bluuebunny/crossref_metadata_2025 huggingface dataset:
An Estimate of the Interatomic Distances in Monohaloacetylene Radical Cations from Photoelectron‐spectroscopic Data
Authors: Heilbronner E. , Muszkat K. A. , Schäublin J.
Published: December 2004

A convenient method is given for the semiquantitative determination of those changes ΔSi in internal coordinates, which describe the structure of the radical cation M+(Ψ) relative to the neutral molecule M in its electronic ground state. The changes ΔSi correspond to those associated with the relaxation process which follows the ionisation M + hv → M+(Ψ) + e, M+ being in the electronic state Ψ. The method, based on the procedure originally developped by Smith & Warsop [3], uses the spacing and relative intensity of the vibrational fine‐structure components of the bands in the photoelectron spectrum of M. From these data are calculated the changes ΔQk in normal coordinates, which are then transformed into the ΔSi by applying the L‐matrix.

The changes ΔRCX, ΔRCC and ΔRCH which describe the structure of the radical cations of the four monohaloacetylenes I(X) (X = F, Cl, Br, I) in their 2IIΩ(1) and 2IIΩ(2) states have been determined. It is shown that the results are in agreement with theoretical expectation and that they confirm the band assignement proposed in a previous communication [2].
Crystallographic Studies of Synthetic Corrinoids. III. Structural similarities and differences between A/D‐seco‐corrinoid complexes of divalent nickel, palladium and platinum
Authors: Currie Murdoch , Dunitz J. D.
Published: December 2004

X‐ray crystal structure investigations of the isomorphous perchlorate salts of complexes of an A/D‐seco‐corrinoid ligand (I) with divalent nickel, palladium and platinum are reported. The structures determined for the Pd‐ and Pt‐complexes are virtually superposable, that of the Ni‐complex, although similar to the other two, shows significant differences with respect to metal coordination and to the spatial relationship of the A and D rings and their substituents. These similarities and differences are discussed in relation to the photochemical A/D cyclization leading to corrin complexes (II).
Studies on Solubilization. (Part I). Note on the synthesis of some quaternary N‐(ω‐aryloxyalkyl) piperidinium, pyridinium, benzyl‐dimethyl‐ammonium, and trimethyl‐ammonium bromides
Authors: Joshi R. K. , Krasnec L. , Lacko I.
Published: December 2004

A series of new N‐(ω‐aryloxyalkyl) piperidinium, pyridinium, benzyl dimethyl ammonium, and trimethyl ammonium bromides is described.
The Interaction of π‐Orbitals in Barrelene
Authors: Haselbach E. , Heilbronner E. , Schröder G.
Published: December 2004

The photoelectron spectrum (PE. spectrum) of barrelene (bicyclo[2.2.2]octatriene, 4) is recorded and the first four bands are correlated with orbitals obtained with the MINDO/2‐SCF procedure. The structural changes accompagnying the ionisation process 4 → 4+ are qualitatively derived from the features of the top‐occupied a′2 (π) MO of 4, which shows complete σ‐π separation. The vibrational pattern of the corresponding PE. band 1. as well as complete energy‐minimisation of the geometries of 4 and 4+ support the conclusion that 4 is a rather strained molecule. The interaction of the three πbonds in 4 are discussed in terms of ‘through‐space’ and ‘through‐bond’ interaction with lower lying σ‐orbitals. It is found that the latter is far from being negligible.
Die Komplexe der Hexamine «penten» und «ptetraen» Thermodynamik ihrer Bildung in wässeriger Lösung
Authors: Paoletti P. , Walser R. , Vacca A. , Schwarzenbach G.
Published: December 2004

The two hexamines (H2NCH2CH2)2N(CH2)nN(CH2CH2NH2)2, «penten» (n = 2) and «ptetraen» (n=3) have been investigated as chelating agents for COIII (preparative Study) and some of the divalent metal ions (potentiometric and calorimetric studies). Both amines function as sexadentate ligands for CoIII, CoII and NiII, but one of the terminal aminogroups is much easier detached from the metal in case of M (penten)v+ than in case of M(ptetraen)v+, thus revealing more strain in the fivemembered chelate rings of the girdle plane of the «penten» complexes. On the other hand, the sixmembered chelate ring in M(ptetraen)v+ is more strained than the five‐membered ring comprising the tertiary nitrogen atoms of M(penten)v+ CuII and ZnII coordinate with both ligands only 5 of the 6 basic nitrogen atoms present. Both hexaamines function as sexadentates again with MnII, but the metal is coordinated with a molecule of water in addition to the 6 nitrogen atoms in the «penten» complex in contrast to the «ptetraen» complex. The thermodynamic functions for the protonation of the hexamines and for the addition of metal ions in aqueous solution are understood in almost every detail. The dielectric shielding of the charges of the reactants exerted by the solvent has to be taken into account; it is reduced by electrostriction as well as by an increase in temperature. It is shown that the approach of charges of equal sign often is an exothermic process.
Höhere, kondensierte Ringsysteme. 6. Mitteilung [1]. NBS‐Dehydrierungen an 9,10‐Dihydrophenanthrensystemen Synthese von [23] (2,7) Phenanthrenophan‐trien
Authors: Baumgartner P. , Paioni R. , Jenny W.
Published: December 2004

The usefulness of the low temperature dehydrogenation by N‐bromosuccinimide is illustrated in the 9, 10‐dihydrophenantheren serie. The syntheses of 2, 7‐di‐chloromethyl‐phenanthrene, 2, 7‐di‐bromomethyl‐phenanthrene and hexabromo‐[23] (2,7) phenanthrenophane by NBS‐dehydrogenation are described. Debromination of hexabromo‐[23] (2,7) phenanthrenophane led to [23] (2,7) phenanthrenophane‐triene. The structure of these new compounds was confirmed by NMR.‐, UV.‐ and mass spectroscopy.
Pyrolysis of N‐Sulfinylaniline Microwave Detection of the SO Molecule. Preliminary communication
Authors: Saito Shuji , Wentrup Curt
Published: December 2004

Gas‐phase pyrolysis of N‐sulfinylaniline at 650–980°C produces SO (3Σ−), identified by its rotational line, J, K = 2,1 → 1,0 in the microwave spectrum, increasing in intensity with the temperature. SO2 was observed with a parallel absorption intensity in the same temperature interval; its partial pressure was determined as ca. 8% at 980°. The results confirm the dissociation of N‐sulfinylaniline into phenylnitrene and sulfur monoxide.
Die molekulare und kristalline Struktur von 9,10‐Dihydro‐4‐(3‐dimethylamino‐propyliden)‐4H‐benzo[4,5] cyclohepta[1,2‐b]thiophen‐hydrochlorid. Untersuchungen über synthetishe Arzneimittel, 19. Mitteilung [1]
Authors: Bastian J. M. , Weber H. P.
Published: December 2004

The α‐isomer of 9,10‐dihydro‐4‐(3‐dimethylamino‐propylidene)‐4 H‐benzo[4,5] cyclohepta [1, 2‐b] thiophen is shown to have the trans configuration by means of an X‐ray analysis of its hydrochloride.
Über den Verteilungssatz der Auxochrome bei Azokörpern, II Dihydroxy‐azobenzole
Authors: Kokkinos K. , Wizinger R.
Published: December 2004

The validity of the rule of repartition of the auxochromes is examined for dihydroxy‐azo and dihydroxy‐4′‐nitro‐azo compounds with hydroxy groups in 2,4‐, 3,4‐ and 2,5‐position. In conformity with the rule the absorption maximum of the 2, 5‐dihydroxy‐azobenzene is situated at a considerably longer wave length than the maximum of 2,4‐dihydroxy‐azobenzene. The 3, 4‐isomer with its absorption maximum at a relatively short wave‐length seems to contradict the rule. On the other hand all alkali salts of both series conform to the rule of repartition in an impressive way.
An Efficient Synthesis of Thyrotropin Releasing Hormone (TRH)
Authors: Rivaille Pierre , Milhaud Gérard
Published: December 2004

A convenient and simple synthesis of L‐pyroglutamyl‐L‐histidyl‐L‐prolinamide is described. Two pathways using the solid phase technique have led to the pure tripeptide.
Zur Photochemie des Caryophyllens und des iso‐Caryophyllens Umlagerungen ihrer 1,5‐Diensysteme nach direkter π,π*‐Anregung in flüssiger Phase
Authors: Schulte‐Elte K. H. , Ohloff G.
Published: December 2004

When caryophyllene (1) and isocaryophyllene (2) are irradiated at their π,π*‐ transitions (λ ≤ 253.7 nm) they rearrange relatively rapidly and in high yield to mixtures of isomeric sesquiterpene hydrocarbons. Compounds 3–11, the structural determinations of which are described, represent 90% of the photoisomers. All the rearrangements involve the 1, 5‐diene systems, and, with the exception of cis‐trans isomerizations, fragmentation of the doubly allylic σ‐bond and disappearance of the trisubstituted double bond always occur. The cyclopropane, acetylene, allene, and 1, 5‐diene compounds resulting are the first examples of this type of photo‐isomerization products obtained from unconjugated monomeric 1, 5‐dienes by direct excitation with light. Their formation appears to be stereospecific, and is dependent on the stereochemistry of the double bond system in 1 and 2. In addition to the cis‐isomer 2 caryophyllene yields only compounds 3, 4, and 5, while from isocaryophyllene, compounds 8, 9, 10 and 11 are formed in addition to 1. The only isomerization products common to both caryophyllenes (1 and 2) are 6 and 7. This behaviour and the lack of positive identification of a biradical (triplet) intermediate lead to the probable conclusion that the greater part of the photoisomerization occurs directly from the excited singlet states. Possible mechanisms for the formation of the photoisomerization products are discussed.
Die Synthese von Insulinfragmenten mit intakter interchenarer Disulfidbrücke A20‐B19
Authors: Kamber B.
Published: December 2004

The synthesis of six insulin fragments is described, in which various sequences of the two chains are linked by the disulfide bridge between A20 and B19. The fragments in question are: A20–21–B19–21, A20–21–B18–21, A20–21–B17–21, A19–21–B19–21, A16–21–B18–21 and A20–21–B12–21.

In order to build up the simpler fragments the disulfide bridge was established by oxidation with iodine of two S‐trityl cysteine peptides in which the carboxyl and amino groups were protected by the t‐butyl and t‐butyloxycarbonyl residue. From the mixture obtained the unsymmetrical cystine peptide was separated in all cases from the two symmetrical ones by counter‐current distribution.

In the synthesis of the more complex fragments advantageous use was made of smaller unsymmetrical fragments prepared as above but having one amino group protected by the N‐trityl residue. After selective elimination of this group it was possible to lengthen the peptide chain at this position.

The free peptides were obtained by removal of the protecting groups with strong acids, in particular concentrated hydrochloric acid. While in this deprotecting step the disulfide bond was stable, conditions are discussed under which disproportionation was observed.

None of the six synthetic insulin fragments showed activity in stimulating rat adipose tissue to convert 14C‐labelled glucose to CO2 in vitro.
Berechnung von freien Hydratationsenthalpien und Koordinationszahlen für Kationen aus leicht zugänglichen Parametern
Authors: Morf W. E. , Simon W.
Published: December 2004

A model for the computation of free energies of hydration and coordination numbers of cations using easily available parameters is described. For 27 mono‐, di‐ and trivalent cations the mean deviation of the calculated from the experimental ΔG°H values is 3.9%. All the computed coordination numbers agree with experimental ones.
Gentisinacetal und Chlorgentisinalkohol, zwei neue Metabolite einer Phoma species
Authors: Séquin‐Frey M. , Tamm Ch.
Published: December 2004

From cultures of a Phoma species (strain S729) (Fungi imperfecti) gentisylalcohol (1), toluhydroquinone (3), and two new metabolites, gentisylacetal (2) and chlorogentisylalcohol (4), have been isolated. The structure of 2 was proven by cleavage to gentisylalcohol (1) and acetaldehyde, and by resynthesis from these moieties. The synthesis of chlorogentisylalcohol (2,5‐dihydroxy‐3‐chloro‐benzyl alcohol) (4) and its two isomers 5 and 6 from chlorohydroquinone (10) via the aldehydes 7,8, and 9 respectively established the structure of this metabolite.
Photochemical Reactions. Part 63 [1]. The photodecarbonylation of α‐aryl aldehydes
Authors: Küntzel H. , Wolf H. , Schaffner K.
Published: December 2004

Ultraviolet irradiation of the aldehydes 6–11 in degassed solutions results exclusively in decarbonylation to the major products 34, 35 and 37–40, and to small amounts of 2, 3‐diphenyl‐2, 3‐dimethyl‐butanes 36 from the phenyl aldehydes 6 and 7. In the presence of tri‐n‐butylstannane, incorporation of stannane hydrogen competes, to substrate‐specific limits, with the intramolecular deuterium transfer in 7 → 35 and 11 → 40. The quantum yields for decarbonylation are Φ ∼ 0.4–1.0 for the phenyl aldehydes 6 and 9, and 0.02 for 8. Hammett correlations of Φ with resonance constants (R) for 6 (X = H, p‐CH3, OCH3) and (CF3) and with ωm+ values for the meta‐substituted isomers are in agreement with the proposed α‐cleavage to an associated radical pair with only moderate free radical character as the primary photochemical step.

Φ for 10 (X = H) is 0.11, and for 10 (X = OCH3) 0.065. It is noteworthy that decarbonylation of 10 (X = OCH3) occurs also at 3340 Å (ΦCO = 0.11) i.e., upon excitation in an absorption band which is presumably lower in energy than the n → π* transition and corresponds to the aromatic Lb transition of 2‐methoxynaphthalene.

Singlet multiplicity of the reactive excited states is probable on the basis of the fact that the decarbonylation of 6 (X = H) and 10 (X = H and OCH3) could be sensitised neither by acetone nor acetophenone, and could be quenched neither by naphthalene nor by cis‐1, 3‐pentadiene and nor by 1, 3‐cyclohexadiene.
Stabilité des carboxylates de terres rares, IV N‐acétylglycinates
Authors: Roulet R. , Chenaux R. , Vu Duc T.
Published: December 2004

The stability constants of N‐acetylgycinates of some rare earths in aqueous solution have been determined by a potentiometric method, and by a solvent extraction technique. The ligand forms 1:1 complexes which are stabilized by relatively large positive entropies of formation, the corresponding enthalpies being endothermic. This backs up the assumption that a conjugate base of an amino acid forms innersphere complexes and acts as a unidentate ligand towards a rare earth cation, like a simple carboxylate.
Chiroptische Eigenschaften und Äquilibrierungen stereoisomerer Yohimbane und ihrer 17‐Ketoderivate
Authors: Bartlett L. , Klyne W. , Dastoor N. J. , Schmid H. , Hrbek J. , Snatzkec G.
Published: December 2004

The chiroptical properties (CD. and ORD.) of four stereoisomeric yohimbanes (1–4) and the corresponding 17‐keto derivatives 5–8 have been studied. The aromatic and the ketonic Cotton effects have been considered in terms of the appropriate Sector and Octant Rules, respectively. Positively charged nitrogen makes an ‘anti‐octant’ contribution to the ketonic Cotton effect.

The chiroptical properties, the NMR. spectra and dehydrogenation reactions with mercuric acetate together indicate the presence of a C/D‐trans‐quinolizidine system in all the compounds studied, except those of the pseudo series (3 and 7), in which a C/D‐cis‐quinolizidine system is present. An explanation of the unexpectedly slow dehydrogenation of the 3‐epi‐allo compounds 4 and 8 is suggested.

Conformational analysis of the results of equilibration experiments on pairs of 3‐epimeric compounds (in both glacial acetic acid at 145° and in K‐t‐butylate at 211°) leads independently to conclusions which agree with those drawn from the physical methods. The great differences between the equilibrium positions of the free bases and the protonated forms are due to the presence in the latter cases of oriented ion pairs R3N+H…︁−O2CCH3.
Molecular Conformation of Benzylideneanilines
Authors: Bürgi H. B. , Dunitz J. D.
Published: December 2004

The non‐planar conformations of benzylideneanilines and the almost planar conformations of stilbene and azobenzene are consistently reproduced by a simple model, which takes into account the dependence of π‐electron energy and non‐bonded interactions on molecular conformation. Other aspects of the molecular geometry of benzylideneanilines.(bond angles influence of p‐substituents) are also discussed.
Synthese und Auftrennung von racemischen, isomeren Desoxo‐demethylcassain‐Derivaten. 1. Mitteilung über Cassain‐Analoga
Authors: Hauth H. , Stauffacher D.
Published: December 2004

For the synthesis of analogues of Erythrophleum alkaloids the tricyclic ketones 3 (trans‐anti‐trans) and 5 (trans‐anti‐cis) were prepared. Reaction of 3 and 5 with triethyl phosphonoacetate led to a mixture of cis/trans compounds, which could be separated in a preparative scale into the uniform racemic isomers 8 and 9, 22 and 23, respectively. Transesterification of these compounds gave the corresponding 2‐dimethylamino‐ethyl esters.
Zur Konfiguration racemischer 14‐Demethyl‐cassensäure‐und ‐isocassensäure‐Derivate. 2. Mitteilung über Cassain‐Analoga [1]
Authors: Hauth H. , Niklaus P. , Stauffacher D.
Published: December 2004

The structures of four synthetic isomeric analogues of cassaine were confirmed by detailed interpretation of their NMR. spectra.
Nachweis von (+)‐epi‐Muscarin in Inocybe geophylla. 36. Mitteilung über Muscarin und verwandte Stoffe
Authors: Bollinger H. , Eugster C. H.
Published: December 2004

Die enantiomeren epi‐Normuscarine lassen sich in Form der diastereomeren α‐Methoxypropionsäureester gas‐chromatographisch trennen. Bei Verwendung von (S)‐α‐Methoxypropionsäure als Veresterungskomponente konnte gezeigt werden, dass das in Inocybe geophylla (Sow. ex Fr.) Quél. (Basidiomycetes) vorkommende epi‐Muscarin das (+)‐Enantionmere darstellt.
Synthèses du nuciféral‐(E)‐(RS)
Authors: Gast Gérard , Naves Yves‐René
Published: December 2004

The synthesis of (RS)‐(E)‐nuciferal has been realized by two ways, starting from 2‐(p‐tolyl)‐propanal, by Wittig's reactions.
Contribution à l'étude du système quaternaire KClRbClCsClH2O: II. L'isotherme de 25°C
Authors: Merbach A. , Gonella J.
Published: December 2004

The experimental study at 25°C of the system KClRbClCsClH2O has shown the existence of a new type of quaternary system with formation of mixed crystals. — The solubility diagram is characterized by the presence of one univariant line and one binary miscibility gap. Two types of solid solutions are present: (K, Rb, Cs) Cl and (K, Rb, Cs) Cl; the incorporation in the latter is small.
Catalytic Aminomethylation of Alkenoic Compounds: I. Reaction of monoolefins with secondary amines, carbon monoxide, and water in the presence of rhodium and iron catalysts
Authors: Iqbal Abul F. M.
Published: December 2004

Reactions, in the presence of rhodium oxide and/or iron pentacarbonyl, of cyclic or acyclic higher olefins with carbon monoxide, water, and secondary amines to give the corresponding aminomethyl‐cycloalkanes or ‐alkanes (equ. 1) are described. As catalyst rhodium oxide is by far superior to iron carbonyl; however, optimum results are obtained with combinations of the two. The method can be applied to synthesis of long‐chain alkylamines, which are valuable as intermediates for synthetic detergents.
n→π*‐Übergänge in Dicarbonylverbindungen Der Einfluss der n, n‐ und π*, π*‐Wechselwirkung
Authors: Hug W. , Kuhn J. , Seibold K. J. , Labhart H. , Wagnière G.
Published: December 2004

By CNDO‐CI calculations we have found that dicarbonyl compounds exhibit only two n → π* transitions in the visible or near UV. region, instead of four as expected from simpler MO‐models. The dominant features of the long‐wavelength electronic spectra may be characterized by the relative energy of the two n and the two lowest π* orbitals. In general we distinguish between three cases:

Large splitting (about 2 eV) both between the n and the π* orbitals. The longest‐wavelength n → π* transition is shifted to the red. The higher transition remains roughly where it would appear in the monocarbonyl compound.

No or very small splitting between either the two n, or the two π* orbitals, or both. Both n → π* transitions merge, roughly, in the wavelength region of the corresponding monocarbonyl compound.

Intermediate (0.5–1.0 eV) splitting between the two n orbitals on one hand, the two π* orbitals on the other. Spectral properties between A. and B.

The splitting between the two n orbitals and the two π* orbitals depends not only on the distance between the two carbonyl groups, but also very strongly on their mutual position and on the nature of the molecular fragment connecting them. As one would expect, in α‐dicarbonyl compounds the splitting between the n orbitals is large, namely 1.8 eV. In some γ‐diketones such as P‐quinone, one still finds, however, a value of 0.7 eV. The splitting between the n orbitals gets significantly lowered if the two carbonyl groups are coaxial, but their 2pπ nodal planes are perpendicular to each other. In planar β‐diketones the splitting between the π* orbitals is small, but may increase to an effective value of 0.4 eV when they are skewed.

Our calculations agree well with measured electronic spectra and CD. data. An electrochromism experiment on camphorquinone convincingly supports our conclusions on α‐dicarbonyl compounds.
Chimie et pharmacologie de l'apiose. IV. (Hydroxyméthyl‐3‐β‐D‐érythrofurannosyl)‐9‐adénine: Synthèse, conformation en solution et essais biologiques préliminaires
Authors: Tronchet J. M. J. , Tronchet Mme J.
Published: December 2004

The title compound, an apionucleoside, has been synthesized and is shown by NMR. to exist mainly in the conformation E3′. The reasons why this branched‐chain nucleoside is not a substrate for adenosine deaminase are discussed. The compound inhibits the growth of Escherichia coli and Staphylococcus aureus in synthetic liquid media.
Reaction of Bicyclo[3.2.1]octenols with Thionyl Chloride. Preliminary paper
Authors: Jefford C. W. , Gunsher J. A.
Published: December 2004

The allylic 1‐methyl‐3‐bromobicyclo[3.2.1]octenyl exo‐2 and exo‐4 alcohols were treated with thionyl chloride in ether or pentane solution at 0°. In each case, a 50/50 mixture of exo allylic chlorides was obtained. No evidence for a predominant SN l′ reaction was detected; reported cases of such SN l′ processes using these conditions should therefore be treated with reserve.
Die Jodierung von desaktivierten aromatischen Aminen in wässeriger Phase
Authors: Toth I.
Published: December 2004

By treatment of deactivated aromatic amines such as 4‐nitroaniline, 4‐aminobenzonitrile or 2‐bromo‐4‐nitro‐aniline with iodine in water at 90–93° for 30–35 hours, in the presence of hydrogen peroxide, monoiodinated products with over 99% purity are obtained in 88–98% yield.
Reaktivität von Koordinationsverbindungen, XXIII [1]. Bildung und Zerfall des Sauerstoffadduktes mit N,N′‐Bis‐(4‐(5)‐imidazolylmethyl)‐äthylendiamin‐kobalt (II)‐Ionen
Authors: Zuberbühler A. , Kaden Th. , Koechlin F.
Published: December 2004

In aqueous solution N, N′‐bis‐(4‐(5)‐imidazolylmethyl)‐ethylenediamine‐cobalt (II) (CoIMEN2+) takes up molecular oxygen giving μ‐dioxygen‐μ‐hydroxo‐bis‐[N, N′‐bis‐(4‐(5)‐imidazolylmethyl)‐ethylenediamine]‐dicobalt (II). (Co IMEN)2 O2 (OH)3+ is exceptionally stable against irreversible autoxydation to CoIII species. Its absorption spectrum is very similar to that of the known analogous complex (CoTRIEN)2 O2 (OH)3+.

The kinetics of formation and dissociation of (CoIMEN)2O2(OH)3+ are studied by spectrophotometry and with an oxygen specific electrode. The rate of the forward reaction is described by vf = [CoIMEN2+]2 · [O2] · (k1 + k2 · [OH−]) with k1 = 9 · 104 M−2 s−1 and k2 = 1 · 1012M−3 S−1, at 25° and I = 0,2. A mechanism including hydroxylated as well as nonhydroxylated intermediates is proposed. Dissociation is preceeded by protonation of the oxygen adduct. At pH 1–2 the rate of dissociation is independent of [H+] and follows first order kinetics: vD = k3 · [(CoIMEN)2O2(OH)3+] with k3 = 2.15 · 10−2 S−1.
Über Sapogenine. 1. Mitteilung. Über die Konstitution eines neuen Sapogenins aus Helleborus odorus Waldtst. et Kit. und Helleborus niger L.
Authors: Linde Hermann F. G. , Isaac Otto , Linde Horst H. A. , Živanov Dobrila
Published: December 2004

A new sapogenin, 1, isolated from Helleborus odorus Waldst. et Kit. and Helleborus niger L. (Ranunculaceae) is shown to be spirost‐5,25 (27)‐dien‐1b̃, 3b̃, 11α‐triol.
Das organoleptische Prinzip von Cassis‐Flavor im Buccublätteröl
Authors: Sundt E. , Willhalm B. , Chappaz R. , Ohloff G.
Published: December 2004

The diastereoisomeres of p‐menthone‐8‐thiol, derived from (+)‐menthol, are the first ketothiols of the terpene series to have been found in nature. Stereochemistry, methods of preparation and olfactory properties of the new compounds are described.
Synthesen der stereoisomeren (±)‐γ‐Damascone
Authors: Schulte‐Elte K. H. , Rautenstrauch V. , Ohloff G.
Published: December 2004

Under the conditions of the Wharton reaction, the (±)‐epoxy‐γ‐dihydroionones 2 and 3 are transformed into the allylic alcohols 4–10. γ‐Damascols 4, 5 and 8 were oxidised to cis‐ and trans‐γ‐damascone 12 and 13. Alternatively, dehydro‐γ‐damascol 18 was obtained by Wittig rearrangement of butinyl ether 17, and converted into damascones 12 and 13.
Spectres de masse des composés organiques. 5e communication. Perte de méthane et d'éthylène à partir des ions butyle
Authors: Liardon Réamy , Gäann Tino
Published: December 2004

The loss of methane and ethylene in the mass‐spectrometric fragmentation of different isomeric butyl ions which originate from butyl halides has been studied. The different carbon atoms in n‐butyl are already equivalent after 10−7 s, whereas the statistical distribution of the hydrogen atoms within the molecule can only be observed for the metastable peaks. A protonated cyclobutane structure is proposed as an intermediate product in the fragmentation of the n‐butyl ion. The fragmentation of this model has been simulated by a computer. This allows prediction as to the time‐scale of fragmentation. The comparison of this model fragmentation with that of isomeric butyl ions shows that, even in the decay of the tertiary butyl ion, the formation of the proposed rearranged cyclic structure competes favorably with the direct fragmentation.
Indolo[3,3a,4‐gh]chinoline und 10a, 6a‐Iminopropano‐indolo‐[3,3a,4‐gh]chinoline. Stereospezifische Synthesen und Umlagerungen. Teil II. 9. Mitteilung über synthetische Indolverbindungen
Authors: Stoll André P. , Niklaus P. , Troxler F.
Published: December 2004

Alkaline hydrolysis of 1‐benzyl‐4, 4‐dicyanoethyl‐5‐oxo‐1,3,4,5‐tetrahydro‐benzo‐[cd]indole under controlled conditions leads to 4‐benzyl‐4,6,7,8‐tetrahydro‐10a, 6a‐iminopropanoindolo[3,3a,4‐gh]quinoline‐9(10H),12‐dione (2a), the first representative of such a ring system. Alkylation of this di‐lactam affords the N‐monoalkyl (2b), the N, N'‐dialkyl (3), and the N, O‐dialkyl (4) derivatives according to the conditions employed. Treatment of compounds such as 2 with sodium in liquid ammonia results in the opening of one of the lactam rings by a stereoelectronically controlled reductive cleavage of the benzylamine bond; subsequent protonation proceeds stereospecifically to give trans‐octahydroindolo[3,3a, 4‐gh]quinolines (viz. 5). The NMR. spectra and the mechanism of the reductive ring opening are discussed.
Synthese von 2‐Thioaldosen über α,β‐ungesättigte Nitrokörper
Authors: Wirz P. , Hardegger E.
Published: December 2004

Die basenkatalysierte Reaktion von Thiocarbonsäuren oder Benzylmercaptan mit dem aus D‐Arabinose leicht zugänglichen α,β‐ungesättigten Nitrokörper III verläuft kinetisch kontrolliert bevorzugt zu Verbindungen der Reihe V mit D‐manno‐Konfiguration. Am Beispiel des Benzylthioäthers Vb wurde ein präparativ gangbarer Weg zur Synthese von 2‐Thio‐D‐mannose (XIV) und 2‐Thio‐D‐glucose (XVIII) gewiesen.
Synthese von D‐ und L‐S‐Auro‐1‐thio‐xylit
Authors: Wirz P. , StanêK J. , Hardegger E.
Published: December 2004

Ausgehend von S‐Benzyl‐1, 2‐O‐isopropyliden‐5‐thio‐α‐D‐xylose (Ia) wurde durch Abspaltung der Isopropylidengruppe, Reduktion und Acetylierung 2,3,4,5‐Tetra‐O‐acetyl‐S‐benzyl‐1‐thio‐L‐xylit (IV) hergestellt, der, mit Natrium in flüssigem Ammoniak entbenzyliert, über das Acetylderivat IVb zum 1‐Thio‐L‐xylit (IV c) führte. IV c wurde als krist. Octaacetyl‐disulfid V charakterisiert und in S‐Auro‐1‐thio‐L‐xylit (IV d) umgewandelt. – Dieselbe Reaktions‐folge mit den enantiomeren Verbindungen führte zum S‐Auro‐1‐thio‐D‐xylit (VI a).
Zur Konstitution des Pigment Red 177
Authors: Manukian B. K. , Mangini A.
Published: December 2004

Auf Grund von Elementaranalyse sowie VIS.‐, IR.‐, NMR.‐ und Massen‐Spektroskopie wird dem Pigmentfarbstoff Colour Index Pigment Red 177 die Struktur des 4,4′‐Diamino‐1, 1′‐di‐anthrachinonyls zugeschrieben.
Synthese und Umlagerungsreaktionen von 2‐(2‐Amino‐anilino)‐2‐imidazolin‐Derivaten
Authors: Härter H. P. , Stauss U. , Schindler O.
Published: December 2004

The nitro‐imidazolines V and VI are formed by addition reaction of ethylenediamine to the isothiocyanates III and IV. The nitro group is then converted by hydrogenation to the amino group, giving XI and XII, which can be acylated selectively to IX and X. By rearrangement in boiling xylene, the compounds XI and XII give the corresponding 2‐(2‐aminoethylamino)‐benzimidazoles XIII and XIV. The benzoylated derivative IX gives the benzimidazole derivative XVIII by rearrangement and subsequent migration of the benzoyl group, while the benzylated derivative XVI gives the rearranged benzimidazole XXII. The benzimidazole structure of the rearranged products is proven by unambiguous synthesis of XIII, starting with 2‐chlorobenzimidazole (VII) and mono‐N‐acetyl‐ethylene‐diamine to give compound VIII, from which XIII is obtained by hydrolysis.
Zur Konfiguration von zwei isomeren rac.‐Cassansäure‐Derivaten.3. Mitteilung über Cassain‐Analoga
Authors: Hauth H. , Stauffacher D.
Published: December 2004

Catalytic hydrogenation of cassenic and isocassenic acid derivatives (1 resp. 2) led to a mixture of the two isomers 3 and 4, which could be separated. The structures of these isomers were confirmed.
Echanges isotopiques d'hydrogène T‐H, T‐D, D‐H et H‐D de la diazoacétone et du diazoacétaldéhyde: Vitesse de protonation et effets isotopiques. Communication préliminaire
Authors: Dahn H. , Malherbe R. , Beaud P.
Published: December 2004

The velocities of four acid‐catalysed hydrogen isotope exchange reactions between diazoacetone (1) and water (T → H, T → D, D → H, and H → D) and of three exchange reactions between diazoacetaldehyde (2) and water (T → H, T → D, and H → D) have been measured. The exchange D → H of 1 was found to be submit to general acid catalysis (αB = 0.6). The rates of protonation of primary and secondary diazocarbonyl compounds of similar structure were found to be quite similar, in spite of difference in mecanism (A‐2 and A‐SE2, respectively).
Infrared Spectra of α‐Thenoyl‐trifluoroacetonates of Metal Ions of the First Transition Series
Authors: Shephard G. S. , Thornton D. A.
Published: December 2004

The IR. spectra of α‐thenoyl‐trifluoroacetone (HTTA) and seventeen of its chelates with metal(II) and ‐(III) ions of the first transition series have been determined. Three series of complexes are represented: the anhydrous metal(II) species, [M(TTA)2]n (M  Ca, Mn, Co, Ni, Cu, Zn); metal(II) dihydrates, [M(TTA)2(H2O)2] (M  Mn, Fe, Co, Ni, Zn); and the metal(III) chelates, [M(TTA)3] (M  Sc, V, Cr, Mn, Fe, Ga). For each metal(II) complex, the spectra of the anhydrous and hydrated compounds are practically identical, suggesting that the anhydrous complexes have the polynuclear octahedral structure established for the corresponding acetylacetonates. Magnetic moment determinations reveal that complexes of the 3d4−3d7 ions all have spin‐free configuration. Several vibrational bands with frequencies < 700 cm−1 are found to exhibit a frequency variation with d‐orbital population which is consistent with the order of crystal field stabilization energies and hence with their assignment as coupled metal‐oxygen stretching modes. Unique features of the spectra of [Cu(TTA)2] and [Mn(TTA)3] are ascribed to structural differences arising from Jahn‐Teller distortion. Tentative assignments for the majority of the ligand vibrations are given.
Spectroscopic Evidence for Symmetry‐Restricted π‐Interaction in Vanadyl β‐Keto‐enolates
Authors: Haigh J. M. , Thornton D. A.
Published: December 2004

Theoretical treatments of the distorted square pyramidal co‐ordination observed in vanadyl β‐keto‐enolates predict restricted interligand conjugation and minimal π‐interaction in the oxovanadium‐ligand bonds. The effects of ligand substitution on the vibrational and electronic spectra of vanadyl β‐keto‐enolates yield evidence that strong σ‐bonding and ionic contributions are chiefly responsible for the strong vanadium‐ligand bonding.
Etude des composés d'addition des acides de Lewis ‐ XXXV. Note sur les composés d'addition entre amides et, respectivement, PdCl2 et PtCl2
Authors: Gioria J. M. , Susz B. P.
Published: December 2004

The adducts of dimethylformamide, diethylformamide, dimethylacetamide and diethylacetamide with PdCl2 and PtCl2 have been prepared and the IR. spectra of the compounds in nujol mull or in CH2Cl · CH2Cl solution are studied. The lowering of the carbonyl frequency (amide I) shows that the metal is linked by a dative bond to the amide oxygen atom acting as a donor; the lowering is about 33 to 59 cm−1.

The decrease of the frequency of the carbonyl group vibration, observed in these cases as for other addition compounds of Lewis acids, is due to an intramolecular electronic displacement in the direction of the amid oxygen atom.
Die elektronische Struktur einfacher Stickstoff‐und sauerstoffhaltiger Verbindungen
Authors: Kuhn J. , Hug W. , Geiger R. , Wagnière G.
Published: December 2004

A general review is given of the UV.‐spectroscopic properties of some simple molecules containing the NβN and NβO bond, respectively. The electronic structure of nitrosomethane, azomethane, trimethylamine oxide, azomethane N,N'‐dioxide, nitromethane, methyl nitrite are reinvestigated by the SCF‐CI method, within the frame of the all‐valence CNDO procedure. These calculations confirm a number of older assignments, but also allow predictions concerning some not settled questions. For instance, nitroalkanes should exhibit not one but two n–π* transitions, namely at 275 nm and around 350 nm. This prediction agrees with conclusions by Djerassi and co‐workers on the spectra of some nitrosteroids.

Particular attention is given to the symmetry and relative energetic position of nonbonding orbitals. The question of “ basicity” and “ease of protonation” is discussed in relation to it. Calculations on the overall charge distribution complement this investigation.
Thermisches Verhalten von 1‐Acylbenzocyclobutenen; eine neue Isochromensynthese
Authors: Hug R. , Hansen H.‐J. , Schmid H.
Published: December 2004

1‐Acyl‐benzocyclobutenes (8, 9, 10), on heating in diluted decane solution at 175–185°, rearrange to the corresponding 3‐substituted isochromenes (11, 12, 13).
Die Umsetzung protonierter Alkene mit Thioäthern: Eine neue Methode zur Darstellung von Sulfoniumverbindungen
Authors: Bosshard H.
Published: December 2004

Thioethers reacted with protonated alkenes yield quantitatively alkylsulfonium salts. The rate of the reaction is dependent on the proton activity of the medium and characterized by a maximum which is determined by the protonation of the nucleophile (thioether). The reaction is following the rule of Markownikoff.
Surface chemistry of polymers. The adsorption of carbon dioxide and sulfur dioxide on polyvinylidene chloride
Authors: Stoeckli H. F.
Published: December 2004

Isotherms for the adsorption of nitrogen (77 K), carbon dioxide (195–247 K) and sulfur dioxide (254–293 K) on polyvinylidene chloride have been measured volumetrically. The B.E.T. cross‐sectional areas of 18 Å2 (CO2) and 24 Å2 (SO2) are comparable to liquid density values. The isosteric heat of adsorption of CO2 is constant for 0.2 < θ < 0.4 and is lower than the latent heat of condensation. For SO2, the two are practically identical up to the monolayer. Entropy calculations show ‘supermobility’ in the case of CO2.
Participation π dans la solvolyse des diazocétones primaires. Communication préliminaire
Authors: Malherbe R. , Tam Nguyen Thi Thanh , Dahn H.
Published: December 2004

In the acid catalyzed hydrolysis of 5,6‐unsaturated diazoketones of suitable geometry (Ib, IIb, IIIb, IVb, VIb), participation of the double bond in the reaction of the diazonium ion is proved (a) by the formation of cyclisation products, and (b) in some cases by the acceleration of the rate determining SN2 substitution process. In the case of VIb the substitution step is so much accelerated that the pre‐equilibrium protonation step becomes rate determining (evidence: inversion of the kinetic solvent isotope effect).
Photoelectron Spectra of Azabenzenes and Azanaphthalenes: III. The orbital sequence in methyl‐ and trimethylsilyl‐substituted pyridines
Authors: Heilbronner E. , Hornung V. , Pinkerton F. H. , Thames S. F.
Published: December 2004

The ionization potentials of methyl‐, t‐butyl‐ and trimethylsilyl‐substituted pyridines have been determined by high‐resolution photoelectron spectroscopy. The results are discussed in terms of destabilizing inductive and stabilizing conjugative effects of the substituents, and have been parametrized on the basis of a HMO‐type perturbation treatment. Our data are in accord with the idea that the topmost occupied orbital in pyridine is a ‘lone pair’ orbital.
Allyl‐Aluminium Compounds
Authors: Stefani A. , Pino P.
Published: December 2004

The preparation of aluminium derivatives containing allyl or methallyl groups is reported. Their reactivity and physical properties are discussed.
Utilisation d'ylides du phosphore en chimie des sucres. XI. Synthèse des quatre didésoxy‐3, 5‐méthyl‐3‐pentoses parl'intermédiaire de sucres insaturés ramifiés
Authors: Tronchet J. M. J. , Graf R.
Published: December 2004

Treated with methylthiomethylenetriphenylphosphorane, 5‐deoxy‐1,2‐O‐iso‐propylidene‐β‐D‐threo‐ and ‐α‐D‐erythro‐furanos‐3‐uloses led with good yields to a mixture of the cis‐trans isomers of the corresponding methylthiovinylidenic sugars. There was no inversion of configuration at C(4) with the thero‐furanosulose and a small one (7%) with its erythro isomer. These unsaturated branched‐chain thio‐sugars are useful synthetic intermediates. For examples, the desulfurization‐hydrogenation (Raney Nickel) of each of these alkenes afforded in good yield two 3‐deoxy‐3‐C‐methyl‐pentoses epimeric at C(3) and having the same configuration at C(4) as the starting alkenes. In all cases the isomer formed by attack from the less hindered face of the double bond was the preponderant one.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 3. Mitteilung. Thiadiazol‐Ringschluss und eine dabei auftretende Methylübertragung
Authors: Rüfenacht K.
Published: December 2004

Methods for the synthesis of 5‐alkoxy‐ and 5‐alkylthio‐1,3,4‐thiadiazol‐2(3H)‐ones and ‐thiones, known in principle, are extended and adapted for large scale preparations.

In the particular case of 5‐methoxy‐1,3,4‐thiadiazol‐2(3H)‐thione the cyclisation of thiocarbazic O‐methyl ester using alcoholic alkali and carbon disulfide added in this order surprisingly yields by transmethylation 5‐methylthio‐1,3,4‐thiadiazol‐2(3H)‐one, isomer of the expected 5‐methoxy‐1,3,4‐thiadiazol‐2(3H)‐thione. This latter compound is obtained when the reactants are applied in the inverse sequence. A possible mechanism for this behaviour is presented.
Nucleosides and Nucleotides. Part 2: Synthesis of both anomers of 1‐(5′‐O‐phosphoryl‐2′‐deoxy‐D‐ribofuranosyl)‐2(1H)‐pyridone [1]
Authors: Séquin U. , Tamm Ch.
Published: December 2004

The two anomeric 1‐(2′‐deoxy‐D‐ribofuranosyl)‐2(1H)‐pyridones 6 and 7 were synthesized from 2‐pyridone and 3,5‐di‐(O‐p‐toluoyl)‐2‐deoxy‐D‐ribofuranosyl chloride (2) via the di‐O‐p‐toluoyl derivatives 3 and 4 using the mercuric halide procedure. Phosphorylation of the nucleosides 6 and 7 by bis‐(2,2,2‐trichloroethyl)‐chlorophosphate gave the phosphate esters 8 and 9 together with some 2‐(bis‐[2,2,2‐trichloroethyl]‐phosphoryloxy)‐pyridine 10, which proved to be very labile. Structure and configuration of compounds 6 to 9 were established by spectral methods, the configurations being derived from the chemical shifts of the sugar protons and the splitting patterns of the anomeric protons (‘triplet‐quartet rule’). The specific rotations of 3, 4, 6, 7, 8 and 9 show that the three pairs of anomers represent exceptions to Hudson's rule of isorotation.

Reductive removal of the trichloroethyl groups in 8 and 9 with zinc proceeds stepwise, yielding the phosphoro‐diesters 13 and 14 and the two desired anomeric 5′‐nucleotides 15 and 16. These latter were purified and characterised as the ammonium salts.

Enzymatic cleavage by the 5′‐nucleotidase of Crotalus adamanteus venom took place only in the ‘natural’ β‐series. The ‘unnatural’ α‐anomers were resistent to the enzyme.

The structure of 10 was established by spectral methods and confirmed by synthesis.
Terpene Compounds as Drugs, XVI. Characterization of the anabolic 19‐nortestosterone 17β‐trans, trans‐ and ‐cis, trans‐homofarnesate
Authors: Pala G. , Mantegani A. , Zugna E. , Gallazzi A. , Vanoni P. C.
Published: December 2004

19‐Nortestosterone 17β‐trans, trans‐ and ‐cis, trans‐homofarnesate 1 and 2 have been prepared and characterized. Their structure and configuration were identified by mode of formation, elemental analyses, IR. and particularly by NMR. spectra.
Indolalkaloide aus den Blättern von Hedranthera barteri (Hook. f.) Pichon. 146. Mitteilung über Alkaloide
Authors: Naranjo J. , Hesse M. , Schmid H.
Published: December 2004

From the leaves of the West African plant (Apocynaceae Hedranthera barteri) has been isolated the phenolic (−)‐desmethyl‐vobtusine (3), alongside the already known bisindole alkaloids (−)‐goziline (1) and (−)‐vobtusine (2). The new alkaloid 3 has been spectroscopically characterised and correlated with (−)‐vobtusine (2).

Furthermore, the ‘monomeric’ alkaloids (−)‐hedrantherine (4) and (−)‐17‐hydroxy‐hedran‐therine (5) were found in the leaves of H. barteri. Both of these alkaloids contain a cyclic semiacetal group. These bases and their derivatives possessing an unchanged β‐anilinoacrylester group show, in the mass spectrometer, the same characteristic fragmentation as vincadifformine (11), whilst their 2,3‐dihydroderivatives bear more of a resemblance to aspidospermine. From the strongly negative Cotton effect of 4 and 22 at 300–350 nm follows the absolute configuration in these bases of centre 12.

Hedrantherine (4) represents the lower half of the bisindole type of vobtusine bases. The upper half has previously been encountered in form of the alkaloid beninine in the rootbark of H. barteri.
Nachbargruppeneffekte bei massenspektrometrischen Fragmentierungsreaktionen: substituierte 1,3‐Diaminopropan‐Derivate. 17. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen
Authors: Lerch Elsbeth , Hesse M.
Published: December 2004

The mass spectrometric behaviour of the 1,3‐diaminopropane derivative 4a (3,7‐diacetyl‐3,7‐diazadodecane) was investigated with regard to the fragmentation reactions of N, N′, N″‐triacetylspermidine (1), as model for the 1,3‐diaminopropane part. It was established that the degradation reactions in 4a and 1 are essentially the same and mainly due to the interaction of two N‐acetyl groups. Thereby it is established that the most important mass spectrometric fragmentation reactions of spermidine derivatives take place within the 1,3‐diaminopropane unit and are independent of the influence of further N‐atoms in the molecule. An ion (m/e 143) was found in the fragmentation pattern of N, N′, N″‐triacetylspermidine whose formation can be explained by interaction of all three N‐acetyl groups. The corresponding ion was not found, in the spectrum of 4a, with only two N‐acetyl groups, thereby confirming the earlier hypothesis.
Sur l'acylation des mäthylfluorànes V. Formylation selon Rieche du mäthy1‐1‐fluoráne
Authors: Chardonnens Louis , Noël François
Published: December 2004

The formylation of 1‐methylfluorene according Rieche yields 1‐methyl‐2‐fluorene‐carbaldehyde, the constitution of which being proved by three independent ways.
Dipolmoment und Konformation von Imino‐äther‐Derivaten
Authors: Exner O. , Schindler O.
Published: December 2004

By means of the dipole moments of several imidic acid esters the conformation at the CO bond and the configuration at the CN bond have been determined. Use was made of the graphical comparison of a phenyl‐derivative with the para‐substituted analogue [7] in combination with cyclic model compounds having forced stereochemistry. The results obtained are conclusive for the N‐alkyl‐derivatives which are in the Eap form A. The imidic acid esters which are unsubstituted at the nitrogen are prevailingly in the same Eap conformation A; another conformation, probably the Zap form B, may also be present in smaller amounts.
Nucleoside und Nucleotide. Teil 3. Über die Polykondensation von Thymidin‐3′‐phosphat nach der Triestermethode
Authors: Falk W. , Tamm Ch.
Published: December 2004

Condensation of a mixture of 25 mole per cent of 5′‐O‐p‐methoxy‐trityl‐thymidine3′‐[(β‐cyanoethyl)phosphate] and 75 mole per cent of thymidine 3′‐[(β‐cyanoethyl)phosphate] in pyridine yielded a mixture of oligonucleotides, the largest being the pentanucleotide. It was demonstrated that longer chains are not obtained due to the formation of a C‐pyridinium‐thymidine nucleotide. For avoiding this undesired side reaction, the condensation was carried out using sym.‐collidine as solvent. The analogous side reaction was not observed, longer chains of oligonucleotide were not obtained, however.
Preparation, Properties and Structure of Phenylthionophosphine Oxide (Phenylmonothiophosphonic Anhydride), [C6H5P(S)O]3
Authors: Daly J. J. , Maier L. , Sanz F.
Published: December 2004

Interaction of phenylthiophosphonic dichloride with H2S in the presence of triethylamine in benzene solution yields phenylthionophosphine oxide (I) which, in solution as well as in the solid state, is a trimer (Ib); an X‐ray structural analysis indicates a nearly planar sixmembered ring structure with PO bonds in the ring.
Mercaptokomplexe von Indium(III)
Authors: Tunaboylu K. , Schwarzenbach G.
Published: December 2004

The complexes of In(III) with thioglycolate (HOCH2CH2S−) have been investigated by pH‐metric methods. Only the mononuclear species In(SR)n(3‐n)+ (n = 1, 2, 3, 4) are formed (Fig. 1): It was difficult to obtain an accurate value for the first stability constant K1 because of the high stability of the 1:1‐complex and therefore mixtures of KCl‐KNO3 were used to keep up the ionic strength of μ = 0.1. In presence of chloride, the constants Kn are smaller because of the formation of chloro complexes and mixed complexes In(SR)nCli(3‐n‐1)+ and the stability constants of these have also been determined. The constants for the complexes without coordinated chloride can finally be obtained by an extrapolation (Fig. 2). The problem of the influence of increasing charge on the stability of various complexes of the isoelectronic 4d10 cations is discussed (Fig. 3).
Utilisation d'ylides du phosphore en chimie des sucres. XII Dérivés du D‐arabino‐hexène‐1‐tétrol‐3,4,5,6
Authors: Tronchet J. M. J. , Baehler Br.
Published: December 2004

The preparation of several kinds of derivatives of 1‐substituted D‐arabinc‐hex‐1‐ene‐3,4,5,6‐tetrols is described. Some of these compounds, having a ‘pseudo‐formyl’ group (CHCHCN, CHCHSO2CH3) are ‘pseudo‐aldehydo‐sugars’. Their ability to react as aldehydo‐sugars was examined in light of their 13C‐NMR. spectra which provide information on their electron density at C(1) and C(2).
Bestimmung der Verteilung von Tritiumatomen in aliphatischen Mono‐ und Dicarbonsäuren
Authors: Jordan P. , Reichen W.
Published: December 2004

In order to determine the distribution of tritiumatoms in non saturated alicyclic hydrocarbon molecules, a new degradation method which gives higher yields than the methods used heretofore, was developed. It is a modification of the method of Hunter‐Popjak. Results obtained with palmitic acid as test substance, and with suberic acid as degradation product of cis‐cyclooctene, are given.