bluuebunny/crossref_metadata_2025 huggingface dataset:
Stoffwechselprodukte von Mikroorganismen. 160. Mitteilung. Conocandin, ein fungistatisches Antibiotikum aus Hormococcus conorum (SACC. et ROUM.) ROBACK
Authors: Müller Johannes M. , Fuhrer Hermann , Gruner Johannes , Voser Walter
Published: December 2004

Metabolites from Microorganisms. 160th Communication. Conocandin, a new Fungistatic Antibiotic.

From a strain of Hormococcus conorum (SACC. ET ROUM.) ROBACK A 32′287, conocandin, a novel type C18‐fatty acid with high and specific in vitro fungistatic activity was isolated by means of counter current distribution and silicagel chromatography. The antibiotic is a viscous oil with the molecular formula C18H30O3. It is characterized by IR. and NMR. spectra, ester derivatives and the products of acid rearrangement and ozonolytic degradation. The structure of (E)‐2‐methylidene‐10‐methyl‐trans‐3,4‐epoxy‐9‐hexadecenoic acid (1) is proposed.
Germanium‐centered radicals. II. ESR. spectra of X‐irradiated single crystals of bis (triphenylgermyl) ether.
Authors: Geoffroy Michel , Ginet Lucien
Published: December 2004

L'exposition d'un monocristal d'hexaphényldigermoxane aux rayons iomsants permet de piéger deux espèces radicalaires fortement localisées sur un atome de germanium. A partir des tenseurs de couplage hyperfin avec 73Ge on a calculé les caractères s et p de l'orbitale contenant l'électron non apparié au niveau du germanium. La comparaison de ces resultats avec ceux relatifs à \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm Ph}_{\rm 3} {\rm G}\mathop {\rm e}\limits^ \bullet $\end{document} [1] montre qu'une des structures les plus probables pour un au moins de ces radicaux est du type \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm R}_{\rm 3} {\rm G}\mathop {\rm e}\limits^ \bullet {\rm OR'}^ \ominus $\end{document}.
Selective Ether Cleavage in the Aporphine Series. Conversion of (S)‐Bulbocapnine into (S)‐Corytuberine and (S)‐Corydine Methyl Ether
Authors: Gerecke Max , Borer René , Brossi Arnold
Published: December 2004

Bulbocapnine methyl ether (2), on treatment with boron halides, affords the aporphine‐1,2‐diol (3), the novel aporphines 5 and 6 or the phenanthrene derivative 11 depending on the reaction conditions. 3 can be further transformed into corydine methyl ether (4); 6 has been converted to corytuberine (8). Similarly, dehydrobulbocapnine methyl ether 9 was converted to 10.
Stereochemistry of Polynuclear Cadmium(II)thioglycolates: Crystal Structure of [ICd8(SCH2CH2OH)12]3+ · 3I− · H2O
Authors: Beat Bürgi Hans , Gehrer Hermann , Strickler Peter , Winkler Fritz Karl
Published: December 2004

Crystals of the title compound are triclinic, a = 27.87 Å, b = 10.77 Å, c = 12.94 Å, α 73.1°, β 116.1°, γ 120.0°, space group P1. The structure consists of octanuclear ions: Eight Cd(II) ions are found at the corners of a distorted cube, the center of the cube is occupied by an iodide, the twelve thioglycolate sulfur atoms bridge the twelve edges of the cube thereby forming a distorted icosahedron. Cadmium ions are either five or seven coordinate. The phase problem for this structure was solved using a combination of very high and very low E‐values.
Primary and Secondary Isotope Effects on Proton Transfers to Diazocarbonyl Compounds
Authors: McGarrity John F.
Published: December 2004

The primary solvent isotope effects on the ASE‐2 type hydrolyses of α‐diazocarbonyl compounds p‐XC6H4CN2CH3 (X = NO2, H, OCH3 and C6H5CON(CH3)2) are found to be identical despite large differences in their overall hydrolysis rates. The secondary solvent isotope effects diminish considerably with diminishing substrate reactivity, and for two substrates they are smaller than those normally anticipated for a simple proton transfer from the lyonium species. An analysis is presented of these and other abnormal secondary isotope effects found elsewhere, involving consideration of the solvation of the reaction complex.
Heterocyclic Spiro‐naphthalenones. Part VI. Some reactions with spiro [naphthalene‐2 (1H), 2′‐pyrrolidine]‐1,5′‐dione leading to various 6‐, 7‐, 8‐, 9‐, 10‐ and 11‐membered azacycloalkanes
Authors: Berney Daniel , Schuh Karlheinz
Published: December 2004

The spirolactam 5 was reduced to the spiro[naphthalene, pyrrolidine] 7 which was N‐aralkylated to give 9 and 17. Cyclization of 9 gave the phenanthridines 10 and 11; similarly, 17 afforded the 7‐ and 8‐membered heterocycles 18 and 19. Compounds 10, 18 and 19 when subjected to an intramolecular Hofmann elimination yielded the 9‐, 10‐ and 11‐membered ring systems, respectively 16, 22 and 23.
Photochemische Umsetzung von optisch aktiven 2‐(1′‐Methylallyl)anilinen mit Methanol
Authors: Scholl Bernhard , Hansen Hans‐Jürgen
Published: December 2004

Photochemical Reaction of Optically Active 2‐(1′‐Methylallyl)anilines with Methanol

It is shown that (−)‐(S)‐2‐(1′‐methylallyl)aniline ((−)‐(S)‐4) on irradiation in methanol yields (−)‐(2S, 3R)‐2, 3‐dimethylindoline ((−)‐trans‐8), (−)‐(1′R, 2′R)‐2‐(2′‐methoxy‐1′‐methylpropyl)aniline ((−)‐erythro‐9) as well as racemic (1′RS, 2′SR)‐2‐(2′‐methoxy‐1′‐methylpropyl) aniline ((±)‐threo‐9) in 27.1, 36.4 and 15.7% yield, respectively (see Scheme 3). By deamination and chemical correlation with (+)‐(2R, 3R)‐3‐phenyl‐2‐butanol ((+)‐erythro‐13; see Scheme 4) it was found that (−)‐erythro‐9 has the same absolute configuration and optical purity as the starting material (−)‐(S)‐4. Comparable results are obtained when (−)‐(S)‐N‐methyl‐2‐(1′‐methylallyl)aniline ((−)‐(S)‐7) is irradiated in methanol, i.e. the optically active indoline (+)‐trans‐10 and the methanol addition product (−)‐erythro‐11 along with its racemic threo‐isomer are formed (cf. Scheme 3). These findings demonstrate that the methanol addition products arise from stereospecific, methanol‐induced ring opening of intermediate, chiral trans, ‐(→(−)‐erythro‐compounds) and achiral cis‐spiro [2.5]octa‐4,6‐dien‐8‐imines (→(±)‐threo‐compounds; see Schemes 1 and 2).
D‐Homosteroide I. Synthese von gestagen‐wirksamen D‐Homopregnan‐Derivaten
Authors: Müller Marcel , Alig Leo , Keller Peter , Fürst Andor , Kerb Ulrich , Wiechert Rudolf
Published: December 2004

The synthesis of a series of hormonally active D‐homopregnane derivatives is reported.
Synthesen von polyhalogenierten Butyrylchloriden, Vorläufern der pyrethroiden Haloketene
Authors: Martin Pierre , Steiner Eginhard , Belluš Daniel
Published: December 2004

Synthesis of Polyhalogenated Butyryl Chlorides, Precursors of Pyrethroid Haloketenes

The copper (I)‐catalyzed free radical addition of halomethanes to acrylates and the addition of halogenated acetic acid derivatives to fluoro‐ or chloro‐substituted ethylenes affords polyhalogenated butyric acid derivatives. Chlorides of these acids serve as precursors for haloketenes used in efficient syntheses of pyrethroids.
Synthese optisch aktiver 2‐Methyl‐ und 2‐Äthyl‐1, 6‐dioxaspiro [4.4]‐nonan‐ und ‐[4.5]decan‐Pheromone aus einem gemeinsamen chiralen Vorläufer
Authors: Hungerbühler Ernst , Naef Reto , Wasmuth Daniel , Seebach Dieter , Loosli Hans‐Rudolf , Wehrli Adolf
Published: December 2004

Synthesis of Optically Active 2‐Methyl‐ and 2‐Ethyl‐1, 6‐dioxaspiro [4.4]nonane‐ and ‐[4.5]decane Pheromones from a Common Chiral Precursor

The versatility of the bromoepoxide6as chiral building block, which is readily available in both enantiomeric forms from malic acid, and which has previously been used for a vermiculine synthesis, is further demonstrated by the preparation of the title compounds1, 3, 4and5. Alkylation of 1,3‐dithiane, first with the 1‐ethoxyethyl‐protected ω‐chloroalcohols8bor9band then with the (S)‐(−)‐bromoepoxide6, followed by oxirane opening withSelectrideor methylGilman‐reagent creates the desired carbon skeletons and functionality patterns14–17, in overall yields of 60–80%. Acetal and thioacetal hydrolyses directly furnish the spiroacetal target structures1and3–5as 3:2‐diastereomeric mixtures; theE/Z‐epimers3are separated by preparative GC.(Fig.).
Linear Stereo‐co‐oligopeptides with Alternating D‐ and L‐Residues. I. Synthesis and Mass Spectrometric Behavior of the Members of a Series with Valine Residues
Authors: Tomasic Lera , Stefani Annibale , Lorenzi Gian Paolo
Published: December 2004

The synthesis of the protected stereo‐co‐oligopeptides with alternating D‐ and L‐valine residues Boc‐(D‐Val)m‐(L‐Val‐D‐Val)n‐OMe (m = 0; n = 1,2,3,4,6,8, and m = 1; n = 1,2,3,4) is described. The synthesis has been carried out by using conventional solution methods. The co‐oligopeptides up to the nonapeptide (m = 1; n = 4) have been prepared in a stepwise fashion. The dodecapeptide (m = 0; n = 6) and the hexadecapeptide (m = 0; n = 8) have been prepared by condensation of smaller peptides, and the criteria used for assessing their stereochemical purity are discussed. Preliminary characterization data are presented. Even the co‐oligopeptides with six or more residues, up to the dodecapeptide included, have given EI/MS. showing the molecular ion peak. The possible reasons for this uncommon behavior are examined.
2, 3‐Disubstituted γ‐Butyrolactams from the Michael‐Additions of Doubly Deprotonated, Optically Active β‐Hydroxycarboxylates to Nitroolefins. Preliminary Communication
Authors: Züger Max , Weller Thomas , Seebach Dieter
Published: December 2004

The conjugate addition of the chiral, non‐racemic alkoxy‐enolates 5 and 6 to nitroolefins furnishes the hydroxynitroesters 7–13, which are catalytically hydrogenated to give the lactams 14–18. The configuration of adduct 7 from nitroethylene was elucidated by NMR. analysis of the acetal 20 derived from 7. The assignment establishes that the reaction follows the stereochemical rule of attack depicted in 21 and previously deduced for other electrophiles, i.e. formation of erythro‐products of type 3b and 4b. No stereocontrol was found at the newly formed chiral centers in α‐ and β‐position to the NO2 group of 8–12.
High Acceleration and Improved Diastereoselectivity of Intramolecular Ene‐Type Reactions by Diethylaluminum Chloride. Preliminary Communication
Authors: Oppolzer Wolfgang , Robbiani Christian
Published: December 2004

The pyrrolidines 2 and 10 were obtained by thermal ene‐reactions at +70° and +180° from the (Z)‐4‐aza‐1, 6‐diene 1 and from the (E)‐4‐aza‐1, 6‐diene 9 in the ratios of 75:25 and 50:50, respectively. On the other hand, these cyclizations proceeded readily in the presence of diethylaluminum chloride at − 78° and − 35° giving in high yield the trans‐pyrrolidine 2 from 1 with 100% and from 9 with 89% diastereoselectivity.
Tieftemperatur 13C‐NMR.‐Spektren von 13C‐und 6Li‐markierten Chlor‐, Brom‐ und Jod‐Lithium‐Carbenoiden. Vorläufige Mitteilung
Authors: Scebach Dieter , Siegel Herbert , Gabriel Josef , Hässig Robert
Published: December 2004

Low Temperature 13C‐NMR. Spectra of 13C‐ and 6Li‐Labelled Chloro‐, Bromo‐, and Iodo‐lithiumcarbenoids

The 13C‐NMR. spectra of tetrahydrofuran solutions of 16 chloro‐, bromo‐, and iodo‐6lithio‐ and ‐7lithio‐carbenoids with 13C‐labelled methane, ethane, ethylene, and cyclopropane C‐skeletons have been measured at temperatures around − 100° (for examples see Fig. 1 and 2). Invariably, the exchange of hydrogen or halogen by lithium causes deshielding (Δδ, see Table 1) of the 13C‐signal by up to 289 and 434 ppm, respectively, and decrease of 1J (1H, 13C) and 1J(13C,13C) couplings (see Table 2) with the C‐atom of up to 104 and 30 Hz, respectively. The 1J(6Li, 13C) and 1J(7Li, 13C) coupling of ca. 17 and 45 Hz, respectively, obtained in ten cases (Table 1) is independant of the substitution pattern of the C‐skeleton and of the particular halogen atom.
Die Konstitution des Alkaloides Juliprosopin aus Prosopisjuliflora A. Dc. 176. Mitteilung über organische Naturstoffe
Authors: Ott‐Longoni Rita , Viswanathan Narayanaiyer , Hesse Manfred
Published: December 2004

The Structure of the Alkaloid Juliprosopine from Prosopis juliflora A. Dc.

A new alkaloid, juliprosopine, has been isolated from Prosopis juliflora A. Dc. (Leguminosae), for which structure 1 is proposed. The piperidine moiety could be elucidated on the basis of spectroscopic data (MS., 1H‐NMR., 13C‐NMR.) of juliprosopine and the derivatives 2–4. The central hexahydroindolizine part and its substitution pattern has been determined mainly on the bases of the Hofmann‐degradation product 11, which yielded the hydrogenation products 13 and 14. By ozonolysis 11 was converted to 16 and 18. It is proposed that juliprosopine was built up in nature by two ‘monomeric’ Prosopis alkaloids and one dihydropyrrol unit.
A Stereoselective Approach to the Spiro [4, 5]decane System via Intramolecular Photocycloaddition and Reductive Fragmentation. Preliminary communication
Authors: Oppolzer Wolfgang , Gorrichon Liliane , Bird T. Geoffrey C.
Published: December 2004

The photoaddition 6→7, followed by a reductive cleavage of the →‐chlorocyclobutylketone 7, gave the stereochemically pure spiro [4,5]decane 8.
Amidine als Zwischenprodukte bei Umamidierungsreaktionen. 9. Mitteilung über Umamidierungsreaktionen
Authors: Heidelberger Christian , Guggisberg Armin , Stephanon Euripides , Hesse Manfred
Published: December 2004

Amidines as Intermediates in Transamidation Reactions

By loss of water in the presence of p‐toluenesulfonic acid/xylole N‐aminoalkyllactames form bicyclic amidines. The corresponding N‐alkylaminoalkyl‐lactames' react to bicyclic amidinium salts or to transamidated products, ring‐enlarged by the N‐alkylamino residue, respectively (s. Scheme 1).

The bicyclic amidines and amidinium salts are partially hydrolyzed by KOH/H2O to lactames (s. Scheme 2). Which of the two possible isomeric lactames are formed is discussed.
Propellanes. LXII. The endo‐ and exo‐adducts of 11‐cyano‐1,6‐methano[10] annulene with 4‐methyl‐1,2,4‐triazoline‐3,5‐dione
Authors: Ashkenazi P. , Kaftory M. , Arad D. , Apeloig Y. , Ginsburg D.
Published: December 2004

The title compounds have been isolated and their structures determined by X‐ray crystallography. Their relative stability is discussed in terms of theory and experiment. The endo‐adduct is the thermodynamically more stable one.
The Synthesis of Polyfunctional Aromatic Ring Systems. Structural Analogues of Phloroglucides, Aranciamycin, Cryptosporin and Terramycin
Authors: Hakimelahi Gholam Hosein , Moshfegh Ali Akbar
Published: December 2004

The synthesis of the title compounds is described. Some of the compounds prepared were found to be active against a number of pathogenic microorganisms in vitro.
Azidiniumsalze. 22. Mitteilung. über 3‐äthyl‐2‐tetrazo‐6‐X‐benzo[d]thiazoline und ihre Reaktivität: Ein Beitrag zur Chemie nucleophiler Carbene
Authors: Balli Heinz , Grüner Heinrich , Maul Rudolf , Schepp Horst
Published: December 2004

3‐Ethyl‐2‐tetrazo‐6‐X‐benzo[d]thiazolines and Their Reactivity: A Contribution to the Chemistry of Nucleophilic Carbenes

The synthesis of 3‐ethyl‐2‐tetrazo‐6‐X‐benzo[d]thiazolines 3 ‐ a new class of azohomologous diazo compounds ‐ by addition of azide ions to azidinium salts 4 is described, their structure and some of their reactions are disscussed. The thermolysis of 3 at ca. 270 K in DMFA or THF generates nucleophilic carbenes 1, whose trapping by electrophilic compounds such as 3, 4, diazonium salts, diazo compounds, methanol, sulfur and tetracyanoethylene could be studied. Direct dimerisation of 1 to 2 (without acid/base catalysis) could not be found, as demonstrated by the behavior of 1e.
Enantiomer‐Selectivity for Phenylethylammonium Ion of Membranes Based on a Chiral Macrocyclic Polyether
Authors: Bussmann Walter , Simon Wilhelm , Oesch Urs , Lehn Jean‐Marie , Plumeré Pierre
Published: December 2004

A chiral macrocyclic crown ether exhibits an enantiomer‐selectivity of 2.6 for α‐phenylethylammonium ion when incorporated in solvent polymeric membranes. The sequence of selectivity of these membranes clearly differs from that of lipophilicity for the different biogenic ammonium ions studied, indicating a significant structural contribution.
3‐Hydroxy‐4‐nitro‐cyclohexanone aus Ketonen und 4‐Nitrobuttersäurechlorid. Eine ringerweiternde Fünfringanellierung
Authors: Weller Thomas , Seebach Dieter , Davis Raymond E. , Laird Brian B.
Published: December 2004

3‐Hydroxy‐4‐nitro‐cyclohexanones from Ketones and 4‐Nitrobutanoyl Chloride. A Ring Enlarging Five‐Ring Annulation

The 6‐nitro‐1, 3‐diketones 5, 8, 9, 10, and 11, prepared by a 1:1 acylation at the C‐atom of non‐hindered lithium enolates with 4‐nitrobutanoyl chloride according to equation 3, are cyclized with sodium hydrogen carbonate in aqueous tetrahydrofuran to give the hydroxy‐nitro‐ketones 13–17. Such cyclic nitroaldols are not formed from the cyclopentanone, ‐heptanone, and ‐octanone, nor from the aryl derivatives 4, 6, 7 and 12, respectively. Except for the vicinally trisubstituted compound 14, the cyclization products are isolated in diastereomerically pure form. A crystal structure X‐ray analysis reveals the trans‐decalone and the cisβ‐nitroalcohol configurations of the product 13 from cyclohexanone (see Fig. 1–3). Acetalization to 21–25 and catalytic hydrogenation of the nitro groups furnishes the amino alcohols 27–31 (Table 4) which are substrates for the Tiffeneau‐Demjanow rearrangement (see Schemes 2, 3, 4 and 5), From the stereoelectronic control of this sextett rearrangement we deduce the configurations of the 1, 4‐diketones 35, 36, 39, 40, 43, 44, 46, and 47 formed under kinetic or thermodynamic conditions. The six‐ring annulation with nitrobutanoic acid and the subsequent rearrangement are shown in Scheme 6; the sequence of reactions described here allows to carry out a ring enlargement of a cyclic ketone by one C‐atom, with simultaneous annulation of a cyclopentanone ring.
Notiz über die Bestimmung der absoluten Konfiguration von (+)‐2‐Hydroxy‐2, 3‐dimethylbuttersäure
Authors: Wetter Hansjürg
Published: December 2004

Note on the Determination of the Absolute Configuration of (+)‐2‐Hydroxy‐2, 3‐dimethylbutyric Acid

Chemical correlation of the title compound 1 with (S)‐3‐isopropyl‐3‐methyl‐5‐trimethylsilyl‐4‐penten‐2‐one (2) showed (+)‐1 to have (S)‐configuration. Key step was the Baeyer‐Villiger oxidation of a very hindered, optically active methyl keton to the corresponding acetoxy compound with trifluoroperacetic acid using slightly modified buffer conditions. It is found, that the erythro/threo assignment of an α, α‐disubstituted β‐hydroxyester intermediate can be based on the observation, that the 1H‐NMR. signal of HC(β) of the erythro isomer appears at lower field than that of the threo isomer.
The Ring Closure of Cyclopenta‐1, 3‐dien‐5‐yl‐carbene to Benzvalene. A mechanistic study of an unusual carbene reaction
Authors: Burger Ulrich , Gandillon Gérard , Mareda Jiri
Published: December 2004

The base‐induced α‐elimination of hydrogen chloride from 5‐chloromethyl‐5‐methylcyclopenta‐1, 3‐diene (19) produces 1‐methyltricyclo [3.1.0.02,6]hexene‐3 (1‐methylbenzvalene) (21) together with toluene and spiro [4.2]heptadiene (23). A common intermediate, 5‐methylcyclopenta‐1, 3‐dien‐5‐yl‐carbene (20), accounts for these results by intramolecular 1, 4‐carbene addition, 1, 2‐carbon shift and CH‐insertion, respectively. Independent synthesis of 2‐methylbenzvalene (24) allows us to show that the classic intramolecular cyclopropanation is completely suppressed by the linear cheletropic ring closure. MINDO/3 predicts the key carbene to have a bisected conformation in its singlet ground state. This ideally fulfills the stereoelectronic conditions for a carbene reaction of least motion. The influence of the methyl substituent upon that process is discussed.
Crystal Structure of (Z)‐1‐Phenyl‐ and of (Z)‐1‐Dimethylamino‐2‐phthalimido‐diazene‐1‐oxide
Authors: Hoesch Lienhard , Bieri Jost H. , Declercq Jean Paul , Germain Gabriel , Van Meerssche Maurice
Published: December 2004

Kristallstruktur von (Z)‐1‐Phenyl‐ und von (Z)‐1‐Dimethylamino‐2‐phthalimido‐diazen‐1‐oxid

Durch Röntgen‐Strukturanalyse wurden die Konstitution und die (Z)‐Konfiguration der im Titel genannten Produkte (3a und 3b) aus der Addition von Phthalimido‐nitren (1) an Nitrosobenzol (2a) bzw. an Dimethylnitrosamin (2b) im Einklang mit früheren, spektroskopischen Strukturzuordnungen bestätigt. In beiden Molekeln (3a und 3b) ist die Phthalimidogruppe nicht mit der Diazenoxidfunktion konjugiert, dagegen besteht offensichtliche Konjugation der zentralen NNO‐Funktion mit der Phenylgruppe in 3a bzw. mit der Dimethylaminogruppe in 3b. Die Ebene der NNO‐Gruppe ist in beiden Molekeln nur wenig gegenüber derjenigen der Substituenten an N(1) verdrillt (5° bei 3a bzw. 7° bei 3b). Die Bindungslänge zwischen N(1) und dem Dimethylamino‐Stickstoffatom in 3b entspricht mit 1,347 Å nahezu einer N,N‐Anderthalb‐Bindung, und beide zuletzt genannten N‐Atome sind coplanar mit ihren jeweiligen drei Liganden. Die Bindungslänge zwischen N(1) und dem benachbarten C‐Atom in 3a von 1,459 Å entspricht derjenigen einer Einfachbindung zwischen sp2‐hybridisierten N‐ bzw. C‐Atomen, analog den Bindungslängen zwischen N(1) und dem benachbarten C‐Atom in 1,2‐Diaryl‐diazen‐1‐oxiden (5; R, R′ = Aryl).
Proof of the Absolute Configuration of (−)‐(S)‐2‐Hydroxy‐β‐ionone by correlation with ursolic acid and with (−)‐trans‐verbenol
Authors: Escher Sina , Giersch Wolfgang , Ohloff Günther
Published: December 2004

(−)‐(S)‐2‐Hydroxy‐β‐ionone (33), (+)‐(2 S, 6 S)‐2‐hydroxy‐α‐ionone (34), and their acetates 35 and 36 have been synthesized from (+)‐(S)‐6‐methylbicyclo [4.3.0]‐non‐1‐ene‐3, 7‐dione (3). The key intermediate (+)‐(1 R, 3 S, 6 S)‐2, 2, 6‐trimethyl‐7‐oxobicyclo [4.3.0]non‐3‐yl acetate (7) was correlated with a degradation product of the pentacyclic triterpene ursolic acid (16). Compound 33 was also synthesized by an alternative route starting from (−)‐trans‐verbenol (42).
Heterodiamantane und strukturell verwandte Verbindungen. III.. Pentacyclische diäther der C11‐reihe. 5, 13‐Dioxapentacyclo‐[6.5.0.02,6.03,12.04,9]tridecan, 4, 13‐dioxapentacyclo [6.4.1.02,7.03,10.05,9]tridecan und 3, 10‐dioxapentacyclo [7.3.1.02,7.04,12.06,11]tridecan
Authors: Ammann Willi , Ganter Camille
Published: December 2004

Heterodiamantanes and Structurally Related Compounds. Part III. The Pentacyclic C11‐Diethers 5, 13‐Dioxapentacyclo [6.5.0.02,6.03,12.04,9]tridecane, 4, 13‐Dioxapentacyclo [6.4.1.02,7.03,10.05,9]tridecane, and 3, 10‐Dioxapentacyclo [7.3.1.02,7.04,12.06,11]tridecane

In connection with the studies on heterodiamantanes and structurally related compounds the three novel pentacyclic diethers 3–5 were prepared starting from the cyclopentadienone dimer 6. All four compounds have as common features a central carbocyclic 6‐membered ring with four axial alkyl substituents and two oxygen functions in 1, 4 position. The required eleventh C‐atom was introduced by dichlorocarbene addition either to 6 ( → 7) (Scheme 2) or to 29 ( → 28) (Scheme 4).

Diether 3 was obtained by reduction of 26 (Scheme 2), a suitable precursor prepared either by intramolecular addition (24 → 26; Scheme 2) or substitution (30 → 26, 31 → 26; Scheme 4), as well as by direct substitution (44 → 3, 42 → 3; Scheme 5). Diether 4 was the product of a direct substitution (39 → 4, 36 → 4; Scheme 5). The synthesis of diether 5 was achieved from the addition product 51 (resulting from the alcohols 47 and 48; Scheme 6).

Diether 4 is the thermodynamically least stable of the three diethers 3–5. It was easily isomerized to 5 on treatment with concentrated sulfuric acid in benzene whereas 3 and 5 remained unchanged under these conditions.
Rates of Proton Abstraction from Conjugated Dienes in the Gas Phase
Authors: Meyer Felix K. , Pellerite Mark J. , Brauman John I.
Published: December 2004

The rates of proton transfer from 2, 4‐hexadiene, 1, 3‐cycloheptadiene, cyclopentadiene and acetone to t‐butoxide have been measured in the gas phase using pulsed‐ion‐cyclotron‐resonance spectroscopy. The rate constants are (units of 10−10 cm3 molecule−1 s−1): 2.7 ± 0.4, 3.8 ± 0.4, 6.1 ± 0.7 and 10.8 ± 1.5, respectively. These results are analyzed in terms of the properties of the encounter complex and reaction transition states. The reaction profile for t‐butoxide + cyclopentadiene is modeled using RRKM theory and an estimate for the central barrier height is obtained.
Carotenoids and Related Compounds. Part 36.. Further syntheses of zeaxanthin and rhodoxanthin
Authors: Ellis Peter R. , Faruk A. Erol , Moss Gerard P. , Weedon Basil C. L.
Published: December 2004

A modification of a previously reported synthesis of zeaxanthin (1), and routes to both zeaxanthin and rhodoxanthin (2) from α‐ionone, are described.
De la chimie des ptérines. 78e Communication.. Synthèse de l'ester tripolyphosphorique de la tétrahydro‐5, 6, 7, 8‐D‐néoptérine. Essai d'interprétation de la biosynthèse de la L‐sépiaptérine
Authors: Antoulas Siméon , Viscontini Max
Published: December 2004

Synthesis of 5, 6, 7, 8‐Tetrahydro‐D‐neopterine tripolyphosphate. Attempt to Interpret the Biosynthesis of L‐Sepiapterine

The synthesis was achieved by phosphorylation of tetrahydro‐5, 6, 7, 8‐D‐neopterine with polyphosphoric acid. The product is sensitive to light, moisture and oxidation like the other tetrahydropetrines. After oxidation in aqueous solution, D, L‐sepiapterine was isolated in 5% yield. The oxidation of non‐phosphorylated tetrahydro‐5, 6, 7, 8‐D‐neopterine under the same conditions led to D‐sepiapterine without inversion of the configuration. These findings were used to give a tentative explanation for the biosynthesis of natural L‐sepiapterine from the D‐neopterine.
New Triterpenes from the Bark of Western White Pine (Pinus monticola DOUGL.)
Authors: Kutney James P. , Eigendorf Günter , Worth Brian R. , Rowe John W. , Conner Anthony H. , Nagasampagi Bhimsen A.
Published: December 2004

Eleven new triterpenes with the lanostene‐type skeleton were isolated from the benzene extract of western white pine bark. Their structures were determined mainly on the basis of physical and spectral data.
Photochemische Reaktionen. 121. Mitteilung. Zur Photochemie von ε,ζ‐Methano‐α,γ‐dienonen und 7,8‐Methano‐1,3,5‐trienen
Authors: Ishii Keitaro , Frei Bruno , Wolf Hans Richard , Jeger Oskar
Published: December 2004

Photochemistry of ε,ζ‐Methano‐α,γ‐dienones and 7,8‐Methano‐1,3,5‐trienes

Irradiation of the δ‐cyclopropyl‐dienone (E)‐6 (λ ≥ 347 nm) gives (Z)‐6, 10 (1,5‐sigmatropic H‐shift), (E/Z)‐9 (electrocyclic process involving C(ε), C(ζ)‐cleavage) and 11 (ring opening).

The corresponding 6‐cyclopropyl‐triene (E)‐7 gives on singlet excitation (δ > 280 nm) 14 (1,5‐sigmatropic H‐shift) and, to a smaller extent, the bicyclo [3.2.0] heptenyl‐dienes (E/Z)‐13. However, on triplet excitation (λ ≥ 347 nm, benzophenone) (E)‐7 gives (E/Z)‐13 as the main products. On both 1π,π*‐ and 3π,π*‐excitation, (Z)‐7 and 15 are formed in small amounts.
Novel Approach to the Synthesis of 6‐Substituted 5,6‐Dihydro‐2(2H)‐pyranones
Authors: Fehr Charles , Galindo José , Ohloff Günther
Published: December 2004

Easily accessible dihydropyrans 9, 10, 12 and 19 are precursors for the synthesis of 6‐substituted 5,6‐dihydro‐2 (2H)‐pyranones and 6‐substituted tetrahydro‐2‐pyranones. Syntheses of massoia lactone (3), argentilactone (5), tuberolactone (4) and jasmine lactone (2) from acrolein (6), acrolein dimer (7) or glutaraldehyde (16) are described.
A 13C‐NMR. Study of naphthalene chromium complexes. Correlation with reactivity: Nucleophilic aromatic substitution reactions
Authors: Desobry Vincent , Kündig Ernst Peter
Published: December 2004

The 13C‐NMR. spectra of the series of complexes η6‐naphthalene · CrL3 (LCO (1), PF3 (2), PF2OMe (6), P(OMe)3 (3), C10H8 (= 3 L) (4) and PMe3 (5)) are reported. Definite assignments of the 13C‐NMR. resonances were made through the synthesis of [2, 3, 6, 7‐2H4]‐naphthalene complexes. The coordinated ring 13C‐resonance are found to undergo a smooth transition to higher field with increasing donor character of the coligands L. A correlation of the coordination shifts with the reactivity of the coordinated naphthalene is proposed. In complexes containing strong acceptor ligands the naphthalene is activated to attack by nucleophiles. Sequential treatment of complexes 1–4, 6 and [C10H8FeC5H5]+[PF6]− (7) with stabilized carbanions and I2 or Ce(IV)‐salt yields α‐substituted naphthalenes in the case of 1, 2, 6 and 7 but not in the case of 3 and 4. Treatment of 3 with an excess of HBF4 results not in the expected metal protonation but in a novel ligand transformation to yield 6.
The Electronic Structure of Phenylene and Naphthylene Bicyclobutanes. Photoelectron spectroscopy and model calculations
Authors: Gleiter Rolf , Gubernator Klaus , Eckert‐Maksić Mirjana , Spanget‐Larsen Jens , Bianco Bernard , Gandillon Gérard , Burger Ulrich
Published: December 2004

The photoelectron (PE.) spectra of 1,2,3‐methenoindane (2), 1,2,3‐metheno‐2,3‐dihydro‐1H‐cyclopenta [b]naphthalene (3) and 1,2,3‐metheno‐2,3‐dihydro‐1H‐phenalene (4) are investigated. The PE. spectrum of 1,3‐methano‐2,3‐dihydrophenalene (7) is reported and compared with that of 4. The experimental results are analyzed in terms of empirical correlation diagrams and the results of semiempirical MINDO/3 and CNDO/S calculations. The analysis indicates that the strong impact of the bicyclobutylene group on the spectroscopic properties of the aromatic π‐systems in 2, 3 and 4 is due to hyperconjugative interactions involving bicyclobutane Walsh orbitals.
Von der basenkatalysierten Ringöffnung von 2H‐Azirinen zu einer α‐Alkylierungsmethode von primären Aminen
Authors: Schulthess Adrian Heinz , Hansen Hans‐Jürgen
Published: December 2004

From a Base Catalyzed Ring Opening of 2H‐Azirines to an α‐Alkylation Method of Primary Amines

It is shown that fluorene‐9′‐spiro‐2‐(3‐phenyl‐2H‐azirine) (1) on treatment with various alcohols in the presence of the corresponding alkoxide ions yields N‐(9′‐fluorenyl)benzimidates 2a‐d (Scheme 1). 2,2,3‐Triphenyl‐2H‐azirine (3) reacts with methanol in a similar manner (Scheme 2). Benzimidates 2a (Scheme 3), 8 (Scheme 4) and and 10 (Scheme 5) can easily be deprotonated by butyllithium (BuLi) or lithium diisopropylamide (LDA) in tetrahydrofuran (THF) to 1‐methoxy‐2‐aza‐allylanions, that can be alkylated, at C(3), exclusively, by various electrophiles (e.g. R‐X(X = I, Br), RCHO or methyl acrylate (see also Scheme 6)). As the acidic hydrolyses (1N HCl) of benzimidates 9 and 11 leads to the corresponding α‐alkylated free amines 15 and 18 (Scheme 7 and 8), benzoyl derivatives 16 and 19 are obtained from the hydrolysis under basic conditions. On the other hand, it is observed that a catalyzed Chapman rearrangement of 9 and 11 results in the formation of N‐benzoyl‐N‐methyl derivatives 17 and 20 (Scheme 7 and 8).

The described reactions offer a simple method for the α‐alkylation of activated primary amines.
The Crystal Structure of the Pentaphenylethane/Acetone Solvate by X‐Ray Analysis
Authors: Bernardinelli Gerald , Gerdil Raymond
Published: December 2004

The crystal structure of the acetone solvate of pentaphenylethane (C32H26 · 1/2 C3H6O; monoclinic, a = 8.625, b = 16.587, c = 16.961 Å, β = 95.75°, space group P21/c, Z = 4) has been determined by X‐ray analysis. The structure was solved by direct methods and refined to a final R of 0.056. The central ethane bond has a length of 1.612 (3) Å. The cavity enclosing the solvent retains the inversion centre in the crystal: as a consequence, a two‐fold disordered orientation was observed for the acetone molecule. The rotational orientation of the methyl groups was found to be staggered with respect to the C, O‐bond.
Eine neue Synthese von DL‐Armentomycin und verwandten 2‐Amino‐4‐polyhalobuttersäuren
Authors: Heinzer Franz , Martin Pierre
Published: December 2004

A New Synthesis of DL‐Armentomycin and Related 2‐Amino‐4‐polyhalobutyric Acids

An efficient method for the synthesis of 2‐amino‐4‐halobutyric acids 2 starting from the corresponding ethyl 2,4‐polyhalobutyrates 1 is presented (s. Scheme 1). The method is illustrated by a high yield synthesis of the known antibiotic DL‐armentomycin (= 2‐amino‐4,4‐dichlorobutyric acid; 2a).
Molecular Structure of the Ethylenediammonium Complex of a Tetracarboxy‐macrocyclic Receptor Molecule
Authors: Daly John J. , Schönholzer Peter , Behr Jean‐Paul , Lehn Jean‐Marie
Published: December 2004

The crystal and molecular structure of the complex formed by the ionized bistartro‐[18]‐crown‐6 receptor molecule 1 with the ethylenediammonium cation, is described. The macrocycle is roughly planar, the carboxy groups of each tartaric acid residue being in a diaxial relationship and extending above and below this plane. This conformation allows ‘lateral’ interactions with bound species to occur.

The substrate is sandwiched between two macrocycles, with one of its NH heads anchored to the polyether core, and the other one in contact with the two carboxy groups of the neighboring molecule.
Polarographische Untersuchungen an symmetrischen Triazacarbocyaninen in Acetonitril
Authors: Hellrung Bruno
Published: December 2004

Polarographic Investigations on Symmetrical Triazacarbocyanine Dyes in Acetonitrile Solution

The reduction behaviour of thirteen symmetrical triazacarbocyanine dyes with different heterocycles in acetonitrile solution has been investigated by means of dc‐ and ac‐polarography, cyclic oscillopolarography and coulometry.

The reduction mechanism has been found to be of the type eec with the first step being reversible and the second step being reversible to irreversible. Reduction potentials, transfer coefficients and specific currents of both steps have been measured (E1/2: −0,110 to −1.025 V vs. Ag/AgCl for the first step) and compared with known properties of carbocyanines and triazenium salts and to HMO calculations.

The effect of substituents X has been studied on the compounds 1,3‐diethyl‐2‐[(1,3‐diethyl‐5‐X‐benzimidazolin‐2‐yliden)triazenyl]‐5‐X‐benzimidazolium‐tetra‐fluoroborate (1a (X)) and 3‐ethyl‐2‐[(3‐ethyl‐5‐X‐Δ4‐1,3‐triazolin‐2‐yliden)triazenyl]‐5‐X‐1,3‐thiazolium‐tetrafluoroborate (1g(X)), and p‐values of 0,36 and 0,72 V, respectively, have been found.
NMR.‐spektroskopische Methoden als Reinheitskriterien isomerer Weinsäuren und Weinsäureester
Authors: Pfenninger Armin , Hochrainer August
Published: December 2004

NMR.‐spectroscopic Methods as Criteria of the Purity of Isomeric Tartaric Acids and Their Esters

meso‐Tartaric acid (2) can be distinguished either from the natural (+)‐(2R, 3R)‐tartaric acid (1) or the ‘unnatural’ (−)‐(2S, 3S)‐tartaric acid (1′) or their racemic mixture, by 1H‐NMR.‐spectral resolution using europium chloride in aqueous solution. Diastereomeric esters have been prepared from different esters of tartaric acid 3 and the Mosher reagent 4 and the purities of the enantiomers of 3 have been checked by 1H‐NMR. spectroscopy.
Influence of the water content of the solvent on the product distribution in the electrohydrodimerization of 2‐cyclohexenones
Authors: Tissot Paul , Surbeck Jean‐Paul , Gülaçar Fazil O. , Margaretha Paul
Published: December 2004

The product distribution of compounds 2, 3 and 4 formed in the electrohydrodimerization (EHD) of 1 was determined as function of the water content of the solvent (CH3CN). The presence of water favours the formation of the glycols 4 and reduces the relative amounts of 1,6‐diketones 2 and hydroxyketones 3, as determined by GC./MS.‐analysis.
A New, Stereoselective Approach to the [3.3.3]Propellane System: Synthesis of (±)‐modhephene. Preliminary communication
Authors: Oppolzer Wolfgang , Marazza Fabrizio
Published: December 2004

The unusual propellane skeleton of the sesquiterpene modhephene (1) has been synthesized starting from cyclopentenone (2). The key step 6 → 7 is an efficient and highly stereoselective intramolecular thermal ene‐reaction. Further elaboration of the propellane 7 gave the enone 10 which had been previously converted to (±)‐modhephene (1) in three steps.
Oxygenation of Co(II) Complexes with Tripodal Ligands
Authors: Mäcke Helmut
Published: December 2004

The kinetics of O2‐uptake of five‐coordinated Co2+/tren complexes (tren = 2,2′, 2″‐tris(2‐aminoethyl)amine) have been studied extensively. The kinetics of formation of (tren)Co(O2, OH)Co(tren)3+ exhibits two steps. The rate law of O2‐addition, the first step, was of the form: rate = (k[H+] + kKa)/([H+] + Ka) [Co(tren)2+][O2]. Second‐order rate constants k = 220 ± 19 M−1s−1 and k = 1.8 ± .035 · 103M−1s−1 agreed well from O2‐uptake and (stopped‐flow) spectrophotometric measurements. The protonation constant of the hydroxo complex obtained by equlibrium measurements (spectrophotometric and by pH‐titration) in anaerobic conditions (pKa = 10.03) agreed well with that derived from kinetic data (p Ka = 9.93); k and k are about a factor 100 smaller than those for the pseudooctahedral Co(trien) (H2O). This and the fact that several other Co(II) complexes with five‐coordinated geometry do not exhibit oxygen affinity led to the proposal that the oxygenation mechanism for Co2+/tren complexes involves fast preequilibria between Co(tren) (H2O)2+ and Co(tren) (H2O) and only the latter is assumed to be reactive. The enhanced rate at high pH is explained by rate determining H2O‐exchange in the O2‐addition step and the ability of coordinated OH− to labilize the neighbouring H2O. This mechanism is furthermore supported by the formation of one kinetically preferred isomer of the peroxo‐bridged dicobalt(III) complex (O2 cis to the tertiary N‐atom) and the large negative activation entropy (−30 eu). The second step is the intramolecular bridging reaction:
equation image
is independent of [Co(tren)2+] and [O2] but exhibits a pH‐dependence of the form k3 = k′3[H + ]/(Ka + [H+]); k−3 ( = 5 · 10−5 s−1) was determined independently and from the two rate constants the equilibrium constant was calculated as ≈ 105. The ligand combination as in Co(tren)2+ was shown to provide an excellent balance to form a reversible oxygen carrier; possible reasons for this are discussed.
Total synthesis of racemic ajmalicine and 19‐epi‐ajmalicine
Authors: Gutzwiller Jürg , Pizzolato Giacomo , Uskoković Milan R.
Published: December 2004

rac.‐Ajmalicine (31) and 19‐epi‐ajmalicine (30) have been synthesized by a convergent route from the preformed D, E‐ring moieties 25 and 27 and tryptophyl bromide. Two syntheses of the trans‐1‐benzoyl‐3‐vinyl‐4‐piperidineacetic acid (13), used in the preparation of 25 and 27, are also described.
Stereochemistry of the Platinum Catalyzed Hydroformylation of Olefins
Authors: Haelg Paul , Consiglio Giambattista , Pino Piero
Published: December 2004

The deuterioformylation of (Z)‐ or (E)‐2‐butene catalyzed by [DIOP]Pt(SnCl3)‐Cl

DIOP=2,3‐O‐isopropylidene‐2,3‐dihydroxy‐1,4‐bis(diphenylphosphino)butane.

gives predominantly erythro‐ or threo‐1,3‐[2H]2‐2‐methylbutanal respectively. Hence, hydroformylation by this catalytic system must take place with cis‐stereochemistry.
Zur Chemie der Spiro‐β‐lactame aus der [2+2]‐Cycloaddition von Ketenen an Iminolactone
Authors: Roth Martin
Published: December 2004

Chemistry of Spiro‐β‐lactams

Reactions of the easily accessible spiro‐β‐lactams 1 are described. These comprise hydrogenation, hydrolyses and alcoholyses, reaction with hydrazine, and lead to new heterocyclic compounds. Some further transformations of the products are shown.
Synthesis, Surface Activity and Micelle Formation of Novel Cyanine Dyes
Authors: Barni Ermano , Savarino Piero , Pelizzetti Ezio , Rothenberger Guido
Published: December 2004

The synthesis, surface activity and micelle formation of three novel cyanine dyes with amphiphilic character is described. It is illustrated by combined surface tension and absorption measurements that in one case self‐assembly is highly cooperative leading to aggregates with unique absorption properties.
A Study of N‐Butyl‐(all‐trans‐retinylidene)amine and Its Protonated Species by 1H‐ and 13C‐NMR. Spectroscopy
Authors: Pattaroni Christian , Lauterwein Jürgen
Published: December 2004

The Schiff base of all‐trans‐retinal was investigated in organic solution by 1H‐ and 13C‐NMR. at high field. Complete assignment of the 1H‐NMR. peaks of N‐butyl‐(all‐trans‐retinylidene)amine (2) and the N‐butyl‐(all‐trans‐retinylidene)‐ammonium ion (3) was achieved by INDOR (internuclear double resonance). The vicinal proton coupling constants of the polyene chain show that the π‐bond orders remain unchanged in N‐butyl‐(all‐trans‐retinylidene)amine relative to all‐trans‐retinal (1), but change towards larger π‐delocalization in the N‐butyl‐(all‐trans‐retinylidene)ammonium ion. At −‐61° only one isomer of N‐butyl‐(all‐trans‐retinylidene)ammonium was observed. This was shown to be trans at the imine linkage and independent of the solvent. The trifluoroacetic acid counter‐ion can approach the positive charge of the N‐atom in the weakly polar solvent dichloromethane but not in the leveling solvent methanol. In dichloromethane the nature of the 1:1 complex is a H‐bonded (O−…H‐N+) ion‐pair whose rate of breaking and forming is rapid at RT. Strong stabilization of the ion‐pair resulted from homo‐conjugation with a second molecule of trifluoroacetic acid. Excess of acid efficiently diminished the isomerization rate at the C,N‐bond.
Synthesis and Biological Properties of Enkephalin‐like Peptides Containing Adamantylalanine in Position 4 and 5
Authors: Do Kim Quang , Schwyzer Robert
Published: December 2004

The syntheses of seven [D‐ala‐2]‐enkephalin analogues, H‐Tyr‐ala‐Gly‐X‐Y, with X‐Y = Phe‐Ada‐OH, Phe‐ada‐OH, Phe‐Ada‐NH2, Phe‐ada‐NH2, Ada‐Leu‐OH, Ada‐Leu‐NH2, and Ada‐Ada‐NH2 are described. The compounds with Y = Ada (= L‐Ada) or ada (= D‐Ada) show pronounced morphine‐like activities in certain bioassays, whereas those with X = Ada were most inactive. The analogues were used to explore the influence of steric, electronic, and hydrophobic properties of the side chains of X and Y on opioid activity (see [14]).
Zur Biosynthese der Rubratoxine
Authors: Nieminen Sirkku , Payne Trevor G. , Senn Peter , Tamm Christoph
Published: December 2004

In order to check the hypothesis that rubratoxin B (2), a C26‐metabolite, is formed biogenetically by head‐to‐tail coupling of two identical C13‐precursors derived from decanoic acid and oxaloacetic acid, two labelled forms of the postulated C13‐intermediate 2‐((E)‐1'‐octenyl)‐3‐[14C]methyl‐ and 2‐((E)‐1'‐octenyl)‐3‐[13C]‐methylmaleic anhydride (10), were synthesized. The labelled compounds 10 as well as a number of other 14C]‐ and [13C]‐labelled potential precursors were administered to growing cultures of Penicillium rubrum STOLL. Significant incorporation rates of acetate (as intact units) and malonate were observed. Propionate was incorporated after decarboxylation. Succinate exhibited the highest rate of incorporation. The results are in agreement with the assumption that the C10‐chain is formed by the fatty acid pathway and the C3‐unit via the tricarboxylic acid cycle. After administration of 10 randomization of the label was observed. Thus the question whether compound 10 is a biogenetic intermediate remains unanswered.
14‐Hydroxytaxodion: Partialsynthese und Reaktionen
Authors: Rüedi Peter , Eugster Conrad Hans
Published: December 2004

The hitherto unknown diterpenoid 14‐hydroxytaxodione (10a) has been prepared by oxidation of 6β‐hydroxyroyleanone. Its solutions exhibit a dynamic structural behaviour (UV./VIS/. and NMR.) and lead to an equilibrium mixture of the 11, 14‐ and the 6, 12‐dioxo forms. By methylation and acetylation the 6, 12‐dioxo form can be isolated. Chloroform solutions of 14‐hydroxytaxodione slowly set up a mixture of coleon V (2a), coleon U (3) and dimeric products (later established as grandidone C, grandidone D and 7‐epigrandidone D). Therefore, coleon V (2a) owing to its strong intramolecular H‐bond is more stable than 7, 14‐dihydroxy‐taxodione (2b).
1,6‐Additionen an 3‐Methyl‐5‐methyliden‐2‐(5H)‐furanon‐Derivate
Authors: Wyss Heinz , Révész Laszlo , Scheffold Rolf
Published: December 2004

1,6‐Additions to 3‐Methyl‐5‐methylidene‐2(5H)‐furanone Derivatives

The anions of thiophenol, methyl malonate and malononitrile react with 3‐methyl‐5,6‐dihydro‐2 (4H)‐benzofuranone (1c) by the formation of the corresponding 1,6‐addition products cis‐5c (63%), trans‐6 (42%) and trans‐7 (76%), respectively. Likewise, the reaction of 3‐methyl‐5‐methylidene‐2 (5H)‐furanone (1b) with thiophenol yields the 1,6‐addition product 5b (66%), and with the sodium salt of methyl aceto‐acetate the 1,6‐addition product 8 (11%) and the dispiro‐dilactone 9 (39%).
Vorkommen neuer bifunktioneller. Ester im Römisch‐Kamillenöl (Anthemis nobilisL.)
Authors: Klimes Ivan , Lamparsky Dietmar , Scholz Ernst
Published: December 2004

Occurrence of New Bifunctional Esters In Roman Camomile Oil (Anthemis nobilis L.)

Some novel aliphatic esters of the unusual 3‐hydroxy‐2‐methylidenebutyric acid have been found in the commercially available essential oil. Additionally, esters of (Z)‐2‐methyl‐2‐butenoic acid of structurally similar diols or other bifunctional alcohols have also been identified. Spectral data as well as a synthetic approach to the new esters of 3‐hydroxy‐2‐methylidenebutyric acid are given.
Détermination de la configuration de glycosylaziridines par dichroïsme circulaire. Note de laboratoire
Authors: Tronchet Jean M. J. , Winter‐Mihaly Eva , Massoud Mohamed A. M. , Martin Olivier R. , Barbalat‐Rey Françoise , Ojha‐Poncet Joëlle , Giust Josiane
Published: December 2004

CD.‐Based Configurational Assignments of Glycosylaziridines

The relationship between CD.‐curves and the configuration of the trans‐2‐benzoyl‐3‐phenylaziridines was known. By studying a series of cis‐ and trans‐2‐glycosyl‐3‐benzoylaziridines we have shown that CD. allows the assignment of the configuration at both asymetric C‐atoms. As benzoylaziridines can easily be obtained from cyano‐ or alkoxycarbonylaziridines without configurational change, the absolute configuration of these last two classes of compounds can also be assessed by this method.
Magnetic Circular Dichroism and Absorption Spectra of 2‐Methyl‐1, 3‐diazaazulene
Authors: Yamaguchi Hiroyuki , Ata Masafumi , Toyoda Koichi , Mametsuka Hiroaki , Takeshita Hitoshi , Baumann Harold
Published: December 2004

The magnetic circular dichroism and UV. spectra of 2‐methyl‐1, 3‐diazaazulene (2) have been measured. The UV. spectrum is interpreted by making use of CNDO/S MO CI calculations. Our assignment of the first and second absorption band coincides with one of the corresponding bands of 1, 3‐diazaazulene (1) given by Small & Burke. The third and fourth absorption bands are in agreement with those published by Hiratsuka et al. and Tanizaki et al. for 1 and 2‐ethoxy‐1, 3‐diazaazulene, respectively.
Temperature and Concentration Dependent Circular Dichroism of Mono‐ and Di‐cis Isomers of (3S,3′S)‐Astaxanthin Diacetate
Authors: Noack Klaus , Thomson Andrew J.
Published: December 2004

The circular dichroism (CD.) spectra of all‐trans‐(3S, 3′S) astaxanthin diacetate and its 9‐cis, 13‐cis, 9,9′‐di‐cis, 9,13′‐di‐cis, and 9,13‐di‐cis isomers conform to the rules previously formulated for optically active carotenoids with a 4‐oxo‐β‐end ring containing an asymmetric C‐atom [1]. Thus the CD. bands of the all‐trans and the di‐cis isomers show the same signs whereas those of the mono‐cis isomers have opposite signs. The CD. spectra of all the astaxanthin diacetate isomers invert sign upon cooling to −180°. The CD. spectra of the 9‐mono‐cis and 9,9′‐di‐cis isomers and to a lesser extent also those of the 9, 13′‐di‐cis and 9, 13‐di‐cis isomers are concentration dependent at −180°, with the longest wavelength band giving at the higher concentration a bisignate CD. curve under the main absorption characteristic of aggregation. This phenomenon has been observed only in isomers with a 9‐cis linkage. It is suggested that steric hindrance prevents such aggregation taking place in the other isomers.