bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radikaltrianionen von Isopyrenen
Authors: Huber Walter 
Published: December 2004

Radical Trianions of IsopyrenesThe radical trianions derived from acepleiadylene (1), dicyclopenta [ef,kl]heptalene (2) and dicyclohepta [cd, gh]‐pentalene (3) are described. Whereas the hyperfine data of \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{3\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{3\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document} are consistent with the predictions of an HMO‐McLachlan‐procedure, the corresponding data of \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{3\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document} substantially differ from the calculated values. The spin distribution in \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{3\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document} is polarized by the counterions in such a way, that the hyperfine data of this radical trianion no longer reflect the D2h‐symmetry of the neutral compound 3 and the radical anion \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document}. In addition, the interaction of the charged organic ion \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{3\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document} with the counterions influences the energy of the low‐lying antibonding molecular orbitals LUMO (lowest unoccupied molecular orbital) and NLUMO (next lowest unoccupied molecular orbital). The passage from a looser ion pair (\documentclass{article}\pagestyle{empty}\begin{document}$ 3^{3\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document}/3Li+) to a tighter ion pair (\documentclass{article}\pagestyle{empty}\begin{document}$ 3^{3\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document}/3Na+, \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{3\scriptstyle {{\relbar}\kern-4pt {.} }} $\end{document}/3K+) causes a change in the orbital sequence of LUMO and NLUMO.
Construction of Large Carbocyclic Rings by Ireland‐Claisen Rearrangement of O‐Silylated Lactone Enolates: Synthesis of (±)‐muscone
Authors: Brunner Rudolf K. , Borschberg Hans‐Jürg 
Published: December 2004

Abstract(±)‐Muscone (5) has been synthesized from methyl 13‐(chloroformyl)tridecanoate (6) in nine steps in an overall yield of 24%. The key steps involve an efficient transformation of the readily accessible 14‐hydroxy‐15‐methyl‐15‐hexadecenoic acid (9) into the tetradecanolide 1 and a subsequent Ireland‐Claisen rearrangement of its triethylsilyl enolate 2 to a 8:1‐mixture of the stereoisomeric 15‐membered carbocycles 4 and 10 (Scheme 4).
On cardioactive steroids. XII. The synthesis of (natural) bufalin and α′‐isobufalin
Authors: Wiesner Karel , Tsai Thomas Y. R. , Sen Alina , Kumar Ravindra , Tsubuki Masayoshi 
Published: December 2004

AbstractAn efficient and simple synthesis of bufalin (1) via furan‐containing intermediates is described. The same method was also used for the synthesis of α‐isobufalin (2) which was prepared with equal simplicity, but in lower yield.
Propellanes. Part LXIX. Preparation of lactones from the three isomeric [4.3.3]propellane‐8,11‐diols
Authors: Bhanumati Soundararajan , Ashkenazi Pnina , Migdal Shmuel , Ginsburg David 
Published: December 2004

AbstractEach of the three isomeric[4.3.3]propellane‐8,11‐diols was lactonized by using 1, ω‐diacids of different chain lengths. The minimal chain length required to bridge the syn‐syn diol is –CO(CH2)11CO–.
Propellanes. Part LXXII. The structure of the 4‐methyl‐1,2,4‐triazoline‐3,5‐dione adduct of the propellane lactone obtained by oxidation of biphenylene
Authors: Ashkenazi Pnina , Kaftory Menachem , Ginsburg David 
Published: December 2004

AbstractThe title compound reacts with the dienophile by attacking the face of a cyclo‐hexadiene ring which is syn‐ to the lactone ring.
Zum Mechanismus der α‐Alkinon‐Cyclisierung: Synthese und Thermolyse von 1‐(1‐Methylcyclopentyl)[3‐13C]prop‐2‐inon
Authors: Koller Manuel , Karpf Martin , Dreiding André S. 
Published: December 2004

On the Mechanism of the α‐Alkynone Cyclization: Synthesis and Thermolysis of 1‐(1‐Methylcyclopentyl)[3‐13C]prop‐2‐ynoneThe relative migratory aptitude of two acetylenic substituents in the α‐alkynone cyclization, a thermal conversion of α‐acetylenic ketones A to 2‐cyclopentenones C, was investigated by isotope‐labeling experiments. The α‐alkynone [β‐13C]‐1, specifically labeled with 13C at the β‐acetylenic C‐atom C(3), was synthesized by an intramolecular Witting reaction (230–300°) of the diacylmethylidenephosphorane [13C]‐7. The latter resulted from acylation of methylidenetriphenylphosphorane with the acid chloride 4 to yield the acylmethylidenephosphorane 5, which in turn was formylated with acetic [13C]formic anhydride ([13C]‐6.) Upon thermolysis of [β‐13C]‐1, its label at C(β) was transferred almost exclusively to C(β) of the 2‐cyclopentenone moiety in the resulting cyclization product [13C]‐2. We conclude that there is a distinct preference for hydrogen migration in the acetylene → alkylidene carbene isomerization (A → B) which precedes the cyclization step (B → C). No evidence was found for a fast reversibility of this isomerization (A ⇄ B) involving both acetylenic substituents.
The He(Iα) Photoelectron Spectra of the Perfluoroderivatives of Trisannelated Benzenes and Tetrakisannelated Cyclooctatetraenes
Authors: Heilbronner Edgar , Wirz Jakob , Soulen Robert L. 
Published: December 2004

AbstractThe He(Iα) photoelectron (PE) spectra of tris(perfluorocyclobuta)benzene 4(F)3,3,4,4,7,7,8,8,11,11,12,12‐Dodecafluorotetracyclo[8.2.0.02,5.06,9]dodeca‐1,5,9‐triene
, tris(perfluorocyclopenta)benzene 5(F)1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9‐Octadecafluoro‐2,3,4,5,6,7,8,9‐octahydro‐1H‐trindene.
, tetrakis(perfluorocyclobuta)cyclooctatetraene 6(F)3,3,4,4,7,7,8,8,11,1l,l2,l2,l5,15,16,16‐Hexadecafluoropentacyclo[12.2.0.02,5.06,9.010,13]hexadeca‐1,5,9,13‐tetraene.
, and of tetrakis(perfluorocyclopenta)cyclooctatetraene 7(F)1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12‐Tetracosafluoro‐1,2,3,4,5,6,7,8,9,10,11,12‐dodeca‐hydrotetracyclopenta[a,c,e,g]cyclooctene.
are reported. A tentative assignment of the PE spectra is derived by empirical correlation with those of relevant reference compounds. The results suggest that 6(F) retains the D4h‐conformation in the gas phase, i.e. A conformation with a planar cyclooctatetraene ring, as observed in the crystal. All four compounds exhibit a sharp increase of their first ionization energies, relative to the corresponding parent hydrocarbons, due to the perfluoro effect.
Photochemical reactions. 132nd communication. Photochemistry of 5,6‐epoxy‐5,6‐dihydro‐7‐methyl‐β‐ionine: Influence of a methyl group at the enone side chain on the oxirane cleavage
Authors: Siewnski Antoni , Henggeler Barbara , Wolf Hans Richard , Frei Bruno , Jeger Oskar 
Published: December 2004

Abstract1n, π*‐Excitation of the γ,δ‐epoxy‐enone (E)‐3 leads exclusively to the conformers (Z)‐3A + B. On 1π, π*‐excitation of (E)‐3, in addition to (Z)‐3A + B, products 6–9 arising from a carbene intermediate e are formed. However, products of an isomerization via C(γ), O‐bond cleavage of the oxirane were not formed on either mode of excitation. On thermolysis, at 80° the conformer (Z)‐3A is transformed into (Z)‐3B, which on photolysis returns to (Z)‐3A and (E)‐3. At 160°, however, (Z)‐3B rearranges to the isomers 6, 10 and 11.
Stereochemistry of an Ene Reaction Involving 1,7‐Dienes; Bicyclo[3.3.1]nonanes from (3‐Cyclohexenyl)diallylcarbinols
Authors: Thomas Alan F. , Lander‐Schouwey Marina 
Published: December 2004

Abstract(3‐Cyclohexenyl)diallylcarbinols undergo a thermal retro‐ene reaction to give crotonylcyclohexenes at ca. 200°. A side‐reaction is an ene reaction to give bicyclo[3.3.1]nonanes. These become the main products above 300°. The stereochemistry of 2‐allyl‐1,4,6‐trimethylbicyclo[3.3.1]‐6‐none‐2‐ols and related compounds is discussed, and a case is described in which the allyl group is not freely rotating.
Molecular Structure of the Bis[tris(2‐aminoethyl)aminecyano]dicobalt(III) Ion and its UV/VIS Spectrum
Authors: Fallab Silvio , Zehnder Margareta 
Published: December 2004

AbstractFormation of μ‐peroxodicobalt(III) complexes has been studied in solutions containing tris(2‐aminoethyl)aminecobalt(II) and additional monodentate ligands X. Depending n the nature and the concentration of X and on pH, singly bridged [(tren)XCoOOCoX(tren)]4+ and/or doubly bridged [(tren)Co(C2OH)Co(tren)]3+ are formed. The UV/VIS spectra of these complexes are discussed on the basis of a theoretical model which stresses the importance of the dihedral angle of the CoOOCo‐group. [(tren)(CN)CoOOCo(CN)(tren)](ClO4)2 has been synthesized and its structure determined by single crystal X‐ray diffraction. The CoOOCo‐group of the cation is planar. Solutions of the complex as well as the solid show two CT bands in the 300–400 nm region.
Complexation de l'argent(I) par des teramines cycliques
Authors: Suet Elisabeth , Laouenan André , Handel Henri , Guglielmetti Robert 
Published: December 2004

Complexation of Silver(I) by Cyclic TetraminesThe nature of Ag(I)‐complexes with 1,4,8,11‐tetraazacyclotetradecane (1), 1,5,9,13‐tetraazacyclohexadecane (2) 1,5,10,14‐tetraazacyclooctadencane (3) and 1,6,11,16‐tetraazacycloeicosane (4) is studied. The effect of ring size on disproportionation of the Ag() cation in the presence of ligand is reported. The stability of Ag(I)‐complexes with 3 and 4 in aqueous solution is determined by means of potentiometric titration.
The structure of melinonine‐E, a quaternary indole alkaloid from Strychnos melinoniana baillon. Part 190: Studies on organic natural products
Authors: Borris Robert P. , Guggisberg Armin , Hesse Manfred 
Published: December 2004

AbstractThe structure of melinonine‐E (2) with relative configuration was established on the basis of spectral data for 2 and its acetate 3.
1, 1‐Difluoro‐1H‐cyclopropa[a]naphthalene
Authors: Müller Paul , Nguyen‐Thi Huong‐Can 
Published: December 2004

Abstract1, 1‐Difluorocyclopropa[a]naphthalene (1b) is prepared in three steps from 4‐bromo‐1,2‐dihydronaphthalene (7) via carbene addition, benzylic bromination and bidehydrohalogenation. Structural evidence for formation of 1b is based on 1H‐ and 19F‐NMR spectroscopy. Compound 1b is stable in solution at −30°. Upon reaction with MeOH/H+ it is converted to a 1:2 mixture of 1‐ and 2‐methylnaphthoate (10 and 11, respectively).
Synthetic routes to trace constituents of algal pheromone bouqets and other information‐imitating substances
Authors: Boland Willhelm , Mertes Karin 
Published: December 2004

AbstractStructural modifications of multifidene (1), viridiene (2) and ectocarpene (5) led to the synthesis of eleven new pheromone components or imitatin substances mostly by Grignard alkylation of cyclopentene and cycloheptadiene synthons. A new lactone α,ω dienol conversion is reported.
Radikalionen von überbrückten [14] Annulenen. Untersuchungen zum Frontorbitaleinfluss auf Reaktivität und Bindungszustand
Authors: Huber Walter 
Published: December 2004

Radical Ions of Bridged [14] Annulenes. Investigations on the Influence of Frontier Orbitals on Reactivity and BondingThe radical anions and the radical cations derived from trans‐15, 16‐dimethyl‐1, 4:8,11‐ethandiyliden[14]annulene (6), trans‐15‐methyl‐1,4:8,11‐ethandiyliden[14]annulene (7) and cis‐15, 16‐propano‐1,4:8,11‐ethandiyliden[14]annulene (8) are described. The hyperfine data of the radical anions 6, 7 and 8 resemble those of the structurally related radical anions of trans‐10b, 10c‐dimethyldihydropyrene (4) and trans‐10b, 10c‐dihydropyrene (5). This finding leads to the conclusion, that the change in the relative arragement of the saturated bridge within the fourteen‐membered π‐perimeter by passing from 4 (5) to 6 (7, 8) does not in fluence the energetic sequence of the lowest unoccupied molecular orbitals. The behavior of 6 and 7 towards oxidation parallels the photochemical reactivity of 4. The hyperfine coupling constants of the radical cations derived from 6 and 7 indicate that the removal of an electron is accompanied by an isomerization of the molecular framework. The investigation of the electron transfer process gby cyclic voltammetry supports these findings. The radical cations prefer the cyclophane‐like structures 6a and 7a, in which the central σ‐bond (C(15)–C(16) bond) is broken.
Differential Bridging in the Solvolysis of Epimeric Bicyclic Sulfonates, Norbornanes, Part 17
Authors: Grob Cyril A. , Waldner Adrian , Zutter Ulrich 
Published: December 2004

AbstractThe solvolysis rates and products of the 2‐exo‐ norbornyl, bicyclo[3.2.1]oct‐8‐yl, bicyclo[3.3.1]non‐2‐yl, bicyclo[3.2.1]oct‐6‐yl, bicyclo[3.2.1]oct‐2‐yl and bicyclo[3.2.2]non‐6‐yl p‐toluenesulfonates 10–15, respectively, are reported. The exo/endo rate ratios for these epimeric secondary tosylates in 80% EtOH varied from 1125 for 11 to 1.6 for 15. The relative rates varied between 2278 for exo‐10 and 4 ·10−3 for endo‐11. The hydrolysis products were mainly rearranged alcohols and olefins. The unrearranged alcohols from the exo‐tosylates were formed with complete or predominant retention of configuration, whereas those derived from the endo‐tosylates were mostly inverted. These results confirm the hypothesis that relative rates, as well as products, are largely determined by the degree of bridging between the cationic center and a dorsal C‐atom in the transition state and in the resulting ion pairs. Since bridging is a directed bonding interaction, it is subject to the same angle and conformational strains as ordinary covalent bonds. But bridging requires less geometrical change than the formation of normal bonds and of nonclassical ions.
Über die Bildung von Dihydro‐1,2‐oxazin‐N‐oxiden durch intramolekulare Addition eines Nitronat‐Anions an eine Carbonylgruppe
Authors: Kienzle Frank , Fellmann Jean‐Yves , Stadlwieser Josef 
Published: December 2004

The Formation of Dihydro‐1,2‐oxazine N‐Oxides through an Intramolecular Addition of a Nitronate Anion to a Carbonyl GroupHighly substituted 4‐keto‐1‐nitroalkanes cyclize under basic conditions to dihydro‐1,2‐oxazine N‐oxides. These N‐oxides are thermally unstable and decompose to 1,4‐diketones, BF3 catalyzes a similar decomposition, but probably via a different mechanism.
Stereoselectivity in reactions of metal complexes IX Stereoselective formation of cobalt(III) complexes with new linear pentadentate ligands
Authors: Bernauer Klaus , Pousaz Philippe 
Published: December 2004

AbstractThe synthesis of cobalt(III) complexes with the new linear pentadentate ligands meso‐ and racemic 2,6‐bis(3S)‐3‐carboxy‐4‐methyl‐2‐azapentylpyridine (2) are described. Only one of the different possible isomers is obtained from each ligand. The structure of the complexes has been assigned on the basis of their 1H‐NMR and CD spectra. The structure of the aqua‐cobalt(III)‐1a and the aqua‐cobalt(III)‐1b has been confirmed by X‐ray analysis. Partial resolution of optical antipodes of the aquacobalt(III)‐1b was achieved by column chromatography and a tentative assignment of their absolute configuration is made.
Photochemical reactions, 136th communication. Photochemistry of conjugated epoxyenones and dienes of the ionone series: Influence of a neighboring spiro‐oxirane function
Authors: O'Sullivan Anthony , Frei Bruno , Jeger Oskar 
Published: December 2004

AbstractThe preparation and photolyses of the diepoxyenones (E)‐8 and (E)‐9 as well as the diepoxydiene (E)‐10 are described. On 1π,π*‐excitation (λ = 254 nm), the diastereoisomeric diepoxyenones (E)‐8 and (E)‐9 undergo isomerization via the ylide intermediate f and the carbene intermediate g leading to the primary photoproducts 17A and 18–21 (Scheme 8). On 1n, π*‐excitation (λ > 347 nm), (E)‐8 shows behaviour typical of epoxyenones undergoing C(γ), O‐bond cleavage of the oxirane and isomerization to compounds 22, (E/Z)‐23 and (E)‐24 (Scheme 10). On singlet excitation, the diepoxydiene (E)‐10, is cleaved to the carbonyl ylide j and the carbenes 1 and m (Scheme 11). The carbonyl ylide j fragments via the dipolar intermediate k to the acetylenic dienone (E)‐31. The carbene 1, showing behaviour typical of vinyl carbenes, furnishes the cyclopropene 30. The alternative carbene m, however, undergoes an insertion reaction into the neighboring oxirane C,C‐bond leading to the proposed but not isolated oxetene 43, which is further transformed to the products 33A _ B by an intramolecular cycloaddition.
Asymmetric induction bny enantiotopically differentiating retro‐claisen reaction of P{rochiral bicyclic β‐diketones
Authors: Duthaler Rudolf O. , Maienfisch Peter 
Published: December 2004

AbstractThe possibility of preparing cycloalkanones with an asymmetric β‐C‐atom by enantiotopically differentiating retro‐Claisen reactions of bicyclic diketones a (Scheme l) is tested with the decalin‐1,8‐diones 1 and 7, as well as with the bicyclo[3.3.0]octane‐2,8‐diones 10 and 11. Treatment of the reactive dione 1 with chiral tetra‐alkyl titanate catalysts results in a low optical induction (13%, Scheme 2). Cleavage with the Nasalts of a‐amino‐alcohols and hydrolysis of the resulting amides or esters gives much better optical yields, reaching 86% ee with dione 1 and (−)‐ephedrine (Scheme 3). Almost as efficient is N‐methylephedrine with 75% optical induction (Scheme 5). Lower enantiotopical differentiation is, however, observed with (−)‐ephedrine and diones 7 (44% ee), 10 (8% ee), and 11 (48% ee) (Schemes 3 and 4, Table l), or with dione 1 and L‐prolinol (37% ee) or (−)‐2‐amino‐1‐butanol (11% ee) (Scheme 5, Table 2). The moderate chemical yields of these transformations (500–70%) can be ascribed to side‐reactions of the ketones under the strongly basic conditions.
Synthesis of a S‐(Carboxymethyl)cysteine Analog of (L‐2‐Amino‐6‐adipyl)‐L‐cysteinyl‐D‐valine and its Cell Free Biosynthetic Conversion into 6‐[2‐(D‐2‐Amino‐2‐carboxyethyl)thio) acetamido]penicillanic Acid
Authors: Shields James E. , Campbell Charles S. , Duckworth Dale C. , Neuss Norbert , Queener Steven W. 
Published: December 2004

AbstractA new tripeptide (dimer), bis[(L‐cysteine‐S‐acetyl)‐L‐hemicystinyl(S2 → S2)‐D‐valine] (6) was synthesized by coupling N‐(tert‐butoxycarbonyl)‐S‐carboxymethyl‐L‐cysteine benzyl ester (1) with S‐trityl‐L‐cysteinyl‐D‐valine benzyl ester and subsequent removal of the protecting groups. After reduction of the disulfide, the free tripeptide Cys (CH2CO‐Cys‐D‐Val) (Ib) was used as a substrate of isopenicillin‐N synthetase in a cell‐free conversion to 6‐[2‐((D‐2‐amino‐2‐carboxyethyl)thio)acetamido]penicillanic acid (IIa).
HNO, an Intermediate in (Light‐induced) Rearrangement Reactions of Nitrosooxy Compounds and Nitrosamines
Authors: Müller René‐Pierre , Murata Shigeo , Nonella Marco , Huber J. Robert 
Published: December 2004

AbstractIR‐spectroscopic investigations of light‐induced rearrangement reactions of nitrosooxymethane (CH3ONO3), nitrosooxyethane (CH3CH2ONO) and N,N‐dimethylnitrosamine ((CH3)2NNO) in low‐temperature rare‐gas matrices have established that these molecules are transformed in two photolysis steps to the previously unknown C‐nitroso compounds nitrosomethanol (CH2(OH)(NO)), 1‐nitrosoethanol (CH3CH(OH)(NO)), and methyl(nitrosomethyl)amine CH2(NO)(NH)(CH3). Evidence for a similar rearrangement reaction has been advanced for N‐Nitrosopyrrolidine magnified image which is converted to C‐nitrosopyrrolidine magnified image. The matrix‐isolation technique in combination with wavelength‐selective irradiation allowed to trap and characterize an intermediate of rearrangement which revealed to be nitroxyl (HNO) complex (CH2…HNO, CH3CHO…HNO, CH3N = CH2…HNO, and magnified image). Since these findings have a close resemblance with rearrangement reactions of more complex nitrosooxy compounds, nitrosamines, or nitrosohydrazines used in organic synthesis, it is suggested that also in these reactions nitroxyl is present as an intermediate species.
Aliphatic Liquid Crystals with Positive Dielectric Anisotropy
Authors: Osman Maged A. , Huynh‐Ba T. 
Published: December 2004

AbstractCyanothyl‐subsituted cylohexyl cyclohexanoates, bi(cyclohexanes) and phenyl cyclohexanes were synthisized. Their mesmorphic behaviour is compared to that of the corresponding cyano derivatives. (Cyanoethyl)cyclohexyl cyclohenxanoates show mesmorphic properties in contrast to the corresponding cyano derivative. Separation of the cyano substituent from the rigid core of an anisotropic aliphatic compound by methylene groups enhances the thermodynamic stability of the mesophase. In aromatic compound, the cyanoethyl group leads to lower clearing points. These phenomena are attributed to teh influence of steric effects on the packing density and to the dependence of the clearing point on molecular association.
Stereoselective Control in the Base‐Catalyzed H/D Exchange of 5,6‐Dimethylidene‐2‐bicyclo[2.2.n]alkanone Tricarbonyliron Complexes. Revision of the Structures of Tricarbonyliron Complexes of 5,6‐Dimethylidenebicyclo[2.2.2]oct‐2‐ene and 5,6‐Dimethylidenebicyclo[2.2.1]hept‐2‐ene
Authors: Barras Charls A. , Roulet Rymond , Carrupt Pierre‐Alain , Berchier Fabienne , Vogel Pierre 
Published: December 2004

AbstractOxidative hydroboration of exo‐ (1) and end‐Fe(CO)3 (2) complexes of 5,6‐dimethylidenebicyclo[2.2.2]oct‐2‐ene are highly stereoselective and give endo ‐alcohol 3 and exo ‐alcohol 4 as major products, respectively, Collins oxidations of 3 and 4 furnish the corresponding exo ‐Fe(CO)3 ‐complexed 5,6‐dimethylidene‐2‐bicyclo‐[2.2.2]octanone 7 and 8. NaBH4 reduction of exo‐complexes 7 gives a mixture of 3 and isomeric exo‐alcohol 18, whereas reduction of endo‐complexes 8 gives the endo‐alcohol, endo‐complexes 19, as the sole product. The base‐catalyzed H/D exchange of 7 and 8 afford the dideuterated exo‐complex 35 and the monodeuterated endo‐complex 32, respectively. Oxidative hydroborations of the exo‐(9) and endo‐Fe(CO)3 (10) complexes of 5,6‐dimethylidenebicyclo[2.2.1]hept‐2‐ene give the corresponding exo‐alcohols 39 and 40. Oxidation of 39 and 40 gives the exo‐ and endo‐complexes 41 and 42, respectively, of 5,6‐dimethylidene‐2‐bicyclo[2.2.]heptanone. Only Hexo C(3) can be exchanged in 42, wheres both H‐atoms at C(3) in 41 are exchangeable. The endo‐Fe(CO)3 group in 8 and 42 blocks the base‐catalyzed H/D exchange of Hendo C(3), thus providing a test for the configuration of Fe(CO)3 group in these systems. These studies have led to a revision of the iron configurations proposed by Hansen et al, [2] for 1, 2, 9 and 10.
Monohaptenic Nα‐Benzoyl‐L‐lysine Derivatives as Anaphylactogens: the Importance of the Unsubstituted Carboxyl Group
Authors: Guenin Raymond , Schneider Conrad H. 
Published: December 2004

AbstractNα‐L‐Iysine with a 2‐carboxy‐4, 6‐dinitrophenyl (Dncp) haptenic group on the ε‐amino function is a potent anaphylactogen in the guinea pig. We prepared Nε ‐Dncp‐ Nα‐benzoly‐L‐Iysinamide and Nε‐Dncp‐Nα‐benzoyl‐L‐lysyl‐1‐aminopropane where the carboxyl group of Iysine is blocked. Both compounds were non‐elections of anaphylaxis.
Determination of the Quadrupolar Coupling Constant and the Asymmetry Parameter of Oxygen‐17 in Acetone by 17O‐ and 1H‐NMR in Nematic Phases
Authors: Tricot Yves , Niederberger Werner 
Published: December 2004

AbstractLinear relationships between the inverse of the quadrupolar coupling constant, 1/χ and the asymmetry parameter η are obtained for the 7O‐nucleus of acetone oriented in four different nematic phases, using the information contained in 1H‐ and 17O‐NMR spectra. The absence of a unique intersecting point of thee relations shows that the quadrupolar constants differ slightly between polar and apolar nematic phases, while the orientation remains similar. By combination of the experimentally derived relations with predictions from the theory of Townes and Dailey, values for χ = 11.15 MHz and η = 0.47 in polar media and χ = 11.35 Mhz and η = 0.15 in an apolar medium are obtained, which are similar to those found in the gas and solid phases.