bluuebunny/crossref_metadata_2025 huggingface dataset:
Homogeneous hydrogenation using hydrogen peroxide‐activated iridium complexes
Authors: van Rantwijk F. , Spek Th. G. , van Bekkum H.
Published: September 2010

Chlorotris (triphenylphosphine) iridium (I) and trans‐carbonylchlorobis (triphenylphosphine) iridium (I) have been treated with hydrogen peroxide to yield catalysts for homogeneous hydrogenation. Evidence is presented that the activation involves selective oxidation of one triphenylphosphine ligand.

Hydrogenation of terminal or cis‐substituted olefinic double bonds, catalyzed by both complexes, is accompanied by extensive isomerization. The kinetics of the hydrogenations are rather complex and remained unexplained. Deuteration experiments revealed some details of the mechanism of hydrogen addition and exchange.
Chemistry of acetylenic ethers 98: Photochemical addition of benzophenone and 4, 4′‐dimethylbenzophenone to 1‐methoxy‐1‐propyne alkylidenecycloheptatrienes
Authors: Polman H. , Boleij J. S. M. , Bos H. J. T.
Published: September 2010

Benzophenone and 4, 4′‐dimethylbenzophenone are added photochemically to 1‐methoxy‐1‐propyne. Besides methyl 3, 3‐diarylacrylates I, the alkylidenecycloheptatrienes II E and II Z are isolated.
Model studies for enzyme inhibition. Part V: Reactions of organophosphorus compounds with α‐cyclodextrin. A quantitative approach of model activity and stereospecificity
Authors: van Hooidonk C.
Published: September 2010

The bimolecular rate constants for reaction of the enantiomers of isopropyl methylphosphonofluoridate, isopropyl p‐nitrophenyl methylphosphonate and isopropyl S‐2‐dimethylaminoethyl methylphosphonothioate with α‐cyclodextrin have been calculated from the dissociation constants (Kdiss) of the prereaction 1:1 inclusion complexes and the maximal rate constants (k2max) for the ensuing nucleophilic reactions. These data are compared with the corresponding rate constants for the inhibition of acetylcholinesterase.

It is concluded that the stereospecificity exhibited by α‐cyclodextrin in its reaction with enantiomeric organophosphorus compounds is reflected mainly in the nucleophilic reaction.
The interaction between polyethyleneimine and sodium dodecyl sulfate in water
Authors: van den Berg J. W. A. , Staverman A. J.
Published: September 2010

The amount of sodium dodecyl sulfate bound by polyethyleneimine is measured under varying concentrations of the reactants and additional ions, in particular H+ ions. The results can be interpreted consistently as the formation of uncharged complexes between the negatively charged dodecyl sulfate ions and the positively charged monomeric groups of the polyethyleneimine molecule.
A synthesis of the decapeptide sequence proposed for the LH‐ and FSH‐releasing hormone
Authors: Beyerman H. C. , Hindriks H. , Hirt J. , de Leer E. W. B. , van der Wiele A.
Published: September 2010

The solid‐phase synthesis is reported of the decapeptide sequence proposed for the hypothalamic hormone which releases the luteinizing hormone (LH) and the follicle‐stimulating hormone (FSH) from the pituitary, the LH‐FSH‐releasing hormone. The threshold dose of LH‐releasing activity was determined in rabbits and rats.
C‐nitroso compounds. Part XXV: Oxidation of alkenes with a photochemically generated adduct between oxygen and 2‐methyl‐2‐nitrosopropane
Authors: Maassen J. A. , de Boer Th. J.
Published: September 2010

Red light irradiation of 2‐methyl‐2‐nitrosopropane (t‐BuNO) in benzene in the presence of oxygen with a high O2/t‐BuNO ratio leads mainly to 2‐methyl‐2‐nitropropane. In styrene part of the solvent is also attacked to give benzal‐dehyde and formaldehyde. Similar photolysis in β‐pinene and cyclohexene gives oxidation on the allylic position, leading to mixtures of α‐β unsaturated alcohols and ketones. Because no double bond shift takes place when β‐pinene is oxidized, singlet oxygen is not involved.

In all cases, the reactive species seems to be an adduct of oxygen and t‐BuNO, which can add to double bonds (styrene) or abstract allylic hydrogens (β‐pinene, cyclohexene).
Synthesis, optical rotatory dispersion and absolute configuration of (+)‐N‐methylallosedridine [(+)‐(2R)‐2‐{(2S)‐2‐hydroxypropyl}‐1‐methylpiperidine] from sedum sarmentosum bunge and its isomers
Authors: Beyerman H. C. , Bordes B. S. L. , Maat L. , Warnaar F. M.
Published: September 2010

The four isomers of N‐methylsedridine {2‐(2‐hydroxypropyl)‐1‐methylpiperidine} were prepared in different ways. The absolute configurations were determined using both optical rotatory dispersion and chemical correlation. The alkaloid occurring in Sedum sarmentosum Bunge is (+)‐(2R)‐2‐{(2S)‐2‐hydroxypropyl)}‐1‐methylpiperidine, (+)‐N‐methylallosedridine (IIIa).
The photoreactions of some N‐arylamides
Authors: Hageman H. J.
Published: September 2010

Acetanilide and its N‐methylated derivative have been irradiated in solution. N‐Methylation appears to result in a higher conversion of the starting material and in the formation of a symmetrically tetrasubstituted hydrazine, in addition to the known ortho‐, and para‐rearranged products and aniline. Unexpectedly the o/p‐ratio of the products did not change upon N‐methylation.
Polyethyleneimine I: Fractionation; Mark‐Houwink relation
Authors: van den Berg J. W. A. , van Treslong C. J. Bloys , Polderman A.
Published: September 2010

A relation between the limiting viscosity number [η] and the weight average molecular weight of polyethyleneimine (PEI) is proposed. Special care was taken to suppress the marked polyelectrolytic character of PEI in water for both viscometric and light‐scattering measurements. For these measurements various fractions were isolated in three different ways from some commercially available PEI′s, all having broad molecular weight distributions. To obtain an impression of the molecular weight distribution of the resulting fractions, some osmotic measurements to obtain the number average molecular weight and some ultra‐centrifuge runs were performed.
Absolute configuration of the cis‐9,10‐epoxystearic acid occurring in shorea robusta seed
Authors: Korver O. , Ward J. P.
Published: September 2010

The optical rotation of (+)‐cis‐9,10‐epoxystearic acid occurring in Shorea robusta seed fat, and its stereospecific, chemical conversion to (‐)‐erythro‐9,10‐dihydroxystearic acid proved that both of these acids have the absolute configuration 9S,10R. Circular dichroism (CD)‐measurements on complexes with praseodimium tris‐dipivaloylmethane are described.
C‐Nitroso compounds. Part XXVI: Photochemistry of C‐nitroso compounds. The photooxidation of ethylbenzene in the presence of 2‐methyl‐2‐nitrosopropane
Authors: Maassen J. A. , de Boer Th. J.
Published: September 2010

Red light photolysis of 2‐methyl‐2‐nitrosopropane (t‐BuNO) in ethylbenzene in the presence of oxygen, leads to acetophenone and 1‐phenylethanol as main oxidation products via hydrogen abstraction by a photochemically generated adduct of oxygen to the nitroso compound. Yields and product distribution depend on the t‐BuNO concentration during the photooxidation, in accordance with the proposed mechanism.

Other hydrocarbons with easily abstractable hydrogens react similarly.
The conversion of endoxides to aromatic compounds with triphenylphosphonium dibromide
Authors: de Wit J. , Wynberg Hans
Published: September 2010

Triphenylphosphonium dibromide converts endoxides into aromatic compounds in good yields. Endoxides having a configuration in which the oxygen atom is shielded from attack by agents normally used for this conversion react under mild conditions. A possible mechanism, involving induced SN1 cleavage of the carbon‐oxygen bond in the endoxides is given.
Reactivity of 2,3‐,2,4‐ and 3,4‐dibromoquinoline towards potassium amide in liquid ammonia
Authors: den Hertog H. J. , Buurman D. J.
Published: September 2010

Aminations of 2,3‐, 2,4‐ and 3,4‐dibromoquinoline with potassium amide in different media have been investigated. Reactions of various types (bromine migration, dimerization, cine‐substitutions and various ring transformations) were found to occur.

Mechanisms for the conversions observed are proposed.
Scytalidic acid, a novel compound from scytalidium species
Authors: Overeem J. C. , Mackor A.
Published: September 2010

The structure of scytalidic acid, a metabolite of Scytalidium FY strain and of Scytalidium album is shown to be 8‐butyl‐8‐hydroxy‐3‐pentyl‐1,5‐cyclononadiene‐1,2,5,6‐tetracarboxylic 1,2: 5,6‐dianhydride.

Scytalidic acid is a new representative of the class of nine‐membered ring compounds comprising byssochlamic, glauconic and glaucanic acids and the rubratoxins.
Molybdenum‐catalysed epoxidation of olefins with alkyl hydroperoxides II. Isolation and structure of the catalyst
Authors: Sheldon R. A.
Published: September 2010

The catalysts isolated from the reaction mixtures of the molybdenum‐catalysed epoxidations of various olefins with tert‐butyl hydroperoxide were all found to be soluble Mo(VI)‐1,2‐diol complexes. The structure of the diol complex is directly related to the structure of the olefin being epoxidized and is independent of the type of molybdenum compound originally added as the catalyst. Separate experiments have shown that the diol complexes are formed in situ by reaction of the molybdenum catalyst with the epoxide in the presence of the hydroperoxide.
Activity coefficients of single ions (VI), in 1,4‐dioxane‐water and acetic acid‐water mixtures
Authors: Bax D. , de Ligny C. L. , Remijnse A. G.
Published: September 2010

The method for the estimation of standard chemical potential differences (Δμ°) of single ions, described previously, is applied to the transfer from water to 1,4‐dioxane‐water and acetic acid‐water mixtures.
Photodehydrocyclizations of stilbene‐like compounds VII: Synthesis and properties of the double helicene, diphenanthro[3,4‐c;3′,4′‐l]chrysene
Authors: Laarhoven W.H. , Cuppen Th. H. J. M.
Published: September 2010

A description of two alternative routes (Schemes 1 and 2) for the synthesis of the title compound (I) is given. Only the second route resulted in the formation of the two diastereomers of I. The physical properties of both isomers are given. The reacemization is discussed.
Hydride transfer reactions. I: Intramolecular hydride shifts in alkyloxocarbonium ions
Authors: Brouwer D.M. , Roobeek C.F. , van Doorn J.A. , Kiffen A.A.
Published: September 2010

The occurrence of intramolecular 1,4‐hydride shifts from alkane carbon to oxocarbonium carbon in acyl cations has been demonstrated in the long‐lived 4‐methyl‐ and 3,4‐dimethylpentanoyl cations in FSO3HSbF5. Strong, though not conclusive evidence has been obtained for an intramolecular 1,5‐hydride shift in the hexanoyl cation. Attempts to observe a 1,5‐hydride shift in 5‐methyl‐hexanoyl ion were unsuccessful owing to the occurrence of side reactions; in FSO3HSbF5 this cation undergoes intermolecular hydride abstraction. The 1,4 shifts are much faster than 1,2‐ or 1,3‐hydride shifts to oxocarbonium carbon, as demonstrated by the absence of the latter reactions, under comparable conditions, in the pentanoyl, 3‐methylpentanoyl and 2‐methylbutanoyl ions. The differences in the relative rates of 1,2‐ 1,3‐ and 1,4‐hydride shifts between oxocarbonium and alkylcarbonium ions are discussed.
Solubilities of some tetra‐n‐butylammonium salts in liquid ammonia at −37°C. Specific conductances of the saturated solutions
Authors: Zwikker J.W. , Nieboer H.
Published: September 2010

The solubilities of (n‐C4H9)4NI, (n‐C4H9)4NClO4, (n‐C4H9)4NNO3 and (n‐C4H9)4NSCN in liquid ammonia at −37°C were determined gravimetrically. Specific conductances of the saturated solutions were measured. Tetra‐n‐butyl‐ammonium nitrate is recommended as supporting electrolyte for electrochemical experiments in liquid ammonia.
Vapour pressure and thermodynamic function changes of mercury
Authors: de Kruif C. G. , van Ginkel C. H. D. , Langenberg A.
Published: September 2010

Thermodynamic function changes of mercury are evaluated as coefficients in Clarke's1 vapour pressure equation.
A simple preparative method for dithioesters
Authors: Meijer J. , Vermeer P. , Brandsma L.
Published: September 2010

A number of dithioesters RC(S)SR′ (Ralkyl, aryl, 2‐thienyl; R′ = alkyl, allyl or propargyl) can be obtained in good yields by reaction of RMgX (X = Cl or Br) in tetrahydrofuran with carbon disulfide, followed by alkylation with alkyl iodides, allyl bromide or propargyl bromide.
Preparation, structure and properties of compounds containing the dipositive tri‐copper hexa(N,N‐di‐n‐butyldithiocarbamato) ion, compounds with copper in the oxidation states II and III
Authors: Cras J. A. , Willemse J. , Gal A. W. , Hummelink‐Peters B. G. M. C.
Published: September 2010

The preparation, some magnetic, spectral and electrochemical properties of the compounds [Cu3(Bu2dtc)6] [MBr3]2(M = Zn, Cd, Hg) are reported. The crystal structure of the compound [Cu3(Bu2dtc)6] [CdBr3]2 has been determined by a three‐dimensional X‐ray analysis. The triclinic cell, space group magnified image with a = 12.629(4), b = 13.706(4), c = 12.506(4) Å and α = 95.84(4). β = 91.45(4), γ = 86.06(3)°, contains one formula unit. Atomic parameters were refined to a conventional R value of 0.05 for 1344 independent non‐zero reflections. The structure consists of two centrosymmetric ionic units [Cu3(Bu2dtc)6]2+ and [Cd2Br6]2−. In the cation one copper atom has an apically distorted octahedral S‐coordination, with CuS distances of 2.30(1), 2.35(1) and 3.19(1) Å. The two other equivalent copper atoms have five‐fold pyramidal S‐coordinations with CuS distances of 2.21(1), 2.22(1), 2.23(1), 2.23(1) and 2.88(1) Å. The Cd2Br ion can be described as a slightly‐distorted edge‐condensed bitetrahedron. Esr single‐crystal spectra prove localisation of the unpaired electron at one copper atom. The I.R. spectra show double CuS and CN stretching frequencies. All these data suggest the compounds to be composed of copper in different states of oxidation. The cation can be described as [(Cu(III)(Bu2dtc)2)2Cu(II)(Bu2dtc)2]2+. The ionic structure is confirmed by conductivity measurements.
Photodehydrocyclizations of stilbene‐like compounds VIII: Synthesis of hexaheliceno[3,4‐c]hexahelicene
Authors: Laarhoven W. H. , de Jong M. H.
Published: September 2010

The synthesis of a new double helicene, hexaheliceno[3,4‐c]hexahelicene, has been described. Of two possible diastereomers only one has been obtained. Presumably the product has the racemic configuration but this assignment is not yet definite.
Infrared study of hydroxyl groups on nickel oxide and silica‐supported nickel catalysts
Authors: Erkelens J. , Eggink‐Du Burck S. H.
Published: September 2010

The decomposition of nickel hydroxide and the decomposition and reduction of some silica supported catalysts have been studied by means of IR spectroscopy.

In the spectrum of decomposed nickel hydroxide two bands remain at 3676 and 3575 cm−1 which may be assigned to the existence of free and disturbed hydroxyl groups on the nickel oxide surface. The presence of these groups only partially explains the previously published water retention after decomposition. The band at 3676 cm−1 also remains in the spectrum of a silica‐supported nickel impregnation catalyst after heat treatment and disappears readily after reduction with hydrogen. IR absorption bands at other positions in other types of supported nickel catalysts possibly originate from the formation of nickel hydrosilicates.

The decomposition of nickel hydroxide was also studied by means of thermogravimetry and it was found that the rate of decomposition at 225°C could be described by a first order law, provided that the degree of conversion was defined as being one at the apparent decomposition stage of about 80%.
Hydride transfer reactions III: Rates of hydride transfer from isobutane to hydroxycarbonium ions
Authors: Brouwer D. M. , Kiffen A. A.
Published: September 2010

The hydride transfer from isobutane to protonated acetaldehyde, to give t‐butyl ion and ethanol (which is subsequently protonated), proceeds at approximately the same rates (k = 6 − 9 × 10−4 M−1S−1 at 0°C) in 9:1 HF‐SbF5 and HF‐BF3. This indicates that protonation of the alcohol formed does not assist the hydride transfer step kinetically. The hydride transfer from isobutane to protonated acetone is slower than that to protonated acetaldehyde by a factor of about 3 × 103.
Chemistry of alkenethiolates. Six‐ and seven‐membered rings with two hetero atoms
Authors: Hoff S. , Blok A.P. , Zwanenburg E.
Published: September 2010

The S‐hydroxy, ‐amino and ‐mercapto alkylation of 2‐acetamidopropenethiolates II is described. Intramolecular cyclization of these functionalized alkenes to acetamido‐substituted 1,4‐oxathianes, 1,4‐dithiane, thiomorpholine, 1,4‐oxathiepane and 1,4‐dithiepane can be achieved in good yields in the presence of base or acid catalysts. The cyclization to 1,4‐oxathianes has been studied in detail and the configuration of the stereoisomers has been assigned on the basis of PMR spectroscopy.
Hydride transfer reactions: IV. Intramolecular hydride shifts in protonated aldehydes
Authors: Brouwer D.M. , Kiffen A.A.
Published: September 2010

Protonated 4‐methylpentanal (1) in 9:1 HF‐SbF5 reacts to give equimolar quantities of 5,5‐dimethyltetrahydrofuryl ion and t‐C6H ions. As the reaction follows first‐order kinetics (k = 4 × 10−4 s−1 at 30°C) and under the same conditions no reaction takes place between protonated acetaldehyde and 5‐methylhexan‐2‐one it is concluded that the reaction of 1 involves an intra‐molecular 1,4‐hydride shift followed by intermolecular hydride transfer from another ion 1 to the resulting C‐protonated alkenol.

The 1,4‐shift in 1 is at least fifteen times faster than the 1,3‐shift in protonated 3‐methylbutanal. The latter ion undergoes a first‐order reaction (with k = 8,3 × 10−5 s−1 at 40°C) but routes other than that involving a 1,3‐hydride shift cannot be ruled out.

The rates of intermolecular and intramolecular hydride transfers to trialkyl‐, alkylhydroxy‐ and alkyloxocarbonium ions are compared, and the differences in relative rates of 1,2‐, 1,3‐ and 1,4‐shifts in these ions discussed.
Les sulfates acides de manganèse: I. L'hydrogénosulfate
Authors: Palavit Par G. , Noël S.
Published: September 2010

The manganese hydrogenosulfat is prepared according to the ternary diagram MnSO4‐H2SO4,‐H2O. It crystallizes in the spatial groups P21/c with two molecules in the cell. A frequences' attribution of the group HSO4 is proposed. From a thermal study, the hypothesis of a decomposition mechanism can be proposed.
Conformation of non‐aromatic ring compounds‐80: Calculation of dihedral angles from vicinal proton coupling constants in mono‐ and di‐substituted glutaric anhydrides
Authors: Koer F. J. , van Asbeck T. M. W. , Altona C.
Published: September 2010

The Lambert‐Buys R‐value method is applied to several six‐membered α‐mono‐α,α‐ and trans‐α,α′‐di‐substituted glutaric anhydrides. A discussion concerning the appearance of the AA′BB′ spectra of the compounds under consideration is given. The vicinal proton coupling constants Jtrans (7.3‐8.1 Hz) and Jcis (4.9‐6.4 Hz) and the corresponding ring dihedral angles (ψ: 49°‐53°) are reported. The results are interpreted in terms of small deformations of the “sofa” conformation due to steric effects of the substituents.
Charge transfer reactions of tris(dimethylamino)phosphine; Solvent effects and esr measurements
Authors: Boekestein G. , Buck H. M.
Published: September 2010

It is demonstrated that the course of the reaction of tris(dimethylamino)phosphine with aromatic bromides is strongly dependent on the nature of the solvent. The reaction in DMF or THF gave rise to the formation of radicals, which could be measured directly or by the method of spin‐trapping, using 2‐methyl‐2‐nitrosopropane as a scavenger.
Ligand hyperfine interactions in oxyhalides of pentavalent chromium, molybdenum and tungsten II
Authors: van Kemenade J. T. C.
Published: September 2010

The electron paramagnetic resonance (EPR) spectra of the ions CrOF5=, MoOF5=, WOF5=, MoOCl5=, MoOBr5=, WOCl5= and WOBr5=, all incorporated into a single crystal of a suitably chosen host lattice, are presented.

An attempt is made to correlate the EPR parameters to bonding orbital coefficients by using the Abragam and Pryce method.

The analysis of the ligand hyperfine tensor components in bonding coefficients gives satisfactory results for the oxyfluorides with an increase in orbital delocalisation going from chromium to molybdenum.

The existing methods of correlating g‐ and A‐tensor to molecular orbital coefficients are reviewed critically and shown to be highly dependent on an arbitrary choice of a charge distribution over the complex.
Chemistry of cyclopropene II: Formation and reactions of 1‐potassio‐, 1‐sodio‐and 1‐lithiocyclopropene in liquid ammonia
Authors: Schipperijn A. J. , Smael P.
Published: September 2010

1‐Metallocyclopropene is instantaneously and nearly quantitatively formed on addition of cyclopropene to an at least equimolar amount of alkali amide in liquid ammonia. Alkylation yields mono‐ and dialkylated cyclopropenes. On standing, 1‐metallocyclopropene slowly converts into a mixture of 1‐metallo‐,2‐cyclopropylcyclopropene, 1,2‐dicyclopropylcyclopropene and cyclopropylidenecyclopropane, in a yield that greatly depends on the reaction conditions. A detailed kinetic study has made it possible to select optimum reaction conditions for the formation of each of these products.

A route has been developed for the synthesis of monoalkylated and 1,2‐dialkylated cyclopropenes, either with identical or with different alkyl groups.
The copper(II)‐ammonia complexes in the synthetic zeolites X and Y
Authors: Vansant E. F.
Published: September 2010

The EPR spectra of the cupric‐ammonia complexes in the zeolites X and Y were studied. Ammonia adsorption in the copper(II)‐X and ‐Y zeolites resulted in the formation of square planar Cu(II)‐NH3 complexes. Desorption of ammonia produced in both zeolites a distorted tetrahedral complex.
Preparation, properties and structure of dihalogenobis(N,N‐DI‐n‐butyldithiocarbamato) complexes of palladium and platinum
Authors: Willemse J. , Cras J. A. , Wijnhoven J. G. , Beurskens P. T.
Published: September 2010

The preparation and properties of M(Bu2dtc)2X2 (M = Pd, Pt and X = Br, I) are reported. From the platinum complexes two isomers were isolated. The crystal structure of the cis‐isomer of Pt(Bu2dtc)2I2 is determined by a threedimensional X‐ray analysis. The orthorhombic cell, space group Fddd, with a = 33.37(3), b = 34.16(3), c = 20.19(2) Å and V = 23010(40) Å3 contains 32 formula units. Atomic parameters were refined to a conventional R value of 0.073 for 1417 independent non‐zero reflections. The platinum atom is distorted octahedrally coordinated by two iodine and four sulfur atoms with average distances of Pt ‐ I = 2.66 and Pt ‐ S = 2.35 Å. The intra‐ and one of the intermolecular I‐I distances (resp. 3.79 and 3.37 Å) are short compared with an I‐I Van der Waals contact.

ESCA spectra show the other isomer to be a Pt(IV) complex too. NMR data suggest a trans‐structure for this isomer.

With Bu4tds these complexes yield M(Bu2dtc)3X (M = Pt, Pd and X = Br, I) of which some properties are given.
Some modifications of the aglycone lactone ring of erythromycin A
Authors: Bojarska‐Dahlig H. , Dziegielewska I. , Gła̧bski T.
Published: September 2010

Treatment of 8,9‐anhydroerythromycin A 6,9‐hemiacetal with hydrogen peroxide leads to the N‐oxide of the 8,9‐epoxy derivative. The latter compound on catalytic reduction yields 8‐hydroxy‐9‐deoxoerythromycin A, forming the cyclic 6,8‐carbonate in reaction with ethylene carbonate.
Base‐catalyzed cyclisation of N,N‐dialkyl‐2,4‐pentadienethioamides to 2‐(dialkylamino)thiophenes
Authors: Meijer J. , Brandsma L.
Published: September 2010

Treatment of N,N‐dialkyl‐2,4‐pentadienethioamides (1) with potassium tert‐butoxide in hexamethylphosphoric triamide causes cyclisation to substituted thiophenes (3) and (4).
Experimental evaluation of the polarisability and the equivalent ionic conductance of alkylammonium ions
Authors: Vansant E. F.
Published: September 2010

The polarisability and the equivalent ionic conductance of the short‐chain alkylammonium ions were determined by refractometric and conductometric measurements in aqueous solutions.
Electron paramagnetic resonance of mixed oxalatochromium(III) complexes in frozen solutions
Authors: Andriessen W. T. M.
Published: September 2010

Electron Paramagnetic Resonance (epr) spectra are reported for the following complexes in frozen solutions: K3Cr(ox)3 (g = 1.98 ± 0.01; D = 0.66 ± 0.09 cm−1; E < 0.05 cm−1), K[Cr(ox)2en]. KI (g = 1.98 ± 0.01; D = 0.61 ± 0.06 cm−1; E = 0.10 ± 0.01 cm−1), [Cr(en)2ox]I (g = 1.98 ± 0.01; D = 0.43 ± 0.09 cm−1; E = 0.09 ± 0.02 cm−1). For the powder spectrum of Cr doped waterfree K3Al(ox)3 the following parameters are reported: g = 1.982 ± 0.001; D = 0.666 ± 0.006 cm−1; E = 0.015 ± 0.001 cm−1.
Synthesis of 2‐(1‐alkenyl)furans and 2‐(1,3‐alkadienyl)furans
Authors: de Jong A.J. , Brandsma L. , Arens J.F.
Published: September 2010

Treatment of the compounds HOCH2CHC(CH3)CCCH(R)OCH3 (R = H or CH3) and HOCH2CHC(CH3)CCC(R1)C(R2)CH2OCH3 (R1 and R2 = H or CH3) with potassium tert‐butoxide in dimethyl sulfoxide affords 2‐(1‐alkenyl)furans and 2‐(1,3‐alkadienyl)furans, respectively, in good yields.
A conformational study of aromatic N‐sulfinylamines
Authors: van Woerden H. F. , Bijl‐Vlieger S. H.
Published: September 2010

Electric dipole moments and PMR spectra of a series of substituted N‐sulfinylanilines, Ar‐N=S=O, indicate that these compounds adopt preferentially a cis or syn structure (Z‐configuration) with respect to the central ‐N=S‐ bond. Direction and magnitude of the group moment of the NSO group are evaluated. From an analysis of the partial moments of the constituent atoms and groups, it appears that the lone pair of electrons in the non‐bonding sp2 orbital of sulfur contributes 1.8‐2.1 D to the total electric moment. In the light of the results obtained it seems likely that an analogous isomeric or rotameric form prevails in the corresponding aliphatic NSO compounds.
Preparation of 1,3‐dienyl ethers and thioethers by alkali amide induced elimination of alcohol, phenol or thiol from 1,4‐bis‐ethers and ‐thioethers derived from 2‐butene‐1,4‐diol
Authors: Everhardus R. H. , Peterse A. , Vermeer P. , Brandsma L. , Arens J. F.
Published: September 2010

Ethers and thioethers of the type RXCH2CH=CHCH2XR (X=O or S; R=alkyl or phenyl) undergo a 1,4‐elimination of RXH upon treatment with alkali amides in liquid ammonia, giving 1,3‐dienyl ethers and thioethers RX‐CH=CH‐CH=CH2 in good or excellent yields.
1,3‐Oxathioles as intermediates in nucleophilic additions to 1‐(acylthio)‐1‐alkynes III: Formation and reactivity of 1,3‐oxathiolium ions
Authors: Wevers H. , Drenth W.
Published: September 2010

In concentrated acids 1,3‐oxathiole (4) is rapidly converted into 1,3‐oxathiolium ion (5). In 0.10‐1.0 mol/1 aqueous perchloric acid ion 5 is quickly equilibrated with 2‐acyl‐1‐alkene‐1‐thiol (6) at a rate almost proportional to the reciprocal of the hydrogen ion concentration. At lower acidities the formation of compound 6 is preceded by the equilibration between ion 5 and an intermediate which is probably 2,5‐dialkyl‐2‐hydroxy‐1,3‐oxathiole (3). Rate constants of these reactions and the pKR⊕ value of ion 5a are obtained. Subsequently, the end product 1‐(acylthio)‐2‐alkanone (2) is formed from intermediate 3.
Dielectric properties of 1‐butanol and of mixtures of 1‐butanol with hexane and with tetrachloromethane
Authors: van den Berg J. F. , Michielsen J. C. F. , Ketelaar J. A. A.
Published: September 2010

The dielectric properties of 1‐butanol and of mixtures of 1‐butanol with hexane and with tetrachloromethane have been determined in the frequency range between 10KHz and 40GHz at temperatures from 249.0°K to 288.2°K.

The Kirkwood correlation factor g computed from the dielectric constant is greater than 1 for 1‐butanol and for most mixtures. This is explained by an excess of the linear multimers with a high dipole moment formed by the association of molecules through hydrogen bonding. The greater part of the dispersion region is to be described by a relaxation process characterized with one relaxation time. The agreement between the dependence on concentration of the relaxation time and the correlation factor confirms the suggestion that this relaxation process is to be ascribed to the linear multimers. Linear multimers are present even in the dilute solution.
Enolization and oxidation: IV. Iron ion catalyzed autoxidation of acetoin
Authors: van den Besselaar A. M. H. P. , Lubach J. , Drenth W.
Published: September 2010

The catalytic effect of iron(III) and iron(II) perchlorate on the autoxidation of acetoin (3‐hydroxy‐2‐butanone) has been studied in perchloric acid solution ranging from 0.125 to 2 mol/1. The experiments have been carried out in water and in aqueous ethanol 1: 1 v/v. A mechanism is presented in which the formation of an intermediate iron(III) enolate is the slow step. In subsequent steps the enolate is oxidized either by iron(III) or by oxygen. In the latter case simultaneous oxidation of iron(II) probably occurs.

Starting from iron(III) as well as from iron(II) a steady state is reached in which the ratio Fe(III)/Fe(II) is in the order of 100.
A novel route for the synthesis of 1‐benzoxepins and some of their reactions
Authors: Reinhoudt D. N. , Kouwenhoven C. G.
Published: September 2010

A 1‐benzoxepin has been synthesized in high yield by cycloaddition of 3‐pyrrolidinobenzofuran to dimethyl acetylenedicarboxylate, followed by thermal rearrangement of the [2 + 2] cyclo‐adduct. A kinetic study of the isomerization revealed that the ring opening occurs via a highly polarized transition state and that this rapid reaction is favoured by the electron‐donating capacity of the pyrrolidino substituent. Hydrolysis of the pyrrolidino group and subsequent reaction afford several 1‐benzoxepin derivatives. At elevated temperatures the 1‐benzoxepins undergo rearrangement to 1‐naphthol derivatives, the rate of which greatly depends on the electron density of the oxepin ring. Upon irradiation the 1‐benzoxepins are readily converted into 2a,7b‐dihydrocyclobuta[b]benzo‐furans.
The reactions of 3‐bromo‐ and 4‐bromo‐1,6‐naphthyridine and of 3‐chloro‐ and 4‐chloro‐1,6‐naphthyridine with potassium amide in liquid ammonia
Authors: Czuba W. , Woźniak M.
Published: September 2010

Mixtures of 3‐amino‐ and 4‐amino‐1,6‐naphthyridine were obtained from both 3‐bromo‐and 4‐bromo‐1,6‐naphthyridine on amination with potassium amide in liquid ammonia. Similar results were obtained with the corresponding chloro derivatives. The relative yields of isomeric amino derivatives indicate that the reaction mechanism involves not only the formation of 3,4‐didehydro‐1,6‐naphthyridine but also simple addition‐elimination (AE).
C‐Alkylations of cyclic 1,3‐diketones
Authors: de Groot Ae. , Jansen B. J. M.
Published: September 2010

Several cyclic 1,3‐diketones can be alkylated at C‐2 in very high yields with ethyl 2‐(bromomethyl)acrylate or diethyl (bromomethyl)maleate. A mechanism involving initial O‐alkylation followed by a Claisen rearrangement to give the C‐alkylated product is proposed.
Cyclobutadienyl dications as intermediates in the rapid degenerate rearrangements of 4‐halo‐1,2,3,4‐tetrasubstituted cyclobutenyl cations
Authors: van der Hout‐Lodder A. E. , de Haan J. W. , Buck H. M.
Published: September 2010

Based on 13C NMR chemical shifts at variable temperatures it is suggested that cyclobutadienyl dications form essential intermediates in the rapid equilibration of 4‐halo‐1,2,3,4‐tetrasubstituted cyclobutenyl cations.
A new method for the preparation of homoaromatic cations: 1‐methoxycyclooctatrienylium cation
Authors: de Dobbelaere J. R. , Buck H. M.
Published: September 2010

The 1‐methoxycyclooctatrienylium ion has been prepared from 7,7‐dimethoxy‐1,3,5‐cyclooctatriene by reaction with PCl5 or SOCl2 in liquid SO2.
Poly(ethylenimine) II. Potentiometric titration behaviour in comparison with other weak polyelectrolytes
Authors: van Treslong C. J. Bloys , Staverman A. J.
Published: September 2010

Potentiometric titration data of poly(ethylenimine) (PEI) and poly(vinylamine) (PVA) are presented. They are described in a phenomenological way by the procedures of Henderson‐Hasselbalch and Mandel, respectively and the conforming parameters are calculated. The values of the parameters are compared for the two polymers mutually and with literature data for other weak polyelectrolytes. Marked specific differences are indicated. These are explained in a qualitative way from the nature of the ionizable group and structure of the polymers. A more quantitative explanation will be attempted in a following paper.
Mechanism of the action of potassium amide in liquid ammonia on 2‐bromopyridine
Authors: den Hertog H. J. , Boer H. , Streef J. W. , Vekemans F. C. A. , van Zoest W. J.
Published: September 2010

Evidence is presented that 2‐bromopyridine is converted by potassium amide in liquid ammonia into 2‐aminopyridine by the addition‐elimination (AE)‐mechanism and not by an EA‐transformation via a didehydropyridine, the “ANRORC”‐mechanism (= subsequent addition of the amide ion to C‐6, ring‐opening with elimination of the bromide ion and ring‐closure) or an abnormal AE‐mechanism (starting with the addition of an amide ion to C‐6).
Potassium bis(3‐phenylbiuretato)cobaltate(III).2DMSO. The crystal structure of a spin triplet cobalt(III) complex, containing dimethyl sulfoxide
Authors: Birker P. J. M. W. L. , Beurskens P. T.
Published: September 2010

The structure of potassium bis(3‐phenylbiuratato)cobaltate(III), crystallizing with two molecules of dimethyl sulfoxide, KCo(HNCON(C6H5)CONH)2.2(CH3)2SO, was determined by X‐ray analysis. The crystals are monoclinic, space group P2/c, with unit cell dimensions a = 7.471 ± 0.014, b = 8.126 ± 0.017, c = 21.467 ± 0.036 Å, β = 95.29° ± 0.13, and two formula units per unit cell. 2286 reflections were measured with an automatic diffractometer. The structure was refined by full matrix least squares methods. For 1019 reflections with I > 1½ σ (I), R = 0.14; for 638 reflections with I > 3 σ (I), R = 0.10. The complex anion is situated on a twofold symmetry axis. The cobalt atom is in almost planar N4‐coordination, with CoN bonds of 1.83 and 1.84 Å. The two DMSO molecules are not coordinated with the cobalt atom, but they are incorporated in the lattice with their oxygen atoms coordinated with the potassium ions.
Chemistry of acetylenic ethers 107. Synthesis of 1,4‐thiaphosphorins and 1,4‐thiarsenins
Authors: Schoufs M. , Meijer J. , Vermeer P. , Brandsma L.
Published: September 2010

1,4‐Thiaphosphorins and 1,4‐thiarsenins (2) have been obtained by addition of phenylphosphine and phenylarsine to di‐l‐alkynyl sulfides under catalytic influence of lithium amide in liquid ammonia.
Bis(tricyclohexylphosphine) complexes of group VI transition metals
Authors: Moers F. G. , Reuvers J. G. A.
Published: September 2010

The reaction of M(CO)6 or M(CO)3L (MCr, Mo or W) with tricyclohexylphosphine (PCy3) yield trans‐M(PCy3)2(CO)4. Cis‐compounds could not be detected by infrared and raman spectroscopy. All attempts to prepare complexes in which more than two PCy3 groups are coordinated to the metal by reaction with an excess of PCy3 were unsuccessful.
Mechanisms of reactions of 3‐bromopyridine 1‐oxide and derivatives with potassium amide in liquid ammonia
Authors: Peereboom R. , den Hertog H. J.
Published: September 2010

3‐Bromopyridine 1‐oxide and some of its derivatives react with potassium amide in liquid ammonia by the elimination‐addition [SN(EA)] mechanism. It depends on the character and the position of the substituent whether the pathway via 2,3‐ or 3,4‐didehydropyridine 1‐oxide is followed. In the amination of 3‐bromoquinoline 1‐oxide a remarkable side‐reaction occurs.
On the occurrence of an SN(ANRORC) mechanism in the amination of 2‐substituted 4‐phenylpyrimidines with potassium amide in liquid ammonia
Authors: Kroon A. P. , van der Plas H. C. , van Garderen G.
Published: September 2010

On amination of 2‐X‐4‐phenylpyrimidine [X = SCH3, SO2CH3, SC6H5, SO2C6H5, SCN, CN, \documentclass{article}\pagestyle{empty}\begin{document}$\rm{N}^\oplus $\end{document}(CH3)3] with potassium amide in liquid ammonia at ‐ 33° and/or ‐75°, 2‐amino‐4‐phenylpyrimidine is in general formed as the main product. Depending on the substituent in position 2, several by‐products are formed: when X is \documentclass{article}\pagestyle{empty}\begin{document}$ \rm{N}^\oplus $\end{document}N(CH3)3, some bis(4‐phenyl‐2‐pyrimidinyl)amine is obtained; in the case of X = SCN. a considerable amount of (4‐phenyl‐2‐pyrimidinyl) disulfide is formed, while for X = SCH3 and SC6H5, 3‐amino‐3‐phenylacrylonitrile is produced. It is proved, using 2‐X‐4‐phenyl‐[1,3‐15N]‐pyrimidines, that the formation of the 2‐amino compound can occur by a ring opening/ring closure sequence [SN(ANRORC) mechanism]. The percentage of the compounds which react by this mechanism is found to be 91% for X = SCH3, 73% for X = SO2CH3, 34% for X = SO2Ph, 90% for X = SCN, 5% for X = CN and 10% for X = \documentclass{article}\pagestyle{empty}\begin{document}$ \rm{N}^\oplus $\end{document}N(CH3)3. By PMR spectroscopy of solutions of 2‐X‐4‐phenylpyrimidine (X = SCH3 and SO2CH3) in liquid ammonia, containing potassium amide, good evidence is found for the presence of Meisenheimer σ‐adducts, formed by an addition of the amide ion to C(6) of the pyrimidine ring.
Interrelations of unsaturated aliphatic compounds I. General considerations
Authors: Arens J.F.
Published: September 2010

Graphs depicting the interrelations of unsaturated systems (eliminations, additions, substitutions and isomerizations) are presented.

Such graphs are suitable frameworks for interrelation studies, especially for tele reactions (a large group of reactions occurring at the ends of conjugated systems and involving only a change of hybridization of the terminal atoms).
The reactions of salicylaldehydes and 2,2‐diary 1‐2H‐chromenes with 1,1‐bis[p‐(dimethylamino)phenyl] ethylene; photochromic chromenes
Authors: Zwanenburg D.J. , Maas Th. A. M. M.
Published: September 2010

The reactions between 1,1‐bis(p‐dimethylaminophenyl)ethylene (Michler's ethylene) (5) and salicylaldehydes (6) were studied for the purpose of synthesizing photochromic chromenes (1). Although we proved the presence of the chromene 1 under some conditions, the only compounds we could isolate were the so‐called “disubstitution products” 7. Reaction of 2,2‐bis[p‐(dimethylamino)‐phenyl]‐2H‐chromene [1a, synthesized by a Grignard reaction of coumarin with p‐(dimethylamino)‐phenylmagnesium bromide] with Michler's ethylene also gives the “disubstitution product” 7a. Reactions of Michler's ethylene with 2,2‐bis(p‐methoxyphenyl)‐2H‐chromene (3) and the spiropyran 11 furnished the “mixed disubstitution products” 9 and 10, respectively. A reaction of the latter with 5‐nitrosalicylaldehyde gives 2,2‐bis[p‐(dimethylamino)phenyl]‐6‐nitro‐2H‐chromene 1b. The photochromism of the synthesized chromenes is described briefly.
Photochemistry of pyrimidine N‐oxides (IV)
Authors: Roeterdink F. , van der Plas H.C. , Koudijs A.
Published: September 2010

Photolysis of 2,4,6‐trimethylpyrimidine 1‐oxide in methanol with light of 254 nm leads to rearrangement into 4(5)‐acetyl‐2,5(4)‐dimethylimidazole and 1,2,4‐trimethyl‐1,6‐dihydro‐6‐oxopyrimidine. In benzene only the formation of the imidazole and an unknown compound X is observed. In both solvents the products are formed from the same primary photoproduct. Ring contraction into an imidazole also takes place on ultraviolet irradiation of 4‐chloro‐2,6‐dimethylpyrimidine 1‐oxide in benzene and of 2,6‐dimethyl‐4‐methoxypyrimidine 1‐oxide in methanol. Results of conventional flash photolysis applied with the aim of getting some information about the intermediary formation of oxaziridines are inconclusive. The role of possible intermediates ‐ oxaziridines, 1,2,4‐oxadiazepines or zwitter ionic species ‐ in these rearrangement reactions is discussed.
Réactivité des germylamines vis à vis de quelques composés α ou β dicarbonylés
Authors: Rivière‐Baudet M. , Satgé J.
Published: September 2010

The trialkylgermylamines R3GeNR′2, condense by 1‐2 dipolar addition on to one of the carbonyl groups of α‐diketones, such as biacetyl or benzil, leading to α‐amino β‐oxoalkoxygermanes. Dialkylbis(dimethylamino)germanes, R2Ge(NR′2)2 also, lead to an insertion derivative on to one of the carbonyl groups of biacetyl or benzil, but the expected 4,5‐bis(dimethylamino)‐2‐germa‐1, 3‐dioxolane is not obtained.

All the α‐amino β‐oxoalkoxygermanes formed in the course of these reactions are thermally unstable. The decomposition proceeds by an intermolecular mechanism, observed previously for α‐amino β‐oxoalkoxygermanes and leads, in the case of amine R3GeNR′2 to an α‐ketoenamine and in the case of R2Ge(NR′2)2 to a diaminodiene.

In the reaction between acetylacetone and (triethylgermyl)dimethylamine, without a solvent, only 1,2 dipolar addition on one of the carbonyl groups of the reagent is observed, to the exclusion of cleavage of the Ge‐N bond. In the same reaction carried out in hexane, Ge‐N bond cleavage by the enolic form of acetylacetone is observed; nevertheless, the formation of a 1‐2 addition derivative on to the carbonyl group still preponderates.

The α‐amino β‐oxoalkoxygermanes formed are thermally unstable and the decomposition by an intramolecular mechanism proceeds by coordination between oxygen of the Ge‐O‐C group and hydrogen of the methylene group in α position to carbonyl.
Reversible halogenation of cyanine dyes
Authors: van Beek H. C. A. , Hendriks C. H. F. , van der Net G. J. , Schaper L.
Published: September 2010

The reaction of bromine or iodine with cyanine dyes results in the formation of an equilibrium mixture of the dye and the halogen used, their 1: 1 addition product, the mesohalogen derivative of the dye, the 1: 1 addition product of the latter and the halogen used, the protonated dye and its dimeric or polymeric forms. The equilibrium constants of the different reactions are presented. The original dyes are easily regenerated from the halogenated products if other halogen acceptors are present in the system. The processes described can be of importance in the chromatic sensitization of photographic materials.
11‐Alkylidene steroids in the 19‐nor series
Authors: van den Broek A. J. , van Bokhoven C. , Hobbelen P. M. J. , Leemhuis J.
Published: September 2010

A number of 11‐methylene‐substituted estrenes and 19‐nor‐pregnenes have been synthesised. In addition, some 11‐(E)‐ethylidene estrenes have been prepared. Evidence is presented establishing the configuration of the ethylidene substituent.
A new synthesis for 1,3‐dichloro‐2‐propanone
Authors: Nollet A. J. H. , Ladage J. W. , Mijs W. J.
Published: September 2010

A new synthesis for 1,3‐dichloro‐2‐propanone (symm‐dichloroacetone) is described using diketene and chlorine as starting materials. The chlorination product of diketene, 2,4‐dichloro‐3‐oxobutyryl chloride, was converted into the corresponding butyric acid derivative. Subsequent decarboxylation by heating gave 1,3‐dichloro‐2‐propanone in 77% overall yield, without isolation of intermediate products.
Hydrobenzothiopyran‐4‐one S,S‐dioxides. Synthesis and structural elucidation
Authors: Kattenberg J. , de Waard E.R. , Huisman H.O.
Published: September 2010

The synthesis of hexa‐ and octahydrobenzothiopyran‐4‐one S,S‐dioxides 1–4 is described. The regioselective and stereospecific H/D‐exchange of the hydrogens α to the SO2 group is accomplished by careful control of reaction conditions. The comparison of the PMR spectra of the deuterio and protio derivatives allows the establishment of the mode of ring fusion.
Poly(vinylamine). Synthesis and characterization
Authors: van Treslong C. J. Bloys , Morra C.F.H.
Published: September 2010

A number of poly(vinylamine) (PVAm) samples with different molecular weight were synthesized following basically the same method as described by Hart. For PVAm and the intermediate macromolecular product, poly(tert‐butyl vinylcarbamate) (PBVC), relations between the limiting viscosity number [η] and the number average molecular weight as determined by osmotic measurements are proposed. For two high molecular weight samples of PVAm also the weight average molecular weight was determined by light‐scattering measurements.
A versatile synthesis of allenic hydrocarbons. Evidence for an organocopper(III) intermediate
Authors: Vermeer P. , Meijer J. , Brandsma L.
Published: September 2010

A number of allenes RR1CCCHR2 2 have been prepared by interaction between acetylenic tosylates R1C≡CCHR2OTs, 1 (R1 = H, alkyl, aryl, H2CC(CH3) or CH3C≡C; R2 = H or t‐C4H9) and organocopper(I) compounds “RCu” (formed from Grignard compounds RMgCl or RMgBr with R = alkyl, aryl or 2‐thienyl and copper(I) bromide in tetrahydrofuran). If R = t‐C4H9 the reaction with catalytic amounts of CuBr also gives good results. Significant amounts of C6H5CHCCH2 or C6H5CDCCH, are formed if C6H5CCCH2OTs is reacted with “CH3Cu” (from CH3MgCl and CuI) at −60° in tetrahydrofuran and the reaction mixture is quenched at low temperatures with methanol or deuteriomethanol. This finding is considered as evidence for the intermediate occurrence of a copper(III) derivative.
Conformation of non‐aromatic ring compounds — 92 Carbon‐13 nuclear magnetic resonance spectra of some 3‐arylglutaric anhydrides
Authors: Koer F.J. , Altona C.
Published: September 2010

Fourier transform carbon‐13 NMR spectra of a series of 3‐(X‐phenyl)glutaric anhydrides [X: H (2),4‐F (3), 4‐Cl (4), 4‐Br (5), 4‐OCH3 (6), 4‐NO2 (7), 3‐Cl (8) and 2,6‐Cl2 (9)] and of 3‐methyl‐3‐(4‐chlorophenyl)‐ (10)‐, 3,3‐diphenyl‐ (11)‐ and 3,3‐(2,2′‐biphenylylene)‐glutaric anhydride (12) have been obtained and interpreted. Spectral assignments of the aromatic side‐chain carbons for 3–9 were made with the aid of additive parameters derived from suitably substituted toluenes for which unequivocal assignments are possible. The carbon‐13 and proton chemical shift data of the glutaric anhydride skeletal carbons and appended protons are compared and discussed in terms of conformational properties of the anhydride ring and its side‐chain. A set of substituent parameters (α: 17.6 ± 0.3 ppm, β: +7.0 ± 0.3 ppm and γ: −1.3 ± 0.3 ppm), which correlates the average effect of the XC6H4 nucleus on the chemical shifts of the glutaric anhydride ring carbon atoms in 2–8, has been generated.
Valence force fields for the difluoroethylenes
Authors: Oskam A. , Elst R.
Published: September 2010

Normal coordinate calculations of cis‐ and trans‐CHFCHF and of CF2CH2 have been undertaken using Modified Valence Force Fields based on vibrational data of all the hydrogen and deuterium isotopes. A definite vibrational assignment is given for CF2CH2 based on new infrared and Raman gas phase spectra.

The calculated valence force fields of cis‐ and trans‐difluoroethylene. vinylidene fluoride and the vinyl halides mutually agree very well.
The nuclear magnetic resonance spectra of diethyl Z‐ and E‐[2‐(methoxycarbonyl)vinyl]phosphonate
Authors: Meppelder F. H. , Beck H. C.
Published: September 2010

The 1H and 31P nmr spectra of the title compounds are reported. The geometrical isomers are assigned from their proton spectra in the vinylene region. A π‐interaction between the P atom and the CC bond is indicated by the difference in the geminal PH coupling constants of the two isomers and by the position of the 31P resonance.