bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Synthesis of (±)‐11‐Deoxydaunomycinone via Regioselective Tandem Diels‐Alder Reactions
Authors: Tornare Jean‐Mare , Vogel Pierre 
Published: December 2004

AbstractThe 2,5‐dimethylidene‐3,6‐bis[(Z)‐(2‐nitrophenyl)sulfenylmethylidene]‐7‐oxabicyclo[2.2.1]heptane (13) can be used to generate polyfunctional and multicyclic molecules with high regio‐ and stereoselectivity via two successive Diels‐Alder additions using two different dienophiles. This principle has been applied to the synthesis of (±)‐11‐deoxydaunomycinone (7), the aglycone of an important antitumor drug. The 2,3‐didehydroanisole adds to 13 and gives the monoadduct 14 with high regioselectivity. No trace of bis‐adduct is observed. The 1,4‐epoxy‐1,2,3,4‐tetrahydro‐5‐methoxy‐3‐methylidene‐2‐[(Z)‐(2‐nitrophenyl)sulfenylmethylidene]anthracene (15) obtained on treating 14 with K2CO3 adds to methyl vinyl ketone to give [(1RS, 2SR, 5RS,12RS)‐5,12‐epoxy‐1,2,3,4,5,12‐hexahydro‐7‐methoxy‐1‐(2‐nitrophenyl)sulfenyl‐2‐naphthacenyl]methyl ketone (16) with high regio‐ and stereoselectivity. The acid‐catalyzed 7‐oxanorbornadiene→phenol rearrangement of 16 is regioselective and gives (5‐acetoxy‐3,4‐dihydro‐7‐methoxy‐2‐naphthacenyl) methyl ketone (20) which was transformed into (±)‐7,11‐dideoxydaunomycinone ((±)‐24), a known precursor of 7.
Physicochemical Properties of Deuterated Compounds. 7th Communication. The H/D exchange between hydrogen and methane over Ni Catalyst
Authors: Poretti Marc , Gäumann Tino 
Published: December 2004

AbstractThe isotopic exchange between hydrogen and methane over Ni catalyst has been studied as a function of temperature, isotopic substitution, and ratio of hydrogen to methane. The experimental results can be described by means of a model in which methane is adsorbed either as methyl or as methylene. The adsorbed species undergo one or several exchanges. The four required parameters are adjusted to the experimental results. The exchange of partially deuterated methane with H2 or D2 allowed us to study the isotopic effect on the adsorption and the exchange processes.
Reactivity of Carbenes and Related Compounds towards Molecular Nitrogen
Authors: Grieve Duncan M. A. , Lewis Graham E. , Ravenscroft Michael D. , Skrabal Peter , Sonoda Takaaki , Szele Ivanka , Zollinger Heinrich 
Published: December 2004

AbstractThe thermal N2 exchange of a number of 15N‐labelled diazo compounds was studied in solution. The compounds involved were 3‐diazo‐1‐methylindolin‐2‐one (1), 9‐diazofluorene (2), 5‐diazo‐1,3‐cyclopentadiene‐1,2,3,4‐tetracarbonitrile (3), 2‐diazo‐2H‐imidazole‐4,5‐dicarbonitrile (4), 4‐diazocyclohexa‐2,5‐dienone (5), and the conjugate acids of 4 and 5, namely 4,5‐dicyano‐1H‐imidazole‐2‐diazonium ion (6) and 4‐hydroxybenzenediazonium ion (7). Only 1, 4, 6, and 7 exchange their diazo group with ‘external’ molecular N2. The results are explained on the hypothesis that only organic species which have an empty σ orbital and which are effective in π electron back‐donation are able to react with N2. Thus, reaction with carbenes is likely to occur only if the carbene is in the 1A2 singlet state and if its electrophilicity is high.
HPLC von Carotinen mit ψ‐Endgruppen und (Z)‐Konfiguration an terminalen konjugierten Doppelbindungen; Isolierung von (5Z)‐Lycopin aus Tomaten
Authors: Zumbrunn Albrecht , Uebelhart Peter , Eugster Conrad Hans 
Published: December 2004

HPLC of Carotenes with ψ‐End Groups and (Z)‐Configuration at Terminal Conjugated Double Bonds; Isolation of (5Z)‐Lycopene from TomatoesFive carotenes bearing (5Z)‐ψ‐end groups were synthesized and carefully characterized: (5Z)‐lycopene (6), (5Z5′Z)‐lycopene (7), (5′Z)‐neurosporene (8), (5′Z)‐β,ψ‐carotene (12), and (5′Z)‐ε,ψ‐carotene (14). Lycopene 6 was isolated from tomatoes and its structure proven by 1H‐NMR spectroscopy.
Über den Einfluss der pK‐Werte von Anilinen auf die Bildung und Folgereaktionen von substituierten Butadienen aus Cumalinsäure‐methylester
Authors: Kvita Vratislav , Sauter Hanspeter , Rihs Grete 
Published: December 2004

The Influence of Aniline pK Values on the Formation and Reactivity of Substituted Butadienes from Methyl CoumalateThe product of the reaction between 2 equiv. of methyl coumalate (1) and 1 equiv. of a substituted aromatic amine depends on the pK value of the latter. Aromatic amines with pK values between 1.05 and 2.8 produce bicyclic lactones 4, whereas those with higher pK values also give 2‐azabicyclo[3.3.1]nona‐3,7‐diene‐9‐carboxylic acids 9. The latter, products of the intramolecular Diels‐Alder reaction 8 → 9, may in certain cases even prevail.
Hetero‐Cope‐Umlagerungen. 4. Mitteilung. Regiokontrollierte Indolsynthesen
Authors: Blechert Siegfried 
Published: December 2004

Hetero‐Cope‐Rearrangements, Regio‐Controlled Synthesis of IndolesThe reaction of O‐deprotonated N‐phenylhydroxylamines 1 with various electron‐deficient allenes 2, 14, 16 gives, via Michael addition and Cope‐rearrangement, substituted anilines 5, which are easily convertible into indoles 6. In this manner, sulfoxides 17, serve as equivalents of 2‐vinylindoles. Diels‐Alder reaction with this 2‐vinylindole equivalent followed by indolisation affords isoquinuclidine derivative 21 which may be a useful precursor for the preparation of Iboga alkaloids.
Tritiation of Peptides to High Specific Radioactivity. Part 1. Synthesis and Biological Properties of [13‐(3H4)Norvaline]‐α‐MSH and of [2,23‐Bis((3H2)tyrosine)]ACTH(1–24)
Authors: Eberle Alex N. , Zeller Albert 
Published: December 2004

Abstractα‐MSH and ACTH(1–24) were tritiated to high specific radioactivity (> 100 Ci/mmol) using a new tritiation apparatus with which the tritiation reaction can be performed at slightly elevated pressure. This allows short reaction times with the least possible damage to the molecule. The starting compounds for the tritiation were [13‐propargylglycine]α‐MSH and [2,23‐Bis(3′,5′‐diiodotyrosine)]ACTH(1–24). Both tritiations were quantitative and yielded products of high purity, full biological activity, and with a specific radioactivity of 115 Ci/mmol and 100 Ci/mmol, respectively.
Studies on the Carbon Zip Reaction of 2‐Oxocycloalkane‐1‐carbonitriles
Authors: Süsse Manfred , Hájíček Josef , Hesse Manfred 
Published: December 2004

AbstractAs a part of continuing interest in the zip reaction, we present the results on a carbon ring‐enlargement reaction of activated ketones with a CN group as a charge stabilizer. Two series of (1‐cyano‐2‐oxocy‐cloalkyl)alkanoates were prepared from 8‐ and 12‐membered cyano‐ketones 1 and 2, respectively, namely the propanoates 3 and 4, the butanoates 6, 8 and 9 as well as the pentanoates 12 and 15. While treatment with t‐BuOK of the former two homologous esters resulted in both ring enlargement and competitive transesterification, the pentanoates 12 and 15 afforded mostly the diastereoisomeric mixtures of bicyclic alcohols 20a–c and 31a,b, respectively, which remained intact on further exposure to base. It was shown that – apart from the base used (t‐BuOK) vs. Li(i‐Pr)2N – the distribution of products was greatly influenced by the ring size of substrates. This is further illustrated by treatment of ketones 34 and 35 with t‐BuOK. While the former rearranged smoothly to diketone 36, no reaction at all took place with the latter. The behavior of the substrates is discussed in terms of steric and energetic reasons.
Synthesen und chemische Reaktionen von ω,ω‐Bis(alkylthio)chinonmethiden des 1,6‐Methano[10]annulens
Authors: Neidlein Richard , Hartz Georg 
Published: December 2004

Syntheses and Chemical Reactions of ω,ω‐Bis(alkylthio)quinonemethides of 1.6‐Methano[10]annulenesThe syntheses of the donor‐acceptor‐substituted compounds 3–5, 9 starting from 2, 7, or 8, furthermore, the syntheses of 12, 15–21 are described. The detailed results of 1H‐ and 13C‐NMR‐spectroscopic measurements are reported.
X‐Ray Diffraction Study of 2‐Aminopropenenitrile at 97 K
Authors: Seiler Paul , Dunitz Jack D. 
Published: December 2004

Abstract2‐Aminopropenenitrile crystallizes in the space group P212121 with two molecules in the asymmetric unit. Both molecules show appreciable pyramidalization at the amino group. The crystal structure is built from approximately centrosymmetric dimers stabilized by hydrogen bonding between the amino group of each molecule and the nitrile group of its partner. The dimers are linked into chains by further hydrogen bonds in which the amino group of one molecule acts as donor, the amino group of the other as acceptor. The two types of molecule thus play different roles in the crystal structure. Electron density difference maps for the two independent molecules show characteristic bonding density features. The molecular structure as obtained by the low‐temperature X‐ray analysis is closely similar to that derived from ab initio molecular orbital calculations and leads to rotational constants close to those obtained from a microwave spectroscopic study.
Asymmetric Diels‐Alder Reactions of Neopentyl‐Ether‐Shielded Acrylates and Allenic Esters: Syntheses of (−)‐Norbornenone and (−)‐β‐Santalene
Authors: Oppolzer Wolfgang , Chapuis Christian , Dupuis Dominique , Guo Maodao 
Published: December 2004

AbstractStarting from (+)‐ or (−)‐camphor, the antipodal alcohols 14 and 18, respectively, have been prepared; the corresponding acrylates 15 and 19 underwent TiCl2(i‐PrO)2‐mediated Diels‐Alder additions to cyclopentadiene to give adducts 20a and 22a respectively, with 95 % endo‐ and 99.2% πpH‐face selectivities. Adduct 22a was converted to enantiomerically pure norbornenone 26. Addition of 1,3‐butadiene to acrylate 15 in the presence of TiCl4 afforded 3‐cyclohexenyl carboxylate 29 with > 95.6 % stereodifferentiation. The TiCl2(i‐PrO)2‐promoted [4 + 2] cycloaddition of cyclopentadiene to allenic ester 43 proceeding with 99 % face differentiation served as the key step for an efficient enantioselective synthesis of (−)‐β‐santalene ((−)‐41) with concomitant recovery of the chiral control alcohol 14.
Synthese von 15‐Hydroxy[9]metacyclophan
Authors: Lorenzi‐Riatsch Annalaura , Wälchli Rudolf , Hesse Manfred 
Published: December 2004

Synthesis of 15‐Hydroxy[9]metacyclophane3‐(1‐Nitro‐2‐oxocyclododecyl)propanal (1) was converted to 15‐hydroxy[9]metacyclophane (3) on two different routes. In the first case the internal aldol reaction product of 1 was treated with K2CO3/THF to give 3 in 29 % yield with regard to cyclododecanone. Alternatively, the aldehyde 1 reacted with a primary amine to form e.g. 4 which gave 3 in the presence of CH3I/K2CO3 in 48 % yield.
1H‐NMR Spectra of Cyclohexa‐1,4‐dienes and Cyclohexenes Annellated to Bicyclo[2.2.1]hept‐2‐enes. The Inter‐Ring Homoallylic H,H Coupling Constants as Stereochemical Probes
Authors: Mahaim Cyril , Carrupt Pierre‐Alain , Vogel Pierre 
Published: December 2004

AbstractThe 360‐MHz‐1H‐NMR spectra of cyclohexa‐1,4‐dienes and cyclohexenes annellated to bicyclo[2.2.1]hept‐2‐enes and 7‐oxabicyclo[2.2.1]hept‐2‐enes show inter‐ring homoallylic coupling constants between the bridgehead protons of the bicyclo[2.2.1]heptenes and the exo‐protons of the allylic methylene groups (0.8 ± 0.15 Hz for bicyclo[2.2.1]hept‐2‐enes; 0.8–1.4 Hz for 7‐oxabicyclo[2.2.1]hept‐2‐enes). Contrastingly, the corresponding coupling between the bridgehead protons and the endo‐protons is absent. The observed values are compared with those calculated by the INDO and CNDO/2 methods and discussed in the light of the bicyclo[2.2.1]hept‐2‐ene bond π‐anisotropy. Vicinal as well as intra‐ring homoallylic coupling constants are consistent with a small puckering of the cyclohexa‐1,4‐diene rings toward the endo‐face. The allylic exo‐methylene protons are more deshielded than the endo‐protons independent of the nature of the substituents, the nature of the bridges, and the degree of unsaturation of the annellated systems. These results constitute a probe for the configuration of cyclohexa‐1,4‐dienes and cyclohexenes annellated to these bicyclic skeletons.
Formale Totalsynthese von (±)‐Isocomen durch Anwendung der α‐Alkinon‐Cyclisierung
Authors: Manzardo Giuseppe G. G. , Karpf Martin , Dreiding André S. 
Published: December 2004

Formal Total Synthesis of (±)‐Isocomen by Application of the α‐Alkinon CyclizationA total synthesis of the racemic form of the sesquiterpene isocomene (A) was accomplished by application of the cyclopentenone anellation B→D (Scheme 1) which includes the α‐alkynone cyclization C→D, a gas‐phase flow thermolytic process. Starting with the known product 2 (Scheme 3) of the anellation B→D, the elaboration of ring C of A proceeded in 9 steps to the α‐alkynone 16 (Scheme 5) which was cyclized at 540° selectively to give the angularly fused triquinane 4 (77%). A two‐step procedure then led to 5 (Scheme 6), a last but one intermediate in a known total synthesis of (±)‐A. The conversion of 16 to 4 also demonstrated the compatibility of an acetoxy function with the anellation sequence B→D.
Pteridine. Teil LXXX. Synthese, Reaktionen und Photochemie von Pteridinthionen
Authors: Heekel Armin , Pfleiderer Wolfgang 
Published: December 2004

Synthesis, Reactions, and Photochemistry of PteridinethionesThe pteridine‐6(5H)‐thione 1 and various pteridine‐7(8H)‐thiones (13, 22, 26) have been synthesized, and their photochemical reactivity has been investigated under aerobic conditions. The formation of different photooxidation products is pH‐dependent. In acidic to neutral media, disulfides (2, 15, 23, 29) are formed, whereas neutral to alkaline solutions favour the formation of pteridinesulfinic (3, 17) and ‐sulfonic acids (6, 16, 24, 30). Prolonged irradiation of the disulfides 2 and 15 led to the intensively yellow fluorescing bis(thio)dilumazines 19 and 20, respectively.
Deoxy‐nitrosugars 12th communication Synthesis of isosteric mono‐phosphonate analogues of β‐and α‐D‐fructose 2,6‐bisphosphate
Authors: Meuwly Roger , Vasella Andrea 
Published: December 2004

AbstractA synthesis of the isosteric mono‐phosphonate analogues 2a and 19 of the β‐and α‐D‐fructose 2,6‐bisphosphate, respectively, is described. Chain elongation of the 1‐deoxy‐1‐nitro‐D‐arabinose 3 (Scheme 1) by a Henry reaction with paraformaldehyde followed by protection of the resulting alcohol (methoxymethyl ether) and a radical‐chain substitution by nitromethane anion gave the key intermediates, the gluco‐anhydroalditol 6 and the manno‐anhydroalditol 7. These products equilibrated under basic conditions. Conversion of 7 to the aldehyde 9, Abramov reaction of 9 with diphenyl phosphite followed by deoxygenation according to Barton gave the phosphonate 11 (Scheme 2). Selective hydrogenolysis of 11, phosphorylation and deprotection gave 2 which was converted to the tetrasodium salt 2a. Similarly, 6 was transformed into the isosteric phosphonate analogue 19 of the α‐D‐fructose 2,6‐bisphosphate (Scheme 3).
Umsetzungen von 1,3‐Thiazol‐5(4H)‐thionen mit Grignard‐ und Organolithium‐Verbindungen: Carbophile und Thiophile Additionen
Authors: Jenny Christjohannes , Heimgartner Heinz 
Published: December 2004

Reactions of 1,3‐Thiazole‐5(4H)‐thiones with Grignard‐ and Organolithium Compounds: Carbophilic and Thiophilic AdditionsOrganolithium compounds and 1,3‐thiazole‐5(4H)‐thiones 9 reacted via thiophilic addition on the exocyclic S‐atom. The intermediate anion E has been trapped by protonation to give 12 and by alkylation to yield 16, respectively (Schemes 5 and 6). In competition with protonation of E, a fragmentation to benzonitrile and a dithioester 14 was observed (Scheme 5). In some cases, the alkylation of E led to the formation of dithioacetals 17 instead of 16 (Scheme 6). Methyl, ethyl, and isopropyl Grignard reagents and 9 in THF underwent again a thiophilic addition yielding 4,5‐dihydro‐1,3‐thiazoles of type 12 (Scheme 3). In contrast to this result, MeMgI reacted with 9a in Et2O via carbophilic addition to 11. Again a carbophilic attack at C(5) of 9 was observed with allylmagnesium and 2‐propynylmagnesium bromide, respectively, in Et2O.
Synthese von Triafulven‐Vorstufen für Retro‐Diels‐Alder‐Reaktionen
Authors: Krebs Jürg , Guggisberg Dominik , Stämpfli Urs , Neuenschwander Markus 
Published: December 2004

Synthesis of Triafulvene Precursors for Retro‐Diels‐Alder ReactionsTriafulvene precursors exo−15 and endo−15 have been prepared by addition of dibromocarbene to benzobarrelene 12 followed by a lithium‐halogen exchange, methylation, and elimination of HBr (12→13→14→15), (Scheme 2). Gas‐phase pyrolysis of exo/endo‐mixtures of 15 above 400° gave minor amounts of naphthalene (16), traces of a hydrocarbon C4H4 identified by MS (presumably triafulvene 1) and predominantly (36%) the isomerization product 17 (Scheme 3). In a second synthetic approach the well‐known cycloheptatriene‐norcaradiene equilibrium of type 26⇆27 has been utilised to prepare various endo‐trans‐3‐(X‐methyl) tricyclo[3.2.2.02,4]nona‐6,8‐dienes 31 (Scheme 5). However, numerous elimination experiments 31→9 failed so far. The structure of two rearrangement products 33 and 34 (Scheme 6) has been elucidated.
Perimeter‐Type Structures in Charged [4n + 2] Annuleno [4n + 2] annulenes. The Importance of the Frontier‐Orbitals
Authors: Huber Walter , Müllen Klaus , Schnieders Christoph , Iyoda Masahiko , Nakagawa Masazumi 
Published: December 2004

AbstractThe tetra(tert‐butyl)[14]annuleno[14]annulene 1 is transformed, via alkali metal reduction, into its radical monoanion, dianion, radical trianion, and tetraanion. The paramagnetic species are characterized by ESR and ENDOR spectroscopy and the diamagnetic species by 1H‐ and 13C‐NMR spectroscopy. Well‐resolved ESR and NMR spectra can only be obtained, if the reduction is carefully monitored. For the interpretation of the data, the ions derived from the structurally related [14]‐ and [22]annulenes 3 and 5 as well from the tetra(tert‐butyl)[14]annuleno[18]annulene 2 serve as suitable model compounds. While the behavior of the neutral annulenoannulene 1 is governed by that of the [14]annulene‐subunit, the corresponding ionic systems can best be described as macrocyclic perimeters. This outcome can be rationalized by the nodal properties of the frontier MO's.
Insight into the Behaviour of a Lithium Enolate in Solution
Authors: Strazewski Peter , Tamm Christoph 
Published: December 2004

Abstract(2S,4S)‐2‐(tert‐Butyl)‐5‐oxo‐1,3‐dioxolan‐4‐acetic acid (1) was dilithiated to the enolate 2 in toluene and THF with lithium diisopropylamide (LiN(i‐Pr)2) under various conditions. Deuteration experiments with 2 showed that two different stable forms of the enolate could be produced, depending on whether the deprotonation of 1 had been carried out in toluene or THF. The generated (i‐Pr)2NH was coordinated to the enolate and, hence, served as a strong lipophilic solvating agent. LiN(i‐Pr)2 could substitute the amine ligands of the two species to a different extent. THF was partially able to displace (i‐Pr)2NH that solvated the species produced in toluene, but the coordination of the amine to the one produced in THF was quantitive. Correlations with given explanations are made.
Cyclometallated Rhodium(III) Complexes with Diimine Ligands
Authors: Mäder Urs , Von Zelewsky Alex , Jenny Titus 
Published: December 2004

AbstractThe synthesis of a mononuclear Rh(III) complex, as a representative example of a series of related species, containing two cyclometallating ligands ppy (2‐phenylpyridine) and one diimine bpy (2,2′‐bipyridine) from a binuclear Cl‐bridged compound is described. The absorption spectrum shows a maximum at 364 nm (ε = 7000), with a very weak shoulder (ε = 10) at 454 nm. This band is tentatively assigned to a metal‐to‐ligand charge‐transfer transition. A reversible, one‐electron reduction appears in the cyclic voltammogram at E1/2 = −1.41 V (vs. NHE) and a irreversible oxydation at Ep = + 1.1 V. A detailed NMR analysis including 13C‐NMR, NOE, SFORD as well as deuteration of the bpy ligand indicates the formation of only one isomer, having a C2 axis, bisecting the bpy ligand, with the two carbon ligands in cis‐position. 103Rh, 13C and 103Rh,H couplings are observed.
Are ionic solids really built of ions? New evidence from x‐ray diffraction
Authors: Seiler Paul , Dunitz Jack D. 
Published: December 2004

AbstractA new, accurate, low‐temperature X‐ray analysis of lithium tetrafluoroberyllate, Li2BeF4, reveals that the charge density in this crystal is better represented as a superposition of spherical neutral‐atom charge distributions than as a superposition of ionic charges. The two distributions are so similar that they are hardly distinguishable by examination of the total charge density in real space. However, the two models are clearly differentiated by analysis of the weak low‐order reflections; the measured intensities are reproduced better by calculations based on neutral‐atom scattering curves. This result may appear to run counter to the current conventional wisdom concerning ionic solids, but it is unlikely to have any important practical consequences.
Cation‐Response Mechanism of Neutral Carrier Based Ion‐Selective Electrode Membranes
Authors: Morf Werner E. , Simon Wilhelm 
Published: December 2004

AbstractResults of voltammetric, potentiometric, chronoamperometric, ion transport, and extraction studies on neutral carrier based, plasticized poly(vinyl chloride) membranes are summarized. They unambiguously confirm that such bulk membranes dispose of immobile anionic sites. These fixed sites lead to a Donnan exclusion of other anions from the membrane and thus to a permselectivity for cations. The results are in perfect agreement with the predictions of earlier membrane models. A rigorous Poisson‐Boltzmann analysis of macroscopic liquid membranes clearly indicates that space‐charge at the membrane/solution interfaces does not influence the electrochemical properties and the ion‐selectivity behavior at steady state.
Diastereoselectivity and Reactivity in the Diels‐Alder Reactions of α‐Chloronitroso Ethers
Authors: Felber Helena , Kresze Günther , Prewo Roland , Vasella Andrea 
Published: December 2004

AbstractThe structure of the α‐chloronitroso ether 1, obtained from the hydroximolactone 2 and tert‐butyl hypochlorite (89%), was established by X‐ray crystallographic analysis. The [4 + 2] cycloadditions of 1 with the dienes 3 and 8–11 led to the N‐unsubstituted 3,6‐dihydro‐2H‐1,2‐oxazines 6 and 12–16 in high enantiomeric excess (Table 1). Due to the additional α‐alkoxy group, the reactivity of 2 is much superior to the one of known α‐chloronitrosoalkanes. The reactive conformation of 1 was deduced from the X‐ray analysis as well as the high diastereoselectivity of the cycloadditions. The importance of the α‐alkoxy group was evidenced from the similar reactivity of the racemic α‐chloronitroso ethers 25–27 which were prepared from the hydroximo ethers 28–30 and tert‐butyl hypochlorite.
Regioselektive Funktionalisierung von N,N‐Diethyl‐1,6‐methano[10]annulen‐2‐carbonsäureamiden
Authors: Neidlein Richard , Wirth Wolfgang 
Published: December 2004

Regioselective Functionalisation of N,N‐Diethyl‐1,6‐methano[10]annulene‐2‐carboxamidesLithiation of N,N‐diethyl‐1,6‐methano[10]annulene‐2‐carboxamide with BuLi followed by quenching with different electrophiles yields 2,10‐disubstituted‐1,6‐methano[10]annulenes.
NMR Studies of Alkaloids. Assignment of the Configuration at C(20) in Tubotaiwine (Dihydrocondylocarpine)
Authors: Lounasmaa Mauri , Koskinen Ari , O'Connell John 
Published: December 2004

AbstractTwo‐dimensional, high‐field NMR methods are employed in confirming the relative configuration at the C(20) ethyl side‐chain junction as S* in the natural alkaloid tubotaiwine (dihydrocondylocarpine).
Neue Heterocyclen: Über Tetrazinodi(heteroarene). Synthese und Struktur
Authors: Eichenberger Thomas , Balli Heinz 
Published: December 2004

Novel Heterocycles: Tetrazinodi(heteroarenes), Synthesis and StructureA series of 7 new symmetric tetrazinodi(heteroarenes) is obtained in a two‐step synthesis by N‐aminating heterocyclic compounds substituted with a leaving group and by treating the latter with an organic or inorganic base. The new compounds are characterized, and the postulated structures are confirmed by X‐ray analysis of a representative example.