bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrophilic Aromatic Substitution of Groups other than Hydrogen. Part I: Ipso Factors and Rate‐Limiting Steps in Dehalogenations by Diazonium Ions. 26th communication on diazo coupling reactions
Authors: Fischer P. B. , Zollinger H.
Published: December 2004

The rates of substitution of the group X in 1‐X‐2‐naphthol‐6‐sulfonic acids (X = H, Cl, Br, and I) by p‐chlorobenzenediazonium ions in aqueous solution have been measured. The rates of the halogenated naphthols relative to that of the parent compound (X = H) are 0.0070:0.0089:0.149 for X = Cl, Br, and I respectively. The reaction of 1‐bromo‐2‐naphthol‐6‐sulfonic acid is catalysed by thiosulfate ions; the relative rate observed for this compound does not, therefore, represent the ipso factor. It is postulated that in its substitution the release of the electrofugal leaving group (Br⊕) is rate‐limiting.
Sigmatropic Reactions in Carbanions. II. The Rearrangement of Allylic Ammonium Ylides
Authors: Rautenstrauch V.
Published: December 2004

Two representative cases of the [2, 3] sigmatropic rearrangement are described, and the mechanism of this reaction is discussed.
Note Concerning the Concepts of Reaction Numbers, Independent Reactions and Resistant Groups in Chemical Thermodynamics and Kinetics
Authors: Bauder A. , Günthard Hs. H.
Published: December 2004

A linear algebraic characterization for sets of independent reactions, independent reaction numbers, conservation laws and resistant groups for both equilibrium and kinetic systems is suggested. Basing on the ranks of two stochiometric matrices N and M, these concepts are discussed and formulas given for setting up of independent sets of equilibrium and kinetic equations. The difference in the definition of independent reaction numbers for these two types of systems is pointed out. A brief consideration is devoted to the transformations of equilibrium and kinetic equations induced by transformation from one set of linearly independent reactions to another. Finally the conservation laws are formulated as chemical invariants within the N, M framework.
Iridium (I) and Platinum (II) Complexes with Cyanine Dye Base Ligands
Authors: Winkler T. , Mayer C.
Published: December 2004

The preparation of cyanine dyes by coordination of cyanine dye bases with transition metals is described. The significance of these complexús for the realization of an excitonic high temperature superconductor is discussed.
Intramolekulare Diels‐Alder‐Additionen in 6‐(But‐3‐enyl)‐6‐methyl‐cyclohexa‐2,4‐dien‐1‐on‐Systemen; eine neue Synthese von Twistanderivaten
Authors: Greuter H. , Schmid H.
Published: December 2004

Alkylation of the sodium salt of mesitol with 2‐bromomethyl‐buta‐1,3‐diene (7) in benzene and subsequent refluxing of the reaction mixture gave 7% 2‐methylene‐3‐butenyl‐mesitylether (8), 12% 5‐methylene‐1,3,8‐trimethyl‐tricyclo[4,3,1,03,7]‐8‐decen‐2‐one (9) and 44% 9‐methylene‐1,3,5‐trimethyl‐tricyclo[4,4,0,03,8]‐4‐decen‐2‐one (10), a twistane derivative. The same procedure, when applied to the sodium salt of 2,6‐dimethyl‐4‐methoxyphenol, gave in 73% yield a 26:18:54 mixture of 2,6‐dimethyl‐4‐methoxyphenyl‐(2‐methylene‐3‐butenyl)‐ether (11), 1,3‐dimethyl‐8‐methoxy‐5‐methylene‐tricyclo[4,3,1,03, 7]‐8‐decen‐2‐one (12), and 1,3‐dimethyl‐5‐methoxy‐9‐methylene‐tricyclo[4,4,0,03, 8]‐4‐decen‐2‐one (13). The tricyclic ketones 9 and 10, or 12 and 13, were also obtained on heating 8 or 11 respectively at 176° in decane solution. Alkylation of the sodium salt of 2,6‐dimethylphenol with 3‐butenylbromide in boiling toluene gave 1,3‐dimethyl‐tricyclo[4,3,1,03,7]‐8‐decen‐2‐one (17) as the only tricyclic product in 8% yield. The structures of the twistane derivatives 10 and 13 as well as those of the ketones 9, 12 and 17 were mainly deduced from spectroscopic data. Furthermore, the ketones 10 and 13 could be converted to the twistane derivatives 20 and 22, possessing C2‐symmetry. On the other hand, compounds 9 and 17 gave only the asymmetric derivatives 18 and 21.
The Loss of CH3COCH2 Moieties from Methylketo Esters upon Electron Impact: A discussion of possible long‐range functional group interaction
Authors: Richter W. J. , Liehr J. G.
Published: December 2004

Methyl 10‐oxoundecanoate and related long‐chain methylketo esters exhibit loss of the terminal CH3COCH2 moiety as one of the most prominent modes of fragmentation in analogy to comparable long‐chain diketones. In view of its absence in simple monoketonic analogues this process is thought to be induced by the distant ester function, e.g. via hydrogen abstraction from a suitable site (C(7)) within the alkyl portion of the molecule to be retained in the fragment. Rearrangement indicative of functional group interaction is thus concealed, and the attempt is made to unravel its incidence and true course by analysis of the further decomposition of the (M‐CH3COCH2) fragment via sequential losses of MeOH and CO, with the emphasis on establishing the origin of the OH hydrogen of the former of these two particles. Extensive deuterium labelling of most of the positions of the central chain, as well as analysis of pertinent high‐resolution data and metastable transitions, is employed in the pursuit of this objective.
Geijerone (3‐Isopropenyl‐4‐methyl‐4‐vinylcyclohexanone), a New, Naturally Occurring C12 Terpenoid
Authors: Thomas Alan F.
Published: December 2004

In the essential oil of Juniperus communis L. (fruit), the title compound (trans‐ isomer) has been identified; its structure being confirmed by synthesis from elemol. The optical rotation of the natural compound was nearly the same as the synthetic sample, suggesting that it is not an artefact formed from a ten‐membered ring precursor during the isolation.
Methylierungs‐Reaktionen an 30‐Oxa‐[14]cytochalasanen
Authors: Binder M. , Tamm Ch.
Published: December 2004

For synthetic studies the protection of the hydroxyl groups of phomin (cytochalasin B) ((7S,22R,26R)‐7,26‐dihydroxy‐22‐methyl‐30‐oxa‐[14]cytochalasa‐6(18), 19t 27t‐trien‐1,29‐dion) (1), the dodecahydro‐derivative 2, and the dihydro‐derivative 4 by methylation was investigated. Treatment of 1 with CH3I/Ag2O gave the iminoether 6. The reaction of 4 with CH2N2/BF3 led to the di‐O‐methyl derivative 8 and to the N‐methyl‐di‐O‐methyl derivative 9, whereas 2 was transformed to the N‐methyl‐di‐O‐methyl compound 10 and to the iminoether 11.

NaBH4 reduction of 3 yielded not only 4 but also the epimeric dihydro derivative 5.
1H‐NMR‐Untersuchungen an Droso‐ und Isodrosopterin – ein Beitrag zur Strukturaufklärung. Pteridine, LV
Authors: Schlobach Heinrich , Pfleiderer Wolfgang
Published: December 2004

The NMR. spectra of droso‐ and isodrosopterin (1) in DMSO‐d6, 1% DCl/D2O solution, CF3CO2D, and conc. sulfuric acid are discussed in detail. Missing of methine and methyl groups and proof for the presence of three isolated methylene functions of which two show a geminal coupling are consistent with the proposed structure of atropisomeric di(7,8‐dihydropterinyl)‐ methane dye stuffs.
Weitere Bufadienolide aus Ch'an Su. Über Krötengifte, 39. Mitteilung
Authors: Höriger Niklaus , Živanov Dobrila , Linde Horst H. A. , Meyer Kuno
Published: December 2004

From the toad venom Ch'an Su the bufadienolides 1, 4, 9, 10, 12, 15, 17, 20, 22, 25 and 18, the latter as diacetate 19 were isolated and their structure elucidated.
Steroide und Sexualhormone. 247. Mitteilung. Die Partialsynthese von Tetrahydrostapelogenin. Vorläufige Mitteilung
Authors: Schaffner B. P. , Wehrli H.
Published: December 2004

A partial synthesis of tetrahydrostapelogenin (5), a hydrogenation product of stapelogenin (4), is described, proofing the structure of 4 proposed by Reichstein [2–3].
Eine Apparatur zur automatischen Bestimmung von Wasserdampf‐Sorptions‐Isothermen und ‐Isobaren
Authors: Bolliger W. , Gál S. , Signer R.
Published: December 2004

An apparatus for the automatic determination of water vapor sorption isotherm and isobares is described. Its main parts are a Cahn electrobalance and a gas circulating system. The gas can be held at constant dew points between – 85 and + 25 degree by an ultracryostal and an ultrathermostate and brings the sorbens to hygroscopic equilibrium.
Steroide und Sexualhormone. 246. Mitteilung [1]. Die Partialsynthese von Batrachotoxinin A
Authors: Imhof R. , Gössinger E. , Graf Walter , Berner‐Fenz L. , Berner H. , Schaufelberger R. , Wehrli Heinrich
Published: December 2004

In addition to the preliminary communication [1] a detailed description of the first partial synthesis of steroidal alkaloid batrochotoxinin A (1) is presented.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäure‐ester mit einem heterocyclischen Substituenten. 6. Mitteilung. 3‐Acyl‐thio‐ und ‐dithio‐carbazinsäure‐alkylester und 2′‐(Dialkoxy‐phosphinothioyl)‐carbonsäurehydrazide sowie deren Ringschluss zu 3‐Acyl‐5‐alkoxy‐ und ‐5‐alkylthio‐1,3,4‐thiadiazol‐2(3H)‐onen bzw. 3‐(Dialkoxy‐phosphinothioyl)‐5‐substit.‐1,3,4‐oxadiazol‐2(3H)‐onen
Authors: Rüfenacht Kurt
Published: December 2004

Thio‐ and dithio‐carbazic acid alkyl esters, acylated in position 3 by radicals of carboxylic, sulfonic, phosphoric, thiophosphoric or thiophosphonic acids, undergo spontaneous ring closure with phosgene, in absence of any acid binding agent, to form the corresponding 3‐acyl‐5‐alkoxy‐ and ‐5‐alkylthio‐l,3,4‐thiadiazol‐2(3H)‐ones. Similarly 3‐thiophosphorylated 5‐substituted 1,3,4‐oxadiazol‐2(3H)‐ones can be prepared from carboxylic acid hydrazides acylated by thiophosphoric acid radicals. In the latter case, however, a stoichiometric amount of pyridine is necessary to avoid cleavage of the PN‐bonding.
Eine stereospezifische Synthese von syn‐Bishomochinon über p‐Benzochinon‐bis(äthylen)ketal
Authors: Heller Jürg E. , Dreiding André S. , O'Connor B. R. , Simmons H. E. , Buchanan G. L. , Raphael R. A. , Taylor R.
Published: December 2004

The bis(ethylene)ketal of p‐benzoquinone (6) has been prepared from the bis(ethylene)ketal of cyclohexane‐1,4‐dione (3) by bromination with bromine in ether followed by dehydrobromination with potassium t‐butoxide. Two intermediate dibromides (4 and 5) were isolated and their constitutions as well as their configurations determined from spectroscopic properties.

Partial hydrolysis of 6 furnished the mono(ethylene)ketal of p‐benzoquinone (9), which was converted stereospecifically to syn‐bishomoquinone (2) by the double addition of sodium dimethylsulfoxonium‐methylide. The intermediate mono(ethylene)ketals of syn‐bishomoquinone (11) as well as of the mono(methylene) addition product (10) were also isolated.
Contribution à la phytochimie du genre Gentiana I. Etude des composés flavoniques et xanthoniques dans les feuilles de Gentiana lutea L. (1re communication)
Authors: Bellmann Günter , Jacot‐Guillarmod André
Published: December 2004

Six polyphenolheterosides have been isolated from the leaves of G. lutea L. by means of thin layer and column chromatography on polyamide. The xanthones mangiferin (III) and gentioside (IV), the flavones isoorientin (V) isovitexin (VI) and two new heterosides (E and F) have been isolated. E gave isoorientin and glucose on hydrolysis and F isovitexin, glucose and gentiobiose. Structure identification has been achieved by UV., IR. and NMR. spectroscopy as well as by synthesis of the corresponding aglycones.
Demethylierungen am Mesembrin
Authors: Pfäffli P. , Hauth H.
Published: December 2004

The N‐methyl group of mesembrine (1) was split off via reaction of chloroformic acid p‐nitrophenyl ester on the keto‐protected alkaloid. O‐Demethylation of 1 with borontribromide produced simultaneous ring closure between the carbonyl function and the aromatic part of the molecule.
Stereoselektive Bildung der C‐C‐Bindung in der Kopplungsreaktion zwischen sek. Alkylmagnesiumbromiden und ungesättigten Halogeniden: Asymmetrische Induktion durch einen optisch aktiven Diphosphin‐Nickel‐Komplex
Authors: Consiglio Giambattista , Botteghi Carlo
Published: December 2004

The catalyzed cross‐coupling reaction of secondary racemic Grignard reagents with unsaturated halides takes place stereospecifically in the presence of the nickel chiral complex 4 although some isomerisation is occurring this reaction can be useful to prepare optically active hydrocarbons.
Die Struktur von Maytenin
Authors: Englert G. , Klinga K. , Raymond‐Hamet  , Schlittler Emil , Vetter W.
Published: December 2004

In den Jahren 1933–37 sind eine Reihe von Arbeiten über die Inhaltsstoffe von Maytenus Chuchuhuasha und über die pharmakologische Wirkung von Chuchuhuasha‐Extrakten. publizier worden [1], deren Inhalt sehr eingehend in der Dissertation von Robert Colas zusammengefasst wurde [2].

Die verschiedenen Maytenus‐Sendungen (hauptsächlich Wurzeln und Stammrinde), die Colas erhielt, stammten aus dem oberen Amazonasgebiet: drei Muster aus Iquitos (Peru) und drei Sendungen aus Leticia (Columbien). Wässerige Extrakte dieser Pflanzen werden von den Eingeborenen jener Gegenden als Aphrodisiakum eingenommen.

Die botanische Bestimmung des Pflanzenmaterials wurde damals von dem einen von uns (R. H.) vorgenommen. Anhand von makroskopischen und mikroskopischen Untersuchungen der Stammrinde, der Blätter und Blüten wurde festgestellt, dass es sich bei einer der Sendungen ein wandfrei um eine neue Maytenus‐Spezies handelte, die als Maytenus Chuchuhuasha (Raymond Hamet et Colas) bezeichnet und die botanisch auch gegen Maytenus communis abgegrenzt wurde. Weniger sicher war die Bestimmung einer zweiten Maytenus‐Spezies, die gelegentlich erhalten wurde. Sie wurde in der Dissertation Colas als «Maytenus non déterminé» bezeichnet und wurde chemisch nicht weiter bearbeitet. Gelegentlich enthielten Pflanzensendungen auch eine neue Salacia‐Spezies (Hippocrataceae), die Salacia Colasi (R. Ben.) benannt wurde. Auch diese Salacia wurde chemisch nicht weiter untersucht.
Organic Phosphorus Compounds 56. The addition of hypophosphite esters to activated olefins, a new method for preparing 2‐substituted ethyl phosphinates
Authors: Maier Ludwig
Published: December 2004

The addition of methylhypophosphite, H2P(O)OCH3, to acrylic acid derivatives, CH2CHX (X  CONH2, CN, CO2R), is described and the physical properties of three new 2‐substituted ethylphosphinates are reported.
Alkyl Transition Metal Compounds IX. Synthesis and structure of [(Me3SiCH2)2Cr(bipy)2] I
Authors: Daly J. J. , Sanz F. , Sneeden R. P. A. , Zeiss H. H.
Published: December 2004

Bis(trimethylsilylmethyyl)‐bis‐(2,2′‐bipyridyl)chromium(III) iodide has been synthesized and its structure determined; the Cr‐C(sp3) bond length is 2.107(9) Å.
Radiolyse des hydrocarbures. 20e communication. n‐Alcanes en phase liquide de l'heptane au dodécane
Authors: Rappoport Serge , Gäumann Tino
Published: December 2004

Effects of dose and temperature on the yields of the majority of the radiolysis products of the n‐heptane, n‐octane, n‐nonane, n‐decane and n‐dodecane have been determined. The G‐values of the products, excepting dimers are approximately the same for all the above n‐alcanes. The temperature dependence, expressed as an apparent activation energy is shown to be equal for all n‐alcanes.
Méthylène‐10,11‐ et méthyl‐11‐prostaglandine
Authors: Vogel Pierre , Crabbé Pierre
Published: December 2004

The title compounds 6 and 7 have been prepared from a natural occurring PG‐A2 derivative. The structure and configuration of these novel prostaglandins are deduced from their mode of preparation and from their spectroscopic properties.
Über kristallines Chrom(III)hydroxid. I
Authors: Giovanoli Rudolf , Stadelmann Willy , Feitknecht Walter
Published: December 2004

When hydroxide ions are added to a solution of Cr(H2O)63+ ions at low temperature a well crystallized chromium hydroxide hydrate is formed, corresponding to the formula [Cr(OH)3‐(H2O)3]∞. Its structure is the inverse of bayerite type, two thirds of the octahedral M3+ positions being vacant. It loses water easily and turns into a totally amorphous hydroxide of variable water content. An amorphous hydroxide is also obtained when solutions are alkalized at higher temperatures or when aged solutions (containing polynuclear complexes) are used.
Electron Paramagnetic Resonance Spectra of planar low‐spin Complexes of Cobalt(II) with Schiff's Bases. I. N,N′‐ethylene‐bis(salicylideneimine)‐cobalt(II). Preliminary communication
Authors: von Zelewsky Alexander , Fierz Hans
Published: December 2004

The anisotropic EPR. parameters of N,N′‐ethylene‐bis(salicylideneimine)‐cobalt(II), magnetically diluted with the corresponding nickel complex, have been determined from single‐crystal measurements. From these data it is concluded that in the cobalt complex dyz and d differ only slightly in energy, the former being the orbital accomodating the unpaired electron in the ground state.
Über die Wirkung von Auxochromen in Flavyliumsalzen, I. 7‐Hydroxy‐flavyliumsalze
Authors: Kokkinos Konstantinos , Wizinger Robert
Published: December 2004

7‐Hydroxy‐flavylium salts absorb at longer wave lengths than the corresponding flavylium salts, yet auxochromes in 4′‐position have a less bathochromic effect in the 7‐hydroxy‐flavylium series than in the flavylium series. As a result the absorption maxima converge. 4′‐Dimethylamino derivatives show a convergence of 22 nm.
Über die Wirkung von Auxochromen in Flavyliumsalzen, II. 5,6‐Benzo‐flavyliumsalze
Authors: Kokkinos Konstantinos , Wizinger Robert
Published: December 2004

Analogously to the 7‐hydroxyflavyliumion the 5,6‐benzoflavyliumion affects auxochromes in 4′‐position not as strongly as the flavylium ion. In the flavylium series the dimethyl‐amino group e.g. causes a bathochromic effect of 137 nm; in the 5,6‐benzoflavylium series however the bathochromic effect is only 109 nm. The absorption maxima of both series converge; in the case of the dimethylamino group the convergence amounts to 28 nm.
Biosynthèse de la proferrorosamine A à partir de la L‐lysine
Authors: Pouteau‐Thouvenot Micheline , Padikkala José , Barbier Michel , Viscontini Max
Published: December 2004

Nous montrons dans ce travail que chez Pseudomonas roseus fluorescens, la L‐lysine semble être le précurseur de l'acide picolique, lui‐même directement incorporé dans le noyau pyridinique de la proferrorosamine A. La L‐lysine, de même que nous l'avons montré pour l'acide L‐glutamique, ne prend pas part à la biosynthèse de la chaîne latérale du propigment.
La séparation d'éléments des terres cériques par chromatographie sur échangeurs d'ions à l'aide de l'acide N‐(2‐hydroxyéthyl)‐iminodiacétique
Authors: Quinche Jean‐Pierre
Published: December 2004

Nous décrivons un procédé de séparation d'éléments des terres cériques par chromatographie de déplacement sur échangeurs d'ions permettant d'obtenir des effluents riches en lanthanides (jusqu'à 0,18M). Les meilleurs résultats ont été obtenus avec la résine Dowex 50 WX2 [VO2+] (200–400 mesh) et une solution éluante de HIDA 0,20M (pH = 8,70).
Photochemische Reaktionen. 72. Mitt. [1]. Zur Photofragmentierung von 14β‐Hydroxy‐20‐oxo‐Δ16‐Steroiden
Authors: Marti Franz , Wehrli Hansuli , Jeger Oskar
Published: December 2004

On UV. irradiation in i‐octane or t‐butyl alcohol the α,β‐unsaturated δ‐hydroxy ketone 2 undergoes fragmentation to the novel 14,15‐seco‐steroid 3.
Struktur von Coleon F
Authors: Rüedi Peter , Eugster Conrad Hans
Published: December 2004

Coleon F is a new, very labile p‐methylenequinone, C20H20O4, which has been isolated from the glands on the leaves of Coleus barbatus (Benth.) Agnew, C. Kilimandschari (Gürcke) Agnew and a C. species P.R.O. Bally No. 10 431. It has been shown to be 18 (or 19) (4 → 3), 16 (or 17) (15 → 16 (or 17))‐diabeo‐abieta‐3,5,7,9,13,16‐hexaen‐11,14‐diol‐2,12‐dione (2).
Zur Problematik der Peptidsynthese an Trägern: Beitrag eines neuen Verfahrens mit löslichen Trägern
Authors: Andreatta R. H. , Rink H.
Published: December 2004

A new procedure for the synthesis of peptides on a soluble carrier is described. It relies on gel filtration for the removal of low molecular weight reactants from the peptide‐polymer complex after each cycle. The advantages of the method are assessed and the insight into the problematics of the carrier synthesis which it provides are discussed. Finally, the use of a monovalent, soluble carrieer molecule of defined chemistry is proposed. Such a carrier should reduce the problems of carrier synthesis to the purely chemical ones commonly associated with peptide synthesis.
Synthese von rac. N‐t‐Butyloxycarbonyl‐thiobenzylglycyl‐thiobenzylglycin und Versuche zur Darstellung des 3,6‐Epidithio‐2,5‐piperazindions
Authors: Petrzilka T. , Fehr Ch.
Published: December 2004

The synthesis of rac. N‐t‐butyloxycarbonylthiobenzylglycyl‐thiobenzylglycine is described. Cyclisation experiments to the corresponding 3,6‐epi‐dithio‐piperazindion(2,5) were unsuccessful.
Chaenorhin, ein macrocyclisches Spermin‐Alkaloid. 149. Mitteilung über Alkaloide
Authors: Bernhard Heinz O. , Kompiš Ivan , Johne Siegfried , Groöger Detlef , Hesse Manfred , Schmid Hans
Published: December 2004

Structure 1 has been elucidated for chaenorhine, an alkaloid isolated from Chaenorhinum organifolium (Scrophulariaceae). The key derivative for the structural elucidation is 13,14,21,22‐tetrahydro‐21,22‐seco‐chaenorhine (21). 21 gave upon hydrolysis spermine and 4‐hydroxydihydrocinnamic acid characterized as the tetraacetyl derivative 18 and as the dimethyl derivative respectively.
Utilisation d'ylides du phosphore en chimie des sucres. XV. Synthèse de sucres à insaturation terminale
Authors: Tronchet Jean M. J. , Baehler Bruno , Eder Hansjörg , Le‐Hong Nghiep , Perret Françloise , Poncet Joëlle , Zumwald Jean‐Bernard
Published: December 2004

Treatment of 3‐O‐benzyl‐1, 2‐O‐isopropylidene‐3‐O‐methyl‐α‐D‐xylo‐pentodialdlo‐1,4‐furanose and 2,5‐anhydro‐3,4‐O‐isopropylidene‐aldehydo‐D‐ribose with moderately stable and stable phosphonium ylides led to the corresponding terminal‐unsaturated sugars obtained as a mixture of cis and trans isomers. The cis:trans ratios were determined by 1H‐NMR. and (or) GLC. They showed that steric factors play an important role in the control of the stereochemistry of these reactions.
Die gezielte Synthese offenkettiger asymmetrischer Cystinpeptide mittels thiol‐induzierter Fragmentierung von Sulfenylthiocarbonanten. Insulinfragmente mit intakter Disulfidbrücke A20‐B19.
Authors: Kamber Bruno
Published: December 2004

The thiol‐induced fragmentations of sulfenyl thiocarbonates (RSSCOOCH3) leading to mixed disulfides was applied to the synthesis of open‐chain asymmetrical cystine peptides. Various fragments of insulin containing the disulfide bridge between A20 and B19 were prepared by this method.
Reinvestigation of the Classical Synthesis of Cinchona Alkaloids. I. A new synthesis of homomeroquinene and quinotoxine
Authors: Grethe Guenter , Lee Hsi Lin , Mitt Toomas , Uskoković Milan R.
Published: December 2004

Eine neue Synthese von N‐benzoyl‐homomerochinen‐äthylester (10 b) und dessen Überführung in Chinotoxin (18) wird beschrieben.
Homopolar and Heteropolar Bond Dissociation Energies and Heats of Formation of Radicals and Ions in the Gas Phase II. The relationship between structure and bond dissociation in organic molecules
Authors: Egger Kurt W. , Cocks Alan T.
Published: December 2004

The preceeding paper presents a critical tabular compilation of 2‐center homo‐ and heteropolar bond dissociation energies. This paper deals with some empirically derived general aspects of these data, particularly regarding relationships between structure and reactivity, i.e. substituent effects on bond dissociation energies. ‘Extra’ stabilization energies generated in electronically delocalized radicals or ions derived from these experimental data are also presented.
Etude conformationnelle dans l'approximation CNDO/BW: barrière de rotation interne de petites molécules organiques
Authors: Weber Jacques , Gerdil Raymond
Published: December 2004

The potential functions for internal rotation of several representative small organic molecules are calculated by the CNDO/BW method. For ethane, methanol, propylene, methyl‐cyclopropane and ethylene the most stable conformation is predicted correctly; although too small a value is calculated for the height of the rotational barrier, with the exception of ethylene for which the calculated value is very close to the experimental one. For glyoxal, butadiene and hydrazine the number of minima in the energy profiles or the or the associated values of the torsional angle are predicted incorrrectly (for butadiene, see however the note added to the proofs).
Die Synthese von all‐trans‐Retinylamin und anderen Polyenaminen
Authors: Kienzle Frank
Published: December 2004

The preparation of various polyene phthalimides using the azocarboxylate method is described. The imides are converted into the corresponding amines by reaction with hydrazine. In this way all‐trans‐retinylamine and β‐ionylamine have been obtained.
Untersuchungen über eine Carbonyl‐Olefinierung mit α‐metallierten Isocyaniden. Die Synthese von β‐Carotin und anderen Polyenen
Authors: Kienzle Frank
Published: December 2004

The synthesis of various polyene isocyanides, e.g. β‐ionyl isocyanide and all‐trans‐retinyl isocyanide is reported. Their use in carbonyl‐olefination was investigated and compared with the Wittig reaction. β‐Carotene was obtained from all‐traws‐retinal and all‐trans‐retinyl isocyanide in good yield.
Tieftemperaturbestrahlungen von 3‐Phenyl‐2H‐azirinen
Authors: Sieber Willi , Gilgen Paul , Chaloupka Stanislav , Hansen Hans‐Jürgen , Schmid Hans
Published: December 2004

2, 2, 3‐Triphenyl‐2H‐azirine (4a) in a matrix of 2, 2‐dimethylbutane/pentane 8:3 (DMBP) at −185° gave rise on irradiation with light of 250–350 nm to a new UV.‐maximum at 350 nm (Fig. 1). We assign the dipole benzonitrildiphenylmethylide (1a) to this new maximum. Irradiation with monochromatic light of 366 nm destroyed this maximum and the initial absorption curve reappeared (Fig. 2). When the azirine 4a was photolysed in DMBP at −185° in the presence of methyl trifluoracetate (TFEM), the maximum at 350 nm was obtained again. This maximum vanished upon increasing the temperature to −160°. Through gas chromatography we were able to show that 5‐methoxy‐5‐trifluormethyl‐2, 2, 4‐triphenyl‐3‐oxazoline (6a) was produced. 6a was also obtained upon irradiation of 4a at room temperature in the presence of TFEM (scheme 1 and table 1). Modification of the previously described experiment, in which the maximum at 350 nm was extinguished in the matrix due to irradiation at 366 nm gave, after warm up, almost no dipole adduct 6a (table 1). From these experiments, an extinction coefficient of 17, 000 for the 350 nm maximum of 1a, was calculated. These experiments have shown that irradiation of triphenylazirine 4a leads to the dipole 1a, which can be reversed photochemically – but not tharmally – into azirine 4a. 1a reacts at less than −160° with TFEM to give adduct 6a. The results which were obtained with triphenylazirine 4a could be correspondingly obtained with 2, 3‐diphenyl‐2H‐azirine 4b (Fig. 3, scheme 2 and table 2). The dipole 1b showed two UV.‐maxima at 330 nm (ε = 17, 500) and 343 nm (ε = 21, 000). Later experiments established, that the two maxima belonged to a single dipole species.

The dipole 1c obtained upon irradiation of 2, 2‐dimethyl‐3‐phenyl‐2H‐azirine (4c) in DMBP at −190°, appears to absorb in the same region as the azirine 4c. The presence of the dipole 1c was univocally established by low temperature trapping experiments with TFEM. The dipole 1a showed no ESR.‐spectrum characteristic for a triplet state. We assume therefore, that 1a is in a singlet state. Photolysis of oxazolinone 7 at −190° in DMBP led to the dipole 1a with loss of CO2. 1a recombines apparently in considerable amount with the CO2 trapped in the matrix to give starting oxazolinone 7 because the 350 nm‐maximum of 1a appeared with low extinction. Irradiation with light of 366 nm into this matrix produccd triphenylazirine 4a. Low temperature trapping experiments with TFEM led to small amounts of 5‐methoxy‐5‐trifluormethyl‐triphenyl‐3‐oxazolinc (6a).
Über Pterinchemie. 42. Mitteilung [1]. Synthese von 6‐Hydroxymethyl‐mono‐, di‐ und triphosphat sowie deren 7, 8‐Dihydroderivate
Authors: Viscontini Max , Furuta Yoshiteru
Published: December 2004

Die Behandlung des 6‐Hydroxymethylpterins mit Polyphosphorsäure führt zur Bildung der Mono‐, Di‐ und Triphosphorsäureester. Durch Chromatographie mittels Ionenaustauscher wurden die einzelnen Ester rein erhalten und konnten charakterisiert werden. Die Reduktion des Mono‐ und des Diphosphates mit Natriumdithionit ergibt die entsprechenden 7, 8‐Dihydroderivate.
Nuclear Quadrupole Resonance and Stereochemistry II. Vicinal cis‐ and trans‐dichloro derivatives of carbocyclic systems
Authors: Ardalan Ziba , Lucken Edwin A. C. , Masson S.
Published: December 2004

The 35Cl quadrupole resonance frequencies of sets of isomeric vicinal dichloro derivatives of carbocyclic molecules are presented. In all cases except one – cis‐ and trans‐1, 2‐dichloro‐acenaphthene – the configuration has only a small effect on the resonance frequency. This implies that the frequency‐differences in cyclic α‐chloroethers reported in Part I of this series [1] are indeed due to a specific interaction with the oxygen atom. The difference between the acenaphthenes may be due to hyperconjugation between the CCl bond and the aromatic system.
Repetitive Excess Mixed Anhydride (REMA) Synthesis of Peptides. The protected C‐terminal hexadecapeptide of secretin
Authors: van Zon A. , Beyerman H. C.
Published: December 2004

The usefulness of the repetitive excess mixed anhydride (REMA) method of peptide synthesis was demonstrated by the prompt synthesis of the protected C‐terminal hexa‐decapeptide of the gastrointestinal hormone secretin, Boc‐Arg(NO2)‐Leu‐Arg(NO2)‐Asp(Bzl)‐Ser(Bzl)‐Ala‐Arg(NO2)‐Leu‐Gln‐Arg(NO2)‐Leu‐Leu‐Gln‐Gly‐Leu‐Val‐NH2,(secretin 12–27). The overall yield was 31%, with an average coupling yield of 93%.

Comparison of the physical constants of all intermediate sequcnces with those published, by Bodanszky et al. and by Wünsch et al. in their syntheses of secrctin, indicated identity. No significant raccmization could be detected in acid hydrolysates on digcstion with L‐amino acid oxidase.
Über den Einfluss nichtpolarer Lösungsmittel auf Lage und Intensität von Absorptionsbanden in den Elektronenspektren apolarer Molekeln: II. Polyacetylene
Authors: Christen Heinz , Kloster‐Jensen Else
Published: December 2004

The dispersive interaction of nonpolar solutes with nonpolar solvents is investigated in model systems consisting of solutions of dimethyl‐tetraacetylene, di‐t‐butyl‐tetraacetylene, dimethyl‐pentaacetylene or di‐t‐butyl‐pentaacetylene in binary mixtures of cyclohexane/carbondisulfide or n‐pentan/carbondisulfide. For this purpose the 1Σ → 1Σ transition in the electronic spectrum of the solutions has been recorded. With increasing concentration of the more strongly interacting solvent component (i.e. carbondisulfide) bathochromic shifts δν of the transition frequency accompanied by a decrease in oscillator strength fM are observed, which are consistent with calculated values based on a previously proposed exciton model [1].
Versuche zur Synthese der 4‐Thio‐D‐glucose
Authors: Vegh L. , Hardegger E.
Published: December 2004

Die saure Hydrolyse des oxydationsempfindlichen Methyl‐(4‐thio‐α‐D‐glucopyranosids) (2) gab nur in geringer Ausbeute das Disulfid 11 der 4‐Thio‐D‐glucose. Versuche, die 4‐Thio‐D‐glucose (31) aus der leicht zugänglichen 1, 6; 3, 4‐Dianhydro‐2‐O‐tosyl‐β‐D‐galaktopyranose (14) über die Anhydroderivate 22 und 30 zu gewinnen, führten zu 4‐Thio‐D‐altrose‐Derivaten (32–35), zu ungesättigten 1, 6‐Anhydrozuckern (23–26), zu 2, 4‐Dithioglucosan‐ und 3, 4‐Dithioaltrosan‐Derivaten (18–21 bzw. 27, 28).
1, 4‐Dimethylcyclohex‐3‐enyl Methyl Ketone, a monoterpenoid with a novel skeleton
Authors: Thomas Alan F.
Published: December 2004

1, 4‐Dimethylcyclohex‐3‐enyl methyl ketone (1) has been isolated from the oil of Juniperus communis L. (fruit). This is the first reported occurrence of this skeleton in nature. A curious effect on the NMR.‐spectrum of the compound (1) by the shift agent, Eu(fod)3, is described.
Utilisation d'ylides du phosphore en chimie des sucres. XVIII Synthèse de furannoses à insaturation conjuguée. Communication préliminaire
Authors: Tronchet Jean M. J. , Cottet Christian , Gentile Bernard , Mihaly Eva , Zumwald Jean‐Bernard
Published: December 2004

Several sugars with conjugated unsaturation (dienes or α, β‐unsaturated carbonyl compounds) have been synthesised by use of Wittig reactions. Keto‐sugars bearing a carbonyl group α to a furanose ring are prone to undergo an elimination leading to conjugated unsaturated systems. This constitutes a novel kind of side‐reaction in the application of Wittig reactions to carbonyl sugars. The synthesis of a new kind of acetylenic sugar is also described.
Bildung von 2‐(1‐Methyl‐1, 4, 5, 6‐tetrahydropyridyl‐3)‐2‐oxazolin‐4‐on aus 1‐Methyl‐1, 4, 5, 6‐tetrahydronicotinsäureamid und Bromessigsäureäthylester und seine Überführung in O‐(1‐Methylnipecotinoyl)glykolsäureamid via das dazu tautomere Cyclol
Authors: Troxler Franz
Published: December 2004

The main product of the reaction between 1‐methyl‐1, 4, 5, 6‐tetrahydronicotin‐amide and ethyl bromoacetate is shown to be the 2‐(1‐methyl‐1, 4, 5, 6‐tetrahydropyridyl‐3)‐2‐oxazoline‐4‐one which on partial hydrogenation followed by reaction with alkali affords O‐(1‐methylnipecotinoyl)glycolic amide, presumably via the tautomeric cyclol.
Heterotricyclodecane XIV. 2‐Oxa‐6‐aza‐adamantan und Derivate
Authors: Portmann Robert Ernst , Ganter Camille
Published: December 2004

The synthesis of 2‐oxa‐6‐aza‐adamantane (21) and several of its derivatives (13–20, 22, 23, 25–34, 37, and 38) was achieved starting from the 9‐azabicyclo[3.3.1]nona‐2,6‐ dienes 2, and 3, and 9‐oxabicyclo[3.3.1]nona‐2,6‐diene (1).
Heterotricyclodecane XV. Synthese von 2,6‐Diaza‐adamantanen
Authors: Portmann Robert Ernst , Ganter Camille
Published: December 2004

The synthesis of several derivatives of 2,6‐diaza‐adamantane (2, 3, 5–9) is described using the diepoxides 1 and 4 as starting materials.
Oxydative Umsetzungen in der Damascon‐Reihe. 1ΔgO2‐ und SeO2‐Oxydation von β‐Damascenon
Authors: Schulte‐Elte Karl H. , Gadola Marcel , Ohloff Günther
Published: December 2004

Photooxygenation of β‐damascenone (1) leads to the 3,6‐endo‐peroxide (2) which has been converted to various oxygenated derivatives in the damascene series. Introduction of oxygen specifically into the 2‐position of β‐damascenone (1) occurs by selenium dioxide oxidation. A series of reduction products of 2‐oxo‐β‐damascone (9) is described.
Amino‐nucléosides IV (Amino‐3‐désoxy‐3‐érythrofurannosyl)‐9‐adénine
Authors: Tronchet Jean M. J. , Graf René
Published: December 2004

The synthesis of 9‐(3‐amino‐3‐deoxy‐β‐L‐(and D)‐erythrofuranosyl)‐adenine is described. This compound is a close analog of the aminonucleoside of puromycin.
Nucleophilic Reactions at Tertiary Carbon. Part 1. The 1,2‐dimethyl‐1‐cyclohexyl cation
Authors: Becker Konrad B. , Grob Cyril A.
Published: December 2004

Stereoisomeric ion pairs are implicated as intermediates in the solvolysis of cis and trans‐1‐chloro‐1,2‐dimethylcyclohexane, cis‐4 and trans‐4, respectively. This follows from the rates and products of these stereoisomeric tertiary chlorides in 80% ethanol and 50% acetone.

The composition of elimination and substitution products from cis‐4 and trans‐4 differs markedly and the differences are accentuated by silver ion. Furthermore, substitution products are formed with predominant inversion of configuration.

The equilibrium constant for isomerization of cis‐4 and trans‐4 shows the latter to be more stable by 0.7 kcal/mol. Since the solvolysis rates of the chlorides are equal, the transition state for trans‐4 is also more stable by 0.7 kcal. By inference the intermediates differ by a similar amount of energy which is ascribed to more efficient solvation of the trans ion pair 13.
Chemistry of Succinylsuccinic Acid Derivatives. Part II. The crystal and molecular structure of diethyl succinylsuccinate
Authors: Mez Hans‐Christian , Rihs Gret
Published: December 2004

X‐ray structure analysis of the title compound (I) is reported. The results are interpreted to predict formation of anti‐tricyclo[4.4.01,6.07,12]‐1,4,7,10‐tetraethoxycarbonyl‐3,6,9,12‐tetrahydroxy‐dodeca‐3,9‐diene on UV.‐irradiation of solid (I).
Partialsynthese von Bufarenogin und Argentinogenin. Über Bufadienolide, 42. Mitteilung
Authors: Spengel Sigrid , Linde Horst H. A. , Meyer Kuno
Published: December 2004

Es wird über die Struktur des Di‐O‐acetylbufarenogins (9) und die des Argentinogenins (14) abschliessend berichtet.
Radiolyse des hydrocarbures. 21e communication. Mécanismes radicalaires et non‐radicalaires dans les n‐alcanes en phase liquide
Authors: Rappoport Serge , Gäumann Tino
Published: December 2004

Contributions of radical and non‐radical processes have been determined in the formation of radiolysis products of n‐heptane, n‐octane, n‐nonane and n‐decane in a large range of temperature. Calculations are based on the combination and the dismutation of radicals, both reactions having nearly the same importance. Hydrogen abstraction reactions become important above – 25°. Intermediate molecular weight products and dimers are formed by statistical combination of the various radicals resulting from CC and CH scission. At low temperature, low molecular weight products are formed by both radical and non‐radical processes, the second one being more important (3/4 for alcanes and 2/3 for olefins). The yield of radicals increases with the chain length of the irradiated n‐alkane and amounts to 4.5 for n‐heptane and 6.8 for n‐decane at – 25°. This increase is due only to radicals from CH scission, while the yield of radicals from CC scission remains constant. Scission of CH2CH2 bonds is favored for bonds inside the molecule, but this affect diminishes with chain length and CH2CH2 rupture is equally probable at all positions for n‐alcanes heavier than decane. Methyl CH scission is 2.7 times less probable than methylene CH scission. The radiolysis of mixtures of protonated and deuterated n‐alcanes is shown to be able to give information concerning basic processes in radiation chemistry.
Zur Photochemie von Δ1,9‐10‐Methyl‐2‐octalon
Authors: Margaretha Paul , Schaffner Kurt
Published: December 2004

Some aspects of the photochemistry of Δ1,9‐10‐methyl‐2‐octalone (1) were reinvestigated. In view of the hitherto neglected substantial thermal reversibility of the photolytic double bond shift under previous conditions of analysis (1) the solvent‐dependent selectivity in product formation in C6H6 and t‐BuOH was confirmed, (2) the essentially exclusive double bond shift and its intermolecular nature in C6F6 were established, (3) the quantum yields of the major products in these three solvents were measured, and (4) the dependence of triplet quenching data on temperature, enone concentration and conversion was shown in C6F6 for the double bond shift. In conclusion, the previously published experimental basis for the postulate of two differentially reactive triplet states of 1 is insufficient, although the postulate itself is not necessarily disproved.
On the Correlation between Ionization Potentials and Excitation Energies, part III: Pyrazine
Authors: Haselbach Edwin , Lanyiova Zuzanna , Rossi Michel
Published: December 2004

A recently suggested scheme for relating ionisation potentials (IP) to excitation energies (E) has been applied to pyrazine and 2,6‐dimethylpyrazine. The results indicate that in these systems the energy gap (ΔE) between the two lowest lying 1n,π*‐states is significantly smaller than that (ΔIP) between the corresponding 2n‐states of the parent radical cations. The values estimated for ΔE on the basis of ΔIP, measurable by photoelectron spectroscopy, disagree with those calculated theoretically but seem to be supported by the experimental evidence available.

Since ΔE = ΔIP would normally be expected, the relationship ΔE < ΔIP actually present in these systems is discussed and related to the different shape of the n‐MO's involved in the ionization and excitation processes.
Über Pterinchemie. 44. Mitteilung. Eine eindeutige Synthese isomerenfreier Folsäure
Authors: Bieri Jost H. , Viscontini Max
Published: December 2004

A new, simplified and unequivocal synthesis of folic acid free of isomers is described. A melt of N(2′)‐acetyl‐6‐formylpterine and dimethyl‐N‐(p‐aminobenzoyl)‐L‐glutamate was quantitatively converted to 6‐azomethin‐pterine‐ester IV. NaBH4‐reduction followed by basic hydrolysis of acetyl and ester groups gives pure folic acid in good yield.
De la chimie des ptérines. 47e communication. Une confirmation de l'existence de dihydroptérines quinoïdiques: formation d'amino‐2‐alloxane pendant l'oxydation de tétrahydroptérines
Authors: Argentini Mario , Viscontini Max
Published: December 2004

L'oxydation, dans des conditions physiologiques, de l'aminomethyl‐6‐diméthyl‐6,7‐tétrahydroptérine conduit à la formation d'amino‐2‐alloxane et d'aldéhyde acétique. Ces résultats étayent deux hypothèses déjà formulées par nous‐mêmes, à savoir: (a) qu'une dihydroptérine quinoidique apparaît comme produit intermédiaire d'oxydation, et (b) que le cycle pyrazine des tétrahydroptérines n'est pas stable et se laisse facilement ouvrir pendant l'oxydation avec possibilité de perte de la structure du noyau ptérinique.
The Mode of Incorporation of Farnesyl Pyrophosphate into Verrucarol. Preliminary communication
Authors: Arigoni Duilio , Cane David E. , Müller Beat , Tamm Christoph
Published: December 2004

In the course of the biosynthesis of verrucarol (3) from farnesyl pyrophosphate in Myrothecium roridum, strain S 1135, a hydride shift occurs from the central double bond of the precursor to C(2) of the product.
Die durch Silberionen katalysierte Umlagerung von Propargyl‐phenyläther
Authors: Koch‐Pomeranz Ursula , Hansen Hans‐Jürgen , Schmid Hans
Published: December 2004

It is known that propargyl‐phenylethers rearrange at about 200° to 2 H‐chromenes [1–4]. It is shown that this rearrangement occurs in benzene or chloroform at lower temperatures (20–80°) in the presence of silver‐tetrafluoroborate (or‐trifluoracetate). The ethers examined are presented in Scheme 1. Thus in chloroform at 61° in the presence of AgBF4, phenyl‐propargylether (3) yields 2 H‐chromene (13). With 0.78 molar equivalents AgBF4 in benzene at 80° the same ether 3 yields a 3:1 mixture of 2‐methyl‐cumaron (14) and 2 H‐chromene (13). From 1′‐methylpropargyl‐phenylether (4) and 2′‐butinyl‐3,5‐dimethylphenylether (5) under similar conditions the corresponding chromenes 16 and 17 resp. are obtained. Rearrangement of propargyl‐ and 2′‐butinyl‐1‐methyl‐2‐naphthylether (6 and 7 resp.) in benzene at 80° in the presence of AgBF4 gives the corresponding allenyl‐naphthalenones 18 and 19 resp. Treatment of propargyl‐ and 2′‐butinyl‐mesityl‐ether (8 and 9 resp.), and propargyl‐ and l′‐methylpropargyl‐2,6‐dimethyl‐phenylether (10 and 11 resp.) in benzene at 80° with AgRF, yields as the only product the corresponding 3‐allenyl‐phenols 21, 22,24 and 25 (Scheme 3). It is shown that in the presence of μ‐dichlor‐dirhodiuni (1)‐tetracarbonyl in benzene a t 80° the ether 4 rearranges to 2‐methyl‐2H‐chromene (16). However with this catalyst the predominant reaction is a cleavage to phenol. No reaction was observed when ethers 3 and 12, (Scheme 7 ) were treated with the tris‐(trimethylsily1)‐ester of vanadic acid in benzene a t 80° (see also [8]).

By analogy with the known mechanism for thc silver catalysis of the reversible propargylesterl/allenylester rearrangement [S], the silver (1)ion is assumed to form a pre‐equilibrium π‐complex with the C, C‐triplebond of the substrate. This complex then undergoes a [3s, 3s]‐sigmatropic rearrangement (Scheme 2). In the case of the others 6, 7 and 12 the resulting allenyldienones were isolated. The 2,G‐dimethyl substituted ethers 8, 9, 10 and 11 resp. first give the usual allenyl‐ dienones (Scheme 3). These then undergo a novel silver catalysed dienon‐phenol‐rearrangement (Sclzenzu4) to give the 3‐allenylphenols 21, 22, 24 and 25. Thc others 3, 4 and 5 with free ortho positions presumably rearrange first to the non‐isolated 2‐allenyl‐phenols 15, 42 and 43 resp.(Scheme 7). These then rearrange, either thermally or by silver (1)ion catalysis to the 2H‐chromenes 13,16 and 17 resp. The rate of the rearrangement of 2‐allenylphenol (15) to 13 at room temperature in benzene or chloroform is approximately doubled when silver ions are present as catalyst.
Sur les dérivés de la fluorénone VI Les acides bromo‐3‐fluorénonecarboxylique‐2 et bromo‐2‐fluorénonecarboxylique‐3 et la bromo‐3‐méthyl‐4‐fluorénone
Authors: Chardonnens Louis , Horváth Ernö
Published: December 2004

Starting from 2‐amino‐3‐bromo‐9‐oxofluorene and from 3‐methylfluorene respectively the preparation of 3‐bromo‐9‐oxofluorene‐2‐carboxylic acid and of 2‐bromo‐9‐oxofluorene‐3‐carboxylic acid is described. A synthesis of 3‐bromo‐4‐methyl‐9‐oxofluorene is also given.
Intramolekulare Additionen α‐lithiierter Amide; eine neue Synthese von 2‐Aryl‐ und 2‐Vinylindolen
Authors: Greuter Hans , Schmid Hans
Published: December 2004

The N‐alkylated 2‐benzoylamino‐benzophenones 2a–e on treatment with lithium diisopropylamide in tetrahydrofuran at − 78° gave the cyclic alchols 3a–e which were dehydrated with phosphorous oxychloride/pyridine to give the indoles 4a–e in 30–72% yield (Scheme 1).
Umlagerung von Prolinol‐Derivaten. 2. Mitteilung. N‐Alkoxycarbonyl‐prolinylester
Authors: Wiegrebe Wolfgang , Herrmann Ernst‐georg , Schlunegger Urs Peter , Budzikiewicz Herbert
Published: December 2004

When heated, esters of N‐alkoxycarbonyl‐prolinol with arylsulfonic acids rearrange to alkylarylsulfonates and perhydro‐pyrrolo[1,2‐c]oxazol‐3‐one by an intermolecular process. The syntheses of pertinent prolinol derivatives are described and their mass‐spectrometric fragmentation processes investigated, using DADI‐analysis.
Steroide und Sexualhormone. 249. Mitteilung [1]. Zur Umwandlung von Dehydroabietinsäure in 14α‐Methylsteroide I Die Partialsynthese von 5‐Methoxy‐17‐oxo‐14α‐methyl‐Δ5, 7, 9‐des‐A‐östratrien
Authors: Wirthlin Toni , Wehrli Hansuli , Jeger Oskar
Published: December 2004

A 18‐step transformation of dehydroabietic acid (1) into ketone 40, convenient starting material for the prparation of 14α‐methylsteroids, is described.
The Crystal and Molecular Structure of 3‐Oxo‐17β‐acetoxy‐Δ4‐14α‐methyl‐8α, 9β, 10α, 13α‐estrene
Authors: Koyama Gunji
Published: December 2004

The crystal and molecular structure of 3‐oxo‐17β‐acetoxy‐Δ4‐14α‐methyl‐8α, 9β, 10α, 13α‐estrene, C21H30O3, has been determined by X‐ray diffraction analysis. The crystals belong to the orthorhombic space group P212121, with the cell dimensions a = 12.093 Å, b = 19.667 Å, c = 7.746 Å; Z = 4. Intensity data were collected at room temperature with an automatic four‐circle diffractometer. The structure was solved by direct methods and the parameters were refined by least‐squares analysis. All the hydrogen atoms were included in the refinement. The final R value was 0.038 for 1413 observed reflections. The conformation of ring A is intermediate between a half‐chair and a 1, 2‐diplanar form. The hydrogens at C(9) and C(10) are anti, the B/C ring junction is trans, and rings B and C adopt chair conformations. Ring D is cis fused and is halfway between C2 and Cs forms.
Photochemie von Benzisoxazolen. (vorläufige Mitteilung)
Authors: Heinzelmann W. , Märky M.
Published: December 2004

The photochemical behaviour of benzisoxazoles 1 is remarkably solvent‐dependent: Irradiation in H2O or CH3O or CH3OH leads to benzoxazoles 2 in a virtually quantitative yield. However, at low concentrations of H2O or CH3OH in acetonitrile or hexane, photolysis of 3‐alkyl‐benzisoxazoles 1b–1e yields salicylamides 4 and salicylesters 5, while under these conditions o‐cyanophenol (3a) is the only photoproduct of benzisoxazole (1a). The course of these photochemical reactions is discussed from the standpoint of solvent‐dependence, multiplicity and the behaviour at low temperatures.