bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steric effects on mesomerism. XVI). Comparative investigations involving ultra‐violet absorption spectra, molecular refractions, rates of reaction, and basic strengths of aromatic amines
Authors: Wepster B. M. 
Published: September 2010

AbstractIn several series of compounds with a more or less strong inhibition of the mesomerism, the variation in ultra‐violet spectrum, molecular refraction, rate of reaction, and basic strength has been investigated. The members of the present series are mainly derivatives of aniline, dimethylaniline, and their para‐nitro and para‐ethoxycarbonyl derivatives. They have been so chosen that any steric inhibition that may occur, concerns exclusively the mesomeric interaction between the amino group and the rest of the system.Upon comparison of the data it is found that none of the aniline derivatives examined shows any appreciable steric inhibition of the mesomerism. It is also on this basis that the relatively low basic strengths of ortho‐alkylanilines have been interpreted as due to steric hindrance to solvation.In the case of the dimethylaniline derivatives, where inhibition of the mesomerism occurs, linear relations are found between the extinction coefficient ϵ and the exaltation of the molecular refraction. Further the reaction rate data are in agreement with the linear relation between ϵ and the mesomeric energy found earlier. It is also on this basis that an estimation has been made of the magnitude of the anomalies in the basic strengths of ortho‐alkyl dimethylanilines. These have been interpreted as being at least mainly due to steric hindrance to solvation.By extrapolations of the straight lines found, data have been obtained on the exaltations of the molecular refractions in dimethylaniline and ethyl para‐dimethylaminobenzoate, and also on the relative importance of inductive and mesomeric effects for the alkaline hydrolysis of the latter compound.
The interaction of sodium, potassium, calcium, and magnesium with human serum albumin, studied by means of conductivity measurements
Authors: van Os G. A. J. , Koopman‐van Eupen J. H. M. 
Published: September 2010

AbstractTo test the usefulness of conductivity measurements in the study of ion interaction with proteins, the binding of Na, K, Ca, and Mg by human serum albumin was investigated.The measurements were carried out with albumin solutions which were defined by a constant negative net charge of 36 units per albumin molecule, corresponding to a mean pH value of 7.5.No or little binding of Na and K by this protein was found. Ca and Mg were bound to a maximum of about 8 ions per albumin molecule. This maximum corresponds to only a fraction of the net initial charge. The results are in agreement with those of other workers.The method proved to be of value for simple, well‐defined systems and has the advantage that all the difficulties encountered in the use of membranes and potential measurements are avoided.Moreover, it may be used when only small amounts of protein are available.
Preparation of quinazoline derivatives through ring‐closure of aromatic ortho‐cyano‐acylamino compounds in alkaline alcoholic or phenolic medium. I. 4‐RO‐substituted quinazolines
Authors: Breukink K. W. , Krol L. H. , Verkade P. E. , Wepster B. M. 
Published: September 2010

AbstractOn boiling aromatic ortho‐cyano‐acylamino compounds in alkaline alcoholic or phenolic solution ‐ medium ROH ‐ 4‐RO‐substituted quinazolines are formed. Some examples of this reaction are described.
Chemistry of acetylenic ethers XXV: Reactions of ethoxyacetylene with aqueous solutions of aliphatic aldehydes
Authors: Vieregge H. , Arens J. F. 
Published: September 2010

AbstractOn shaking ethoxyacetylene (IV) with aqueous solutions of aliphatic aldehydes at room temperature, β‐hydroxy‐esters (V) are obtained, in some cases together with small amounts of the corresponding α,β‐unsaturated esters (VI).
The infra‐red absorption spectra of some salts of dimethyl, diethyl, and diisopropyl phosphate
Authors: Maarsen J. W. , Smit M. C. 
Published: September 2010

AbstractThe infra‐red absorption spectra of some salts of (H3CO)2PO2−, (H5C2O)2PO2−, and (i H7C3O)2PO2−have been investigated.From the spectra of the cyclohexylammonium salts, which give relatively simple spectra in CCl4and CS2solutions, an unambiguous interpretation of the PO2(ionic) stretching frequencies could be given.
Vapour‐liquid equilibria: System Acetone(1)‐benzene(2)‐cyclohexane(3)
Authors: Kurmanadharao K. V. , Krishnamurty V. V. G. , Venkatarao C. 
Published: September 2010

AbstractVapour‐liquid equilibrium data of the ternary system acetone‐benzene‐cyclohexane have been determined at 760 mm Hg pressure, using a modified Colburn still. No ternary azeotrope has been observed in this system.The experimental data are found to be thermodynamically consistent according to the method proposed by Krishnamurty and Venkatarao for testing data on ternary and multi‐component systems.The activity coefficient data of the present system have been satisfactorily correlated by the ternary modified Margules expressions with Ct = 0.7. The smoothed experimental data are in close agreement with the T‐x‐y data calculated by using the 3‐suffix modified Margules equations with the above ternary constant.The present system is of considerable interest, since all the binary systems show positive deviations and such systems are more generally met with industrially in connection with extractive distillation processes. Further, in the present ternary system, two of the binary sub‐systems form minimum boiling azeotropes.
Reaction of pyridine carboxylic esters with sodium borohydride
Authors: Bigot J. A. , de Boer Th. J. , Sixma F. L. J. 
Published: September 2010

AbstractEsters of nicotinic and isonicotinic acids are reduced to the alcohols by sodium borohydride in the presence of aluminium chloride, with difficulty. Ethyl isonicotinate easily forms a stable borine (BH3) complex, obtainable in 80% yield.
The reaction of α‐methylstyrene with formaldehyde
Authors: Beets M. G. J. , van Essen H. 
Published: September 2010

AbstractBy reacting α‐methylstyrene with formaldehyde in the presence of catalytic amounts of mineral acid, 4‐methyl‐4‐phenyl‐m‐dioxan is obtained in high yield. At higher acid concentrations and in the presence of a large excess of formaldehyde, however, a series of secondary reactions occur, all characterized by the formation of a double bond followed by further condensation with formaldehyde and, where possible, cyclization by formation of m‐dioxan or tetrahydropyran rings. These reactions have been studied, a number of reaction products have been isolated and their structures have been established.Also in the case of styrene an extremely slow secondary reaction of the same type could be realized and its products have been studied. The mechanism of these reactions is discussed.
Substitution reactions in the pyridine nucleus at elevated temperatures (I). The bromination of 2,6‐dibromopyridine
Authors: Den Hertog H. J. , Combé W. P. , Kolder C. R. 
Published: September 2010

AbstractThe bromination of 2.6‐dibromopyridine between 450° and 550° has been investigated.Two types of substitution reactions have been observed. When a mixture of 2,6‐dibromopyridine and bromine is passed over an iron bromide‐ or copper bromide‐pumice contact the 3‐ and 5‐hydrogen atoms are replaced by bromine. In an empty tube or a tube packed with pumice firstly the 4‐hydrogen atom is substituted by bromine, 2,4,6‐tribromopyridine being formed. The last mentioned reaction is slow. At 450°, with a contact time of about 3 minutes and a ratio dibromopyridine: bromine = 1:1.3, only 3% of 2,6‐dibromopyridine is converted. The reaction rate rises quickly when the temperature is increased; at 530° under corresponding conditions 35‐40% of the starting substance reacts.
Photochlorination of butyryl, valeryl and caproyl chloride
Authors: Smit P. , Den Hertog H. J. 
Published: September 2010

AbstractThe photochlorination at room temperature of butyryl, valeryl and caproyl chloride in the liquid phase has been investigated.The acid chlorides were allowed to interact with a third of the equimolecular amount of chlorine under irradiation with a mercury lamp. The reaction mixtures obtained were separated by fractional distillation and counter current distribution according to Craig.The monochloro‐derivatives of the acid chlorides were characterized by preparing the ρ‐toluidides. The identity of α‐, β‐, δ‐ and ϵ‐chlorocaproic acids was established by synthesis.It is found that butyryl chloride yields <2% α‐, 50‐55% β‐ and 45‐50% γ‐chlorobutyryl chloride; valeryl chloride yields <1.5% α‐, 15‐20% β‐, 50‐55% γ‐ and 30‐35% δ‐chlorovaleryl chloride, while caproyl chloride produces < 1 % α‐, 5‐10% β‐, 25‐30% γ‐, 40‐45% δ‐and 20‐25% ϵ‐chlorocaproyl chloride.These results can be explained by reckoning with the fact that secondary hydrogen atoms are replaced more rapidly than primary and taking into account the deactivating effect of the carbonyl chloride group along the chain.
The vibrational spectra of the methane‐phosphonate and the dimethylphosphinate ion
Authors: Gerding H. , Maarsen J. W. , Zijp D. H. 
Published: September 2010

AbstractFrom the Raman spectra of H3CPO32− and (H3C)2PO2− the PO force constants have been calculated for the simplified models CPO32− and C2PO2−, thus neglecting the hydrogen atoms. A steady increase in PO stretching force constant has been found in the sequence PO43− to X3PO.The spectra of the corresponding acids have been interpreted as far as possible.
The Raman and infra‐red spectra of methane‐sulphonic acid and the methanesulphonate ion
Authors: Gerding H. , Maarsen J. W. 
Published: September 2010

AbstractThe Raman and infra‐red spectra of H3CSO3H and some of its salts have been obtained, with Raman polarization data for the acid.An interpretation of the spectra is given and force constants have been calculated.
The kinetics of the oxidation of 2,4‐dimethylphloroglucinol
Authors: Stein H. N. , Tendeloo H. J. C. 
Published: September 2010

AbstractFollowing previous researches on the oxidation of phloroglucinol H. N. Stein and H. J. C. Tendeloo, Rec. trav. chim. 74, 905 (1955).
)Idem, ibid. 75, 1233 (1956).
)Idem, ibid. 75, 1240 (1956).
), we investigated the kinetics of the oxidation of 2.4‐dimethylphloroglucinol by K3Fe(CN)6. Our aim was to examine whether this oxidation could be described by the same mechanism as was found with phloroglucinol itselfH. N. Stein and H. J. C. Tendeloo, Rec. trav. chim. 74, 905 (1955).
). magnified imageIn addition, we wanted to obtain some data for a more detailed insight into this mechanism, as was done by Weissberger et al. J. E. Lu Valle and A. Weissberger, J. Am. Chem. Soc. 69, 1567 (1947)
) Idem, ibid. 69, 1576 (1947).
) Idem, ibid. 69, 1821 (1947).
) in the case of derivatives of hydroquinone.
Oxidation potentials of conjugated hydrocarbons
Authors: Hoijtink G. J. 
Published: September 2010

AbstractA linear relationship is found when the oxidation potentials of various aromatic hydrocarbons are plotted against the root of the Hückel secular equation corresponding to the highest occupied π‐orbital. In accordance with theory a straight line is also obtained by plotting the oxidation potentials of alternant hydrocarbons against the reduction potentials. The oxidation and reduction potentials of the non‐alternant hydrocarbon fluoranthene do not satisfy this condition.
Steric effects on mesomerism: XVIII). Steric inhibition of the mesomerism in aromatic amines with bulky N‐alkyl groups of compact structure: Nitrosation and coupling of the four N‐methyl‐N‐butylanilines
Authors: van Hoek T. C. , Verkade P. E. , Wepster B. M. 
Published: September 2010

AbstractNitrosation and coupling experiments with the four N‐methyl‐N‐butyl‐anilines are described. N‐methyl‐N‐tert.butylaniline cannot be nitrosated and reacts only very slowly with actively coupling diazonium salts.
Phosphatide acids and derivatives. VIII). Synthesis of monobenzyl esters of phosphatidic acids
Authors: Gielkens J. W. , Hoefnagel M. A. , Stegerhoek L. J. , Verkade P. E. 
Published: September 2010

AbstractThe preparation of dibenzyl esters of phosphatidic acids and their mono‐debenzylation by boiling with anhydrous sodium iodide in acetone solution is described.
Fries rearrangement of o‐chlorophenyl and o‐tolyl arene‐sulphonates
Authors: Baliah V. , Uma M. 
Published: September 2010

Abstracto‐Chlorophenyl benzenesulphonate, o‐chlorophenyl p‐toluenesulphonate, o‐tolyl benzenesulphonate and o‐tolyl p‐toluenesulphonate undergo the Fries rearrangement when heated with anhydrous aluminium chloride, to furnish, In each case, a mixture of o‐ and p‐hydroxy‐sulphones. The structures of all the sulphones, thus obtained, have been established by synthesizing them unequivocally.
Nitration with acids consisting of HNO3 and SO3
Authors: Heertjes P. M. 
Published: September 2010

AbstractThe nitrating potentialities of mixed acids consisting of HNO3 and SO3 as compared with mixed acids of HNO3 and H2SO4 have been investigated on three examples, viz the easy nitration of p‐chloronitrobenzene to chloro‐2:4‐dinitrobenzene, the difficult nitration of this compound to chloro‐2:4:6‐nitrobenzene and the relatively easy nitration of 2:4‐dinitrotoluene to 2:4:6‐trinitrotoluene in which oxidation can be rather marked. The experiments have been carried out batch‐wise and continuously.From the experiments it could be concluded that the HNO3‐SO3 acids with an SO3 content between 40 and 72% SO3 are good nitrating acids. For difficult nitration the use of acid with ∼70% SO3 shows a definite advantage over acids of HNO3 and H2SO4. For the acids containing ∼45% of SO3, which in view of their thermal stability can only be used for relatively easy nitrations, the difference between the two types of acids is not very large. However, the advantage of the better SO3‐economy with the HNO3‐SO3 acids is always present.
Investigations on pyrazine derivatives III: The preparation of 2,3‐dihydroxypyrazine 5,6‐dicarboxylic acid
Authors: Mager H. I. X. , Berends W. 
Published: September 2010

AbstractBy following the oxidation of a quinoxaline derivative spectrophotometrically, it has been possible for the first time to work out a simple preparative method for a hydroxylated pyrazine 2,3‐dicarboxylic acid.
The reactivity of pyridine towards sulphuric acid at elevated temperatures
Authors: Den Hertog H. J. , van der Plas H. C. , Buurman D. J. 
Published: September 2010

AbstractWhen pyridine is heated with 100% sulphuric acid in the presence of mercuric sulphate as a catalyst at about 275°, pyridine‐3‐sulphonic acid is formed as the chief product, together with very small amounts of byproducts.The course of the reaction is more complicated at somewhat higher reaction temperatures. At 330° a mixture is obtained which contains, together with pyridine‐3‐sulphonic acid and the 4‐isomer, 4‐hydroxypyridine in considerable amount.The sulphonation of pyridine is a reversible process. When pyridine‐3‐sulphonic acid is heated with 100% sulphuric acid and mercuric sulphate at ∼ 330°, a mixture is formed containing chiefly pyridine, together with pyridine‐4‐sulphonic acid, 4‐hydroxypyridine and the starting substance.
Chemical studies on insecticides VII : Dipole moments of some esters of phosphoric and phosphorothioic acid
Authors: Ketelaar J. A. A. , Gersmann H. R. , Hartog F. 
Published: September 2010

AbstractIn order to compare the partial bond moments of “energy rich” and other phosphorus acid esters dipole moments of a number of esters have been determined from dielectric constant measurements.Literature values of dipole moments of phosphorus acid derivatives are also presented.
Some remarks on the relative antifungal activities of N‐substituted dithiocarbamates: (Short communication)
Authors: Links J. 
Published: September 2010

AbstractA hypothesis, that explains the relative antifungal activities of the lower N‐substituted dithiocarbamates (and the relative plant growth regulating properties of some of them) by hyperconjugation, is critically discussed and an alternative, tentative explanation is given.
The Copper‐rich part of the copper‐barium system
Authors: Braun P. B. , Meijering J. L. 
Published: September 2010

AbstractThe system Cu‐Ba was examined up to 75% Ba by weight. At 675° C there is a peritectic three‐phase equilibrium Cu + liquid ⇋ Cu13Ba. The compound Cu13Ba has KZn13 structure. At 550° C there is a eutectic three‐phase equilibrium liquid ⇋ Cu13Ba + CuxBay. Composition and structure of the latter could not be determined owing to experimental difficulties.
The preparation of some alkyl p‐nitrophenyl methylphosphonates
Authors: de Roos A. M. 
Published: September 2010

AbstractThe lower homologues in the series of the alkyl p‐nitrophenyl methyl‐phosphonates have been prepared by reaction between p‐nitrophenyl methylphosphonochloridate and an alcohol. Some alkyl methylphosphonochloridates have also been synthesized, starting from methylphosphonic dichloride. Boiling points and refractive indices of the yellow p‐nitrophenyl compounds and of the colourless chloridates have been recorded, as well as the infrared spectrum of iso‐butyl p‐nitrophenyl methylphosphonate.
The ozonolysis of phenanthrene)
Authors: Wibaut J. P. , de Boer Th. J. 
Published: September 2010

AbstractPhenanthrene reacts quickly with one mole of ozone at the 9,10‐double bond. In chloroform a polymeric mono‐ozonide (II) is obtained, which can be converted into diphenic acid. In methanol the reaction takes a different course resulting in the formation of a cyclic methoxy‐hydroxy‐peroxide (V) and a cyclic dimethoxy‐peroxide (VI).
The vapour pressure of tungsten trioxide in gas mixtures containing water vapour
Authors: Meyer G. , Oosterom J. F. , van Oeveren W. J. 
Published: September 2010

AbstractThe increased volatility of tungsten trioxide in an inert atmosphere containing water vapour, must be ascribed to the formation of a volatile compound.The composition of this compound is probably WO31H2O. The equilibrium between solid WO3, water vapour and gaseous compound shifts as the temperature is increased towards the formation of the compound. Thus on lowering the temperature the compound will break down again into anhydrous oxide and water.Hence this compound has the same empirical composition as tungstic acid (H2WO4). Experiments in this laboratory have shown that solid tungstic acid passes over into the anhydrous oxide at ∼ 180° and a pressure of 10 atmospheres (quadruple point WO31H2O ‐ WO3‐L ‐G). At the temperatures at which our investigation has been carried out therefore, the assumption that the gaseous compound can exist also in the solid state, must be regarded as improbable.
The fries rearrangement of 1‐naphthyl acetate
Authors: Cullinane N. M. , Bailey‐Wood V. V. 
Published: September 2010

AbstractThe rearrangement of 1‐naphthyl acetate in nitrobenzene solution, catalysed by aluminium chloride, to give 2‐ and 4‐acetylnaphthol, appears to be intramolecular in nature. A mechanism to account for the experimental results is proposed. While the main product is the p‐hydroxy‐ketone, moderate yields of the ortho‐substituted product are also obtained.
The formation of diacetyl and acetoin from α‐acetolactic acid
Authors: de Man J. C. 
Published: September 2010

Abstract
Of several ions tested, only Fe+3, Cu+2 and Al+3 catalysed the decarboxylation of α‐acetolactic acid at pH 4.8.
At pH 2.2, only Fe+3 and Cu+2 were active.
Fe+3 and Cu+2 were shown to form complexes with α‐acetolactic acid.
Fe+3 and Cu+2 not only decarboxylated but also oxidized α‐acetolactic acid, with, as a result, formation of diacetyl.
Decarboxylation of α‐acetolactic acid by these ions is compatible with the mechanism suggested by Martell and Calvin.
α‐Acetolactic acid is subject to autoxidation. 2‐Butene‐2,3‐diol may be an intermediate product.
Studies on polarographic maxima. Part I. Concentration of the maximum suppressor in relation to its lowering of the interfacial tension
Authors: Khalafalla S. E. , el Din A. M. Shams , Marei S. A. 
Published: September 2010

AbstractPolarographic maxima have been studied in the light of the electrocapillary curves produced by the successive addition of the maximum suppressor. An interesting agreement has been noticed between the minimum concentration of the suppressor required to eliminate the polarographic maximum completely and the point of greatest negative slope in the interfacial‐tension concentration curve. The results show that polarographic maxima are eliminated when the adsorption of the maximum suppressor on the mercury‐solution interface reaches its maximum value.
Les Arènesulfonylsulfates Méthyliques, Intermediaires D'Une Synthese des Sulfones Aromatiques
Authors: Joly Robert , Bucourt Robert , Mathieu Jean 
Published: September 2010

AbstractLes arènesulfonylsulfates de méthyle sont obtenus soit par addition d'anhydride sulfurique sur la molécule d'un arènesulfonate de méthyle, soit par dismutation entre un acide arènesulfonique et le pyrosulfate de méthyle. Ces nouveaux dérivés réagissent aisément avec des composés aromatiques pour conduire aux sulfones, symétriques ou non, avec des rendements élevés.
The chlorination of 4‐aminobenzoic acid and its methyl ester
Authors: van der Stelt C. , Nauta W. Th. 
Published: September 2010

AbstractChlorination of 4‐acetylaminobenzoic acid (III) afforded 4‐acetylamino‐3,5‐dichlorobenzoic acid (IV, m.p. 237‐238°), which could be saponified easily to 4‐amino‐3,5‐dichlorobenzoic acid (II, m.p. 290°). Direct chlorination of 4‐aminobenzoic acid (I) in a mixture of glacial acetic acid and hydrochloric acid afforded 3,4,4,6,6‐pentachloro‐1‐cyclohexen‐5‐one‐2‐carboxylic acid (V, m.p. 178‐180°), a compound already obtained by Zincke by the chlorination of 4‐hydroxybenzoic acid (VI). Compounds with a higher content of chlorine could be prepared by the chlorination of the methyl ester of I (VIII). The reaction carried out in a neutral medium led to the nitrogen containing compound IX with m.p. 151‐153° and gross formula C8H5NO2Cl8 to which the structure of a methyl 1,2,3,3,5,5,6‐heptachloro‐4‐chloriminocyclohexane‐1‐carboxylate was attributed. Reduction with stannous chloride converted IX into methyl 4‐amino‐3,5‐dichlorobenzoate (X), which can be used as a starting product for IX. Chlorination of VIII in a mixture of glacial acetic acid and hydrochloric acid yielded a compound XI with m.p. 129‐131° and gross formula C8H5O3Cl7 as the main reaction product to which the structure of a methyl 1,2,3,3,5,5,6‐heptachlorocyclohexan‐4‐one‐1‐carboxylate has been attributed. Acid hydrolysis converted IX into XI. From the same reaction mixture two other stereo‐isomers of XI also were isolated, be it in minor quantities (XII m.p. 140–142°, XIII m.p. 213‐215°). The stereoisomerism of the three compounds is caused by the different spatial arrangement of the chlorine atoms attached to carbon atoms 1, 2 and 6. Reduction converted the three isomers into methyl 3,5‐dichloro‐4‐hydroxybenzoate (XIV). Chlorination of the methyl esters of VI and XIV also afforded amounts of XI. A fourth chlorination product could be isolated from the reaction mixture of VIII, viz. a compound with m.p. 199‐200° and gross formula C8H6O4Cl6 (XVI). Reduction with stannous chloride converted it into a compound XVII with m.p. 121‐122° and gross formula C8H8O4Cl2. Both compounds contain an extra hydroxyl group. Lack of material prevented further establishment of the structure. The infrared spectra of a number of polychloro‐compounds are given.
Chemistry of acetylenic ethers XXXVII. Synthesis of β‐lactams (2‐azetidinones) from imines and ethoxyalkynes
Authors: van Leusen A. M. , Arens J. F. 
Published: September 2010

Abstractβ‐Lactams VII are formed when ethoxyalkynes II are slowly added to boiling solutions of aromatic imines VI in xylene. In all probability aldoketenes III are intermediate products. The yields are moderate to good.