bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction between dimethylpyruvic acid and biotin with a mould
Authors: Brouwer J. N. , Ylstra J. , Berends W. 
Published: September 2010

AbstractThe separation of dimethylpyruvic acid observed by Katsuki from the mould, Piricularia oryzae, with a deficiency of biotin, has been investigated. The formation of dimethylpyruvic acid does not depend on aeration. Addition of biotin leads to the absorption of dimethylpyruvic acid so that there is possibly a connection between the separation of this acid and the function of biotin.A method for the determination of dimethylpyruvic acid in the presence of pyruvic acid and α‐ketoglutaric acid has been worked out.
The stepwise degradation of “trismethylene‐trinitrobenzene”: Nucleophilic aromatic addition II
Authors: de Boer Th. J. , van Velzen J. C. 
Published: September 2010

Abstract“Trismethylenetrinitrobenzene” (I) has been degraded in five steps to cis‐ and trans‐nitrocyclopropanecarboxylic acid (IX and X), via the sequence, depicted in chart 1: I (C9H9N3O6 → II (C8H8N2O8) → V (C7H8N2O6) → VI (C7H8N2O7) → VII (C5H5NO6) → IX and X (C4H6NO4).II is a dicyclopropanedicarboxylic acid which very easily loses one molecule of CO2, to give no longer a carboxylic acid, but a lactone V.The unusual “decarboxylation‐lactonisation” process involves rupture of a CC bond in one three‐membered ring, and lactonisation with the carboxyl group attached to the unbroken three‐membered ring.The lactone V can be oxidised further to the keto acid VI and the nitro‐cyclopropanedicarboxylic acid VII. The latter upon decarboxylation affords IX and X. The structures of these hitherto all unknown degradation products are established by chemical, physical and spectroscopical (including NMR) evidence, thus lending support to the presence of two cyclopropane rings in “trismethylenetrinitrobenzene”.
Über Muscaridin
Authors: Kögl F. , Salemink C. A. , Schuller P. L. 
Published: September 2010

AbstractThe present communication gives a preliminary description of the isolation of a new alkaloid from Amanita muscaria L. besides muscarin and acetylcholin. The constitution of this base, called muscaridin, is established as the quaternary trimethylammonium salt of 6 amino‐2,3‐dihydroxy‐hexan.
Physical properties of organic thiones. Part II. Electronic absorption spectra of compounds containing the thiocarbonyl group
Authors: Janssen M. J. 
Published: September 2010

AbstractElectronic absorption spectra of compounds containing a thiocarbonyl group bound to carbon, sulphur or oxygen are reported. The spectra were taken, whenever possible, in cyclohexane, ethanol and concentrated sulphuric acid.The bands are compared with those of nitrogen‐containing thiones and an empirical assignment of the different types of bands is given.
Note on the preparation of 3‐hydroxy‐5‐hydroxymethyl‐2,4‐dimethyl‐pyridine: (4‐Desoxyadermine)
Authors: Wibaut J. P. , Uhlenbroek J. H. , Kooyman E. C. , Kettenes D. K. 
Published: September 2010

AbstractThe intermediate steps in the synthesis of 4‐desoxy‐adermine described some time agoH. M. van Wagtendonk and J. P. Wibaut, Rec. trav. chim. 61, 728 (1942).
have been improved upon, particularly the conversion of the last intermediate 3‐amino‐2,4‐dimethyl‐5‐methyl‐amino‐pyridine (VII) to desoxyadermine. As a result of these improvements, desoxyadermine can now be synthesized in an overall yield of 15%, based on the starting materials acetyl acetone and cyanoacetamide.
Propriétés Chimiques dans L'Eutectique LiCl‐KCl Fondu
Authors: Delarue Guy 
Published: September 2010

AbstractNous avons étudié qualitativement la solubilité des oxydes et des sulfures métalliques dans l'eutectique LiCl‐KCl fondu. Les courbes intensité‐potentiel montrent que les solutions obtenues contiennent respectivement les particules O2− et S2− que l'on peut oxyder chimiquement ou électrochimiquement.
Solubility and mobility of aromatic hydrocarbons in pyridine
Authors: Fortuin J. M. H. , Dormans H. N. M. , van Krevelen D. W. 
Published: September 2010

AbstractThe solubilities of some aromatic hydrocarbons in pyridine have been measured. The entropies of fusion derived from these measurements agree qualitatively with the values which can be calculated, if it is assumed that their molecules obtain one rotational and three translational degrees of freedom when melting occurs.
Phosphatidic acids and derivatives: X. Diastereoisomerism with O,N,N‐tribenzyl‐glycerol‐α‐kephalins
Authors: Hoefnagel M. A. , Stegerhoek L. J. , Verkade P. E. 
Published: September 2010

AbstractO,N,N‐tribenzyl‐glycerol‐α‐kephalins have been obtained in two diastereoisomeric forms. Upon hydrogenolysis the two isomers give the same kephalin.This diastereoisomerism, due to the presence of an asymmetric carbon atom and an asymmetric phosphorus atom, is discussed in some detail.
The calibration of millivoltmeters and thermoelements and the combination of the two
Authors: Meyer G. , Oosterom J. F. 
Published: September 2010

AbstractA calibration method for thermoelements combined with millivolt‐meters is described, which yields an accurate result in a comparatively short time. The method has been described for the use of Pt‐Pt Rh. thermoelements; it can naturally be employed for other thermoelements as well.
The alkaline hydrolysis of oxazolidinediones‐2,4
Authors: Rekker R. F. , Nauta W. Th. 
Published: September 2010

AbstractControversial structures have been assigned 1,2 to the nitrogen‐containing carboxylic acid which is one of the products formed on hydrolysis of N‐substituted oxazolidinediones‐2,4. The present publication solves the problem in favour of our previous suggestions.
Study of the reactions between titanium tetrachloride and ethylaluminium compounds in hydrocarbon solution: I. Formation and properties of brown precipitates
Authors: Arlman E. J. , de Jong J. R. 
Published: September 2010

AbstractThe reaction between TiCl4 and AlEt3, AlEt2Cl and AlEtCl2 at 80°C in isooctane was investigated for those Al/Ti ratios at which brown precipitates are formed. In these reactions Ti(IV) is not reduced beyond Ti(III). The extent of reduction was determined by oxidimetry and colorimetry; the two methods gave concordant results.Among the gaseous reaction products ethyl chloride was determined quantitatively by gas chromatography. Its formation is ascribed to a secondary reaction:

The C2H5 radicals are formed in the main reaction in which the ethyl‐aluminium chlorides are converted into AlCl3 and the triethylaluminium into Al2EtCl5.By means of the conversions indicated above the relation between the percentage of reduction of Ti(IV) to Ti(III) and the Al/Ti ratio is accounted for quantitatively. The precipitates formed in the system AlEt3/TiCl4 were found to consist mainly of the brown modification of TiCl3 in which about one sixth of the titanium is replaced by aluminium.
Mechanism of reactions of unsaturated ethers and thioethers. I: Add catalyzed addition of water to acetylenic thioethers
Authors: Drenth W. , Hogeveen H. 
Published: September 2010

AbstractThe acid catalyzed addition of water to ethylthioethyne has been studied in aqueous solution. The reaction is general acid catalyzed and it is faster in H2O than in D2O. Substitution of a tertiary butyl group for the ethyl group results in a rate enhancement. The entropies of activation ΔS≠ for the hydration of ethylthioethyne and tertiary butylthioethyne are ‐ 6.1 and ‐ 0.6 cal. mole−1, deg.−1, respectively. These facts strongly suggest that protonation of the alkylthioethyne is the rate controlling step of the reaction.
Studies on vitamin D and related compounds XIV Investigations on sterols XVII: The photoisomerization of pre‐ergocalciferol and tachysterol2
Authors: Rappoldt M. P. 
Published: September 2010

AbstractThe quantum yields of the isomerizations of pre‐ergocalciferol and tachysterol2 in ether at 20° under the influence of ultraviolet light of 2537 Å were found to be 0.49 and 0.11 respectively. Ergosterol is not formed from tachysterol2 during irradiation but originates exclusively from pre‐ergocalciferol. The origin of lumisterol2 is somewhat less certain; it seems to be formed from tachysterol2.
Synthesis of a tyrosine “homologue” of lysine‐vasotocin
Authors: Beyerman H. C. , Bontekoe J. S. 
Published: September 2010

AbstractThe synthesis is described of the protected linear decapeptide: N‐benzyloxycarbonyl‐S‐benzyl‐L‐cysteinyl‐L‐tyrosyl‐L‐tyrosyl‐L‐isoleucyl‐L‐glutaminyl‐L‐asparaginyl‐S‐benzyl‐L‐cysteinyl‐L‐prolyl‐Ne‐tosyl‐L‐lysylglycineamide (II, Fig. 2).Removal of the blocking groups from II, followed by oxidation, yielded a preparation assumed to contain a “homologue” of lysine‐vasotocin with two consecutive molecules of tyrosine instead of one (Fig. 1, n = 2).
Mechanism of reactions of unsaturated ethers and thioethers II: Dipole moment and charge shift in acetylenic ethers
Authors: Drenth W. , Hekkert G. L. , Zwanenburg B. G. 
Published: September 2010

AbstractElectric dipole moments of the following compounds have been measured in benzene solution: C2H5OC2H5, H2CCHOC2H5, HC ≡ COC2H5, H3CC ≡ COC2H5, HC ≡ COCH3 and H3CC ≡ COCH3. The charge shift, caused by resonance, in HC ≡ COC2H5 and HC ≡ COCH3 amounts to approximately 0.11 e.
Synthesis of an analogue of lysine‐vasopressin, with phenylalanine “replaced” by two consecutive tyrosyl radicals
Authors: Beyerman H. C. , Bontekoe J. S. 
Published: September 2010

AbstractA synthesis is described of the protected linear decapeptide: N‐benzyloxycarbonyl‐S‐benzyl‐L‐cysteinyl‐L‐tyrosyl‐L‐tyrosyl‐L‐tyrosyl‐L‐glutaminyl‐L‐asparaginyl‐S‐benzyl‐L‐cysteinyl‐L‐prolyl‐Ne‐p‐toluene‐sulphonyl‐L‐lysylglycineamide (VI) in analytically pure form.Removal of the blocking groups from VI, followed by cyclization through oxidation, yielded a preparation which was assumed to contain an analogue of lysine‐vasopressin, with L‐phenylalanine “replaced” by two consecutive L‐tyrosyl radicals.This synthesis was performed in connection with our previous studies on the relation between chemical structure and biological activity in the oxytocin and vasopressin field.
The chemistry of the N‐alkylaldimines. II. The reaction of N‐propylpropanaldimine with acid chlorides
Authors: Breederveld H. 
Published: September 2010

AbstractN‐Propylpropanaldimine adds on acid chlorides with formation of the corresponding N(1‐chloropropyl)‐N‐propylamides, which on heating split off hydrochloric acid to yield the N(1‐propenyl)‐N‐propyl derivatives as the final products.N(1‐Propenyl)‐N‐propylacetamide, N(1‐propenyl)‐N‐propylbenzamide, diethylamino‐(1‐propenylpropylamino)‐dichlorosilane and dichlorophosphor‐N(1‐propenyl)‐N‐propylamidic acid have been prepared by this method.
Interpretation of cell responses in the laplace transformed state as an approach to the study on electrode kinetics
Authors: Wijnen M. D. 
Published: September 2010

AbstractIt is proposed to interpret cell responses in the Laplace transformed state. Information concerning the electrode reaction can then be obtained from the measured response on the basis of the derived response, both responses being in the transformed state.Advantages of the approach are: (a) interpretation of a measured response may be simpler and more exact in the transformed state than in the non‐transformed state; (b) the tedious inverse transformation of a derived relationship is omitted.The approach is illustrated on two cases of the so‐called potential‐step electrolysis.Methods for the experimental Laplace transformation of a measured response are outlined.
A new synthesis of 3‐aryl‐4‐hydroxycoumarins
Authors: van Zanten B. , Th. Brinkman U. A. , Th. Nauta W. 
Published: September 2010

AbstractIn the course of an investigation into the synthesis and properties of 3‐aryl‐4‐hydroxycoumarins a new direct synthesis of these compounds was found. In an acid medium 4‐hydroxycoumarin can be coupled directly to a diazotized aniline to form the desired 4‐hydroxycoumarin derivative.
Thermal quantities of cycloparaffins: Part IV. Heats of combustion of cycloparaffins with 10‐17 C atoms
Authors: Coops J. , van Kamp H. , Lambregts W. A. , Visser B. J. , Dekker H. 
Published: September 2010

AbstractThe heats of combustion at 25° of purified samples of the cycloparaffins having from 10 to 17 C atoms, have been measured. A brief description is given of the preparation and purification of the samples. The enthalpies ‐ ΔHR, given in the table below refer to the reactions:

at 25° and 1 atm.magnified imageA discussion will be given in a later paper.
A synthesis of 1‐hydroxy‐8‐methoxyanthraquinone‐3‐carboxylic acid
Authors: Bellaart A. C. , Koningsberger C. 
Published: September 2010

AbstractThe structure of 1‐hydroxy‐8‐methoxyanthraquinone‐3‐carboxylic acid, previously obtained by the action of dimethyl sulphate on the sodium salt of synthesized rhein monoglucoside, has now been confirmed by synthesis.
Chemistry of acetylenic ethers XLVII: Preparation of α‐ketols from ethoxyethynylcarbinols
Authors: Weiland J. H. Sperna , Arens J. F. 
Published: September 2010

AbstractA method is described for converting ethoxyethynylcarbinols I into α‐ketols V, via the intermediate products II to IV inclusive. The synthesis occurs stereospecifically and, starting from the ethoxy‐ethynylcarbinol VII, derived from 3β‐acetoxyandrost‐5‐en‐17‐one VI, affords almost exclusively 3β,21‐dihydroxypregn‐5‐en‐20‐one XI in about 50% yield.
Aromatic sulphonation II: Orientation in the sulphonation of toluene
Authors: Vollbracht L. , Cerfontain H. , Sixma F. L. J. 
Published: September 2010

AbstractThe isomer distribution for the homogeneous sulphonation of toluene at 25.0° in 82.3 ± 0.3 wt‐% aqueous sulphuric acid has been determined by the inverse isotope dilution method as 65.1% para. 2.9% meta and 32.0% ortho. Combining these data with the relative reactivity of toluene to benzene (kt/kb) = 66.1) 1 the partial rate factors were calculated as fpMe 258; fmMe 5.7 and foMe 63.4.
Direct substitution in pyridine ring systems by basic reagents
Authors: Vajda T. , Kovács K. 
Published: September 2010

AbstractPyridine reacts directly with an alkylamine in toluene in the presence of powdered sodium or potassium. The yield of the 2‐alkylamino‐pyridine increases proportionally with the amounts of pyridine and sodium used. α‐Picoline and quinoline react in the same manner. Some derivatives of these heterocyclic bases have been prepared by reaction with primary alkyl‐ or aralkyl‐amines. Experiments with aromatic or secondary amines were unsuccessful. A mechanism has been proposed for this direct substitution in view of the experimental facts.
Condensations of isatinic acid with ureas, ethyl carbamate and guanidine
Authors: Stefanović Gj. , Lorenc Lj. , Lj. Mihailović M. 
Published: September 2010

AbstractBy condensing the potassium salt of isatinic acid ‐ (o‐aminophenyl)‐glyoxylic acid ‐ with urea, N‐substituted ureas and ethyl carbamate, 2‐hydroxyquinazoline‐4‐carboxylic acid was obtained, in excellent yield. In a similar condensation with guanidine, potassium isatinate reacted quantitatively to give 2‐aminoquinazoline‐4‐carboxylic acid. Various derivatives were obtained from these new acids by methylation and decarboxylation reactions.
Investigations in the vitamin B6‐series: I. synthesis of nor‐vitamin B6
Authors: van der Wal B. , de Boer Th. J. , Huisman H. O. 
Published: September 2010

AbstractThe synthesis is described of nor‐vitamin B6(nor‐pyridoxol) by a selective demethylation of a suitable vitamin B6precursor. The demethylation is accomplished in a three step process following the sequence CH3→ CHO → COOH → H, in which SeO2appears to be a particularly selective oxidant for the first step. The nor‐vitamin B6proves to be biologically inactive on the growth ofSaccharomyces carlsbergensisas well as in growth‐tests on ratsG. PolandK. J. Klein Obbink,ibid.80, 217 (1961)..
Tests of the biological activity of nor‐vitamin B6
Authors: Pol G. , Obbink H. J. Klein 
Published: September 2010

AbstractNor‐vitamin B6 is inactive as a substitute for vitamin B6 in growth tests with Saccharomyces carlsbergensis and does not inhibit the effect of vitamin B6. It has little, if any, effect on the growth of vitamin B6‐deficient rats.
Fuming sulphuric acid: Dependence of the concentration of sulphur trioxide and its activity coefficient on the composition of oleum
Authors: Cerfontain H. 
Published: September 2010

AbstractUV absorption measurements of fuming sulphuric acid solutions of varying composition (3‐60% sulphur trioxide) were made at 25±2°. From these measurements the concentration dependence of sulphur trioxide on acid composition was estimated and compared with calculated sulphur trioxide concentrations assuming the simple equilibriumH2SO4 + SO3 ⇌ H2S2O7 [6].From this comparison it was deduced that K6 ≥ 5 mole−1 ·l. The sulphur trioxide concentration in 100% sulphuric acid at 25 ± 2° was calculated with this value for K6 to be 8 × 10−5 mole·l−1 at the most.Evidence is put forward that the activity coefficient of sulphur trioxide is almost independent of the composition of oleum over the acid range studied.
Liquid‐liquid extraction of metal salts from acidic solutions using amine salts: Derivation of a formula for D o/a
Authors: van Ipenburg K. 
Published: September 2010

AbstractIn this article on the SX of metal salts by amine salts some formulae have been derived for the distribution ratio D o/a for a metal salt, partitioning between an acidic aqueous layer and an organic phase, containing amine salts.The effects of association of the amine salt, or of the extracted complex or both, are taken into account, as is the effect of the simultaneous extraction of two or more metal salts, the formation of more than one complex per metal salt and the presence of different kinds of anions.The ways, in which formulae may be derived, if two or more active solvents are present in the organic phase at the same time, or when the diluent does not behave inertly, are outlined.
The condensation of rhodanine and derivatives with pyridine and quinoline aldehydes
Authors: Allan F. J. , Allan G. G. , Thomson J. B. 
Published: September 2010

AbstractThe condensation products of rhodanine, 3‐ethylrhodanine, 3‐phenylrhodanine, 3‐allylrhodanine and 3‐carboxymethylrhodanine with various substituted and unsubstituted pyridine and quinoline aldehydes have been prepared for bacterial and fungicidal evaluation. An earlier series of unsubstituted pyridylmethylene‐rhodanines has thus been extended to include products substituted in either or both of the heterocyclic rings. Such substitution may enhance the already known fungicidal character of such rhodanine‐aldehyde condensation products. The products obtained by the condensation of the quinoline aldehydes may be considered as substituted in a similar manner as the less accessible dialkylpyridine products and it is possible that these two types of compounds will show a similarity in biological activity. Condensations between the rhodanines and the aldehydes were carried out in acid medium and crystalline coloured condensation products were obtained in good yield.
Reserpine analogues: III. Alkoxy‐β‐phenylethylamine derivatives
Authors: Kralt T. , Asma W. J. , Moed H. D. 
Published: September 2010

AbstractThe synthesis of a series of compounds resembling in some respects the reserpine alkaloid and containing a β‐phenylethylamine configuration substituted at the phenyl group with alkoxyl groups is described.
The halogenation of aromatics: Part VI. Types of reactions occurring in the gas‐phase halogenation of benzene derivatives
Authors: Engelsma J. W. , Kooyman E. C. 
Published: September 2010

AbstractA series of chlorinations of benzene derivatives C6H5X showed that three main reaction types may be distinguished, viz. a) substitutions into the nucleus with retention of X (X = C6H5‐O, Cl, F, CN, CCl3, COCl, COOCH3), b) substitution within the group X (X = alkyl, CHO, probably OCH3) and c) exchange of X for Cl (X = NO2, CHO, Br, probably Cl).Bromination of chlorobenzene led to bromobenzene and bromochlorobenzenes as well as to dibromobenzenes and dichlorobenzenes. Isomer distributions in the latter two dihalides were slightly different from those found in the bromination of bromobenzene and chlorination of chlorobenzene, respectively.Some of the mechanisms involved are briefly discussed.
Stereoselective preparation of DL‐4‐allohydroxyproline
Authors: Beyerman H. C. 
Published: September 2010

AbstractA convenient preparation is described of DL‐4‐allohydroxyproline by reduction of DL‐4‐oxoproline with sodium borohydride in aqueous methanol. This reduction proceeds without appreciable formation of DL‐hydroxyproline, as shown by paper chromatography and by paper electrophoresis. The allo‐configuration of the reduction product (OH/COOH in cis‐position) was proved further by conversion of the latter into its lactone hydrobromide.
Studies on cyclohexane derivatives: I. A chemical proof of the configuration of the two 1,4‐dimethyl‐cyclohexanes
Authors: van Bekkum H. , Kleis A. A. B. , Massier A. A. , Verkade P. E. , Wepster B. M. 
Published: September 2010

AbstractStarting from cis‐ and trans‐cyclohexane‐1,4‐dicarboxylic acid, cis‐and trans‐1,4‐dimethylcyclohexane are prepared in a way that leaves no doubt as to the configuration of the latter compounds.
Studies on cyclohexane derivatives: II. Preparation and chemical proof of the configuration of the two 4‐methylcyclohexanecarboxylic acids
Authors: van Bekkum H. , Kleis A. A. B. , Massier A. A. , Medema D. , Verkade P. E. , Wepster B. M. 
Published: September 2010

AbstractThe preparation of pure low‐melting 4‐methylcyclohexanecarboxylic acid (m.p. 30.5‐31.5°) is described for the first time.By chemical means it is proved that low‐melting 4‐methylcyclohexanecarboxylic acid possesses the cis‐configuration and the high‐melting isomer the trans‐configuration. For this purpose these acids were converted into cis‐ and trans‐1,4‐dimethylcyclohexane respectively, using reactions which take place without any change of configuration at the cyclohexane nucleus. The configuration of these two hydrocarbons has been proved in the first paper of this series.
Migration of an acyl group in glycerol derivatives: II. Transformation of diacylglycerol‐β‐iodohydrins into diphenyl diacylglycerol‐α‐phosphates
Authors: Hoefnagel M. A. , Hartman‐Köhler A. H. , Verkade P. E. 
Published: September 2010

AbstractThe action of silver diphenyl phosphate on a diacylglycerol‐α‐iodohydrin or the isomeric diacylglycerol‐β‐iodohydrin in benzene as medium gives the diphenyl diacylglycerol‐α‐phosphate in practically equal and very satisfactory yields. In the latter case therefore a migration of an acyl group from an α‐ into the β‐position occurs.The reaction has been studied for the compounds with stearoyl, 4‐methoxybenzoyl, and 2,6‐dimethyl‐4‐nitrobenzoyl as the acyl group. It proceeds almost equally smoothly in all cases.On the basis of these facts the reaction mechanism is briefly discussed.
Contact angles; wetting and de‐wetting of mercury: Part II. Theory of wetting
Authors: Smolders C. A. 
Published: September 2010

AbstractA theory is given for the behaviour of contact angles, as a function of the concentration of surface active substances, observed in wetting and de‐wetting experiments of metal and mineral surfaces.It is shown, that the change of the contact angle with solute concentration can be related quantitatively to the adsorption densities at the three interfaces, which meet at the line of contact.Some published results are discussed in terms of the theory developed.
The V‐T‐x space model of the ethylene‐naphthalene system II
Authors: van Welie G. S. A. , Diepen G. A. M. 
Published: September 2010

AbstractProjections of the V‐T‐x space model of the ethylene‐naphthalene system are derived from the observations recorded in the preceding publication 1 together with some supplementary measurements. The value for the critical volume at the second critical endpoint is found to be 77.0 ml/mol.A number of T‐x and V‐x sections through the space model are derived from the same observations.