bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaktionen mit γ‐Chloracetessigesterderivaten
Authors: Boosen Karl‐Josef 
Published: December 2004

Reactions with derivatives of γ‐chloroacetoacetic acidEthyl 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 LoroglossineLoroglossine, 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 thiacyclesAllylation 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

Abstract31P‐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

AbstractThe 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

AbstractOf 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 reactionThe 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‐olenDie 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 diboraneIt 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 derivativesThermal 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

AbstractThe 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

AbstractThree 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 PropenylbenzenesThe 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 halopyridines2‐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 Compounds3‐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

AbstractPhotochemical 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

AbstractThe 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

Abstract13C‐ 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

AbstractThe 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

Abstractε‐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 systemIn 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.