0.003 kcal/mole, in very good agreement with the value predicted by the statistical theory from the equilibrium composition of the argon clathrate at 25°.

The dissociation pressure of xenon‐quinol clathrate at 25° is 0.058 atm.
Preparation of adipic acid by oxidation of cyclohexanol and cyclohexanone with nitric acid: Part I. Reaction mechanism
Authors: van Asselt W. J. , van Krevelen D. W.
Published: September 2010

The oxidation of cyclohexanol with nitric acid to adipic acid proceeds via two stable intermediates known from the literature1 viz. 6‐hydroxyimino‐6‐nitro hexanoic acid and the hemihydrate of 1,2‐cyclohexanedione, two substances forming beside each other in a given ratio. This ratio can be calculated as a function, of the temperature and of the nitric acid and nitrous acid concentrations. The nitrous acid plays a very important part in the oxidation process. The oxidation of cyclohexanone proceeds in the same way as that of cyclohexanol, provided sufficient nitrous acid is present. In the absence of HNO2 the oxidation does not proceed at all at low temperatures.

The catalysts used ‐ ammonium vanadate and copper nitrate ‐ have very different functions. Under the influence of the vanadate the hemihydrate of cyclohexanedione is rapidly converted to adipic acid, whereas in the absence of vanadate this substance is slowly broken down to glutaric acid, succinic acid and oxalic acid. Copper is effective only at higher temperatures where it prevents the further break‐down of unstable intermediates.
The preparation and reactions of some rhodanines
Authors: Nederlof A.
Published: September 2010

3,3′‐Diethyl‐Δ5,5′‐birhodanine (III, R  C2H5) was obtained as a by‐product from the reactions of 3‐ethylrhodanine with 2,4‐dinitrobenzaldehyde and 1‐chloro‐2,4‐dinitrobenzene under suitable conditions. The synthesis of 5‐arylidene substituted rhodanines was achieved from condensations of rhodanines with anils of aromatic aldehydes in glacial acetic acid. III (R  C2H5, CH2 · CHCH2 and CH2COOC2H5) were prepared by heating the appropriate rhodanines in pyridine containing p‐toluenesulphonyl chloride. Reduction of III with zinc and glacial acetic acid gave the corresponding 5,5′‐birhodanines, which were easily auto‐oxidised in solutions to the related III. Rhodanine and some of its congeners react with 1‐chloro‐2,4‐dinitrobenzene in ethanol containing sodium acetate to give 2,2′,4,4′‐tetranitrodiphenyl sulphide. The methylene group of 3‐aminorhodanine reacted with p‐nitrobenzaldehyde in boiling ethanol, while the amino group was attacked when the reaction was carried out in glacial acetic acid at room temperature. Pyridine solutions of 5‐unsubstituted rhodanines were unstable.
Microbiological conversion of 19‐nortestosterone: (II) 10‐ and 11‐hydroxylation
Authors: de Flines J. , van der Waard W. F. , Mijs W. J. , Szpilfogel S. A.
Published: September 2010

Fermentation of 19‐nortestosterone with Curvularia lunata or with Botrytis paeoniae yielded mainly the 10β‐hydroxy‐derivative. Fermentation with Aspergillus ochraceus afforded the 11α‐hydroxy‐derivative in good yield.

10β‐Hydroxy‐19‐nortestosterone with Corynebacterium simplex yielded 10β, 17β‐dihydroxy‐19‐norandrosta‐1,4‐dien‐3‐one.
Separation of some DL‐amino acids into their optical isomers by paper adsorption chromatography
Authors: de Ligny C. L. , Nieboer H. , de Vijlder J. J. M. , van Willigen J. H. H. G.
Published: September 2010

A systematic research was made into the conditions producing optimum separation of the optical isomers of amino acids by paper chromatography, using as pilot substances racemic mixtures of the amino acids histidine, tryptophan and kynurenin and methanol‐water mixtures as eluents. The optimum separations, i.e. the smallest ratios of the moving‐rates of the slow and the fast component, were obtained by elution with a 90 vol% methanol‐water mixture at as low a temperature as possible (in our case −15°). In this way the separation of the optical isomers of dl‐cystine by paper chromatography, which has not yet been reported, could be accomplished.
The use of potassium chloride as a standard substance in solution calorimetry
Authors: Somsen G. , Coops J. , Tolk M. W.
Published: September 2010

The integral heats of solution of some samples of potassium chloride have been measured carefully with an adiabatic calorimeter. The results indicate that it is necessary to revise the value of the heat of solution of potassium chloride in water.
Investigations on pyrazine derivatives VIII: On the preparation of some aminopyrazines by the Curtius reaction
Authors: Schut W. J. , Mager H. I. X. , Berends W.
Published: September 2010

The possibility of preparing 2‐aminopyrazine 5‐carboxylic acid and some of its derivatives by the Curtius reaction was investigated. The final step could be accomplished satisfactorily especially by hydrogenolysis or acid hydrolysis of the corresponding benzylurethanes.
Internal reactions in the Grignard‐complex containing compounds with alkoxy‐groups: Part II. Cyclic acetals
Authors: Blomberg C. , Vreugdenhil A. D. , Homsma T. J.
Published: September 2010

If one molar equivalent of 2‐methyl‐, 2‐ethyl‐ or 2‐n‐propyl‐1,3‐dioxolane is used for the preparation of Grignard‐reagents in benzene, the five‐membered hetero‐ring is opened with formation of a magnesium halide 2‐alkoxyethan‐1‐olate.

The steric and electronic effects of the alkyl groups of the Grignard‐reagent and those of the dioxolane molecule are discussed.
The constitution of the Grignard reagent Part II
Authors: Vreugdenhil A. D. , Blomberg C.
Published: September 2010

Association numbers of magnesium compounds in tetrahydrofuran have been investigated. One Mg‐atom is incorporated in the molecules of the Grignard reagent, of MgBr2, and of Et2Mg.
The self‐condensation of sodium 2,4,5‐trihalothiophenolates
Authors: van Zwieten P. A. , Seutter E. , Huisman H. O.
Published: September 2010

The formation of polymeric materials from sodium 2,4,5‐trichloro‐ and sodium 2,4,5‐tribromothiophenolates is described. The reaction takes place upon heating the sodium thiophenolates in high‐boiling solvents. So far no evidence is available for the structures of these polymers.
The halogenation of aromatics: Part VIII. Transbromination of toluene and chlorobenzene with bromobenzene under the influence of aluminium bromide‐[82 Br]
Authors: Louw R. , Kooyman E. C.
Published: September 2010

Transbromination of chlorobenzene and of toluene with bromobenzene under the influence of aluminium bromide‐[82 Br] is accompanied by some bromine exchange between organic and inorganic bromides. However, since many bromine atoms are transferred for every bromine atom exchanging with the catalyst, the bromine atoms present in the brominating species (e.g. Br⊕Al2Br7⊖) are not in a state of rapid equilibration. The ratio of transfer and exchange is appreciably greater for toluene than for chlorobenzene as the acceptor.
Reactions of aliphatic halides with solutions of alkali metals in liquid ammonia: II.The behaviour of some arylcarbinyl chlorides towards solutions of sodium in liquid ammonia
Authors: Verkade P. E. , de Vries K. S. , Wepster B. M.
Published: September 2010

The behaviour of some primary, secondary, and tertiary arylcarbinyl chlorides towards solutions of sodium in liquid ammonia has been studied. Particular attention has been devoted to the biaralkyls formed.
Phosphorus metabolism and the photoproduction of oxygen and hydrogen in anaerobic chlorella
Authors: Lindeman W. , Spruit C. J. P.
Published: September 2010

The concentrations of oxygen and of phosphorylated intermediates of the photosynthetic carbon cycle have been followed simultaneously in illuminated suspensions of anaerobically adapted Chlorella cells. Initially, very little phosphoglyceric acid is available, and “reducing power” generated by illumination, is utilized chiefly by an active hydrogenase. In the presence of sufficiently high concentrations of carbon dioxide, phosphoglyceric acid is formed from ribulose diphosphate and competes with the hydrogenase for photochemical reducing power. As soon as the oxygen produced photochemically has reached a concentration sufficient to inhibit the hydrogenase, the reducing power is used up entirely in normal photosynthesis.
Oxidative decarboxylation of cyclohexanecarboxylic acid
Authors: Bigot J. A. , Kerkhoffs P. L.
Published: September 2010

Cyclohexanecarboxylic acid is converted to a mixture of cyclohexanone and cyclohexene by reacting it at temperatures around 200° with an oxygen‐containing gas and steam in the presence of metal‐salt catalysts.
Miscellaneous glycerol derivatives: II Diacid triglycerides
Authors: Verkade P. E.
Published: September 2010

Below some data are given concerning a number of diacid triglycerides which have been synthesized in my laboratory in the course of time and about which (for reasons which are irrelevant in this context) nothing has ever been published. The preparation invariably took place in the familiar way, i.e. by the action of an acyl chloride on a mono‐ or a diglyceride at room temperature, or sometimes at 35‐40°, in the presence of pyridine and of chloroform or benzene as a neutral solvent; the yields were always very good.

With the triglycerides, polymorphism is a very frequently occurring phenomenon. I cannot therefore guarantee that we always obtained the most stable modification of the compounds prepared by us.
Heat of dissociation of hexaphenylethane as measured by ESR: (Short communication)
Authors: Fleurke K. H. , de Jong J. , Nauta W. Th.
Published: September 2010

The heat of dissociation of hexaphenylethane in m‐xylene as a solvent, measured by means of electron spin resonance, amounts to 10.9 ± 0.29 (2.7%) kcal/mol.

The ESR method appears to have important advantages over other techniques for this purpose.
Oxidation of propene‐1‐14C to acrolein on copper catalysts
Authors: Sixma F. L. J. , Duynstee E. F. J. , Hennekens J. L. J. P.
Published: September 2010

Propene‐1‐14C was partially oxidised with air to acrolein on a copper catalyst. The acrolein formed was degraded: equal amounts of radioactivity were found on carbon atoms 1 and 3, while essentially no radioactivity was found on the middle carbon atom (2). The “unreacted” propene was also degraded: a major part of the radioactivity was still on carbon atom 1, while a small part (10‐20%) was on carbon atom 3; no radioactivity was found on the middle carbon atom (2). These facts indicate that the oxidation of propene to acrolein on a copper catalyst takes place via a symmetrical intermediate.

Partial isomerisation of unreacted propene also occurred when copper shavings were used as a catalyst. When D2O was present during the reaction, the unreacted propene was monodeuterated to only a very small extent (∼2%).
Thermal substitution reactions of cupric benzoate III
Authors: Schoo W. , Veenland J. U. , de Boer Th. J. , Sixma F. L. J.
Published: September 2010

Among the reaction products of cupric benzoate and ammonia a small amount of aniline is found. Using [1‐14C]‐benzoic acid the position of the amino group is identified as ortho in relation to the original carboxyl group.
Synthesis and absolute configuration of Tanret's (‐)‐pelletierine
Authors: Beyerman H. C. , Maat L.
Published: September 2010

The synthesis is described of (‐)‐pelletierine picrate identical with Tanret's pelletierine picrate from Punica granatum L. and of its antipode by oxidation, respectively, of (‐)‐ and of (+)‐sedridine. The sedridines are alkaloids with known absolute configuration of the piperidine asymmetric carbon atom. From this follows the Ds‐configuration of (‐)‐pelletierine.
Preparation of 9,10‐dimethyltriptycene
Authors: de Koe P. , van Bennekom A. J. , Coops J.
Published: September 2010

The synthesis of 9,10‐dimethyltriptycene is described.
Efficiency of chromatographic procedures: III. The efficiency of various kinds of Whatman paper for the separation of amino‐acids
Authors: de Ligny C. L. , Schmidt H. M. , de Vries W.
Published: September 2010

The efficiency of ten kinds of Whatman paper for the separation of amino‐acids with a 4 : 1 : 5 butanol‐acetic acid‐water mixture has been investigated.
New musk odorants V: A new synthesis of polyalkylindanes starting from styrenes
Authors: Spoelstra D. B. , Weber S. H. , Kleipool R. J. C.
Published: September 2010

Polyalkylindanes of the type described in earlier communications

S. H. Weber, D. B. Spoelstra and Ernest H. Polak, Rec. trav. chim. 74, 1179 (1955).

S. H. Weber, J. Stofberg, D. B. Spoelstra and R. J. C. Kleipool, ibid. 75, 1433 (1956).

may also be prepared by condensation of styrenes and alkenes under the influence of suitable catalysts

This new synthesis of polyalkylindanes is the subject of French Patent, 1, 109, 699 of Oct. 10, 1954, assigned to Polak's Frutal Works Inc., others pending.

.
Investigations on organotin compounds XIX: The preparation of some organotin compounds with heterocyclic nitrogen bound to tin
Authors: Luijten J. G. A. , van der Kerk G. J. M.
Published: September 2010

Procedures are given for the preparation of 20 organotin compounds in which a trialkyl‐ or triphenyltin group is bound to nitrogen in pyrrole, pyrazole, benzpyrazole, imidazole, 1,2,4‐triazole, benzimidazole, 1,2,3‐benztriazole, 1,2,3‐triazole and 3‐amino‐1,2,4‐triazole. In addition, the preparation is described of two dialkyldi‐1,2,4‐triazolyltin compounds.
On the determination of tropan‐3‐one in the form of its reineckate
Authors: Beyerman H. C. , Enthoven P. H. , Verkade P. E.
Published: September 2010

The use of ammonium reineckate for the isolation and quantitative determination of tropan‐3‐one formed in Schöpf reactions, as recommended by Gál, Simonyi, and Tokár, is studied and appears to be by no means advisable.
Square wave conductometry
Authors: Wijnen M. D. , Ijzermans A. B. , Schmieman J. H.
Published: September 2010

Theoretical and practical aspects of square wave conductometry are discussed. Equilibrium conditions for a simple bridge circuit are compared with those for classical sine wave conductometry. It is shown that square wave conductometry is less dependent on the choice of the cell parameters.

As an example, square wave conductometry is applied to the titration of hydrochloric acid and acetic acid with sodium hydroxide, using both wire and plane electrodes. The influence of the presence of a redox couple upon the equilibrium condition appears to be negligible in square wave conductometry.
The reaction of methylene with ethers
Authors: Frey H. M.
Published: September 2010

Little quantitative work has been published on the reactions of methylene with ethers. Doering et al

1 W. E. Doering, L. H. Knox, and M. Jones, J. Org. Chem. 24, 137 (1959)

studied the reaction of methylene with diethyl ether and found ethyl propyl ether and ethyl isopropyl ether with relative yields 55.5 : 45.5. This implies that the methylene inserts 1.2 times as rapidly in the secondary C‐H bonds as in the primary C‐H bonds. They found no evidence for any carbon rearrangement of a diethyl ether‐methylene ylid but indicated that a hydrogen rearrangement from such an “ylid” would lead to deviations from statistical attack in the required direction. Franzen and Fikentscher

V. Franzen, and L. Fikentscher, Annalen 617, 1, (1958).

were able to show, directly, by the use of labelled compounds that none of the insertion products arose by a carbon skeleton rearrangement. They also showed that in the reaction of methylene with diethyl ether some methyl ethyl ether is formed but no quantitative data was obtained.
Alkaloids in Pausinystalia yohimbe (K.Schum.) ex pierre: Part II. The isolation of a new alkaloid
Authors: van der Meulen Th. Hajonides , van der Kerk G. J. M.
Published: September 2010

Using column chromatography a new alkaloid has been isolated from several barks containing yohimbine.
Mechanism of reactions of furans I: A kinetic study of the acid‐catalyzed hydrolysis of furan and 2,5‐dimethylfuran
Authors: Stamhuis E. J. , Drenth W. , van den Berg H.
Published: September 2010

The kinetics of the hydrolysis of furan and 2,5‐dimethylfuran in aqueous perchloric acid solution at 25° have been investigated by spectroscopic and vapour pressure methods. The logarithm of the first order rate constant is linear in Hammett's acidity function, H0. The solvent deuterium isotope effect, kH/kD, of the hydrolysis of 2,5‐dimethylfuran amounts to 1.7.

A mechanism is proposed in which the first step is a slow proton transfer to the α‐carbon atom of the furan ring.
A new method for the synthesis of α‐esters of N‐acylglutamic acids
Authors: Nefkens G. H. L. , Nivard R. J. F.
Published: September 2010

N‐Benzyloxycarbonyl‐, N‐tosyl‐ and N‐phthaloylglutamic acids have been converted into various α‐esters by addition of an equimolecular amount of a base triethylamine or dicyclohexylamine) and treatment with an appropriate alkyl halide or dialkyl sulphate. The esters were isolated as dicyclohexylammonium salts and appeared free of the corresponding γ‐esters after one crystallization (Table I). The method surpasses older procedures by its symplicity and higher yield, but fails for the synthesis of p‐nitrophenyl or tert.butyl esters.

The α‐esters of corresponding aspartic acid derivatives are not obtained in this way.
Synthesis of the N‐terminal octapeptide sequence derived from glucagon
Authors: Beyerman H. C. , Bontekoe J. S.
Published: September 2010

A synthesis is described of the N‐terminal octapeptide sequence derived from the pancreatic hormone glucagon (glucagon 1–8).
Investigations on organotin compounds. XXI: The preparation of organotin‐substituted acetylenes by the decarboxylation of organotin acetylenecarboxylates
Authors: Luijten J. G. A. , van der Kerk G. J. M.
Published: September 2010

A number of triorganotin salts of acetylenemono‐ and di‐carboxylic acids upon being heated lose carbon dioxide to give organotin‐substituted acetylenes.

Some others decompose in an irregular way and in one case simultaneous decarboxylation and disproportionation occurs.

Tributyltin azide adds to diethyl acetylenedicarboxylate with the formation of 1‐tributylstannyl‐4,5‐di‐ethoxycarbonyl‐1,2,3‐triazole.
Saturated five‐membered heterocyclics, I. Preparation of 1,2,4‐triazolidines
Authors: Strating J. , Weening W. E. , Zwanenburg B.
Published: September 2010

A simple synthesis of 1,2,3,4,5‐substituted 1,2,4‐triazolidines is given.
Addition of organotin hydrides across the nitrogen‐nitrogen double bond; Hydrogenolysis of the tin‐nitrogen bond by organotin hydrides
Authors: Noltes J. G.
Published: September 2010

Triorganotin hydrides readily add across the nitrogen‐nitrogen double bond of azobenzene and diethyl azodicarboxylate to produce organotin‐substituted hydrazine derivatives.

The reduction of these azo compounds and of aryl isocyanates by triorganotin hydrides proceeds by formation of a 1: 1 adduct and subsequent hydrogenolysis of the tin‐nitrogen bond of the adduct.
Spectropolarimetry II. The optical rotatory dispersion of α‐amino‐acids and α‐hydroxy‐acids
Authors: Dirkx I. P. , Sixma F. L. J.
Published: September 2010

The rotatory dispersion of 26 amino‐acids and 5 hydroxy‐acids was studied. It was found that the carboxyl absorption‐band at about 205 nm to 210 nm is optically active. L‐Amino‐acids as well as L‐hydroxy‐acids show a positive Cotton effect. For a number of amino‐acids a correlation exists between peak‐height and molecular structure. Except for proline, hydroxy‐proline and cystine, all acids studied show very similar rotatory dispersion curves.
The phase angle in second harmonic alternating current polarography
Authors: Kooijman D. J. , Sluyters J. H.
Published: September 2010

Second harmonic polarograms in which, as predicted by theory, every reversible redox system gives rise to two peaks have been described in the literature1, 2, 3. In this paper the π radians phase difference between these two peaks is demonstrated, making use of the second harmonic content of the output of the oscillator driving the polarographic circuit. Anomalies in the case of the Tl(Hg)/Tl⊕‐ and the In(Hg)/In⊕⊕⊕‐electrode are discussed.
The condensation of 2,6‐dimethylphenol with glyoxal and with benzil
Authors: Mcgowan J. C. , Anderson Janet M. , Walker Nancy C.
Published: September 2010

1,1,2,2‐Tetrakis(4‐hydroxy‐3,5‐dimethylphenyl)ethane has been prepared by the condensation of 2,6‐dimethylphenol with glyoxal. The tetraacetate has been isolated, after acetylation, from the product of the reaction between 2,6‐dimethylphenol and α,β‐dichlorovinyl phenyl ether and the tetramethyl ether has been obtained directly from 2,6‐dimethylanisole and glyoxal sulfate.

Benzil and 2,6‐dimethylphenol can be condensed to give benzoyl‐4,4′‐dihydroxy‐3,3′,5,5′‐tetramethyltritane and there is evidence that the dimethyl ether of this compound is formed when 4‐methoxy‐3,5‐dimethylbenzophenone is reduced with zinc dust in acetic acid.
A thioaldehyde S‐oxide
Authors: Strating J. , Thijs L. , Zwanenburg B.
Published: September 2010

The preparation of the first representative of the thioaldehyde S‐oxides is described.
Studies on polypeptides II: Synthesis of the heptapeptides (des‐Asp1) ‐Lys2‐Ile5‐angiotensin II, (des‐Asp1) ‐D‐Lys2‐Ile5‐angiotensin II, (des‐Asp1) ‐Orn2‐Ile5‐angiotensin II, (des‐Asp1)‐Cit2‐Ile5‐angiotensin II and the hexapeptide Val‐Tyr‐Ile‐His‐Pro‐Phe
Authors: Schattenkerk Cecile , Visser G. Heymens , Kerling K. E. T. , Havinga E.
Published: September 2010

Experimental data are reported on the syntheses of the angiotensin II hexapeptide Val‐Tyr‐Ile‐His‐Pro‐Phe and of the heptapeptides obtained by coupling the hexapeptide benzyl ester with the p‐nitrophenyl esters of benzyloxycarbonyl L‐lysine, D‐lysine, L‐ornithine and L‐citrulline and subsequent hydrogenolysis of the protecting groups.
Niobium and tantalum diselenides
Authors: Kadijk F. , Huisman R. , Jellinek F.
Published: September 2010

Niobium and tantalum diselenides have been found to exist in the following polymorphous forms: 2s‐NbSe2, 3s‐NbSe2, 4s‐NbSe2, 2s‐TaSe2, 3s‐TaSe2, 4s‐TaSe2, and 6s‐TaSe2. Unit‐cell dimensions are collected in Table I and the crystal structures of the various forms are schematically shown in Fig. 1. All the polymorphs have hexagonal or rhombohedral layer structures. In the 2s‐, 3s‐ and 4s‐ phases the metal atoms have a trigonal‐prismatic environment, but in 6s‐TaSe2 half of the metal atoms have octahedral and half have trigonal‐prismatic coordination. The conditions of preparation of the various forms are discussed. Excess of selenium over the composition MSe2 leads to mixtures of the MSe3 and MSe2 phases. Excess of metal results in the formation of phases of the type M1+xSe2, where the additional metal atoms are accommodated in the octahedral interstices between the MSe2 slabs.
The enthalpy of solution of caesium fluoride in water at 25.00°C
Authors: Somsen G. , Weeda L.
Published: September 2010

The enthalpy of solution of CsF in water at 25.00°C has been carefully measured with an adiabatic calorimeter. The value at infinite dilution is: ΔH°sol = −36.08 ± 0.17 kj/mole.
The influence of steric and electronic factors on acidity. III. Cinnamic Acids, substituted in α‐, β‐ or Ortho‐Positions
Authors: Hogeveen H.
Published: September 2010

The apparent acidity constants of a series of ortho‐, α‐ and/or β‐substituted cinnamic acids (cis‐ and trans‐), with substituents CH3, Br and Cl, have been measured in 50% (by vol.) aqueous ethanol at 25°.

The data on α‐ and/or β‐substitution by Br and Cl are discussed on the basis of electronic substituent effects. Similar substitution by CH3 invokes the enhanced secondary steric effect of this group and a large departure from additivity of substituent effects is observed in α,β‐dimethyl‐trans‐cinnamic acid.

The acidity constants of β‐substituted cis‐cinnamic acids follow the Hammett equation with satisfactory fit.

Ortho‐substitution by Cl in cis‐cinnamic acid probably implies a direct field effect between substituent and carboxylic anion.
Studies in IVth group organometallic chemistry. XVI: Synthesis of organogermanium compounds containing the p‐phenylene group. Some infrared characteristics of p‐phenylene derivatives of silicon, germanium, tin and lead
Authors: Leusink A. J. , Noltes J. G. , Budding H. A. , van der Kerk G. J. M.
Published: September 2010

A few oligomeric and polymeric p‐phenylenegermanes have been prepared by Wurtz‐type condensation reactions from p‐chlorophenyl‐ and chlorogermanes. The oligomeric and polymeric products obtained have been characterized by infrared spectroscopy, elementary analysis and molecular weight determinations.

Infrared spectra in the rocksalt region of phenyl and p‐phenylene derivatives of silicon, germanium, tin and lead are discussed. The spectra of the p‐phenylene compounds show some characteristic absorption bands shifting to lower frequencies as the weight of the metal atoms in the molecule increases.
Studies in the zinc reduction series: Relationship of zinc and acid to zinc and alkali reductions of aldehydes and ketones
Authors: Risinger G. E. , Garrett J. M. , Winkler J. A.
Published: September 2010

The zinc and alkali reductions of benzaldehyde, acetophenone, and derivatives of these compounds are discussed. Further evidence is presented to support the bimolecular nature of the reductions. It is also concluded that the major differences between acid and alkali reductions reside in secondary effects of the reaction conditions rather than in the reductive portion of the reaction.
Acetate pyrolysis in the gas phase; a proposed reaction mechanism
Authors: Rummens F. H. A.
Published: September 2010

The pyrolysis of some acetates has been studied in the gas phase, at low concentrations, normal total pressure and in the temperature range 450‐650°K. Reaction rates, activation data and reaction products indicate that, for allyl‐acetate derivatives, the activated complex consists of an anti‐bonding electronical state involving a homolytic cleavage of the R‐OCOCH3 bond. Linalyl acetate, neryl acetate and geranyl acetate particularly, are shown to have a common activated complex. As a consequence, the tertiary linalyl acetate will, upon heating, isomerise partly to the primary neryl and geranyl acetates in a 1,3 rearrangement reaction.
The synthesis of certain furyl‐substituted polyheterocyclic six‐membered rings
Authors: Holland Dewey G. , Amstutz E. D.
Published: September 2010

Interest in the antibacterial drug, 5‐nitrofurfural semicarbazone has led to the synthesis of a number of heterocyclic systems in which ring‐closure has been carried out on the semicarbazone (or similar) structure.
Aromatic sulfonation XI: Sulfonation of benzene and toluene with sulfur trioxide; sulfone formation and sulfonic acid isomer distribution.
Authors: Cerfontain H. , Telder A. , Vollbracht L.
Published: September 2010

The sulfonation of benzene and toluene with sulfur trioxide without solvent has been studied extensively.

With benzene at low conversion benzenesulfonic acid and diphenylsulfone are the only products. At 25° the sulfone: sulfonic acid ratio changes from 0.2 to 0.6 on varying the SO3 : C6H6 ratio from 0.13 to 1.3. At a SO3 : C6H6 ratio > 1.3 benzene‐1,3‐disulfonic acid and diphenylsulfonesulfonic acid are found among the reaction products as well. With toluene the sulfone formation is less than with benzene.

The isomer distribution of the monosulfonic acids formed in the sulfonation of toluene has been determined at various temperatures between −44 and 65°. Under all conditions the degree of meta‐substitution is low (1‐5%) whereas that of para‐substitution is high (∼ 80%). The difference in activation enthalpy between para‐ and meta‐substitution is −2.7 ± 0.4 kcal · mole −1, that between para‐ and ortho‐substitution 1.3 kcal · mole −1. The latter enthalpy difference is explainable by an intramolecular hyperconjugative proximity effect in the transition state leading to ortho‐substitution. The entropy of activation is greater for para‐ than for ortho‐substitution, indicating steric hindrance for ortho‐substitution.

The formation of sulfonic acid and sulfone is discussed in terms of the mechanism:magnified image
Trityl derivatives of amines: IIIreplacement of an N‐alkyl group of aromatic secondary amines by the trityl group
Authors: Verkade P. E. , Tollenaar F. D. , van Rij J. H. , van der Goot H.
Published: September 2010

Tritylation of N‐methyl‐para‐toluidine, N‐ethyl‐para‐toluidine, and N‐methyl‐para‐chloroaniline resulted in the N‐trityl derivatives of the corresponding aromatic primary amines. The tritylation thus was accompanied by a dealkylation. N‐trityl‐N‐methyl‐para‐toluidine could be prepared.
Diuretics I: 8‐Sulfamoyltheophylline and 7‐substituted derivatives
Authors: Dolman H. , van der Goot J. , Mos G. H. , Moed H. D.
Published: September 2010

8‐Sulfamoyltheophylline (V) was prepared by oxidative chlorination of 7‐benzyl‐8‐mercaptotheophylline, followed by amidation and debenzylation.

This compound, built up from two diuretic principles, appeared to have no diuretic properties. On the other hand the intermediate 7‐benzyl‐8‐sulfamoyl‐theophylline exhibited an appreciable diuretic activity, while lacking the other pharmacological properties of theophylline. In addition this compound inhibited carbonic anhydrase. On the basis of these findings the synthesis was undertaken of a number of other 7‐substituted 8‐sulfamoyltheophyllines.

The present report deals with the preparation of these heterocyclic sulfonamides, derived from V by the introduction of alkyl, aralkyl and aryl groups at the 7‐position.
pH dependence of the synthesis of isopelletierine from Δ1‐piperideine
Authors: Wisse J. H. , de Klonia H. , Visser B. J.
Published: September 2010

The synthesis of isopelletierine from Δ1‐piperideine and acetoacetic acid was investigated in the pH region 1 to 12. Paper chromatography was used to analyze the reaction mixtures. Depending on reaction time fair to good yields were obtained over the pH range 2 to 12. The experimental data are discussed in the light of two mechanisms proposed by Schöpf et al.
Transport in charged membranes
Authors: Dorst W. , Staverman A. J. , Caramazza R.
Published: September 2010

Using the formalism of irreversible thermodynamics, general conditions are derived for osmotic salt and solvent permeation. It is found that in many types of low charged membranes abnormal osmosis may occur; for the more selective ion exchangers, however, solvent flow is usually directed towards the concentrated phase, whereas electrolyte flux may be parallel or opposed to the activity gradient, regardless of the nature of the membrane. Application of the theoretical results in a particular system requires membrane composition data and leads to a set of “friction coefficients” rik. Determination of all rik values even in a simple system like sodium chloride, water and membrane requires an extensive set of experimental data. Though the complete set has not yet been obtained, rik values could be estimated from data on osmosis, transference, conductivity and diffusion. The friction between co‐ion and membrane appears to have a predominant effect on dialysis efficiency.
Titration of molybdenum (V) with ceric sulfate, using methyl orange and methyl red as indicators
Authors: Rao K. Bhaskara
Published: September 2010

The suitability of Methyl Orange and Methyl Red as indicators in the titration of molybdenum (V) with ceric sulfate has been investigated. It has been found that molybdenum (V) can be titrated with ceric sulfate at room temperature (1) in hydrochloric acid medium with 2‐3 drops of 0.2% Methyl Orange as indicator; and (2) in sulfuric acid medium with 2‐3 drops of 0.2% Methyl Orange or Methyl Red as indicator.
Synthesis of DL‐β‐phellandrene
Authors: Deorha D. S. , Sareen Sneh Prabha
Published: September 2010

β‐Phellandrene (I) is synthesized from 4‐isopropylcyclohex‐2‐en‐1‐one (II) by the Wittig reaction.
Diuretics III: Derivatives of 7‐benzyl‐8‐sulfamoyltheophylline
Authors: Dolman H. , van Der Goot J. , Moed H. D.
Published: September 2010

The synthesis of a number of derivatives of the diuretic compound 7‐benzyl‐8‐sulfamoyltheophylline (1) is described. These new compounds were obtained by introducing substituents in the benzyl group and by altering the sulfamoyl function; they also include two isomers of I.
Reaction of steroidal alcohols with isobutene. Usefulness of t‐butyl as a hydroxyl‐protecting group in a synthesis of testosterone
Authors: Beyerman H. C. , Heiszwolf G. J.
Published: September 2010

Acid‐catalysed addition of isobutene to steroidal alcohols gives the t‐butyl ethers in high yields. These ethers are acid‐labile, but alkali‐resistant.

The t‐butyl group is readily split off with trifluoroacetic acid.

The usefulness of the method is demonstrated by a simple synthesis of testosterone benzoate from dehydroepiandrosterone.
The chemistry of cycloheptatriene: Part X: Photochemical shift of hydrogen in cycloheptatrienes
Authors: Ter Borg A. P. , Kloosterziel H.
Published: September 2010

The photo‐isomerization of 7‐deutero‐ and several phenyl‐substituted cycloheptatrienes has been investigated.
Resolution of isopelletierine: A second synthesis of pelletierine
Authors: Beyerman H. C. , Maat L.
Published: September 2010

The resolution of 1‐(2‐piperidyl)propan‐2‐one (isopelletierine) with the enantiomeric 6,6′‐dinitrobiphenyl‐2,2′‐dicarboxylic acids, as described by Galinovsky, Bianchetti, and Vogl, was modified and extended. We thus obtained pelletierine picrate and pelletierine sulfate with melting points and optical rotations in agreement with the values recorded in the literature for these derivatives of the natural product.
The dehydrobromination of 1,2‐dibromo‐1,2,3,4‐tetrahydronaphthalene
Authors: Willems A. G. M. , Pandit U. K. , Huisman H. O.
Published: September 2010

Dehydrobromination of 1,2‐dibromo‐1,2,3,4‐tetrahydronaphthalene with piperidine has been shown to give 1‐bromo‐3,4‐dihydronaphthalene.
Some thermodynamic properties of phosphorus trifluoride
Authors: Finch Arthur
Published: September 2010

Thermodynamic functions for PF3 (g.) are calculated from 100° to 298‐15°K. New values for ΔGf0 (PF3)g. and the P‐F bond energy are reported.
On the titanium‐carbon bond in CH3TiCl3
Authors: la Lau C.
Published: September 2010

Available spectral data on CH3TiCl3 — although far from complete ‐ suffice to estimate the Ti‐C and Ti‐Cl stretching force constants. The former is of particular interest.

The assignment of the skeletal vibrations is briefly discussed in view of conflicting conclusions in literature.

Although a refined force field (Urey‐Bradley Field) might be preferred in principle, arguments are given for the use of the valence‐force‐field approximation in the present case. The calculations are based on the pseudo five‐mass system XTiCl3, of point group C3v.

Assuming valence forces, the most appropriate two of the three frequency equations for the totally symmetric (a1) vibrations of this system have been used.

The same procedure was applied to the related molecules CH3SiCl3 and CH3SnCl3; the combined results indicate the soundness of this approach.

The force constant thus found for this Ti‐C bond has the rather low value 1.85 ± 0.2 × 104 dyn/cm.
The reaction of 2‐picolyllithium with schiff bases
Authors: Shuman Richard F. , Amstutz E. D.
Published: September 2010

The reaction of 2‐picolyllithium with Schiff bases produced N,1‐disubstituted 2‐(2′‐pyridyl)ethylamines in fair to good yields with a few exceptions. Schiff bases derived from N‐methylpyrrole‐2‐carbaldehyde and aniline or 4‐chloroaniline undergo addition with 2‐picolyllithium followed by spontaneous deamination producing 2‐{2′‐[2″‐(N″‐methylpyrryl)]vinyl}pyridine. A similar addition‐deamination sequence occurred using 2‐quinaldyllithium and N‐[4′‐(2″‐diethylaminoethoxy)benzylidene]‐4‐chloroaniline. Benzylmagnesium chloride was also reacted with Schiff bases to produce N,1‐disubstituted phenethylamines.
The polarographic reduction of some phenanthridine derivatives
Authors: Keene B. R. T. , Tissington P.
Published: September 2010

Molecular overcrowding is shown to have a marked effect on the polarographic behaviour of suitably substituted phenanthridine derivatives in both aqueous and non‐aqueous solvent systems.
Studies in group IV organometallic chemistry. XVIII: The reaction of trialkyltin hydrides with alkyl propiolates
Authors: Leusink A. J. , Marsman J. W. , Budding H. A. , Noltes J. G. , van der Kerk G. J. M.
Published: September 2010

The reaction of trialkyltin hydrides with alkyl propiolates results in the formation of at least six products. The structure of five compounds has been established by gas chromatography, infrared and nuclear magnetic resonance spectroscopy, and elementary analysis.

The main products are shown to be α‐trialkylstannyl‐ and cis‐ and trans‐β‐trialkylstannyl‐acrylates. With decreasing size of the substituents on tin nonterminal addition of the trialkylstannyl group, resulting in the formation of α‐trialkylstannylacrylate, becomes the predominant reaction.
The molecular structure of two isomers of S6(NH)2
Authors: van de Grampel J. C. , Vos Aafje
Published: September 2010

Preliminary results of the X‐ray investigation of the crystal structure of the S6(NH)2 isomer with m.p. 130°C are reported. The NH‐groups in the eight‐membered ring of the S6(NH)2 molecules are in 1‐4 position.
Structure of a cyclic hexameric phosphonitrilic molecule
Authors: Wagner A. J. , Vos Aafje
Published: September 2010

Preliminary results of the X‐ray analysis of hexameric phosphonitrilic dimethylamide, N6P6(NMe2)12, are given. The molecular structure is compared with that of tetrameric phosphonitrilic derivatives.
Alkali metal hyperfine splitting and oscillation of the alkali ion in the alkali‐radical ion complex of pyracene
Authors: de Boer E.
Published: September 2010

The ESR spectra of the ion pairs consisting of the anion of pyracene and the potassium or sodium cation, in 2‐methyltetrahydrofuran, at low temperatures exhibit a line width alternation which is caused by the oscillation of the cation in the potential well. The behaviour of the metal hyperfine interaction in rubidium‐and cesium‐pyracene complexes in relation to temperature has led us to the conclusion that the spin density at the alkali nucleus is composed of negative and positive contributions. The difference in temperature dependence between the two results in a reversal of the sign of the spin density at the alkali nucleus at a very specific temperature, depending on the solvent used.
Ring closure with incorporation of hydrazine during Wolff‐Kishner reduction
Authors: Egmond G. J. N. , van Gorkom M. , van Dorp D. A.
Published: September 2010

Two cyclopentapyridazinones, 6,7‐dihydro‐5H‐4‐hydroxy‐7‐pentylcyclopenta‐[c]3(2H)‐pyridazinone and 4a,5,6,7‐tetrahydro‐4H‐7‐pentylcyclopenta[c]3(2H)‐pyridazinone, have been obtained as reaction products of the attempted Wolff‐Kishner reduction of ethyl (2‐oxo‐3‐pentylcyclopentyl)glyoxylate.
On the impedance of galvanic cells: XIII. Characteristics of streaming mercury electrodes
Authors: Ijzermans A. B. , Sluyters J. H.
Published: September 2010

Methods for evaluating the effective length of the streaming mercury electrodes according to Heyrovsky1 and Schwabe2 have been indicated. At open circuit the charging of the double layer causes changes of concentration at the electrode surface. Only at the former type of electrode do these give rise to a shift of the electrode potential.
On the impedance of galvanic cells: XIV. The impedance and admittance of streaming mercury electrodes; experimental verification
Authors: Ijzermans A. B. , Sluyters J. H.
Published: September 2010

The views developed in part XII1 and part XIII2 of this series are verified by experiment. Measurements at the streaming mercury electrodes according to Heyrovsky3 and Schwabe4 are found to agree perfectly. From the results the reaction rate constants of the system Zn++/Zn(Hg) both in 1 M KCl and in 0.88 M NaClO4 + 10−3 N HClO4 are calculated. The diffusion constant of the Hg2++ ion in 1 N HClO4 and the thickness δ of the diffusion layer are reported.