bluuebunny/crossref_metadata_2025 huggingface dataset:
Über das makrocyclische Spermidinalkaloid Inandenin. 138. Mitteilung über Alkaloide.
Authors: Veith H. J. , Hesse M. , Schmid H.
Published: December 2004

The novel spermidine alkaloid inandenine was isolated from Oncinotis inandensis Wood et Evans. It was found to be a mixture of two isomers A and B, which could not be separated hitherto. Chemical and mass‐spectrometric investigations revealed that both alkaloids possess the macrocyclic 21‐ring structure 3a and 3b. These two formulae differ only with respect to the position of the ketogroup. Structural elements of the two bases are 9‐oxo‐ and 10‐oxo‐palmitic acid, respectively, and spermidine.
Über die Reaktion von Schwefel mit N,N'‐Dimethyl‐äthylendiamin und Formaldehyd. Eine neue Methode zur Herstellung von 1, 3‐Dimethylimidazolidin‐2‐thion und N‐Formyl‐N'‐thioformyl‐N, N'‐dimethyl‐äthylen‐1,2‐diamin
Authors: Maier Ludwig
Published: December 2004

The reaction of sulfur with N, N'‐dimethylethylenediamine and formaldehyde has been studied. A simple, one step process for the preparation of N‐formyl‐N'‐thioformyl‐N, N'‐dimethylethylene‐1, 2‐diamine (I) and 1, 3‐dimethylimidazolidine‐2‐thione (II) is reported. The physical properties and 1H‐NMR. spectra of I and II are given.
Photoelectron‐spectroscopic Evidence Concerning “Homo‐aromaticity”
Authors: Bischof P. , Gleiter R. , Heilbronner E.
Published: December 2004

The first of the two π‐bands in the photoelectron spectrum of cis‐cis‐cis‐1, 4, 7‐cyclononatriene (I, symmetry C3v) shows a Jahn‐Teller split. This is consistent with the prediction of molecular orbital theory that the top occupied orbitals of I are e(π) and a1(π) respectively. From the difference ϵ(e(π)) ‐ ϵ(a1(π)) = 0.90 to 0.97 eV a value of β1,3 = −0.68 eV = 0.27 β (β = ‐2.5 eV) is obtained for the homoconjugative interaction of two π‐orbitals in I. This value represents almost exclusively through‐space interaction between the π‐orbitals. Through‐bond interaction (hyperconjugation) is a minor effect in I. A comparison of the photoelectron data of bicyclo [4.2.1] nonatriene with those of norbornene and cycloheptadiene shows that homoconjugation (homo‐aromaticity) can only be detected by photoelectron spectroscopy if the interacting π‐bonds (basis orbitals) are symmetry equivalent or have accidentally (almost) degenerate energies.
Über Pterinchemie. 33., vorläufige Mitteilung. Luftoxydation von 6,6‐disubstituierten Tetrahydropterinen, ein Beitrag zur Frage der Existenz von Parachinoid‐dihydropterinen
Authors: Viscontini M. , Frater‐Schroeder M. , Cogoli‐Greuter M. , Argentini M.
Published: December 2004

Die Luftoxydation von 6,6‐disubstituierten Tetrahydropterinen führt nicht, wie vermutet, zu Parachinoid‐dihydropterinen, sondern unter Verlust einer der beiden Seitenketten zu 7, 8‐Dihydropterinen. Dieses Ergebnis wird im Zusammenhang mit der existierenden Theorie der Tetrahydropterin‐Oxydation kurz diskutiert.
Oxydation allylique sélective en chimie des sucres au moyen du réactif de Fétizon. Note de laboratoire
Authors: Tronchet J. M. J. , Tronchet Mme J. , Birkhäuser Mme A.
Published: December 2004

D‐glucal is selectively oxidised to the corresponding enone with a 60–80% yield by Fétizon's reagent (Ag2CO3‐celite).
Die photosensibilisierte Oxydation einwertiger Phenole zu Chinonen
Authors: Pfoertner K. , Böse D.
Published: December 2004

The photosensitized oxidation of methyl substituted phenols with free para‐positions starts with an electrophilic attack of position 4 by singlet oxygen. This follows from the course of the reaction using phenols with methyl groups in different positions. The influence of the solvent shows that the hydroperoxide formation from the primary oxygen adduct proceeds via an inter‐molecular hydrogen shift. The solvent is the hydrogen donator, whereas the phenoxy radicals resulting from the oxidation of the phenol by the excited sensitizer are the hydrogen acceptors. Finally, the quinones are formed from the hydroperoxides by elimination of water.
Mechanismus und Selektivität des Alkali‐Ionentransportes in Modell‐Membranen in Gegenwart des Antibioticums Valinomycin
Authors: Wipf H.‐K. , Olivier A. , Simon W.
Published: December 2004

Selective transport of potassium ions through synthetic membranes impregnated with valinomycin in octane‐2‐ol in the presence of equal amounts of K+ and Na+ or Li+ ions is induced on application of a potential difference across these membranes. By using 14C‐labelled valinomycin it is shown that transport of potassium ions is accompanied by an equivalent transport of valinomycin within the membrane, consistent with the formation of a 1 : 1 complex of K+ with valinomycin. The exchange of ligands is shown to occur during the transport process so that a carrier‐relay mechanism, as proposed earlier for macrotetrolide‐mediated potassium transport, accounts for all experimental results on the bulk membranes studied.
ESR. Spectra of the Radical Anion of Dimethyl‐phenyl‐phosphine
Authors: Gerson F. , Plattner G. , Bock H.
Published: December 2004

ESR. spectra of the radical anion (I⊖) produced from dimethyl‐phenyl‐phosphine (I) both by electrolysis and reaction with alkali metals have been studied upon variation of temperature. The coupling constant assigned to the 31P nucleus depends strongly on temperature, whereas the coupling constants attributed to protons do not exhibit such a dependence. The π‐spin populations at the benzene ring of I⊖ give evidence ‐ in accordance with other experimental data [1] [2] – that the dimethylphosphino substituent is electron‐attracting. This effect is thought to be due mainly to P ← Cπ delocalization, which is analogous to the SiCπ interaction in trimethylsilyl‐substituted π‐systems [3].

The ESR. spectrum previously [4] ascribed to I⊖ is shown to arise from a secondary radical. The formation and structure of this radical are briefly discussed.
The Partial O‐Demethylation of Aromatic‐Substituted 3,4‐Dihydroisoquinolines
Authors: Brossi A. , Teitel S.
Published: December 2004

A detailed study has shown that all possible aromatic dimethoxy‐substituted 3,4‐dihydroisoquinolines can be partially O‐demethylated by controlled acid hydrolysis. Based on the structure elucidation of the monophenols thus obtained, it was established that preferential cleavage occurs at the 5‐methoxyl with the 5,6‐ and 5,8‐isomers 1 and 3, respectively, at the 6‐methoxyl with the 6,8‐isomer 4, at the 7‐methoxyl with the 5,7‐isomer 5, and at the 8‐methoxyl with the 7,8‐isomer 2.
Der Stoffwechsel von Verbindungen mit Dreifachbindung V. Der Abbau von Diincarbonsäuren und Kohlenwasserstoffen in vivo
Authors: Bernhard Karl , Kaempf Ekkehard
Published: December 2004

10,12‐Heneicosadiynoic acid (I), 5,7‐hexadecadiynoic acid (IV), and 10,12‐docosadiynedioic acid (VI) were fed to rats. As metabolites 4,6‐undecadiynedioic acid (II), 5,7‐dodecadiynedioic acid (V), and 4,6‐decadiynedioic acid (VII) respectively were isolated from the urine. 10,12‐Heptadecadiynoic acid (III) also yielded metabolite II. Furthermore 9,11‐eicosadiyne (X) and for comparison purposes eicosane (XI), hexadecanedioic acid (VIII), and docosanedioic acid (IX) were fed. X and XI were incorporated into depot fat and liver lipids to a cetain degree. The diynes I, II, IV, and X are new compounds.
Steric Rate‐Retardation in the Chromium Trioxide Oxidation of 4,6‐Dimethyl‐benzocyclobutenol
Authors: Müller Paul
Published: December 2004

The rate of oxidation of 4, 6‐dimethyl‐benzocyclobutenol

This nomenclature is preferred in the literature [1] [2] to the more systematic name (7‐hydroxy‐3, 5‐dimethyl‐bicyclo [4.2.0] octa‐1,3,5‐triene).

(1) with chromium trioxide has been measured. After correction for the influence of the two methyl substituents the rate of oxidation of 1 is lower than that of 1‐tetralol (9) and 1‐indanol (10) by factors of 3 and 5 respectively. The lower oxidation rate of 1 as compared to 9 and 10 is interpreted in terms of a steric rate retardation arising from angle strain in the developing carbonyl function of 4, 6‐dimethylbenzocyclobutenone (4).
Stabilité des carboxylates de terres, III. Maléates, méthylsuccinates et malates
Authors: Roulet R. , Feuz J. , Vu Duc T.
Published: December 2004

The stability constants of maleates, methylsuccinates and malates of rare earths have been determined at 25.0 °C and at ionic strength 0,100 (NaClO4) by a potentiometric method. Each ligand forms 1 : 1 and 1 : 2 complexes in aqueous solution, the malates being the most stable. The first and the second dissociation constants of the ligand acids were also measured. The 1 : 2 maleates of La, Pr, Nd, Sm, and Eu have been isolated.
Dünnschichtchromatographie als Hilfsmittel in der Radiochemie. 5. Mitteilung. Abtrennung von Hg aus einem Gemisch von Kationen
Authors: Seiler H.
Published: December 2004

The separation of Hg from a mixture of many cations by thin‐layer chromatography, and its subsequent determination by activation analysis is described.
Reaction of Isocyanates and Isothiocyanates with Butyraldazine; Formation of 1‐Substituted 2‐Pyrazolines
Authors: Zirngibl Ludwig , Tam S. W.
Published: December 2004

Phenyl isothiocyanate reacts with butyraldazine in presence of acidic catalysts to form a 2‐pyrazoline (IV) whereas phenyl or benzyl isocyanates under similar conditions yield a mixture of the two isomeric 2‐pyrazolines XIa and XII. On reaction with Ac2O, IV gave the 1‐acetyl derivative V. Reduction with LiAlH4 led to the corresponding pyrazolidines. Reexamination of Kost's three step preparation of a 1‐phenylthiocarbamoyl 2‐pyrazoline [19] such as X via formic acid cyclization [18] of butyraldazine revealed that his first step product was apparently a mixture of two stereoisomeric 1‐formyl‐2‐pyrazolines VIIIa and VIIIb. A mechanism for the formation of these pyrazolines is proposed.
Preparation of a 2‐Methylcyclodopa Derivative
Authors: Fischer Nikolaus , Dreiding André S.
Published: December 2004

Die Herstellung von O,O‐Diacetyl‐S‐2‐methylcyclodopa‐methylester (7) durch Oxydation von S‐2‐Methyldopa‐methylester (4) und anschliessende Reduktion und Acetylierung ist beschrieben. Im Gegensatz zu Cyclodopa (2) wird 2‐Methylcyclodopa‐methylester (6) am Stickstoff durch Acetanhydrid und Pyridin nicht acetyliert.
Organische Phosphorverbindungen 40. Methoden zur Herstellung von Pentamethylen‐1,5‐bis‐(dihydroxyphosphonylmethyl‐phosphinsäure) [1]
Authors: Maier Ludwig
Published: December 2004

Alkyl‐pentamethylene‐1,5‐bis‐(dialkyloxyphosphonylmethyl‐phosphinates) (VII) are formed in high yield by heating alkyl pentamethylene‐1,5‐diphosphonites, (RO)2P(CH2)5P(OR)2, with alkyl chloromethylphosphonates, ClCH2P(O)(OR)2, at 170° for several hours until evolution of alkyl halides ceases. Hydrolysis to the corresponding acid (VIII) is effected by refluxing with conc. HCl for 40 h.

The synthesis and properties of some other 1,5‐diphosphorus‐substituted pentanes, i.e., H2P(CH2)5PH2, Cl2P(CH2)5PCl2, (Et2N)2P(CH2)5P(NEt2)2, (EtO) (HO)P(CH2)5P(OH)(OEt), and (HO)2P(CH2)5P(OH)2, are also reported.
Ligandenverdrängungsreaktionen von Kobalt‐dicyclopentadienyl mit tertiären Phosphiten – Darstellung und Eigenschaften der Komplexe C5H5Co[P(OR)3]2
Authors: Harder V. , Müller J. , Werner H.
Published: December 2004

The reaction of Co(C5H5)2 with tertiary phosphites mainly gives the half‐sandwich type compounds C5H5Co[P(OR)3]2 (R = CH3, C2H5, C6H5), which are characterised by means of their IR., UV., and NMR. spectroscopic data. The mass spectra of the new compounds are discussed.
Crystallographic Studies of Synthetic Corrinoids. II. Molecular structure of a C/D‐seco‐corrinoid nickel(II) complex
Authors: Dobler M. , Dunitz J. D.
Published: December 2004

An X‐ray crystal structure analysis of the perchlorate salt of the C/D‐seco‐corrinoid nickel(II) complex I is reported. The structural transformations that occur in the base‐catalysed iminoester‐enamine condensation of I leading to the corrin complex II are discussed.
Der Mechanismus der Hydrolyse von Chlortriazinen in protischen Lösungsmitteln. II. Mitteilung Über nukleophile uromatische Substitutionen
Authors: Rys P. , Schmitz A. , Zollinger H.
Published: December 2004

The complex kinetics found for the hydrolysis of 1, 3, 5‐trichloro‐s‐triazine in 9/91% (v) acetone/water at 10.0°C have been evaluated as a function of the hydroxyl ion and the acetate ion concentration using an analogue computer. The kinetics are consistent with a nonsteady state mechanism in which the primary intermediate anion is protonated giving a neutral species whose concentration goes through a maximum during the course of the reaction. This secondary intermediate forms the final product by deprotonation and release of a chloride ion. The product itself can undergo a second (reversible) deprotonation.

In dimethylsulfoxide the analogous intermediate of the hydrolysis of 1, 3‐dimethoxy‐5‐chloro‐s‐triazine can be identified by analysis of the NMR. and UV. spectra.
Komplexone VL. Reaktionsenthalpie und ‐entropie bei der Bildung der 1 : 1‐Komplexe der Seltenen Erdionen mit 1,3‐Diaminopropan‐N, N, N′, N′‐tetraacetat
Authors: Anderegg G. , Wenk F.
Published: December 2004

The stability constants of the 1 :1 complexes of trimethylenediamine‐N, N, N′ N′ tetraacetate ‘TMTA’ with rare earth trivalent cations have been checked. The heats involved in complex formation have been determined.

The thermodynamic data show a similar trend as for those of the EDTA complexes, but the discontinuities in the plots ΔH vs. 1/r and ΔS vs. 1/r are displaced towards lower values of 1/r.

A change of the coordination number and of the number of coordinated water molecules for the complexes along the series La3+ – Lu3+ is suggested. The simultaneous presence in solution of species differing only in the number of bonded H2O for some members of the series has been confirmed by spectrophotometric measurements in the temperature range 2 to 70°.

All facts support the conclusion that in dilute solution all SEIII aquo ions exhibit the same coordination number.
Organische Phosphorverbindungen 44 Darstellung und Eigenschaften von Bis‐(ß‐chloräthyl)‐phosphinsäure‐Derivaten [1]
Authors: Maier Ludwig
Published: December 2004

Reaction of ClCH2CH2PCl2 with ethylene oxide gives the phosphonous acid ester ClCH2CH2P (OCH2CH2Cl)2 which on heating to 120° rearranges to the phosphinic acid ester (ClCH2CH2)2P(O)OCH2CH2Cl (3). Chlorination of 3 with PCl5 in CCl4‐solution yields the phosphinic chloride (ClCH2CH2)P(O)Cl (4), which on treatment with P2S5 at 170° produces the thioderivative, (ClCH2CH2)2P(S)Cl, (5). Treatment of 4 and 5 with alcohols, mercaptanes, or amines in the presence of an acid binding agent leads to the corresponding phosphinic and thiophosphinic acid derivatives, (ClCH2CH2) P (X)Y, (X = O, S; Y = OR, SR, NR2) (6). Reaction of 6 with excess base yields the corresponding divinylphosphinic and divinylthiophosphinic acid derivatives (CH2 = CH)2P (X) Y (X = O, S; Y = OR, SR, NR2) (7).

Bis‐(ß‐chloroethyl)‐phosphinates, e. g. (ClCH2CH2)2P (O) OEt, undergo a Michaelis‐Arbuzov reaction when heated with phosphites to 160–170° to give bis‐(phosphonylethyl)‐phosphinates, e.g. (EtO) (O)P[CH2CH2CH2P(O)(OEt)2]2 (8), which on hydrolysis with conc. HCl under reflux yield the corresponding acid HO2P(CH2CH2PO3H2)2.
Über Ketoxime der 9,10‐Dihydro‐4H‐benzo[4,5]cyclohepta[1,2‐b]thiophene und ihre Umlagerungen zu 4,5,10,11‐Tetrahydro‐benzothienoazocinen. Untersuchungen über synthetische Arzneimittel, 18. Mitteilung [1]
Authors: Bastian J. M. , Ebnöther A. , Jucker E.
Published: December 2004

Les oximes des dihydro‐9,10‐4 H‐benzo [4,5] cyclohepta [1, 2‐b] thiophénones‐4 et leurs dérivés ont été synthétisés et transposés selon Beckmann en benzo [b] thiéno [2, 3‐f] azocines et benzo [c] thiéno‐[2,3‐g]azocines. Des dérivés basiques de ces nouveaux composés tricycliques ont été synthétisés.
Thermisches Verhalten von Cyclopropa[c]chromenen
Authors: Hug R. , Fráter Gy. , Hansen H.‐J. , Schmid H.
Published: December 2004

The Cyclopropa[c]chromenes 14, trans‐and cis‐15, trans‐and cis‐16 and 17 rearrange on heating > 200° in N, N‐diethylaniline to give 2‐alkyl‐2H‐chromenes 7, 8, 21, 22. The rate determining step of this rearrangement is the ‘homoelectrocyclic’ ring opening of the cyclopro‐pa[c]chromenes to give ω‐allyl‐quinomethanes of type 4. These intermediates show fast [1,5s] and [1,7a] H‐shifts, followed by electrocyclic ring closure. Deuterium labelling experiments are in agreement with this mechanism. The remarkable dependence of the rates of rearrangement with respect to the stereochemistry of the cyclopropa[c]chromenes (cf. table 2) suggests that in the first step only one of the two possible disrotatory modes of ring opening is involved.
Über den Verteilungssatz der Auxochrome bei Azokörpern, I. Di‐ und Tetramethoxy‐xobenzole
Authors: Kokkinos K. , Wizinger R.
Published: December 2004

The validity of the rule of repartition of the auxochromes is examined for some symmetric tetramethoxy‐azobenzenes, dimethoxy‐azobenzenes, and dimethoxy‐4′‐nitro‐azobenzenes whose methoxy groups are in 2,4‐, 3,4‐ and 2,5‐position. The rule is confirmed with 2,4‐and 2,5‐derivatives. The long wave lengths absorption maxima of 3,4,3′,4′‐tetramethoxy‐azobenzene and of 3,4‐dimethoxy‐4′‐nitro‐azobenzene are situated at shorter wave lengths than expected.
Neue alkaloide aus Adhatoda vasica Nees
Authors: Johne S. , Gröger D. , Hesse M.
Published: December 2004

In addition to the known alkaloid peganine (1) from young plants of the Acanthacea Adhatoda vasica, the base anisotine (7) and the three new alkaloids vasicoline (4), adhatodine (5), and vasicolinone (6) were isolated and analysed. Mainly on the basis of spectral properties (UV., IR., NMR. and mass spectrometry) the structures were assigned. By atmospheric oxygen the bases vasicoline and adhatodine are oxidized in position 7; it is therefore remarkable that these bases are present as such in the plant.
Etude de Composés d'Addition d'acides de Lewis‐XXXII [1]. Composés d'addition d'aldéhydes aliphatiques et aromatiques et de diverses cétones
Authors: Filippini Franchino , Susz Bernard‐P.
Published: December 2004

Treize composés d'addition d'aldéhydes et de cétones ont été préparés avec divers acides de Lewis (HgCl2, ZnCl2, CdCl2, SbCl5 et NbCl5). A l'état solide, ils possèdent une stoechiométrie bien définie. Pour tous ces composés d'addition, la fréquence de vibration ω(CO) de la base de Lewis (1600–1700 cm−1) subit un abaissement marqué Δω, allant de −15 cm−1 (HgCl2) à −167 cm−1 (NbCl5), ce qui prouve que leur formation est due à l'établissement d'une liaison de coordination entre l'atome d'oxygène donneur et l'acide de Lewis.

Il existe une bonne corrélation linéaire entre ω(CO) des aldéhydes aromatiques ou entre Δω de leurs composés d'addition avec SbCl5 et la constante ωr du type de Hammett ou le potentiel de demi‐vague de la réduction polarographique.

Les auteurs ont calculé les constantes de force de H2CO·SbCl5 en se référant aux valeurs expérimentales des fréquences de vibration, en appliquant la méthode FG à un modèle plan de 5 masses. L'abaissement de FCO est d'environ 7%, alors que Δω/ω vaut environ −5%. La variation de longueur de la liaison carbonyle contribue pour 55,7% à l'énergie potentielle de ω(CO) de H2CO et pour 56,4% à celle de H2CO·SbCl5.
Die Valenzisomerisierung des trans‐15, 16‐Dimethyl‐dihydropyrens ‐ ein beitrag zur frage nach der aktivierungsenergie symmetrie‐verbotener prozesse. Vorläufige mitteilung
Authors: Schmidt W.
Published: December 2004

Concerted electrocyclic processes which are forbidden according to the symmetry conservation rules of Woodward & Hoffmann, may nevertheless take place at low activation energies. The necessary conditions are exemplified by the unique case of the trans‐15, 16‐dimethyl‐dihydropyrene ⇌ 15, 16‐dimethyl‐[2.2]metacyclophane‐4,9‐diene system.
Über die Bedeutung des Histidins im «Thyrotropin‐releasing» Hormon (TRH)
Authors: Gillessen D. , Studer R. O. , Piva F. , Steiner H.
Published: December 2004

The syntheses and biological activities of 4 analogues of the thyrotropin‐releasing hormone (TRH) are described. In these analogues the histidine residue has been replaced by L‐lysine, L‐α,γ‐diaminobutyric acid, β‐(3‐pyrazolyl)‐L‐alanine, and L‐arginine. All analogues exhibited the characteristic biological responses of TRH. For the β‐(3‐pyrazolyl)‐L‐alanine analogue as well as for TRH the bioassays suggest an induction of a strong and rapid resynthesis of thyrotropin (TSH) in higher (μg) concentrations.
Notiz zur Konstitution des Laurepukins. 8. Mitteilung über natürliche und synthetische Isochinolin‐Derivate
Authors: Weiss Ek. , Bernauer Karl , Girardet A.
Published: December 2004

The alkaloid (−)‐laurepukine is shown to possess one of the epimeric N‐oxide structures 4 or 5. Oxidation of (−)‐pukateine (3) by hydrogen peroxide gives (−)‐laurepukine and, as a second product, 6‐epi‐laurepukine.
Die Komplexbildung der neutralen Amidgruppe mit Cu2+ in wässeriger Lösung
Authors: Kaden Th. , Zuberbühler A.
Published: December 2004

The interaction between Cu2+ and the terdentate ligands N‐picolinoyl‐ethylenediamine, glycine‐2‐pyridylmethylamide, Nα‐(2‐pyridylmethyl)‐glycinamide and Nα‐(2‐pyridylmethyl)‐glycine‐ethylamide, respectively, has been studied by spectrophotometry and potentiometry. At high pH values the ionised amide group undergoes complex formation and the resulting chelates have similar structures and stabilities. In slightly acidic solution however, each ligand gives rise to a different species. These facts are explained by assuming that the neutral amide group coordinates through its carbonyl oxygen atom. The stability constant and the absorption spectrum of each complex have been calculated by computer programmes.
Strahlungschemie von Kohlenwasserstoffen. 19. Mitteilung. Die Deuteriumabspaltung in isotop‐isomeren Cyclohexanen
Authors: Ballenegger M. , Ruf A. , Gäumann T.
Published: December 2004

The G‐value for D2 production has been measured for C6D12 and for gem‐, cis‐, and trans‐C6H10D2. The G‐values for the unimolecular process are 0.24, 0.023, 0.010 and 0.004, resp. In C6D12 two bimolecular processes can be distinguished: one includes ‘hot’ D‐atoms, e. g. a species that shows no isotope effect for the hydrogen abstraction yielding D2 and HD, resp.; its G‐value is 1.22. The other process goes via thermal D‐atoms, it has a G‐value of 1.97 and gives an isotope effect for abstraction: kD/kH = 0.075 (10°C). In the partially deuteriated cyclohexanes, only the former process can be observed. Its G‐value depends on the irradiation temperature and phase, is independent of the position of the D‐atoms in the molecule and amounts to 0.035 (10°C), 0.028 (−40°C solid), 0.040 (−40°C liquid with 25% hexane). The following conclusions can be drawn: the unimolecular detachment shows no intramolecular isotope effect in partially deuteriated molecules and comes only from the gem‐, cis‐ and trans‐positions. Most of the G‐values for the D2 and HD production by different reaction paths can be cross‐checked by G‐values from different mixtures. The agreement between these values is excellent.
Etude de la séparation de traces de mercure ionique par adsorption, en milieu aqueux, sur verre sodocalcique. Application à la séparation Hg2+‐organomercuriels
Authors: Haerdi W. , Gorgia E. , Lakhoual N.
Published: December 2004

The separation conditions of traces of ionic mercury from aqueous solution on microbeads of soda lime are studied theoretically and established experimentally. The formation of a stable complex of the ion with ethylene diamine allows to operate at pH 7–8. The efficiency of the exchange is close to 96%. The methods allows the separation and essay of ionic mercury in presence of various organomercuric compounds.
Struktur von Coleon C, einem neuen Blattfarbstoff aus Coleus aquaticus Gürcke
Authors: Rüedi P. , Eugster C. H.
Published: December 2004

From the yellow glands on the leaves and inflorescences of Coleus aquaticus Gürcke (Labiatae) a new, yellow diterpenoid hydroquinone, coleon C, C20H26O6, was isolated and its structure elucidated as 1. The compound contains a novel 1‐hydroxyprop‐2‐yl‐side chain at C(13).
Synthese und Eigenschaften von Thiazolo[3,2‐a]pyrimidinen und Thiazolo [3,2‐a] pyrrolo [2,3‐d]pyrimidinen
Authors: Bormann G. , Troxler F.
Published: December 2004

From the alkali‐catalysed reaction of thiouracil with bromoacetaldehyde diethyl acetal three products are isolated in nearly the same quantity: 2‐(2, 2‐diethoxyethylthio)‐uracil (2) and two cyclization products: 3, a thiazolo[3, 2‐a]pyrimidin‐5‐one, and 4, athiazolo[3, 2‐a]pyrimidin7‐one. By warming with acid both 2 and 4 yield 3. Rearrangement of 4 to 3 proceeds also by heating the hydrochloride. Similar cyclizations leading to thiazolo[3, 2‐d]pyrrolo[2, 3‐d]pyrimidin‐5‐ones are also described. Bromine substitutes 3 in position 6. The bromo derivative 6 on treatment with primary or secondary amines affords 7‐amino compounds.
Structure of boromycin
Authors: Dunitz J. D. , Hawley D. M. , Mikloš D. , White D. N. J. , Berlin Yu. , Marušić R. , Prelog V.
Published: December 2004

The structure II of boromycin C45H74BNO15 (cf. [2]) has been established by combination of chemical evidence with X‐ray analysis. The antibiotic is a D‐valine ester of a Böeseken‐complex of boric acid with a macrodiolide of a new type.
Farbstoffsensibilisierte Photo‐Oxygenierung von(−)‐cis‐Pulegol und (+)‐Pulegon. Zur Addition von O2(1Δg) an Doppelbindungen mit allylständiger. Hydroxyl‐ oder Carbonyl‐Gruppe
Authors: Schulte‐Elte K. H. , Gadola M. , Müller B. L.
Published: December 2004

(−)‐cis‐Pulegol (1) and (+)‐pulegone (2) readily add one mole of oxygen on dyesensitized photo‐oxygenation in solution, forming almost exclusively allyl hydroperoxides.

The product distributions and structures of the peroxides (B–E) have been derived from analysis of their reduction products. Compound 1 yielded only the diols 4, 5 and 6, besides the epoxyketones 7 and 8 formed directly from the hydroperoxide C (proportions of 4–8, ∼21:56:13:4:6), while 2 gave the keto‐alcohols 9,10 and 11 (∼80:6:14) as the sole products.

The course of addition of O2(1Δg) on 1 and 2 was found in all cases to be independent of solvent and photosensitizer.
Recherches sur les arǒmes, 18e communication Sur l'arǒme de viande de boeuf grillée, I. Pyrazines
Authors: Flament I. , Ohloff G.
Published: December 2004

A combined gas chromatography‐mass spectrometry analysis of roasted meat flavor prepared by pyrolysis of water‐soluble components of fresh beef has yielded 17 alkylpyrazines (5 already found in heated beef fat), one being a new flavor compound. The mass spectrum of this compound is given.
Rates of Chromium(VI)‐Oxidation of Benzocyclenols
Authors: Müller Paul
Published: December 2004

The oxidation rate of benzocyclobutenol (6) and of the homologous alcohols up to 1‐benzocyclo‐octenol (7) with chromium (VI) has been determined in 90% acetic acid. The rate profile for the oxidation reaction is similar to that obtained for the solvolysis of the corresponding chlorides, and clearly shows a low reactivity for the benzocyclobutenyl skeleton, for reactions in which the hybridization changes from sp3 to sp2. On the other hand, semicarbazone formation occurs faster with benzocyclobutenone (6a) than with the homologous ketones. The implication of these results for the oxidation mechanism is discussed.
Totalsynthese von Steroiden. 1. Mitteilung. rac‐17β‐Hydroxydes‐A‐androst‐9‐en‐5‐on
Authors: Saucy G. , Borer R. , Fürst A.
Published: December 2004

In connection with earlier work on the synthesis of 9β, 10α‐steroids, a new and practical synthesis of rac‐17α‐hydroxy‐des‐A‐androst‐9‐en‐5‐one (19) has been developed, based on a novel stereoselective condensation of 7‐hydroxy‐1‐nonen‐3‐one (3) with 2‐methyl‐cyclopentane‐1, 3‐dione (9) and subsequent transformations of the resulting tricyclic diene ether 12.
Silbermercaptide und ‐mercaptokomplexe
Authors: Tunaboylu K. , Schwarzenbach G.
Published: December 2004

The complex formation of silver(I) has been studied with the anions of simple mercaptans RSH which have been rendered soluble by replacing some H in the substituent R by OH. All equilibria constants refer to a solvent of ionic strength μ = 0,1 and 20°C.

Monothioglycol HOCH2CH2SH (pK = 9.48) forms an amorphous insoluble mercaptide {AgSR} (s), ionic product [Ag+] [SR−] = 10−19.7. The solution in equilibrium with the solid contains the molecule AgSR at a constant concentration of 10−6.7 M which furnishes the formation constant of the 1:1‐complex: K1 = 1013. 0. The solid is soluble in excess of mercaptide (AgSR+SR− → Ag(SR)2−: K2 = 104. 8) as well as in an excess of silver ion (AgSR + Ag+ → Ag2SR+K ≈︁ 106).

With the bulky monothiopentaerythrite (HOCH2)3CCH2SH (pK = 9.89) no precipitation occurs with silver when the mercaptan concentration is below 10−3. 2M. A single polynuclear Ag10(SR)9+ (β10.9 = 10175) is formed in acidic solutions which breaks up with the formation of Ag2SR+ (β2.1 = 1019.0) when an excess of silver ion is added. Below the mononuclear wall ([RS]total < 10−6) Ag2SR+ is formed via the mononuclear AgSR (K1 = 1013). At higher mercaptan concentrations ([RS]tot > 10−3.2) an amorphous precipitate is formed which has almost the same solubility product as silver thioglycolate ([Ag+] [SR−] = 10−19.1).

Apparently silver(I) forms with mercaptans always the complexes Ag2SR+, AgSR and Ag(SR)2−. Above the mononuclear wall, these species condense to chain‐like polynuclears which are cations Ag(SRAg)n+ in presence of an excess of Ag+, and anions SR (AgSR)n− when the concentration [RS−] is larger than [Ag+]. Usually n becomes rapidly very large as soon as the condensation starts (n → ∞: precipitate). The decanuclear Ag(SRAg)9+ formed with thiopentaerythrit is somewhat more stable than the shorter chains (n < 9) and larger chains (n > 9), because it can tangle up to a ball by coordination of bridging mercapto‐sulfur to the terminal silver ions (figure 12, page 2179). This ball seems to be further stabilized by hydrogen bonds between the many alcoholic OH groups of the substituent R = (HOCH2)3CCH2. The stability of the bonds AgS, however, is little influenced by the substituent R which carries the mercaptide sulfure.
Photochemical Reactions. Part 67. photochemistry of saturated aliphatic and cyclic β‐keto sulfoxides (CαS)‐ and α‐cleavage – A new case of photostereomutation
Authors: Ganter C. , Moser J.‐F.
Published: December 2004

The photochemical behaviour of saturated aliphatic (2, 4, and 5) and bicyclic (18 and 19) β‐keto sulfoxides has been studied. Photostereomutation of the sulfoxide group was observed on irradiation of 4a, 4b, 18, and 19. Most likely an internal energy transfer from the excited carbonyl to the sulfoxide group is operating on direct irradiation of such compounds.

Prolonged photolysis of an aliphatic β‐keto sulfoxide, which is nonalkylated a t the α‐carbon (2), yielded a product due to preferential (Cα‐S)‐cleavage (24). Mono‐ (4) and dialkylated‐ (5,6, and 8)analogues primarily afforded products due to α‐cleavage (26–31 and 32). The carboxylic acid S‐methylesters (26–31) were exclusively formed by an intermolecular path. Prolonged irradiation of the bicyclic β‐keto sulfoxides 18 and 19 favored the formation of a desulfurized compound 34 due to initial (Cα‐S)‐cleavage.
Molecules and Crystals, 1926–1970
Authors: Robertson J. M.
Published: December 2004

Some features in the history and development of the X‐ray crystallography of organic molecules are described, from the simple but fundamental structures of the 1920's and 1930's to the complex biological structures of today. The most important developments were probably the introduction of phase determining methods based on the use of heavy atoms, and the invention of the electronic digital computer.
Anil‐Synthese. 4. Mitteilung. Über die Basen‐katalysierte Umsetzung von 4‐Methyl‐azobenzol‐Derivaten mit Anilen aromatischer Aldehyde
Authors: Weickhardt B. , Siegrist A. E.
Published: December 2004

4‐Methyl‐azobenzol‐Derivate ohne elektronenanziehende Substituenten und ohne Gruppen, die mit Basen Salze bilden, werden mit Anilen aromatischer Aldehyde in Dimethylformamid in Gegenwart von Kaliumhydroxid oder Kalium‐t‐butylat zu Styryl‐Derivaten umgesetzt («Anil‐Synthese»). Bei Anwesenheit von elektronenanziehenden Gruppen dagegen werden die 4‐Methyl‐azobenzol‐Derivate zu symmetrischen Dibenzyl‐ bzw. Stilben‐Derivaten oxydiert. Mit 4‐Benzyl‐azobenzol‐Derivaten gelingt die Anil‐Synthese nur bei gleichzeitiger Anwesenheit von Elektronen‐Donatoren in 4′‐Stellung des Azobenzols.
Stoffwechselprodukte von Mikroorganismen. 98. Mitteilung. Phosphinothricin und Phosphinothricyl‐Alanyl‐Alanin
Authors: Bayer E. , Gugel K. H. , Hägele K. , Hagenmaier H. , Jessipow S. , König W. A. , Zähner H.
Published: December 2004

From cultures of Streptomyces viridochromogenes a new antibiotic, phosphinothricylalanyl‐alanine, has been isolated. The new amino acid phosphinothricin is 2‐amino‐4‐methyl‐phosphino‐butyric acid, its structure is confirmed by synthesis.

The tripeptide is highly active against Gram‐positive and Gram‐negative bacteria and against the fungus Botrytis cinerea. Phosphinothricin is an active glutamine synthetase inhibitor.
The Acidity of Malondialdehyde and the Stability of its Complexes with Nickel(II) and Copper(II)
Authors: Osman M. M.
Published: December 2004

The acidity of malondialdehyde as well as the stability of its 1 :1‐complexes with NiII and CuII have been determined (Table). In comparison with the enolates of aliphatic β‐dike‐tones the anion C3H3O2− has not only a strikingly reduced basicity, but is also a grossly inferior ligand for metal cations.
Synthesis of δ‐Lactones from Glutaraldehyde
Authors: Rosenberger M. , Andrews D. , DiMaria F. , Duggan A. J. , Saucy G.
Published: December 2004

A novel and general synthesis of δ‐lactones from glutaraldehyde is described. The dialdehyde is first reacted with an alkyl or substituted alkyl Grignard reagent to afford a δ‐hydroxyaldehyde in good yield. These aldehydes exist preferentially in the cyclic hemiacetal form (δ‐lactols). Oxidation of the latter compounds to give δ‐lactones is readily achieved with silver oxide or bromine. The δ‐lactols and δ‐lactones serve as intermediates for the total synthesis of steroids.
13C‐kernresonanzspektroskopische Untersuchung der Wechselwirkung von Makrotetrolid‐Antibioticamit Na+, K+, Rb+, Cs+, NH4+ und Ba2+
Authors: Pretsch E. , Vašák M. , Simon W.
Published: December 2004

The 13C NMR. spectra of nonaction have been recorded at 22.6 MHz. Additivityrules, chemical shift reagents and spectra of model compounds enabled a full assignment of the lines to be made. A comparison of the spectra of the nonactin complexes with Na+, K+, Rb+, Cs+, NH4+ and Ba2+ showed that no H‐bridges between NH4+ and the nonactin carbonyls exist. This is corroborated by the infrared spectra of the complexes.
Poly‐aminoalkylation d'amines, en solution aqueuse ou aquo‐alcoolique, à l'aide d'acides amino‐2‐alkylsulfuriques
Authors: Rabinowitz Joseph
Published: December 2004

Alkali stable primary and secondary amines (of the types H2NCH2CH2OPO3Na2, H2NCH2COONa, H2NCH2CH2OH, H3CNHCH2CH2OH, etc.) heated with n mole‐equiv. of a 2‐amino‐1‐alkylsulfuric acid in aqueous solution, in the presence of 2 n mole‐equiv. of NaOH, giverise to a mixture of poly‐aminoalkylated derivatives with an average degree of aminoalkylation close to n. If the amine is insoluble in water, a mixture of water+an alcohol can be used. In the case of N‐methylaminoethylsulfuric acid, the reaction is carried out in a closed vessel since the intermediate N‐methylaziridine boils at 27,5° under normal pressure.

These polyaminoalkyl derivatives are capable of being acylated, alkylated, and cyclized. Some stearylated products are described.
Steroids and sex hormones. Part 245. Partial synthesis of batrachotoxinin A. Preliminary communication
Authors: Imhof R. , Gössinger Miss E. , Graf W. , Berner H. , Berner‐Fenz Mrs. L. , Wehrli H.
Published: December 2004

Im Rahmen der vorliegenden Mitteilung wird über den erstmaligen partialsynthetischen Aufbau des Steroidalkaloids Batrachotoxinin A (23) [4] berichtet. Als Ausgangsmaterial der Synthese diente das 20‐Oxo‐pregnan‐Derivat 2, das von uns bereits früher [3] aus dem 18,20‐Lacton 1 [2] dargestellt worden ist.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 4. Mitteilung. 3‐Isopropyliden‐dithiocarbazinsäure‐alkylester und deren Ringschluss zu 5‐Alkylthio‐1,3,4‐thiadiazol‐2(3H)‐onen
Authors: Rüfenacht K.
Published: December 2004

Impurities in crude oily dithiocarbazic acid (2′‐methoxy)‐ethyl ester causing troubles in the ring closure to 5‐(2′‐methoxy‐ethylthio)‐1,3,4‐thiadiazol‐2(3H)‐one and in succeeding reactions are eliminated by using the crystalline 3‐isopropylidene‐dithiocarbazic acid (2′‐methoxy)‐ethyl ester, which can be obtained directly by alkylation of potassium dithiocarbazate with 2‐methoxy‐ethyl bromide in presence of acetone. By the action of phosgene followed by that of water, the isopropylidene compound yields the oily 5‐(2′‐methoxy‐ethylthio)‐1,3,4‐thiadiazol‐2(3H)‐one by splitting off the isopropylidene group and by ring closure in one single step.
The Photochemical Methylenecyclopropane Rearrangement of Feist's Ester
Authors: Kagan Jacques
Published: December 2004

In contrast to the thermal rearrangement, the photochemically induced methylenecyclopropane rearrangement of diethyl trans‐methylenecyclopropane‐2,3‐dicarboxylate (I) and of ethyl ethoxycarbonylcyclopropylideneacetate (syn or anti) produced diethyl cis‐methylenecyclopropane‐2,3‐dicarboxylate. A true photoequilibrium was not observed.
Glykoside von Marsdenia erecta R. Br. 2. Mitteilung: Versuche zur Strukturbestimmung der Genine. Glykoside und Aglykone, 330. Mitteilung
Authors: Saner A. , Stöckel K. , Reichstein T.
Published: December 2004

Structures for the genins of the ester glycosides of Marsdenia erecta are suggested. They are based on the behaviour in alkaline hydrolysis of these ester glycosides, their NMR. and mass spectra and ORD. data. All genins are derived from three acyl‐free pregnane derivatives, i.e. drevogenin‐P (1), 17 β‐marsdenin (3) and marsectohexol (7). The structure of 1 is known, 3 and 7 are new compounds, i.e. 3 = 3β,8β,11α,12β,14β‐pentahydroxy‐Δ5‐pregnen‐20‐one and 7 = 3β,8β,11α,12β,14β,20ξ‐hexahydroxy‐Δ5‐pregnene.

Formulae 13–17 were attributed to the acyl‐genins A‐1, A‐2, A‐3, A‐4 and A‐5, but only two of them were pure compounds, i.e. acyl‐genin A‐3 = 11,12‐di‐O‐tiglyl‐17β‐marsdenin (15) and acyl‐genin A‐5 = 11,12‐di‐O‐acetyl‐marsectohexoi (17). Acyl‐genin A‐1 is a mixture of the two esters 13a + 13b derived from drevogenin‐P, and similarly acyl‐genin A‐2 is a mixture of the esters 14a + 14b derived from 17β‐marsdenin. The poorly characterised acyl‐genin A‐4 is most probably a mixture of the esters 16a + 16b, also derived from 17β‐marsdenin.
Untersuchungen zur Physisorption und Chemisorption von Wasser auf Zinkoxid‐Oberflächen
Authors: Mattmann G. , Oswald H. R. , Schweizer F.
Published: December 2004

The investigation of different zinc oxide samples by means of thermogravimetry and infrared spectroscopy has shown that the surface of the samples is covered by an approximately monoatomic layer of hydroxide groups. Furthermore, varying amounts of carbonate groups are found which are due to the presence of zinc hydroxide carbonate II [Zn5(OH)6(CO3)2]. Below relative water vapour pressures of p/p0 = 0.2 (25°C), two hydrogen bridges connect one physisorbed water molecule with two chemisorbed surface hydroxide groups. In addition, about the same amount of water is physically adsorbed between vapour pressures of p/p0 0.2 and 0.8. At still higher relative humidity, a multimolecular layer is built up which reaches a thickness of about 200 water molecules at p/p0 = 1.0.

All samples show in the v‐OH region of the IR. spectrum a broad absorption with four bands, A, B, C, and D. The position of the bands and the change of their intensities when rising the temperature of the samples up to 600°C indicate that both bands of longer wave lengths, C and D, arise from physically adsorbed water molecules, while the bands A and B are due to hydroxide groups located on the crystallographic faces (0001) and (0001), respectively.
Dérivés C‐glycosyliques. VII. Synthèse et réactions de nitrones dérivées de sucres. Communication préliminaire
Authors: Tronchet J. M. J. , Mihaly Melle E.
Published: December 2004

The syntheses of three types of sugar nitrones (aldonitrone, ketonitrone and α‐β unsaturated aldonitrone) are described. On 1,3‐dipolar cycloaddition with phenylacetylene, the aldonitrone gave two Δ4‐isoxazolines epimeric at the new asymetric carbon, while the same reaction on the ketonitrone led to a spiro‐Δ4‐isoxazoline. The reaction of these nitrones with carbon nucleophiles like phenylethynylmagnesium bromide constitutes a novel chain‐extension reaction in carbohydrate chemistry.
Zur‐Reaktionsweise von Enaminen mit Cyclopropenonen III. Isolierung eines Produktes der «C, C‐Insertion»
Authors: Bilinski V. , Dreiding A. S.
Published: December 2004

From the reaction of the N‐(2‐Methylpropenyl)‐pyrrolidin 6 with diphenylcyclopropenone 7 we isolated as a byproduct 5‐Methyl‐2, 4‐diphenyl‐1‐pyrrolidino‐hexa‐1, 4‐diene‐3‐one 9. The structure was proven by an interpretation of the IR.‐, NMR.‐ and MS.‐spectra. This result is of importance since it represents the first case of a direct ‘C, C‐insertion’ product 4 from the reaction of an enamine 1 and a cyclopropenone 2 and because structures of type 4 (including 9) have previously been postulated for the main products of this reaction, which were later shown to be amides 3 (including 8).

Acid hydrolysis of the β‐amino‐dienone 9 yielded the dihydropyrone 10 and the cyclopentenone 11. These isomeric products are considered to be the result of two electrocyclic reactions, one of a hexa‐2,4‐diene‐al 12 and the other of a hexadienylium ion 14.
Thermodynamique des mélanges liquides binaires. Volume de mélange d'alcanes normaux et ramifies
Authors: Steiger M. , Boissonnas Ch. G. , Fernández‐García J. G. , Stoeckli H. F.
Published: December 2004

Volumes of mixing were determined by dilatometric measurements between 15° and 50°C for isomeric alkanes with n‐hexadecane and n‐dodecane. The negative excess volumes vary linearly with temperature.
Composés d'addition des halogénures de niobium(V) et de tantale(V): VI. Réactions d'échange des composés du chlorure de niobium(V) avec quelques nitriles
Authors: Merbach A. , Bünzli J. C.
Published: December 2004

The ligand exchange reactions NbCl5·ŘN + RCN* ⇄ NbCl5 · RCN* + RCN are studied by NMR. spectroscopy for R = Me3C, Me, FCH2, CICH2, BrCH2, ICH2. The reaction is of zero order in RCN and of first order in NbCl5 · RCN and thus a dissociative mechanism is suggested for all the ligands studied. The enthalpies and entropies of activation are determined over 50° to 90° temperature ranges. There is a linear correlation between ΔG≠ and the free enthalpy of formation of NbCl5 RCN. However this correlation is shown to hold only for series of adducts having the same donor group.
Über das Aroma der gelben Passionsfrucht. (Passiflora edulis f. flavicarpa). Vorläufige Mitteilung
Authors: Winter M. , Klöti R.
Published: December 2004

A concentrate of the volatile flavor of yellow passion fruit (Passiflora edulis f. flavicarpa) has been prepared. Investigation by gas liquid chromatography and mass spectrometry led to the identification of 165 compounds, 161 of which were not previously found in passion fruit. Some of these substances are new naturally occurring flavor compounds.
Steroidal Heterocycles 15. 4,4‐Dialkyl‐Δ5‐3‐oxosteroids, 1,4′‐spiro [cycloalkyl‐Δ5hyphen;3‐oxo‐steroids] and Derivatives
Authors: Neumann H. C. , Stonner F. W.
Published: December 2004

Homologs of 17‐hydroxy‐4,4‐17α‐trimethyl‐3‐oxo‐androst‐5‐ene‐2α‐carbonitrile (6d), such as the 4,4‐diethyl‐(6a), 4,4‐cyclopentyl‐(6c) and 4,4‐cyclohexyl‐(6b) analogs were synthesized.
Einlagerung hochenergetischer Tritiumatome in cis‐Cycloocten
Authors: Jordan P. , Reichen W.
Published: December 2004

The substitution, in liquid cis‐cyclooctene, of thermal tritiumatoms and reoil tritiumatoms from the nuclear reaction 6Li(n, α)3H was studied, and compared to earlier results obtained with cyclohexene. An explanation for the observed very distinct differences is proposed.
Stoffwechselprodukte von Mikroorganismen. 107. Mitteilung [1]. Die Struktur des Chlorothricins, eines neuartigen Makrolid‐Antibioticums
Authors: Muntwyler R. , Keller‐Schierlein W.
Published: December 2004

Chemical and spectroscopic evidence for the structural formula 9 of chlorothricolide methyl ester, derived from the aglycone of the antibiotic chlorothricin, is given. By chemical degradation and spectroscopic investigations structure 41 is deduced for the intact antibiotic.
α‐Chlor‐nitrone I: Darstellung und Ag+‐induzierte Reaktion mit Olefinen. Über synthetische Methoden, 5. (vorläufige) Mitteilung
Authors: Kempe U. M. , Das Gupta T. K. , Blatt K. , Gygax P. , Felix Dorothee , Eschenmoser A.
Published: December 2004

Organic synthesis may be said to be in need of enophiles, i.e. reagents that would undergo cycloaddition reactions with any isolated olefinic double bond, in contrast to most of the classical Diels‐Alder or 1,3‐dipolar addition reagents which, as a rule, require activated olefins in order to participate smoothly in cycloaddition processes. This paper introduces α‐chloronitrones as precursors of a new class of such reagents; they undergo an Ag+‐induced reaction with unactivated olefins with great ease to give products considered to result from 1,4‐cycloadditions of N‐alkyl‐N‐vinyl‐nitrosonium ions to the carbon‐carbon double bond (see scheme 2). This process is believed to have a number of synthetic applications, two of them being illustrated in two subsequent communications.
Premières études sur la biogénèse de la proferrorosamine A
Authors: Pouteau‐Thouvenot M. , Padikkala J. , Barbier M. , Helbling A. , Viscontini M.
Published: December 2004

Nous avons pu montrer à l'aide de substances radioactives que l'acide picolique est le précurseur immédiat de la proferrorosamine A. L'acide glutamique peut être transformé par Pseudomonas roseus fluorescens en acide picolique puis être incorporé dans la partie pyridinique du propigment tandis que les atomcs de carbone formant le noyau pyrrolinique provienncnt d'autrcs métabolites que nous n'avons pas encore identifiés. La lysine semble jouer le même rêle que I'acide glutaminique et ceci d'une manière encore plus prononéc.
The Reaction of Norbornene with Lead Tetraacetate and Thallium Trinitrate. Preliminary communication
Authors: Kagan Jacques
Published: December 2004

The reaction of norbornene with lead tetraacetate is found to be much more complex than previously reported. In acetic acid and in benzene, the syn‐7‐norbornenyl, 3‐nortricyclyl, and syn and anti‐7‐acetoxy‐exo‐2‐norbornyl acetates were characterized. In methanol, the isolated products represented most of those expected from the competition of methanol and acetate in the neutralization of the intermediate carbocations. The reaction of norbornene with thallium trinitrate in the above solvents yielded very complex mixtures besides the above mentioned products which were formed in about 50% yield.
The Effect of Solvent Variation on Nucleophilic Substitution Rates of Methyl Tosylate
Authors: Müller Paul , Siegfried Bernard
Published: December 2004

Rates of the reactions between bromide ion and methyl tosylate have been determined in 12 solvents and extrapolated to infinite dilution. The data are correlated with Parker's solvent activity coefficients by means of an empirical equation of the type: logks – logk0 = A log0γ + B with the constants A = 0.788 and B = 0,108 and a correlation coefficient of 0.983.
Die Wechselwirkung zwischen Walsh‐ und π‐Orbitalen im 7‐Cyclopropyliden‐norbornadien
Authors: Brogli F. , Heilbronner E. , Ipaktschi J.
Published: December 2004

The qualitative analysis of the PE.‐spectrum of 7‐cyclopropylidene‐norbornadiene (3) shows that the ‘through‐space’ interaction of the eA‐Walsh orbital with the antisymmetric linear combination \documentclass{article}\pagestyle{empty}\begin{document}$ {{\pi _ - = (\pi _a - \pi _b)} \mathord{\left/ {\vphantom {{\pi _ - = (\pi _a - \pi _b)} {\sqrt 2}}} \right. \kern-\nulldelimiterspace} {\sqrt 2}} $\end{document} of the two π‐orbitals in 3 is of the same order as the analogous interaction between π‐ and the π‐orbital of the exocyclic double bond in 7‐isopropylidene‐norbornadiene (2).