bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Allyl Ester as Carboxy‐Protecting Group in the Stereoselective Construction of Neuraminic‐Acid Glycosides
Authors: Kunz Horst , Waldmann Herbert , Klinkhammer Uwe 
Published: December 2004

AbstractThe application of the allyl‐ester moiety as protecting principle for the carboxy group of N‐acetylneuraminic acid is described. Peracetylated allyl neuraminate 2 is synthesized by reacting the caesium salt of the acid 1 with allyl bromide. Treatment of 2 with HCl in AcCl or with HF/pyridine gives the corresponding 2‐chloro or 2‐fluoro derivatives 3 and 4, respectively (Scheme 1). In the presence of Ag2CO3, the 2‐chloro carbohydrate 3 reacts with di‐O‐isopropylidene‐protected galactose 5 to give the 2–6 linked disaccharide with the α‐D‐anomer 6a predominating (α‐D/β‐D = 6:1; Scheme 2). Upon activation of the 2‐fluoro derivative 4 with BF3 · Et2O, the β‐D‐anomer 6b is formed preferentially (α‐D/β‐D = 1:5). In further glycosylations of 4 with long‐chain alcohols, the β‐D‐anomers are formed exclusively (see 10 and 11; Scheme 4). The allyl‐ester moiety can be removed selectively and quantitatively from the neuraminyl derivatives and the neuraminyl disaccharides by Pd(0)‐catalyzed allyl transfer to morpholine as the accepting nucleophile (see Scheme 5).
Chaetoglobosin M, a New Metabolite of a Mutant of Diplodia macrospora, belonging to the family of (1H‐indol‐3‐yl)‐substituted 10,11‐diethyl‐10,11‐dinorcytochalasans
Authors: Spöndlin Christoph , Tamm Christoph 
Published: December 2004

AbstractFrom a mutant of Diplodia macrospora, chaetoglobosin M (5), ergosterol, β‐sitosterol, and a third sterol, most likely stigma‐5,7,22‐trien‐3β‐ol, were isolated. Metabolite 5 is a new member of the (1H‐indol‐3‐yl)‐substituted 10,11‐diethyl‐10,11‐dinorcytochalasans. Its structure was determined by 1H‐ and 13C‐NMR and mass spectrometry.
Synthesis of New unnatural Macrocyclic Trichothecenes: 4‐epiverrucarin A. 47th Communication on verrucarins and roridins
Authors: Jeker Nicolas , Tamm Christoph 
Published: December 2004

AbstractThe 4‐epiverrucarin A (24), a new unnatural macrocyclic trichothecene, was synthesized starting from 4‐epiverrucarol (20). The latter was obtained by metal‐hydride reduction of the 4‐oxo derivative 19. Subsequent conversion of 20 into the monoester 30 and then the diester 32 followed by macrolactonization of the latter yielded 4‐epiverrucarin A (24). Attempts to invert the configuration of the naturally occuring 3α‐OH group of a trichothecene were unsuccessful. The cytostatic (P‐815) and immunosuppressive (MLR) activity of several natural and unnatural trichothecenes was determined in vitro.
Synthese, 13C‐NMR‐Spektren und räumliche Struktur von ‘Push‐Pull’‐Diacetylenen
Authors: Galli Roberto , Neuenschwander Markus , Engel Peter 
Published: December 2004

Synthesis, 13C‐NMR Spectra, and X‐Ray Investigation of ‘Push‐Pull’ DiacetylenesPhenyl‐substituted ‘push‐pull’ diacetylenes 1f and 1g have been prepared by acetylation and benzoylation of the appropriate lithiodiynylamines 4 (Scheme 2). 13C‐NMR spectra of diacetylenes 1a–g (Table 1) are discussed with respect to the expected polarisation of the diacetylene unit by ‘push’ and ‘pull’ substituents. X‐Ray investigations of 1c, 1e, and 1f have been performed in view of the planned solid‐state polymerisation of ‘push‐pull’ diacetylenes. In the crystalline state, diacetylenes 1c and 1f are stacked, however, the stacking parameters do not allow a solid‐state polymerisation.
The Azo(Azoxy) Functionality as a π2 Component in Photo [2+2] cycloadditions ‘syn’‐ and ‘anti’‐3,4‐diazatricyclo[4.2.2.22,5]dodeca‐3,7‐diene, syntheses, photolyses, X‐ray‐structure analysis, and PE spectra
Authors: Marterer Wolfgang , Prinzbach Horst , Rihs Grety , Wirz Jakob , Lecoultre Jaques , Heilbronner Edgar 
Published: December 2004

AbstractThe propensity of the NN bond to undergo photo [2 + 2] cycloadditions has been further explored. In the specifically designed 1,5‐azo/enes 1–3, no [2 + 2] cycloaddition has been observed upon either direct or sensitized excitation with light of various wave lengths at temperatures down to 77 K, in line with expectations based on X‐ray (1: d = 2.71 Å, ω = 129°) and PE measurements (1: I1 = 8.00, I2 = 9.05 eV; 2; I1 = 8.00, I2 = 9.25eV). The steric/stereoelectronic demands for the participation of the NN bond in pericyclic reactions are clearly more stringent than those for the CC bond.
Stoffwechselprodukte von Mikroorganismen. 251. Mitteilung. Die Esmeraldine A und B, tief grüne Farbstoffe aus Streptomyces antibioticus, Stamm Tü 2706
Authors: Keller‐Schierlein Walter , Geiger Adrian , Zähner Hans , Brandl Matthias 
Published: December 2004

The Esmeraldines A and B, Green Pigments from Streptomyces antibioticus, Strain Tü 2706From a strain of Sterptomyces antibioticus, Tü 2706, two dark green substances, the esmeraldines A and B, 4 and 3, respectively, were isolated. The structural elucidation was carried out by spectroscopic comparison with some simpler phenazines obtained from the same organism, saphenamycin (1) and related compounds, and by a series of chemical transformations. Esmeraldin B (3) is the 6‐methylsalicylic acid ester, and esmeraldin A (4) a mixture of higher saturated and unsaturated fatty acid esters of esmeraldic acid. The latter is a heterocyclic compound with seven rings and four N‐atoms, formally derived by condensation of two phenazine residues of the saphenic acid family. The esmeraldins are mixtures are of diastereoisomers.
Hetero‐Diels‐Alder‐Reaktion mit 1,3‐Thiazol‐5(4H)‐thionen
Authors: Tromm Peter , Heimgartner Heinz 
Published: December 2004

Hetro‐Diels‐Alder Reaction with 1,3‐Thiazol‐5(4H)‐thionesOn heating in toluene to 180° and on treatment with BF3·Et2O in CH2Cl2 room temperature, 1,3‐dienes react with the CS group of 1,3‐thiazol‐5(4H)‐thiones 1 in a reversible Diels‐Alder reaction to give spiro[4.5]‐heterocycles of type 6. A 1:1 mixture of two regioisomeric cycloadducts is formed in the thermal reaction with 2‐methylbuta‐1,3‐diene (isoprene, 5b). In contrast, the formation of one regioisomer is strongly preferred in the BF3‐catalyzed reaction. Frontier‐orbital control as well as steric factors seem to be responsible for the observed regioselectivity. BF3‐Catalyzed, cyclic 1,3‐dienes and 1 also undergo a smooth Diels‐Alder reaction. Whereas cyclohexa‐1,3‐diene (5c) reacts with 1a and 1b to give a single isomer (presumably the ‘exo’‐adduct), cyclopenta‐1,3‐diene (5d) leads to a ca. 3:1 mixture of ‘exo’‐and ‘endo’‐isomer.
Palladium(0)‐Catalyzed Cyclizations of Simple 1‐Aryl‐1,7‐octadien‐3‐yl Acetates. Preliminary communication
Authors: Oppolzer Wolfgang , Swenson Rolf E. , Pachinger Werner 
Published: December 2004

AbstractDienyl acetates 2 lacking a geminal disulfone or a malonate group cyclize selectively to (E)‐l‐methylidene‐2‐styrylcyclopentanes 4 in the presence of 7 mol‐% of [Pd(PPh3)4].
Konkurrenz von Endoperoxid‐ und Hydroperoxid‐Bildung bei der Umsetzung von Singulett‐Sauerstoff mit cyclischen, konjugierten Dienen. Teil I
Authors: Matusch Rudolf , Schmidt Gerhard 
Published: December 2004

Competition of Endoperoxide and Hydroperoxide Formation in the Reaction of Singlet Oxygen with Cyclic, Conjugated DienesRose‐bengal‐sensitized photooxygenation of (−)‐(R)‐α‐phellandrene (1) in MeOH at room temperature yielded a complex mixture of products, contrary to previous reports describing cis‐(3S, 6R)‐epidioxy‐p‐menthene (2) and trans‐(3R, 6S)‐epidioxy‐p‐menthene (3) as the only products. The mixture was separated by prep. HPLC (silica gel, pentane/Et2O 9:1). Besides the known endoperoxides 2 (yield 39%) and 3 (26%), all those hydroper‐oxides, which can be deduced from an ene reaction of 1O2 with 1, were isolated, i.e. 4β‐p‐mentha‐2,5‐dien‐1β‐yl hydroperoxide (4) (14%), 4β‐p‐mentha‐2,5‐dien‐1α‐yl hydroperoxide (5) (9%), (2R, 4R)‐p‐mentha‐1(7), 5‐dien‐2‐yl hydroperoxide (6) (2,1%), (2S, 4R)‐p‐mentha‐1(7),5‐dien‐2‐yl hydroperoxide (7) (1,5%) and (1R)‐p‐mentha‐3,6‐dien‐yl hydroperoxide (8; 1,5%; Scheme 1). Furthermore, the constant cis/trans ratio for all diastereoisomeric pairs (2/2, 4/2, 6/2) was striking. With the help of the two possible conformers 1a and 1b of the starting material a model of a common first step for endoperoxide as well as for hydroperoxide formation is developed. A photooxygenation at −50° supports this model. The absolute value of the cis/trans ratio changes in the same way for the endoperoxides and the hydroperoxides.
Electronic and Molecular Structure of the C8H Valence Isomers 1,3,5‐Cyclooctatriene+· and Bicyclo[4.2.0]octa‐2,4‐diene+· from their Electronic absorption Spectra in Freon
Authors: Bally Thomas , Roth Kuno , Straub Rolf 
Published: December 2004

AbstractThe molecular cations of 1,3,5‐cyclooctatriene (COT+·) and bicyclo[4.2.0]octa‐2,4‐diene (BCO+·) can be observed intact in γ‐irradiated Freon glasses, as opposed to Ar matrices where ionization is accompanied by extensive rearrangements. This proves the superiority of the Freon‐glass method for the generation of metastable primary cations. The electronic absorption (EA) spectra reveal a) that a previous analysis of the BCO+· electronic structure on the basis of the ultraviolet photoelectron (UP( spectrum of BCO was incomplete, and b) that COT undergoes planarization upon ionization, in accord with qualitative expectations and MNDO calculations. A previously proposed LCBO model was used to assess the influence of the above geometry change on the electronic structure of COT+·.
Stereoselektive Synthesen von Taxan‐Derivaten
Authors: Neh Harribert , Kühling Andrea , Blechert Siegfried 
Published: December 2004

Stereoselective Synthesis of Taxane DerivativesSubstituted racemic 4,8,12‐trinortaxanes were prepared stereoselectively in several steps from the dienone 10. A variant of the de Mayo reaction with bicyclononenones 4 and cyclohexen produced the desired configuration at C(8) of the taxane framework. Retro‐aldol cleavage of the tetracycle 5 led to the taxane skeleton 6. Stereoselective reduction followed by treatment with base afforded 7b. Hydrolysis of the acetal group and further reduction yielded 9 in which the relative configuration corresponds to the one of the natural products.
Template‐Dependent Incorporation of Spin‐Labeled Thymidine Analogs into Viral DNA
Authors: Pauly Gary T. , Bobst Elisabeth V. , Bruckman David , Bobst Albert M. 
Published: December 2004

AbstractThe synthesis of novel pppUd analogs substituted at position C(5) with tethered nitroxide radicals is reported. It is shown that these analogs can serve as good substrates for E. coli DNA polymerase (Pol I) and T‐4 DNA polymerase using lambda‐phage DNA as template. The template‐dependent incorporation of the substrates was established by radio‐labeling and ESR experiments.
Synthesis of the Oviposition‐Deterring Pheromone (ODP) in Rhagoletis cerasi L. Preliminary communication
Authors: Ernst Beat , Wagner Beatrice 
Published: December 2004

AbstractFor the assignment of the configuration at C(8) and C(15) of the natural oviposition‐deterring pheromone 1 in Rhagoletis cerasi L., the four possible stereoisomers of 1 are synthesized. By condensing the C6 building blocks (5R)‐4 and (5S)‐4 with the boron enolates of the C10 building blocks (4S)‐13 and (4R)‐13, followed by decarboxylative dehydration, all stereoisomers of 16 are available (Scheme 5). Glucosylation of 16 followed by formation of the taurin amide gives, after deprotection, the four stereoisomers (8R,15S)‐1, (8R,15R)‐1, (8R,15S)‐1, and (8S,15S)‐1 (Scheme 6).
The Chemistry of Thujone. Part XIV.. Synthesis of biologically active aryl terpenoid analogues
Authors: Carvalho Chris , Cullen William R. , Fryzuk Michael D. , Jacobs Helen , James Brian R. , Kutney James P. , Piotrowska Krystyna , Singh Vinod K. 
Published: December 2004

AbstractEmploying thujone‐derived intermediates, a series of achiral (9a–d; Scheme 1) and chiral (11b and 11d; Scheme 2) terpene analogues related to the biologically active ‘terpenoid’ hybrids have been prepared. The stereochemistry of the key epoxidation reaction was established by correlation of the product 11b with the previously reported alcohol (R)‐20 of known absolute configuration (Scheme 3).
Vinyl Carbanions. Part 36.. Synthesis of 3‐deoxy‐D‐manno‐2‐octulosonic acid (KDO) and derivatives
Authors: Esswein Angelika , Betz Rainer , Schmidt Richard R. 
Published: December 2004

AbstractThe β‐C‐lithiated acrylamide 3A has been proven to be an ideal pyruvate β‐carbanion equivalent useful in a highly diastereoselective KDO synthesis. The starting material 3 was prepared from pyruvate diethyl acetal in four convenient steps. Direct lithiation with 2 equiv. of LDA generated the dilithiated species 3A quantitatively. Reaction with 2,3:4,5‐di‐O‐isopropylidene‐D‐arabinose (11) was highly D‐manno‐selective. The product 12 was obtained readily from the reaction mixture via crystallization. Ring closure to the butenolide 13, subsequent PhS‐group removal with Bu3SnH and pyridinium bromide, and hydrogenolytic debenzylation afforded the known butenolide 19; this KDO precursor gives KDO in two convenient steps. Butenolide 19 was also transformed via two high‐yielding steps into the 4,5:7,8‐di‐O‐cyclohexylidene‐KDO derivative 22, a valuable starting material for KDO α‐glycoside syntheses.
Highly Stereoselective Total Syntheses of 2,5‐Anhydro‐4‐deoxy‐D‐ribo‐hexonic Acid and of (1S)‐1‐C‐(6‐amino‐7H‐purin‐8‐yl)‐1,4‐anhydro‐3‐deoxy‐D‐erythro‐pentitol (= cordycepin C)
Authors: Gasparini Fabrizio , Vogel Pierre 
Published: December 2004

AbstractHighly regio‐ and stereoselective monohydroxylation of the CC bond of (+)‐7‐oxabicyclo[2.2.1]hept‐5‐en‐2‐one (8) was achieved via LiAlH4 reduction of the corresponding 5,6‐exo‐epoxy dimethyl acetal 9. The reaction gave exclusively (–)‐(1R, 2R, 4S)‐6,6‐dimethoxy‐7‐oxabicyclo[2.2.1]heptan‐2‐exo‐ol (10) which was transformed into 2,5‐anhydro‐3‐O‐benzyl‐4‐deoxy‐D‐ribo‐hexonic acid (15) and 2,5‐anhydro‐4‐deoxy‐D‐ribo‐hexonic acid (6) via ozonolysis of (–)‐(1R, 4S, 6R)‐6‐exo‐benzyloxy‐2‐{[(tert‐butyl)dimethylsilyl]oxy}‐7‐oxabicyclo[2.2.1]hept‐2‐ene (14). Cordycepin C (5) was derived from 6 and 4,5,6‐triaminopyrimidine using CsF/DMF to generate the adenine heterocycle.
Die absolute Konfiguration der Iridale und Cycloiridale unterschiedlicher Herkunft
Authors: Marner Franz‐Josef , Jaenicke Lothar 
Published: December 2004

The Absolute Configuration of Iridals and Cycloiridals of Different OriginNatural irones are known to occur in enantiomeric forms within Iris oils of different origin. They are formed by oxidative degradation of the cycloiridals (C31‐triterpenoids) found in rhizomes of various Iris species. The absolute configuration of iridals from different varieties is determined by ozonolysis of the triterpenoids and comparison of their degradation products with authentic samples of known configuration. It is shown that the initial cyclization of squalene resulting in the formation of a monocyclic seco‐ring‐A iridal has the same stereo‐chemical course throughout all Iris species studied. The subsequent cyclization of the homofarnesyl side chain of the iridals, however, produces cycloiridals with enantiomeric irone moieties within different subspecies of the sword lilies.
Neue Dimethinmerocyanin‐Farbstoffe mit der (Sulfobutyl)benzothiazol‐Gruppe als Donor‐Teilchromophor und deren Aggregationsverhalten in wässriger Lösung
Authors: Kussler Manfred , Balli Heinz 
Published: December 2004

Novel Dimethinemerocyanine Dyes with the (Sulfobutyl)benzothiazole Group as Donor Part of the Chromophor and their Aggregation Tendency in Aqueous SolutionA series of novel dimethinemerocyanine dyes with the (sulfobutyl)benzothiazole group as the donor part of the chromophor is synthesized in good yield and their aggregation tendency in H2O without addition of salt investigated. The merocyanine dye 2b only gives J‐aggregation in H2O. The dyes 1a–f and 2a exhibit an intense, red‐shifted absorption band due to J‐aggregation in H2O in the presence of Me4NCl. In contrast, the dyes 1g and 2c–f show a slightly red‐shifted absorption band. The degree of aggregation in H2O is investigated by ultracentrifugation of the representative 2e. Indeed, the slightly red‐shifted absorption band in H2O is due to aggregation of ‘oligomers’ of the dye. Contrary to the aggregation of ‘polymers’ of dyes (J‐aggregation), we suggest the term ‘K’ band for the slightly red‐shifted absorption band. The hemicyanine dye 5 gives the same absorption band in MeOH and in MeOH/H2O 1:3. The dye 11 shows an absorption band in H2O that is probably blue‐shifted because of negative solvatochromism. The merocyanine dye 13 gives H‐aggregation in H2O.
Models for Copper‐Dioxygen Complexes: The chemistry of copper(II) with some planar tridentate nitrogen ligands
Authors: Piguet Claude , Bocquet Bernard , Müller Edgar , Williams Alan F. 
Published: December 2004

AbstractThe solution chemistry of Cu(II) with a series of five planar tridentate nitrogen ligands, 2,6‐bis(benzimidazol‐2‐yl)pyridine (bzimpy, 1), 2,6‐bis(l‐methylbenzimidazol‐2‐yl)pyridine (mbzimpy, 2) 2,6‐bis(benzothiazol‐2‐yl) pyridine (bzthpy, 3), 2,6‐bis(benzoxazol‐2‐yl)pyridine (bzoxpy, 4), and 2,2′, 6′, 2″‐terpyridyl (terpy, 5) is reported. Electronic and EPR spectra are consistent with the complexes [CuL]2+ having essentially tetragonal structure in solution, with the fourth coordination site in the plane of the ligand occupied by solvent. bzthpy and bzoxpy show smaller ligand‐field splittings than bzimpy, mbzimpy, and terpy, and are easily decomplexed from the copper. Substitution of the coordinated solvent molecule in the plane of the ligand is observed with Cl− and OH− (provided that the ligand has no acidic protons) for all ligands except terpy. The reaction between [Cu(mbzimpy)]2+ and imidazole has been studied by potentiometric titration in MeCN/H2O 1:1 and shows strong binding of the imidazole in the plane (log K = 4.5 at 25°), and also the formation of an imidazolate‐bridged dinuclear species.
Stoffwechselprodukte von Mikroorganismen. 253. Mitteilung. Hormaomycin, ein neues Peptid‐lacton mit morphogener Aktivität auf Streptomyceten
Authors: Andres Nikolaus , Wolf Heinz , Zähner Hans , Rössner Ellen , Zeeck Axel , König Wilfried A. , Sinnwell Volker 
Published: December 2004

Hormaomycin, a Novel Peptide Lactone with Morphogenetic Activity on StreptomycesA culture identified as Streptomyces griseoflavus (strain W‐384) has been found to produce a novel peptide‐lactone antibiotic designated hormaomycin (6). The empirical molecular formula of the compound is established to be C55H69ClN10O14. The constituent amino acids of the antibiotic are suggested to be allothreonine (1; 1), isoleucine (2; 1), 3‐methyl‐phenylalanine (3; 2), and, for the first time identified from a natural source, 4‐[(Z)‐prop‐1‐enyl]‐proline (4; 1) and 3‐(2‐nitrocyclopropyl)‐alanine (5; 2). The amino acids were delivered by acidic hydrolysis and assigned by high‐resolution‐ GC/MS analysis (after transformation to derivatives) in combination with extended 2D‐NMR experiments of the antibiotic itself. From the latter, it became plausible that the N‐terminus of the peptide chain is acylated by a Cl‐containing derivative of 1H‐pyrrol‐2‐carboxylic acid. Hormaomycin is active against some Gram‐positive bacteria. In addition, the antibiotic exhibits potent aerial mycelium‐inducing activity and effects the production of antibiotics.
Novel Trinor‐eremophilanes (Dendryphiellin B, C, and D), Eremophilanes (Dendryphiellin E, F, and G), and Branched C9‐Carboxylic Acids (Dendryphiellic Acid A and B) from the Marine Deuteromycete Dendryphiella salina (SUTHERLAND) PUGHet NICOT
Authors: Guerriero Antonio , D'Ambrosio Michele , Cuomo Vincenzo , Vanzanella Fortunato , Pietra Francesco 
Published: December 2004

AbstractFurther investigation of global extracts from cultures of the marine deuteromycete Dendryphiella salina leads to the isolation of three novel trinor‐eremophilanes esterified by branched C9‐carboxylic acids, dendryphiellin B(= (+)‐(1R*,2S*,7R*,8aR*)‐1,2,6,7,8,8a‐hexahydro‐7‐hydroxy‐1,8a‐dimethyl‐6‐oxonaphthalen‐2‐yl (6R*, 2E, 4E)‐6‐hydroxy‐6‐methylocta‐2,4‐dienoate; (+)‐2), dendryphiellin C (=(+)‐(1R*, 2S*, 7R*, 8aR*)‐1,2,6,7,8,8a‐hexa‐hydro‐7‐hydroxy‐1,8a‐dimethyl‐6‐oxonaphthalen‐2‐yl (6S, 2E, 4E)‐6‐methylocta‐2,4‐dienoate; (+)‐3)), and dendryphiellin D (=(+)‐(1R*, 2S*, 7R*, 8aR*)‐1,2,6,7(8,8a‐hexahydro‐7‐hydroxy‐1,8a‐dimethyl‐6‐oxonaphthalen‐2‐yl (6R*,2E,4E)‐6‐(hydroxymethyl)octa‐2,4‐dienoate; (+)‐4). An intact eremophilane, dendryphiellin E (5), and its ethanolysis product dendryphiellin F whose absolute configuration is represented by structural formula (+)‐6 are also isolated from the above extracts. Dendryphiellin E exists as an open form 5a in equilibrium with a closed form 5b. A similar equilibrium exists between the open form 8a and the closed form 8b of a non‐esterified eremophilane, dendryphiellin G (8), which is isolated too from the above extracts and proves structurally related to the cyclic portion of 5. Finally, the free, branched C9‐carboxylic acids dendryphiellic acid A ((+)‐9) and B ((+)‐10) which correspond to side chains of the above esterified terpenes are also isolated from the above extracts.
Acid‐Catalyzed Cyclization Reactions of Substituted Acetylenic Ketones: A new Approach for the Synthesis of 3‐Halofurans, Flavones, and Styrylchromones
Authors: Obrecht Daniel 
Published: December 2004

AbstractAcetylenic acetals of type I (Scheme 1) and acetylenic ketones of type III (Scheme 1), 37 and 38 (Scheme 7) are versatile synthetic precursors for the synthesis of various heterocycles by acid‐catalyzed cyclization reactions. By this way, substituted 3‐halofurans of type II and IV (Scheme 1) and flavones and styrylchromones (Scheme 7) can be synthesized in good‐to‐excellent yields. The high degree of regioselectivity in the synthesis of the 3‐halofurans (Scheme 4) is the result of the regioselective β‐addition of HX (X = Cl, Br, I) to the acetylenic aldehyde and acetylenic ketone moieties. A possible mechanism is depicted in Scheme 5. Since 3‐halofurans can easily be metalated and substituted, this approach constitutes a new synthesis of highly substituted furans.
Neue Sulfobutyl‐haltige Bis(dimethinmerocyanin)‐Farbstoffe mit isolierten Chromophoren im Molekül und deren Aggregationsverhalten in wässeriger Lösung
Authors: Kussler Manfred , Balli Heinz 
Published: December 2004

Novel Bis(dimethinemerocyanine) Dyes with Isolated Chromophores in the Molecule Containing the Sulfobutyl Group and their Aggregation Tendency in Aqueous SolutionThe bis(dimethinemerocyanine) dyes 7a–c with Chromophores separated by a polymethylene chain as ‘isolator’ are synthesized in good yield. Their aggregation tendency in organic solvents, organic solvents/H2O mixtures, and in H2O is investigated. In organic solvents, the dyes 7a–b show a splitted absorption band, due to interaction of the two Chromophores of the dye. In H2O, 7a exhibits an intense absorption band at 496 nm (ϵ = 224 300 1·mol−1·cm−1) with a small width \documentclass{article}\pagestyle{empty}\begin{document}$ (\tilde v_{{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace} \!\lower0.7ex\hbox{$2$}}} = 1000\;{\rm cm}^{ - 1}) $\end{document} and shoulders at 552 and 580 nm. In presence of starch, this absorption band shifts to 617 nm, probably due to J‐aggregation. The dye 7b shows the same spectral behaviour as 7a. In contrast, 7c exhibits an absorption band without splitting in organic solvents; the interaction of the Chromophores has disappeared. In H2O and in H2O containing starch, 7c shows a wide absorption band, due to interaction of the Chromophores of the dye.
A Simple and Efficient Method for the Preparation of Binaltrorphimine and Derivatives and determination of their K opioid antagonist selectivity
Authors: Schmidhammer Helmut , Smith Colin F. C. 
Published: December 2004

AbstractThe bimorphinans 1 (binaltrorphimine), 3, and 7 have been prepared by treatment of the parent morphinan‐6‐ones naltrexone (5), naloxone (4), and dihydrocodeinone (6), respectively, with N‐methylhydrazine sulfate in AcOH at room temperature. Compound 3 showed opioid antagonist potency and selectivity for K receptors which were somewhat lower in comparison to 1.