bluuebunny/crossref_metadata_2025 huggingface dataset:
Mehrkernige Kobaltkomplexe. II. Herstellung und Struktur von [(tren) (NH3)Co(O2)Co(NH3) (tren)](SCN)4 · 2H2O
Authors: Thewalt Ulf , Zehnder Margareta , Fallab Silvio
Published: December 2004

Polynuclear Cobalt Complexes. II. Preparation and Structure of [(tren) (NH3)Co(O2)Co(NH3) (tren)](SCN)4 · 2H2O

The title compound is obtained on oxygenation of [Co(tren)(H2O)2]2+ in 6M aqueous ammonia or by ligand exchange starting from [(NH3)5Co(O2)Co(NH3)5]‐(NO3)4. An X‐ray structure determination was made. The substance forms monoclinic crystals, space group P21/c, lattice constants a=10,135, b=8,473, c=19,484 Å, β=108,58°, with two formula units in the cell. The final R is 0,066. The binuclear cation has a center of symmetry, so the CoOOCo unit is planar; the CoOO angle is 111,5°. The tertiary nitrogen atoms of both chelate groups are cis to the O2 bridge, as found in doubly bridged [(tren)Co(O2,OH)Co(tren)](ClO4)3 · 3H2O.

On acidification in solution, the singly bridged cation [(tren) (NH3)CoO2Co(NH3)(tren)]4+ (a) loses the bound O2 completely. But unlike the doubly bridged cation b, the rate of dissociation of a is independent of pH (Fig. 5). At higher pH (8–10) bridging a→b (Fig. 2) occurs. Both reactions must have the same rate determining step, the first order rate constants being of the order of 2 · 10−3 s−1 (25°, 0,35M KCl).
Nouveaux types de sucres acétyléniques. Communication préliminaire
Authors: Tronchet Jean M. J. , Bonenfant Alain
Published: December 2004

Novel types of acetylenic sugars

The coupling, following Cadiot's procedure, of a 6‐bromo‐5,6‐dideoxy‐1,2‐O‐isopropylidène‐3‐O‐methyl‐α‐D‐xylo‐hex‐5‐yno‐1, 4‐furanose (1) with phenylacetylene, 2‐propyn‐1‐ol or terminal acetylenic sugars gave with excellent yields the expected diynes (an enediyne when the terminal acetylene was the 3,5, 6‐trideoxy‐1,2‐O‐isopropylidene‐α‐D‐glycero‐hex‐3‐en‐5‐yno‐1,4‐furanose 7). The chloro analogue 8 of 1 on treatment with lithium thiophenate gave the corresponding phenylthio‐acetylenic sugar 9. An acetylene was also formed by reacting the gem‐difluoro‐olefinic sugar 10 with butyllithium whereas the same olefinic sugar and its 3‐O‐benzyl analogue 11 gave only a gem‐fluoro‐arylthio‐olefinic sugar (13–15) as a mixture of the Z and E isomers (Z/E > 4) when treated with the conjugate base of an arylmercaptan.
The Photochemistry of 2‐Cyclopentenyl Methyl Ketones
Authors: Gonzenbach Hans‐Ulrich , Tegmo‐Larsson Inga‐Mai , Grosclaude Jean‐Pierre , Schaffner Kurt
Published: December 2004

2‐Cyclopentenyl and 3‐phenyl‐2‐cyclopentenyl methyl ketones (15–18, 30, 31) undergo a 1,3‐acetyl shift on direct irradiation, and the oxa‐di‐π‐methane rearrangement to photochemically non‐interconverting endo and exo bicyclo‐[2.1.0]pentyl methyl ketones on triplet sensitization. Exceptions include the 2‐methyl‐3‐phenyl‐2‐cyclopentenyl methyl ketone 32 and the 1‐phenyl‐2‐cyclo‐pentenyl methyl ketone 44 which are unreactive on direct irradiation and on triplet sensitization, respectively, and the 2‐phenyl‐2‐cyclopentenyl methyl ketones 42 and 43 which do not react under either condition. The reactive triplet of the 3‐phenyl‐2‐cyclopentenyl methyl ketone 30 has been identified as the localized styrene π,π*‐state of ET=59 kcal/mol by comparison of its phosphorescence at 77K in rigid glasses with that of 1‐phenyl‐cyclopentene, and by the independence of the quantum yield on sensitizer energy in the range of 61–74 kcal/mol.
N‐Alkyl‐2‐pyrrolidones as Derivatives for the Structure Elucidation of Long‐chain Primary Alcohols by Mass Spectrometry
Authors: Vetter Walter , Meister Walter , Oesterhelt Gottfried
Published: December 2004

One unsaturated and three branched long‐chain primary alcohols have been converted into N‐alkyl‐2‐pyrrolidones for investigation by mass spectrometry. The EI. mass spectra of these derivatives have been found to exhibit unambiguously the branching points and, albeit less clearly, the position of a double bond in the chain.
Diterpenoide Drüsenfarbstoffe: Coleon L, ein neues Diosphenol aus Coleus somaliensis S. MOORE; Revision der Strukturen von Coleon H, I, I′ und K
Authors: Rüedi Peter , Eugster Conrad Hans
Published: December 2004

Leaf‐gland Pigments: Coleon L, a New Diosphenolic Compound from Coleus somaliensis, S. MOORE; Revision of the Structures of Coleon H, I, I′ and K

From leaf‐glands of C. somaliensis a new, highly oxidized diosphenolic hydroquinone belonging to the abietane series was isolated in minute quantities. The new compound, coleon L (4c; C24H30O10), is very labile and transformed into its tautomer coleon K (5d) on standing in solution. 1H‐NMR. spectra of coleon L showed clearly that the points of attachment of the two acetoxy groups are at C(3) and C(16) contrary to the positions expected from our previously published structure 3 for coleon K. Application of a recently elaborated conversion of trans‐A/B‐6,7‐diketones of type 5 into the cis‐isomers 6 allowed to assign unambiguously the β‐configuration to the hydroxyl group at C(3) using pyridin induced solvent shifts. This confirmed structure 4c and 5d for coleon L and K, respectively. Based on similar reasons, the configuration at C(3) of coleon H, I and I′ had to be revised, the structures of these coleons being 4b, 5b and 5c, respectively.
Reaktionen mit γ‐Chloracetessigesterderivaten
Authors: Boosen Karl‐Josef
Published: December 2004

Reactions with derivatives of γ‐chloroacetoacetic acid

Ethyl γ‐chloroacetoacetate reacts with ammonia to give ethyl β‐amino‐γ‐chloro‐crotonate; with aniline, however, β‐anilino‐crotonic acid γ‐lactone is formed. The reaction of ethyl α‐cyano‐γ‐chloro‐acetoacetate with arylamines yields 1‐aryl‐2‐amino‐3‐ethoxycarbonyl‐pyrrolin‐4‐ones.
Die Konstitution des Loroglossins. 163. Mitt. über organische Naturstoffe
Authors: Gray Robert W. , Guggisberg Armin , Segebarth Klaus Peter , Hesse Manfred , Schmid Hans
Published: December 2004

The Constitution of Loroglossine

Loroglossine, a characteristic constituent of orchids, is shown to be bis[4‐(β‐D‐glucopyranosyloxy)‐benzyl]‐(2R, 3S)‐2‐isobutyl‐tartrate (1). Base catalysed hydrolysis and esterification with diazomethane gave 1 mol‐equiv. of dimethyl (+)‐2‐isobutyl‐erythro‐tartrate ((+)‐3) and 2 mol‐equiv. of a glucoside which after acetylation formed 4 identical with a synthetic sample. The structure of (+)‐3 follows from the synthesis of (±)‐3 by osmium tetroxide oxidation of isobutyl‐maleic acid anhydride and subsequent esterification. The absolute configuration of (+)‐3 was based on Horeau experiments and NMR. data of the diastereomeric mixture of its esters 15 and 16 and pure 15 with (S)‐(+)‐ and (R)‐(−)‐α‐phenyl‐butyric acid, respectively.
Repetierbare Ringerweiterungen durch [2,3]‐sigmatropische Umlagerungen in cyclischen Allylsulfonium‐allyliden; Synthese von mittleren und grossen Thiacyclen. Vorläufige Mitteilung
Authors: Schmid Rudolf , Schmid Hans
Published: December 2004

Repeatable ring expansions by [2,3]‐sigmatropic shifts in cyclic allylsulfonium allylides; synthesis of medium‐ and large‐sized thiacycles

Allylation of a 2‐vinyl thiacyclus with allyl bromide in 2,2,2‐trifluoroethanol followed by ylide generation by use of aqueous potassium hydroxide results in a [2,3]‐sigmatropic rearrangement with formation of a new 2‐vinyl thiacyclus enlarged by three carbon atoms (Scheme 1). In this way, starting from the 5‐membered ring 1, a series of four ring enlargement sequences leads to the 17‐membered thiacycles 9 and 10 via the 8‐, 11‐ and 14‐membered rings 4, 7 and 8 (Scheme 2).
A 31P‐NMR. Study of Some Phosphite Complexes of Platinum (0)
Authors: Pregosin Paul S. , Sze S. N.
Published: December 2004

31P‐NMR. spectra for a series of phosphite complexes of platinum (0) have been measured. Low temperature studies have revealed the existence in solution of the mixed complexes Pt[PPh3]2[P(OPh3)3]2 and Pt[PPh3][P(OPh)3]3 of which the former is isolable.
Building Blocks for the Synthesis of Maytansinoids. Preliminary Communication
Authors: Götschi Erwin , Schneider Fernand , Wagner Hans , Bernauer Karl
Published: December 2004

The dienal 14 and the ketone 19, both potential building blocks of maytansinoids, were synthesized starting from ethyl vanillate (2) via the aldehyde 9. It could be shown in a preliminary experiment that the dienal 14 can be coupled with 2‐lithio‐1,3‐dithiane to afford compound 16 which exhibits the correctly substituted aromatic part of maytansine as well as its C(9) to C(15) moiety.
Heterotricyclodecane. XXIV. 2‐Aza‐7‐oxa‐twistane (bzw. 2‐Oxa‐7‐aza‐twistane) und 2‐Aza‐7‐oxa‐isotwistane
Authors: Szczepanski Henry , Ganter Camille
Published: December 2004

2‐Aza‐7‐oxa‐twistanes (or 2‐oxa‐7‐aza‐twistanes, respectively)

Die nicht mit den IUPAC‐Regeln übereinstimmende Numerierung (b): 2‐Aza‐7‐oxa‐twistane, Substituent an C(10) (vgl. Korrekte Nomenklatur (a): 2‐Oxa‐7‐aza‐twistane, Substituent an C(5)), wurde zwecks besserer Übersicht und Vergleichsmöglichkeit mit anderen 2,7‐Dihetero‐twistanen und ‐isotwistanen, Für eine umfassende Übersicht vgl. [2], speziell auch mit den korrekt numerierten C(10)‐substituierten 2‐Aza‐7‐oxa‐isotwistanen c deshalb gewählt, weil dadurch in diesen beiden Verbindungstypen b und c, welche chemisch ineinander überführbar sind (vgl. vorliegende Arbeit), sich entsprechende Atome gleich numeriert werden Können. Dadurch erhält je das den Substituenten tragende C‐Atom die Nummer 10 und je das zwischen C(10) und N(2) liegende Brückenkopfatom die Nummer 1. Beim Twistan d wurde die Doppelbindung entsprechend ihrer Herkunft aus einem C(10)‐substituierten Twistan b als in Stellung 9 bezeichnet. Vollständigkeitshalber sind die der korrekten Nomenklatur (vgl. a) entsprechenden Namen der Verbindungen 10–13 und 22, 23 und 25 nachfolgend aufgeführt; 10: 5N (7)‐Brom‐2‐oxa‐7‐aza‐twistan; 11: N(7)‐Methyl‐5N (7)‐2‐oxa‐7‐aza‐twistan; 12: 2‐Oxa‐7‐aza‐twist‐4‐en; 13: N(7)‐Methyl‐2‐oxa‐7‐aza‐twist‐4‐en; 22: N(7)‐Methyl‐5O (2)‐acetoxy‐2‐oxa‐7‐aza‐twistan; 23: N(7)‐Methyl‐2‐oxa‐7‐aza‐twistan‐5O (2)‐ol; 25: N(7)‐Methyl‐2‐oxa‐7‐aza‐twistan. magnified image

and 2‐aza‐7‐oxa‐isotwistanes
Generation and Reactions of Tetrasubstituted N‐Lithiomethyl‐succinimides
Authors: Schlecker Rainer , Seebach Dieter
Published: December 2004

Of the isoelectronic 6‐electron systems 1a, 1b, 1c (Table 1) the deprotonated amides 2 might be useful derivatives for amine acidification (eq. (1)) if the carbonyl group is sterically protected as shown in 3. The tetrasubstituted succinimides 4, 5, 7, 8 and 9 (diacylamines) undergo the reactions (b), (c) and (d) of Scheme 1 with various bases. Besides deprotonation, the ‘self addition’ to give dimers 4b, 5b, 8b and 9b is the most prominent transformation (Table 2). Only in 9 is the steric hindrance to carbonyl addition large enough to get the lithiomethyl‐succinimides 9c in 80% yield (sec.BuLi/THF/HMPT/‐100°) as evidenced by derivatization with alkyl halides, aldehyde, ketones, methyl benzoate, and chloro trimethylsilane (→9d ‐ 9j, Table 3). The possible structures and bonding descriptions for 9c which ‘decomposes’ above −40° are discussed; the acidity of the precursor 9 is shown by equilibration studies to be comparable with that of diphenylmethane.
Neue β‐Lactam‐Antibiotika. Zur Funktionalisierung von 3‐Hydroxy‐3‐cephem‐4‐carbonsäureestern durch die Wittig‐Reaktion. Modifikationen von Antibiotika. 16. Mitteilung [1]
Authors: Scartazzini Riccardo
Published: December 2004

New β‐lactam antibiotics. Functionalisation of 3‐hydroxy‐3‐cephem‐4‐carboxylic esters through the Wittig reaction

The 3‐hydroxy‐ceph‐3‐em‐esters 1a, b reacted smoothly with stabilized phosphor‐ylids to give a series of derivatives which were converted into the microbiologically active acids 14a, c, 15c and 20 by known procedures. The synthesis of the amides 23, 24, 26 and of the ester 28 from the 3‐carboxymethyl‐derivative 19 is also reported.
Synthesis and Rearrangement of 7‐Halobicyclo[3.2.0]hept‐2‐en‐6‐ols
Authors: Brook Peter R. , Jonathan Duke A. , Glenville Griffiths J. , Roberts Stanley M. , Rey Max , Dreiding André S.
Published: December 2004

Synthese und Umlagerung von 7‐Halo‐bicyclo[3.2.0]hept‐2‐en‐6‐olen

Die Reaktion von verschiedenen 7‐halogen‐substituierten Bicyclo[3.2.0]hept‐2‐en‐6‐onen mit komplexen Metallhydriden oder mit Methylmagnesiumiodid zu den entsprechenden 7‐Halo‐bicyclo[3.2.0]hept‐2‐en‐6‐olen verläuft unter Angriff des Nucleophils trans zum Halogen, um dem vicinalen Kohlenstoff‐Halogen‐Dipol auszuweichen. In Gegenwart von starken Basen unterliegen die Halohydrine einer Umlagerung, die je nach der durch die intramolekularen Wechselwirkungen bedingten Konformation, entweder unter Hydridverschiebung zu Bicyclo[3.2.0]hept‐2‐en‐6‐onen oder, unter Ringverengung, zu Bicyclo[3.1.0]hex‐2‐en‐6‐carbaldehyden führt.
Regiospezifische Reduktionen von 1,3,3‐trisubstituierten Succinimiden mit Diboran
Authors: Süess Rudolf
Published: December 2004

Regiospecific reduction of 1,3,3‐trisubstituted succinimides by diborane

It is possible to reduce 1,3,3‐trisubstituted succinimides regiospecifically by diborane at the less substituted carbonyl group to yield the corresponding lactams. This method was used specially for the reduction of 2,8‐diazaspiro[4,5]decane‐1,3‐diones to 2,8‐diazaspiro[4,5]decan‐1‐ones. These results are in contrast to those of Speckamp et al. [4a‐h] in which sodiumborohydride/HCl was the reducing agent. Possible explanations for the selective reductions are discussed, using the principles of steric approach control of Dunitz & Bürgi [6] and of Baldwin [8].
The Crystal and Molecular Structure of 4‐Aza‐5‐oxo‐tricyclo[4.4.0.03,8]decane (Aza‐twistanone)
Authors: Ramakumar Suryanarayana Rao , Venkatesan Kailasan , Weber Hans Peter
Published: December 2004

Die kristalline und molekulare Struktur von 4‐Aza‐5‐oxo‐tricyclo[4.4.0.03,8]decan (Aza‐twistanon)

Die kristalline Struktur von Aza‐twistanon wurde durch eine Röntgenstruktur‐analyse untersucht. Die Kristalle gehören zur monoklinen Raumgruppe P21/n mit den Zelldimensionen a = 6,662(6), b = 13,36(2), c = 8,606(9) Å, β = 98,97(2)°, V = 757 Å3, Z = 4. Die Struktur wurde mit Direktmethoden gelöst und bis zu R = 0,035 verfeinert (mittlere σ(c) = 0,003 Å3).

Die cis‐Amidgruppe ist relativ stark deformiert und hat einen Torsionswinkel Cα–C′–N–Cα von 14,5(4)° (Deformation aus der Ebene χc = 5,0(5)° und χN = 13,5(4,0)°). Die gegenüberliegende äthylenbrücke weist einen Torsionswinkel von 25,1(5)° auf. Die entsprechenden Winkel in Twistan betragen je 20°. Das tricyclische Gerüst von Aza‐twistanon hat approximative C2‐Symmetrie (Symmetrie von Twistan: D2).
Herstellung neuer polycyclischer Verbindungen durch intramolekulare Diels‐Alder‐Reaktionen von Cyclohexa‐2,4‐dien‐1‐on‐Abkömmlingen
Authors: Greuter Hans , Schmid Hans , Fráter György
Published: December 2004

Synthesis of new polycyclic compounds by means of intramolecular Diels‐Alder reactions of cyclohexa‐2,4‐dien‐1‐one derivatives

Thermal rearrangement of mesityl penta‐2,4‐dienyl ether (1), consisting of the isomers E (93%) and Z (7%), furnished, besides mesitol, the two mesityl penta‐1,3‐dienyl ethers 2 (24%) and 3 (3%), and the two tricyclic ketones 4 (4,5%) and 5 (12,5%) (Scheme 1). A probable mechanism for this formation of 2 involves a [1,5]‐hydrogen shift in (Z)‐1. Isomerisation of (E)‐1 to (Z)‐1 at 145° occurs via reversible sigmatropic [3,3]‐ and [5,5]‐rearrangements of (E)‐1 to the cyclohexadienones 38 and 39 respectively (see Chapter A p. 1710, and Scheme 15). Formation of 3 from either (Z)‐1 or 2 is rationalized by a series of pericyclic reactions as outlined in Chapter A and Scheme 16.

The tricyclic ketones 4 and 5 are undoubtedly formed by internal Diels‐Alder reactions of the 6‐pentadienyl‐cyclohexa‐2,4‐dien‐1‐one 6 (Scheme 2). In fact, at 80° 6 is converted into 4 (5%) and 5 (35%). At 80° the cyclohexadienone derivative 7 furnished the corresponding tricyclic ketones 8 (15%) and 9 (44%) (Scheme 2). 5 and 9 contain a homotwistane skeleton. 8 and 9 are easily prepared by reaction of sodium 2,6‐dimethylphenolate with 3‐methyl‐penta‐2,4‐dienyl bromide at ambient temperature, followed by heating, and finally separation by cristallization and chromatography.

The cyclohexadienones 6 and 7 have mainly (E)‐configuration. Here too (E) → (Z) isomerization is a prerequisite for the internal Diels‐Alder reaction, and this partly takes place intramolecularly through reversible Claisen and Cope rearrangements (Scheme 17). On the other hand, experiments in the presence of 3,5‐d2‐mesitol have shown (Table 1) that intermolecular reactions, involving radicals and/or ions, are also operating (see Chapter B, p. 1712).

Two different modi (I and II) exist for intramolecular Diels‐Alder reactions (Scheme 18). Whereas only modus I is observed in the cyclization of 5‐alkenyl‐cyclohexa‐l,3‐dienes, in that of (2)‐cyclohexadienones 6 and 7 (Scheme 2) both modi are operating. Only in modus 11‐type transitions is the butadienyl conjugation of the side chain retained, so that modus 11‐type addition is preferred (Chapter C p. 1716).

Analogously to the synthesis of the tricyclic ketones 4, 5, 8 and 9, the tricyclic ketone 15 (Scheme 4) and the tetracyclic ketone 11 (Scheme 3) are prepared from mesitol, pentenyl bromide and cycloheptadienyl bromide, respectively.

From the polycyclic ketones derivatives such as the alcohols 16, 17, 18, 19, 23, 24 and 25 (Schemes 9 and 11), policyclic ethers 20, 21, 22 and 26 (Scheme 10), epoxides 30, 32 (Scheme 13), diketones 31, 33 (Scheme 13) and ether‐alcohols 35 and 36 (Scheme 14) have been prepared. Most of these conversions show high stereoselectivity.
Cis, anti, cis‐Tricyclo[5.3.0.02,6]deca‐4,9‐dione
Authors: Shani Arnon , Tashma Zeev
Published: December 2004

The chemical behavior and some physical properties (dipole moment, IR. vs. Raman spectra) of the titled compound are not fully consistent with a strictly centrosymmetric structure which might be expected for the anti configuration. The carbonyl groups are less reactive toward nucleophilic reagents and sp2 → sp3 transformations as compared to cyclopentanone systems.
New Indigo Syntheses. Preliminary Communication
Authors: Gosteli Jacques
Published: December 2004

Three novel routes for the preparation of the dyestuff indigo are described. Two of the methods use isatoic anhydride, the third one styrene as starting materials. Key reactions are acylation of both dimsyl and nitromethane anions, Pummerer rearrangement and Nef reaction. A novel nitration of styrene is the basis of the third method.
Thermische (E), (Z)‐Isomerisierungen bei substituierten Propenylbenzolen
Authors: Wehrli Rudolf , Heimgartner Heinz , Schmid Hans , Hansen Hans‐Jürgen
Published: December 2004

Thermal (E), (Z)‐Isomerizations of Substituted Propenylbenzenes

The thermal isomerizations of (E)‐ and (Z)‐3,5‐dimethyl‐2‐(1′‐propenyl)phenol ((E)‐ and (Z)‐3), (E)‐ and (Z)‐N‐methyl‐2‐(1′‐propenyl)anilin ((E)‐ and (Z)‐4), (E)‐ and (Z)‐3,5‐dimethyl‐2‐(1′‐propenyl)anilin ((E)‐ and (Z)‐5, (E)‐ and (Z)‐2‐(1′‐propenyl)mesitylene ((E)‐ and (Z‐6), (E)‐ and (Z)‐2‐(1′‐propenyl)mesitylene ((E)‐ and (Z)‐7), (E)‐ and (Z)‐2‐(1′‐propenyl)toluene ((E)‐ and (Z)‐8), (E)‐ and (Z)‐4‐(1′‐propenyl)toulene ((E)‐ and (Z)‐9) as well as of (E)‐ and (Z)‐2‐(2′‐butenyl)‐mesitylene ((E)‐ and (Z)‐10) in decane solution were studied (Scheme 2). Whereas the isomerization of the 2‐propenylphenols (E)‐ and (Z)‐3 occurs already between 130 and 150° (cf. Table 1), the isomerization of the 2‐propenylanilins 4 and 5 takes place only at temperatures between 220 and 250° (cf. Tables 2 and 3). The activation values and the experiments using N‐deuterated 4 (cf. Scheme 4) show that 2‐propenylphenols and ‐anilins isomerize via sigmatropic [1,5]‐hydrogen‐shifts. For the isomerization of the methyl‐substituted propenylbenzenes temperatures > 360° are required (cf. Tables 4 and 5). The activation values of the isomerization of (E)‐ and (Z)‐6 and (E)‐ and (Z)‐9 are in accord with those of other (E), (Z)‐isomerizations which occur via vibrationally excited singlet biradicals (cf. Table 7). Nevertheless, thermal isomerization of 2′‐d‐(Z)‐8 (cf. Scheme 6) demonstrates that during the reaction deuterium is partially transfered into the ortho‐methyl group, i.e. 1,5‐hydrogen‐shifts must have participated in isomerization of (E)‐ and (Z)‐8 (cf. Scheme 8). Under the equilibrium conditions 2,4,6‐trimethylindan (17) is formed slowly at 368° from (E)‐ and (Z)‐6, very probably via a radical 1,4‐hydrogen‐shift (cf. Scheme 9). In a similar way 2‐ethyl‐4,6‐dimethylindan (19; cf. Table 6) arises from (E)‐ and (Z)‐7. Thermolysis of (E)‐ and (Z)‐10 in decane solution at 367° results in almost no (E),(Z)‐isomerization. At prolonged heating 19 and 2,5,7‐trimethyl‐1,2,3,4‐tetrahydronaphthalene (20) are formed; these two products arise very likely from an intermolecular radical process (cf. Scheme 10).
Herstellung substituierter 2‐Amino‐3‐hydroxypyridine durch nucleophilen Substituentenaustausch an Halogenpyridinen
Authors: Mattern Günter
Published: December 2004

Synthesis of substituted 2‐amino‐3‐hydroxy‐pyridines by nucleophilic displacement of a halogene in halopyridines

2‐Amino‐3,5‐dihalogeno‐pyridines (halogene: chlorine and/or bromine) react with bases in aqueous‐alcoholic or in aprotic polar solvents to the corresponding 2‐amino‐3‐hydroxy‐5‐halogeno‐pyridines. In higher alcohols as solvents pyridyl‐alkylethers are formed which then undergo ether‐cleavage. As a by‐product a mono‐dehalogenated compound, 2‐amino‐5‐halogeno‐pyridine, is formed, but no 2‐amino‐3‐halogeno‐pyridine is dependent on the nature of the leaving group at position 3, on the base, and on the solvent. Copper or its salts accelerate the formation of pyridin‐3‐ols as well as the dehalogenation of the pyridines at position 3.

No evidence has been found for the formation of a 3,4‐pyridine by dehydrohalogenation of the halopyridines or for the formation of 2‐amino‐3‐halogeno‐5‐hydroxy‐pyridines by the ANRORC‐mechanism. Hence it is assumed that the above mentioned reactions proceed via a radical‐anion mechanism.
Eine einfache Synthese von Rosenfuran und verwandten Verbindungen
Authors: Ly Nguyên Dinh , Schlosser Manfred
Published: December 2004

A Simple Synthesis of Rose Furan and Related Compounds

3‐Brom‐2‐furyllithium was found to be easily accessible by treatment of 3‐bromofuran with lithium diisopropylamide. It served as a key compound for the synthesis of furan derivatives, among them the “rose furan”.
Iron Carbonyl Induced Reactions of Norbornene Derivatives with Substituted Acetylenes
Authors: Hayakawa Kenji , Schmid Hans
Published: December 2004

Photochemical reactions of norbornadiene with substituted acetylenes in the presence of Fe(CO)5 gave various products of different types, depending on the nature of the acetylene. The results are summarized in Table 1. The cyclopentanone 1 was always formed in these reactions. In the reaction of disubstituted acetylenes such as dimethyl acetylenedicarboxylate and ethyl phenylpropiolate, the cyclopentenones 2 and 5 were formed, respectively. By contrast, propiolic esters produced the cyclohexenones 3 and 4, in which the ester group was attached on the β carbon with respect to the keto group. Plausible mechanisms for the formation of these products are shown in Schemes 7 and 8. The reaction of diphenylacetylene gave the cyclohexendione 7 as well as the cyclopentenone 6. Two enedione products 8 and 9 were obtained from the reaction of phenylacetylene. Compound 9 was converted to the aromatic diacetate 13 by heating with acetic anhydride in pyridine. On irradiation in the presence of Fe(CO)5 norbornene reacted similarly with dimethyl acetylenedicarboxylate and phenylacetylene to give the cyclopentenone 14 and the cyclohexenone 15, respectively. Compound 15, upon heating, isomerized to hydroquinone 16, which on acetylation gave the diacetate 17.
On Reactions of Oxygenated Cobalt(II) Complexes. XI. Note on the Mechanism of O2 Uptake by Cobalt(II) Chelates with Tetra‐ and Pentadentate Amines
Authors: Exnar Ivan , Mäcke Helmut
Published: December 2004

The synthesis of two new polyamines containing 2‐pyridyl and 6‐methyl‐(2‐pyridyl) groups is described. The equilibria between H+ and Co2+ and the new ligand 1,9‐di(2‐pyridyl)‐2,5,8‐triazanonane (dptn) as well as the protonation of the hydroxo complexes of 1,6‐di(2‐pyridyl)‐2,5‐diazahexane‐Co(II) (Co(dpdh) and 1‐(6‐methyl‐2‐pyridyl‐6‐(2‐pyridyl)‐2,5‐diazahexane‐Co(II) (Co(mdpdh)) have been studied in aqueous solution using the pH method. The coordination ability of the pyridine containing ligand dptn is compared with the chelating tendency of the analogous aliphatic amine (tetren). In spite of the lower basicity of the pyridine derivative the stability constants of its Co(II) complex is higher by a factor of thirty. The absorption spectra give evidence for a pseudooctahedral geometry of Co(dpdh) (H2O) and Co(dpdh)(H2O)(OH)+. Oxygen‐uptake measurements indicate the formation of binuclear peroxo species. The potentiometric equilibrium data indicate the presence of dibridged species (dpdh)Co(O2, OH)Co(dpdh)3+ and (mdpdh)Co(O2, OH)Co‐(mdpdh)3+. The kinetics of the rapid O2‐uptake was measured over a wide pH range on a stopped‐flow apparatus. For Co(dpdh)2+ and Co(mdpdh)2+ we found a second order rate constant independent of pH up to pH 9, but in more alkaline solutions it increases and reaches an upper limit around pH 12.3. The data could be fitted by a rate law of the form k1 = (k′1[H+] + k″1 KH) ([H+] + KH)−1. This variation with pH was explained by a rapid equilibrium Co(dpdh) (H2O) ⇌ Co(dpdh)(H2O)(OH)+ + H+(KH). The enhanced rate constants of the hydroxo species must arise from a rate determining H2O replacement by O2, dominated by Co‐OH2 bond breaking and the expected ability of an OH− group to labilize neighboring H2O molecules. The protonation constant of the hydroxo complex obtained by equilibrium measurements (pKH = 11.19 ± 0.03) was in good agreement with that derived from kinetic data (11.12 ± 0.04). The hydrolysis of Co(dptn)(H2O)2+ influences the rate of O2‐incorporation in a different way. In this system retardation occurs as a result of hydrolysis ascribed to the slower leaving of OH− compared to H2O. This was expected if a mechanism with rate determining H2O replacements by O2 holds.
A 13C‐ and 195Pt‐NMR. Study of the Complexes trans‐PtCl2 (amine) (CH2CH2)
Authors: Pregosin Paul S. , Sze S. N. , Salvadori Piero , Lazzaroni Raffaello
Published: December 2004

13C‐ and 195Pt‐NMR. spectra for the complexes trans‐PtCl2(amine)(CH2CH2) have been measured. For amine = (S)‐N‐methyl‐α‐methylbenzylamine the two diastereomers present may be distinguished from the values 3J(Pt,C). The 195Pt‐chemical shift is shown to be sensitive to subtle differences stemming from intramolecular non‐bonded interactions.
Conjugative Stabilization in an “Antiaromatic” System: The Conformational Mobility of 1,5‐Bisdehydro[12]annulene
Authors: Gygax Ruedi , Wirz Jakob , Sprague Joseph T. , Allinger Norman L.
Published: December 2004

The isodynamical interconversion between the quasiplanar equilibrium conformers 1b and 1c of 1,5‐bisdehydro[12]annulene requires a free energy of activation ΔG# = 4.5 ± 0.2 kcal/mol (120 K) which was determined by line shape analysis of its temperature‐dependent NMR. spectrum. Force field calculations indicate that this barrier reflects the energy needed to disrupt the cyclic π‐conjugation in going to the nonplanar transition state 1a.
ε‐Aminocaproylcholine: Chemical Synthesis, Biological Properties, and Interactions with Receptor Molecules
Authors: Frank Jörg , Kriwaczek Verena Marly , Marchand Claudine , Schwyzer Robert
Published: December 2004

ε‐Aminocaproylcholine, [14CH3‐]ε‐aminocaproylcholine, and their Sepharose‐2B derivatives (6) were synthesized. ε‐Aminocaproylcholine is a full cholinergic agonist (nicotinic) with a potency intermediate between that of acetylcholine and of carbachol. ε‐Aminocaproylcholine is not hydrolysed by acetylcholine esterase, but is an inhibitor. Its Sepharose‐2B derivatives are shown to be effective affinity‐chromatographic agents for the isolation of acetylcholine‐binding proteins (receptors).
Synthese von Nickelkomplexen mit porphinoidem Ligandsystem
Authors: Löliger Jürg , Scheffold Rolf
Published: December 2004

Synthesis of nickel complexes with a porphine‐type ligand system

In the presence of nickel(II) salts the bicyclic vinylogous amidine 1 is dimerized to the diamagnetic (1‐amino‐10,20‐diaza‐octahydroporphinato)nickel(II) complex 3. The condensation proceeds through a paramagnetic octahedral nickel(II) complex 2. Starting from 3, the (hexadecamethyl‐10,20‐diaza‐hexahydroporphin)nickel bis (tetrafluoroborate) 7 (a (hexaaza [16]annulene)nickel(II) complex) was prepared in two steps. This highly electrophilic compound adds methoxide ions in consecutive and reversible steps to form first the (1‐methoxy‐10,20‐diaza‐octahydroporphinato)nickel tetrafluoroborate 8 and then the [cis‐1, 11‐dimethoxy‐decahydroporphinato (2‐)]nickel 6. 6, 7 and 8 were fully characterized and interconverted by addition and elimination reactions.
Photochemische und nicht‐photochemische A/D‐Secocorrin→Corrin‐Cyclisierungen bei 19‐Carboxy‐ und 19‐Formyl‐1‐methyliden‐1,19‐secocorrinaten. Decarboxylierbarkeit und Deformylierbarkeit von Nickel (II)‐19‐carboxy‐ bzw. 19‐formyl‐corrinaten. Vorläufige Mitteilung
Authors: Pfaltz Andreas , Bühler Niklaux , Neier Reinhard , Hirai Koichi , Eschenmoser Albert
Published: December 2004

Photochemical and non‐photochemical A/D‐secocorrin→corrin‐cyclizations of 19‐carboxy‐ and 19‐formyl‐1‐methylidene‐1,19‐secocorrinates. Decarboxylation (and deformylation) of nickel(II)‐19‐carboxy‐(resp. 19‐formyl)‐corrinates

Nickel (II) 1‐methylidene‐2,2,7,7,12,12‐hexamethyl‐15‐cyano‐19‐carboxy‐1,19‐secocorrinate can be induced to cyclize with concomitant decarboxylation to the corresponding corrinate (Scheme 9). Experiments with deuterated derivatives (Scheme 10) indicate that in this decarboxylative A/D‐secocorrin→corrin‐cyclization the ring closure step precedes decarboxylation. In accord therewith is the finding that the corresponding intermediate nickel(II) 19‐carboxy‐corrinate (synthesized via photochemical cyclization of the corresponding cadmium complex, Schemes 6 and 9) decarboxylates under very mild conditions.

Nickel(II) 1‐methylidene‐2,2,7,7,12,12‐hexamethyl‐15‐cyano‐19‐formyl‐1,19‐secocorrinate cyclizes smoothly to the corresponding 19‐formyl‐corrinate in the presence of acetic acid/triethylamine. The formyl group of the cyclization product can be eliminated hydrolytically in essentially quantitative yield by treatment with 2N KOH in ethanolic solution (Scheme 11). The non‐photochemical (A→D)‐cyclization of 19‐formyl‐1,19‐secocorrinoids represents formation of the corrin chromophore at the oxidation level of porphyrinogens and exemplifies how a C1‐fragment that eventually leaves the ligand can fulfill a specific function in the (A→D)‐ring closure to a corrin.
Adducts of Niobium (V) and Tantalum (V) Halides. XV. Ligand Exchange of the Adducts with Some Phosphoryl Compounds
Authors: Favez Christian M. P. , Merbach André E.
Published: December 2004

The ligand exchange MX5·L + *L⇌MX5·*L + L for the octahedral adducts MX5·L, in an inert solvent (CH2Cl2 or CHCl3) with neutral ligands, proceeds via a dissociative D mechanism when M = Nb, X = Cl and L = phosphoryl compound. A dissociative interchange Id mechanism is suggested when M = Nb or Ta, and X = F. A first order rate law and positive values for ΔS* (+4 to +14 cal K−1 mol−1) are observed for the exchanges on the pentachloride adducts. However, a second order rate law and large negative values for ΔS* (‐15 to ‐24 cal K−1 mol−1) are found for the intermolecular neutral ligand exchange (measured by 1H‐NMR.) and for the intramolecular fluorine exchange (measured by 19F‐NMR.) reactions on the pentafluoride adducts. The fluorine exchange is 2 to 5 times faster than the ligand exchange. The exchanges, on the pentachloride and on the pentafluoride adducts, are slowed down with increasing donor strength of the phosphoryl compound.
Diterpenoide Drüsenfarbstoffe aus Labiaten: Coleone U, V, W und 14‐O‐Formyl‐coleon‐V sowie 2 Royleanone aus Plectranthus myrianthus BRIQ.; cis‐ und trans‐A/B‐6, 7‐Dioxoroyleanon
Authors: Miyase Toshio , Rüedi Peter , Eugster Conrad Hans
Published: December 2004

Leaf‐gland Pigments: Coleons U, V, W, 14‐O‐Formyl‐coleon‐V, and two Royleanones from Plectranthus myrianthus BRIQ.; cis‐ and trans‐A/B‐6,7‐Dioxoroyleanones

From leaf‐glands of the South‐African P. myrianthus (Labiatae) the following diterpenoids have been isolated and their structures established: coleon U, C20H26O5 (6, 11, 12, 14‐tetrahydroxy‐abieta‐5, 8, 11, 13‐tetraene‐7‐one, 2a); coleon V, C20H26O5 (11, 12, 14‐trihydroxy‐abieta‐8, 11, 13‐triene‐6, 7‐dione, 4a); coleon W, C22H28O8 (16(or 17)‐acetoxy‐6, 11, 12, 14, 17 (or 16)‐pentahydroxy‐abieta‐5, 8, 11, 13‐tetraene‐7‐one, 6); 14‐O‐formyl‐coleon‐V, C21H26O6 (14‐formyloxy‐11, 12‐dihydroxy‐abieta‐8, 11, 13‐triene‐6, 7‐dione, 4b); 7α‐formyloxy‐6β‐hydroxyroyleanone, C21H28O6 (7α‐formyloxy‐6β, 12‐dihydroxy‐abieta‐8, 12‐diene‐11, 14‐dione, 1a); the already known 6β, 7α‐dihydroxyroyleanone (1c) and a dimeric abietane derivative whose structure is not yet elucidated. This is the first record of a co‐occurrence of coleons and royleanones in the same plant. In the course of chemical investigations of 4a and 4b the highly oxidized trans‐ and cis‐A/B‐6,7‐dioxoroyleanones (5a and 5b) were obtained.
Transition‐metal complexes with bidentate ligands spanning trans‐positions. V. Crystal and molecular structures of complexes [RhCl(CO) (1)] and [PdCl2(1)]; 1 = 2,11‐bis (diphenylphosphinomethyl)benzo [c]phenanthrene
Authors: Bachechi Fiorella , Zambonelli Luigi , Venanzi Luigi M.
Published: December 2004

The structures of [RhCl(CO) (1)] and [PdCl2 (1)], where 1 is the bidentate ligand (C6H5)2P·CH2·C18H10· CH2·P(C6H5)2, have been determined from threedimensional X‐ray counter data collected on single crystals of the C6H5·CN solvates. The two compounds are isomorphous and crystallize in the triclinic system, space group P 1, Z = 2: a = 14.580 (8), b = 13.029 (10), c = 11.909 (6) Å, α = 106.33 (5), β = 100.47 (4), γ = 95.73 (5)° for the rhodium complex; a = 14.361 (5), b = 13.044 (7), c = 11.897 (4) Å, α = 105.97 (4), β = 100.27 (3), γ = 94.76 (4)°, for the palladium complex. In both complexes the metal atom is four‐coordinate with slightly distorted square‐planar configuration. In both cases the ligand 1 spans trans positions with M‐P bond lengths in the ranges of the literature data. Also the other bond distances fall in regular ranges. Ligand 1 has almost the same conformation in both complexes and is characterized by a strong out‐of‐plane deformation of the benzophenanthrene system as a consequence of severe overcrowding.
Synthese von radioaktiv markierten Bromacetyl‐ und Diazoacetyl‐α‐melanotropin‐Derivaten zum Studium von kovalenten Hormon‐Makromolekül‐Komplexen
Authors: Eberle Alex , Hübscher Willy , Schwyzer Robert
Published: December 2004

Synthesis of radioactive α‐melanotropin derivatives containing a bromoacetyl or diazoacetyl group for studies of covalent hormone‐macromolecule complexes

α‐Melanotropin derivatives and fragments covalently bound to human serum albumin through their N‐terminal end exhibit almost the same biological activity as the corresponding free Nα‐acetylated peptides [6]. The preparation of such complexes requires derivatives with a ‘reactive’ N‐terminal acetyl group. We describe here the synthesis of three α‐melanotropin fragments and of two specifically tritiated α‐melanotropin derivatives containing Nα‐bromoacetyl or Nα‐diazoacetyl groups: BrCH2CO · Glu‐His‐Phe‐Arg‐Trp‐Gly‐Lys‐Pro‐Val · NH2, BrCH2CO · Glu‐His‐Phe‐Arg‐Trp‐Gly · OH, BrCH2CO · Trp‐Gly‐Lys‐Pro‐Val middot; NH2, BrCH2CO · D‐Ala‐Tyr(3H2)‐Gly‐Nva‐Glu‐His‐Phe‐Arg‐Trp‐Gly‐Lys‐Pro‐Val · NH2, and N2 = CHCO · Gly‐Tyr(3H2)‐Ser‐Nva‐Glu‐His‐Phe‐Arg‐Trp‐Gly‐ Lys‐Pro‐Val · NH2. The latter two analogues displayed a specific radioactivity of about 20 and 36 Ci/mmol, and a biological activity of 2 · 109 and 6 · 109 U/mmol respectively. They are also being used for affinity and photoaffinity labelling of receptor molecules and antibody combining sites.
Chemical selectivities disguised by mass diffusion. III. A comparison of two versions of a simple model of mixing‐disguised reactions in solution. 3rd communication on the selectivity of chemical processes
Authors: Nabholz Felix , Ott Roland J. , Rys Paul
Published: December 2004

A simple mixing‐reaction model has been developed [1] which allows a description and simulation of the coupling of the mass diffusion with the chemical reaction during the mixing process of two miscible reactant solutions. For competitive, consecutive as well as for competitive, parallel second‐order reactions the general behaviour and the dependence of the product distribution on diffusion effects are calculated for semi‐continuous reaction conditions using various simplifying assumptions. The usefulness of these assumptions is discussed with reference to the calculated predictions of two versions of the mixing‐reaction model.
Synthesen und Thermolysen von 1‐Alkinyl‐2‐methyl‐1,2‐epoxy‐cycloalkanen. ‐ Versuche zur Ringerweiterung um drei Kohlenstoffatome
Authors: Karpf Martin , Dreiding André S.
Published: December 2004

Syntheses and Thermolyses of 1‐Alkynyl‐2‐methyl‐1,2‐epoxy‐cycloalkanes. ‐ Attempts at Ring Enlargement by Three Carbon Atoms

The 1‐alkynyl‐2‐methyl‐1,2‐epoxy‐alkene 2 and ‐cycloalkenes 9, 28 and 29 were obtained by epoxidation of the conjugated en‐ynes 1, 7, 26 and 27. The 12‐membered ring en‐ynes 26 and 27 were synthesized by ethynylation or propynylation of 2‐methylcyclododecanone (19) to the 1‐ethynyl‐ or 1‐(1′‐propynyl)‐cyclododecanols 20 A/B and 21 A/B, respectively, followed by dehydration to give separable mixtures of the regio‐ and stereoisomeric en‐ynes 22, 24, 26 and 23, 25, 27, respectively.

Gas‐phase thermolyses of the epoxides 2, 9, 28 and 29 were carried out under reduced pressure through a quartz tube at 550–600°. The formation of 5‐hexine‐2‐one (3) and 4,5‐hexadien‐2‐one (4) from 2 can be explained by [1, 5]‐ and [1, 3]‐ hydrogen shifts, respectively, and subsequent Claisen‐type rearrangements. Thermolysis of the six‐membered carbocyclic epoxide 9 induced the expected ring expansion by three carbon atoms to give 14% 4‐cyclononynone (12), along with the ketones 13, 14 and 15 as by‐products, which probably arose from surface induced heterolytic C, O‐bond fission and Wagner‐Meerwein‐type rearrangement processes.

Preliminary experiments with the thermolysis of the 12‐membered carbocyclic ethynyl‐epoxide 28, yielded a mixture, which contained 4‐cyclopentadecynone (30) and afforded, after hydrogenation, cyclopentadecanone (31, exaltone®) in 36% yield as the semicarbazone. Traces of 3‐methylcyclopentadecanone (32, rac, ‐muscone) were identified after thermolysis and hydrogenation of the propynyl‐epoxide 29.
Synthèse partielle de la (20S)‐ψ‐vincamine et de la (20S)‐épi‐16ψ‐vincamine
Authors: Le Men Jean , Caron‐Sigaut Catherine , Hugel Georgette , Le Men‐Olivier Louisette , Lévy Jean
Published: December 2004

Partial Synthesis of (20S)‐ψ‐Vincamine and (20S)‐epi‐16ψVincamine

An attempt of classification of the indole alkaloids is presented; (20S)‐ψ‐vincamine. (20S)‐16‐épi‐ψ‐vincamine and (20S)‐ψ‐apo‐vincamine have been prepared from catharanthine by partial synthesis.
Kristalline und molekulare Struktur von N‐Isopropyl‐7endo‐phenyl‐5,9‐methano‐6,7,8,9‐tetrahydro‐5 H‐benzo‐cyclohepten‐6exo‐yl‐amin
Authors: Weber Hans Peter , Petcher Trevor James
Published: December 2004

Crystal and Molecular Structure of N‐Isopropyl‐7endo‐phenyl‐5,9‐methano‐6,7,8,9‐tetrahydrobenzocyclo‐hepten‐6exo‐yl‐amin

The structure of the title compound was determined by X‐ray analysis of its hydrochloride. Space group Iba2, a=32.58, b=15.55, c=7.30 Å. The structure was refined by LS‐methods with 718 significant data to R=0.053.
Über die Carotinoide Flavoxanthin und Chrysanthemaxanthin: 1H‐NMR.‐, 13C‐NMR.‐ und Massen‐Spektren und absolute Konfiguration. (Kritische Überprüfung veröffentlichter chemischer und physikalischer Daten)
Authors: Cadosch Herbert , Vögeli Ulrich , Rüedi Peter , Eugster Conrad Hans
Published: December 2004

On the Carotenoids Flavoxanthin and Chrysanthemaxanthin: 1H‐NMR., 13C‐NMR. and Mass Spectra, Absolute Configuration, Survey of Published Data

Very pure flavoxanthin (1) and chrysanthemaxanthin (2) have been reisolated from flower heads of Taraxacum officinale. Both compounds were characterized by chromatographic, chemical and chiroptical data and extensive NMR. measurements. Examination of many published data on 1 and 2 led to the conclusion that flavoxanthin has often been mistaken for chrysanthemaxanthin and vice versa.

Chemical degradation of 1 and 2 to (−)‐loliolide (5) coupled with NMR. evidence (ASIS, spin‐decoupling, NOE) allowed the assignment of the absolute configurations of 1 and 2. Thus (+)‐flavoxanthin is (3S,5R,8R, 3′R,6′R)‐5, 8‐epoxy‐5, 8‐dihydro‐β, ε‐carotene‐3, 3′‐diol and (+)‐chrysanthemaxanthin its C(8)‐epimer.
Hexakis (methylidene)‐cyclohexane (“[6]Radialene”). Chemical and spectral properties
Authors: Schiess Peter , Heitzmann Markus
Published: December 2004

Upon flash pyrolysis between 580 to 660°, 2,4,6‐tris(chloromethyl)mesitylene (2) leads to products formed through the loss of one, two and three molecules of HCl. The highly reactive chlorine free product is shown to be [6]radialene (1) both by its chemical reactions and by its spectral properties.
Struktur und Reaktivität eines Triazolobenzodiazepin/Oxalylchlorid‐Addukts
Authors: Heckendorn Roland , Gagneux André R.
Published: December 2004

Structure and Reactivity of a Triazolo‐benzodiazepine/Oxalyl Chloride Adduct

Reaction of oxalyl chloride with N, N‐dimethyl‐{8‐chloro‐6‐(0‐fluorophenyl)‐ 4H, 11 H‐[1,2,4]triazolo [1,5‐α] [1,4]benzodiazepine}‐2‐carboxamide (6a), the syn‐thesis of which is described, leads to the cyclic adduct N, N‐dimethyl‐{2,12,12‐trichloro‐13a‐(0‐fluorophenyl)‐11‐oxo‐10,11,12,13a‐tetrahydro‐5H, 9H‐[1,3]oxazolo [3,2‐d] [1,2,4]triazolo [1,5‐a] [1,4]benzodiazepine}‐7‐carboxamide (7a). Upon thermolysis 7a is partly reconverted to the starting diazepine 6a via loss of the elements of oxalyl chloride. Reduction of 7a with sodium borohydride also yields 6ain addition to its dihydro derivative 9. Energetic treatment of 7a with sodium methoxide leads to the unexpected methoxydiazepines 10a and 10b, and mild treatment of 7a with sodium methoxide to the stereoselective formation of the two precursors of 10, namely the chloromethoxy derivative 11 and the dimethoxy derivative 12. Epimerization of 11 followed by nucleophilic substitution gives a mixture of two dimethoxy compounds, 12 and its epimer 14. The configurational assignments of these derivatives are based upon X‐ray analysis of 12. A possible pathway for this unexpected substitution reaction is proposed.
On the Calculation of the Electronic Reorganization of Canonical and Localized Koopmans' Ions
Authors: Jungen Martin
Published: December 2004

Conditions and implications for the calculation of self‐consistent single determinant wave functions for Koopmans' ions are discussed and a recipe for practical computations is given. The concept of Koopmans' ions has been extended to localized ions and a definition for their reorganization energies is proposed. Calculations on formaldehyde serve as a numerical illustration.
1H‐ und 13C‐NMR.‐spektroskopische Untersuchungen an den vier diastereomeren (±)‐Dihydropalustraminsäure‐methylestern; Strukturkorrelation mit (−)‐Dihydropalustraminsäure‐methylester sowie mit dem Alkaloid Palustrin. 14. Mitteilung über Schachtelhalmalkaloide
Authors: Rüedi Peter , Eugster Conrad Hans
Published: December 2004

1H‐and13C‐NMR. spectra of methyl esters of the diastereomeric (±)‐dihydropalustramic acids; structural correlation of (−)‐dihydropalustramic acid with the alkaloid palustrin

Unambiguous assignment of cis‐trans configuration at the piperidine ring of the four diastereomeric methyl esters of the (±)‐dihydropalustramic acids is based on the interpretation of 1H‐ and 13C‐NMR. data. (−)‐Dihydropalustramic acid, the important degradation product of the alkaloid palustrin is shown to be threo‐cis‐[6‐(1‐hydroxypropyl)‐2‐piperidyl]acetic acid. The same conclusion holds for palustrin and dihydropalustrin. Therefore, palustrin is threo‐cis‐17‐(1‐hydroxy‐propyl)‐1,5,10‐triazabicyclo[11.4.0]heptadec‐15‐en‐11‐one.
Absolute Konfiguration der Equisetumalkaloide (+)‐Palustrin, Palustridin ((+)‐Monohydrochlorid) sowie der (−)‐Dihydropalustraminsäure und weiterer Derivate. 16. Mitteilung über Schachtelhalmalkaloide
Authors: Wälchli Peter Christian , Mukherjee‐Müller Gabriele , Eugster Conrad Hans
Published: December 2004

Determination of the absolute configuration of alkaloids from Equisetum sp.,e.g. (+)‐palustrin, palustridin ((+)‐hydrochloride), and (−)‐dihydropalustramic acid and derivatives

The absolute configuration of the title alkaloids has been determined using chiroptical methods (ORD., superposition of CD. values of appropriate models and a modified Horeau method). (+)‐Palustrin is (13R, 17 S, 1′S)‐17‐(1‐hydroxypropyl)‐1,5,10‐triazabicyclo [11.4.0]heptadec‐15‐en‐11‐on.
Synthese von threo‐cis/threo‐trans‐ und erythro‐cis/erythro‐trans‐Dihydropalustrin. 17. Mitteilung über Schachtelhalmalkaloide
Authors: Wälchli‐Schaer Elisabeth , Eugster Conrad Hans
Published: December 2004

Synthesis of threo‐cis/threo‐trans‐ and erythro‐cis/erythro‐trans‐dihydropalustrin

The first synthesis of a threefold protected spermidine, namely 3‐benzyloxycarbonyl‐N1‐phthaloyl‐N2‐tosylspermidin (9) is presented. Each of the protecting groups can be removed selectively. After hydrazinolysis the resulting N3‐benzyloxy‐carbonyl‐N2‐tosylspermidine (10) has been condensed with methyl (2 E)‐cis‐7,8‐epoxy‐2‐decenoate to the threo‐cis/trans piperidines 17, and with methyl (2 E)‐trans‐7,8‐epoxy‐2‐decenoate to the erythro‐cis/trans piperidines 17, respectively. After catalytic removal of the Z group, the resulting aminoesters 13 and 18, in a melt with imidazole, underwent ring closure to the 13‐membered lactames 14 and 19, respectively. reductive deprotection of the N‐tosyl group with sodium/ammonia led to the stereoisomeric palustrines 15 and 20, respectively.
Infrared and Raman spectroscopic studies of benzothiazolinic spiropyrans and merocyanines
Authors: Guiliano Michel , Davin‐Pretelli Eliane , Mille Gilbert , Chouteau Jacques , Guglielmetti Robert
Published: December 2004

Les spectres IR. de cinq spiropyrannes benzothiazoliniques (ét solide et dissous) et les spectres Raman de trois d'entre eux (état solide) ont été enregistrés de 4000 à 400 cm−1 et ont permis une interprétation des vibrations moléculaires de ces composés. Une analyse plus sommaire, faite dans le but de caractériser la structure spiropyrannique a été étendue au moyen de la spectroscopie IR. à une série de vingt et un composés. L'étude IR. a également porté sur deux mérocyanines. Nous avons analysé et essayé d'interpréter les principales perturbations spectrales observées lors du passage d'un composé spiropyrannique (forme fermée) à la forme ouverte.
Anti‐ and syn‐Tricyclo [4.2.1.12,5]decane. Preliminary communication
Authors: Ernst Beat , Ganter Camille
Published: December 2004

The two novel tricyclic C10H16 compounds anti‐ and syn‐tricyclo [4.2.1.12,5]‐ decane (16 and 17, respectively) were synthesized starting either from the photodimer 2 (anti) or the two cycloaddition products 8 (anti) and 9 (syn).
Vitispiranes, Important Constitutents of Vanilla Aroma
Authors: Schulte‐Elte Karl H. , Gautschi Fritz , Renold Walter , Hauser Arnold , Fankhauser Peter , Limacher Josef , Ohloff Günther
Published: December 2004

The preparation of the vitispiranes 9 and 10, identified among the volatiles of vanilla, from the theaspiranes 1 and 2 via the intermediates 4 and 5 and the allyl alcohols 7 and 8, respectively, is described. The theaspiranes 1 and 2 can be obtained from the compounds 11–15 or 24–26.
A Di‐π‐Methane Rearrangement in the Photolysis of a 4‐Oxa‐steroidal α,β‐Unsaturated Enol‐lactone. Photochemical reactions VIII
Authors: Vallet José Alberto , Boix José , Bonet Juan‐Julio , Briansó Marie Claire , Miravitlles Carlos , Briansó José Luis
Published: December 2004

The irradiation of 17β‐acetoxy‐4‐oxa‐1,5‐androstadien‐3‐one (12) yielded the two stereoisomeric spiro‐lactones 13 and 14, which result from a di‐π‐methane photorearrangement. A third product, the oxa‐anthrasteroid 15, was also isolated (Scheme 3).