bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycosyl Imidates, 62. – Synthesis of the Heptasaccharide Moiety of Ganglioside BGM1
Authors: Greilich Ulrike , Zimmermann Peter , Jung Karl‐Heinz , Schmidt Richard R. 
Published: July 2007

AbstractThe synthesis of the O‐acetyl protected heptasaccharide moiety (2) of BGM1 was performed according to the following reaction sequence: Reaction of 2,3‐di‐O‐acetyl‐4,6‐O‐benzylidenegalactosyl trichloroacetimidate 4 (as donor) with 3‐O‐unprotected 2‐azidogalactose 5 (as acceptor) gave β(1→3)‐connected disaccharide 6. Subsequent O‐deacetylation followed by reaction with galactosyl donor 8 afforded regioselectively trisaccharide 9 which was converted into tetrasaccharide 12 by treatment with fucosyl donor 11. Transformation of 12 via acid‐catalyzed O‐deisopropylidenation, O‐acetylation, anomeric O‐desilylation, and then base‐catalyzed treatment with trichloroacetonitrile afforded trichloroacetimidate 16 as tetraosyl donor. Reaction of 16 with the known 4b‐O‐unprotected sialyllactose derivative 17 gave in acetonitrile at −40°C in the presence of TMSOTf as the catalyst the desired heptasaccharide 18. Azido group reduction with propanedithiol, N‐acetylation, hydrogenolytic O‐debenzylation, and O‐debenzylidenation under acidic conditions followed by O‐acetylation afforded the target molecule 2. The structural assignments were based on the 1H‐NMR data.
Pheromone Synthesis, CLIV. Synthesis of the Stereoisomers of 3‐Methyl‐4‐octanol to Determine the Absolute Configuration of the Naturally Occurring (3S,4S)‐Isomer Isolated as the Male‐produced Aggregation Pheromone of the African Palm Weevil, Rhynchophorus phoenicis
Authors: Mori Kenji , Kiyota Hiromasa , Rochat Didier 
Published: July 2007

AbstractThe relative configuration of the naturally occurring 3‐methyl‐4‐octanol (1), the male‐produced aggregation pheromone of Rhynchophorus phoenicis, was determined as syn by a GC comparison of the synthetic (±)‐syn‐ and (±)‐anti‐1 with the natural product. Enantioselective synthesis of both (3R,4R)‐and (3S,4S)‐1 was achieved by starting from the optically active epoxide 9, and the natural product was shown to be (3S,4S)‐1 by a GC comparison on a chiral stationary phase.
Pheromone synthesis, CXLVII. – Synthesis of (1R,3S,6R,9S,10S)‐9,10‐Epoxytetrahydroedulan, the Main Component of the Hairpencil Secretion of Male Danaid Butterfly Euploea klugii
Authors: Mori Kenji , Aki Shinji , Kido Masaru 
Published: July 2007

AbstractThe natural and (+)‐enantiomer of 9,10‐epoxytetrahydroedulan 1, (1R,3S,6R,9S,10S)‐9,10‐epoxy‐1,3,7,7‐tetramethyl‐2‐oxabicyclo[4.4.0]decane, the main component of the hairpencil secretion of Euploea klugii, was synthesized via (−)‐dihydroedulan II (2) by starting from (S)‐2,4,4‐trimethyl‐2‐cyclohexen‐1‐ol (D).
Darstellung von aliphatisch und cycloaliphatisch verbrückten Porphyrin‐Chinonen als Modellverbindungen zur Untersuchung der lichtinduzierten Ladungstrennung in der Photosynthese
Authors: von Gersdorff Jörg , Kirste Burkhard , Kurreck Harry 
Published: July 2007

Synthesis of Porphyrin Quinones with Aliphatic and Cycloaliphatic Bridges as Model Compounds for Studying the Light‐Induced Charge Separation in PhotosynthesisCovalently linked porphyrin quinones (P–Qs) are well‐suited as biomimetic model compounds in studying the light‐induced charge separation occuring in primary processes of photosynthesis. We report on a synthetic strategy which leads to P–Qs with the porphyrin donor covalently linked to the quinone acceptor via aliphatic and cycloaliphatic spacers. Preparation of two diastereomeric cyclohexylene‐bridged P–Qs 1 and 2 and of 3 bearing a butylene spacer is described. Structures, including the spatial arrangements of the donor, bridge and acceptor, are determined by various NMR techniques. These data are compared with those deduced from simple force‐field calculations using the molecular modelling program ALCHEMY II (Tripos Associates) and MNDO (MOPAC‐6) calculations.
Transition Metal‐catalyzed Oxidations, 6. – Total Synthesis of Hallachrome and Related 1,2‐anthraquinones
Authors: Krohn Karsten , Khanbabaee Karamali 
Published: July 2007

Abstract9,10‐Anthraquinones 3b–3k are prepared by Diels‐Alder reaction of juglone (5a) and 7‐methyljuglone (5b) with the dienes 4a and 4b, then reduced to the corresponding 1‐anthracenols 2b–2d, 2f and 2i that are immediately oxygenated to the ortho‐anthraquinones 1b–1d, 1f and 1i with [MoO(O2)2]·py·HMPT. The 1,2‐anthraquinones dimerize in solution or upon BBr3 treatment. The naturally occurring 1,2‐anthraquinone hallachrome (1a) is prepared by selective protection of the bisphenol 3h as monosilyl ether 3i, oxygenation to the silylated ortho‐anthraquinone 1i and fluoride‐mediated deprotection to 1a.
Natural Product Chemistry, 161. – Oxidation of (±)‐Almeine with Aqueous Potassium Permanganate
Authors: Reisch Johannes , Iding Marlies 
Published: July 2007

AbstractTreatment of (±)‐almeine (3) with aqueous potassium permanganate affords the dihydrofuro[3,2‐c]quinolin‐4(2H)‐ones 4 and 5.
Oxidative Rearrangement of 2′‐Acetamidochalcones with Thallium(III) Nitrate: A New Route to 3‐Aryl‐4(1H)‐quinolones
Authors: Tökés Adrienne L. , Antus Sándor 
Published: July 2007

AbstractA convenient synthesis of the 3‐aryl‐4(1H)‐quinolones (azaisoflavones) 8 and 10 has been achieved by oxidative rearrangement of the 2′‐acetamidochalcones 2 and 4, respectively.
Synthesis and Spectroscopic Characterization of New NIR Absorbing (2‐Thienyl)‐ and (4‐Dialkylaminoaryl)‐substituted Croconic Acid Dyes
Authors: Keil Dietmar , Hartmann Horst , Reichardt Christian 
Published: July 2007

AbstractBy condensation of croconic acid (7) with 2‐(dialkylamino)‐thiophenes6a–dand with 3‐(dialkylamino)phenols9a–cthe deeply colored, sparingly soluble croconic acid dyes (“croconines”)8a–dand10a–c, respectively, have been prepared. These croconines have been characterized by UV/Vis, IR, and1H‐NMR spectrometry. They exhibit strong electronic absorption bands in the near infrared (NIR) region (λmax≈ 750–850 nm; cf. Table 1).
Preparative Bioorganic Chemistry, XVII. – Reduction of a Prochiral Diketone, 9‐Methyl‐trans‐decalin‐1,8‐dione, with Baker's Yeast
Authors: Mori Kenji , Takayama Shuichi , Yoshimura Seiji 
Published: July 2007

AbstractReduction of 9‐methyl‐trans‐decalin‐1,8‐dione (1) with baker's yeast affords (8S,9R,10R)‐8‐hydroxy‐9‐methyl‐trans‐1‐decalone (8) as the major product in 47% yield. Its (8S,9S,10S)‐isomer (9, 14% yield) and (1S,8S)‐9‐methyl‐trans‐decalin‐1,8‐diol (10, 7% yield) are obtained as minor products. Baker's yeast cannot reduce 9‐methyl‐cis‐decalin‐1,8‐dione (2).
Tmob Side Chain‐protected S‐Cysteine‐ and homo‐S‐Cysteinesulfonamides, their Nα‐Protected and Nω‐Aminoethylated Derivatives
Authors: Videnov Georgi , Aleksiev Boris , Stoev Mincho , Paipanova Tamara , Jung Günther 
Published: July 2007

AbstractThe 2,4,6‐trimethoxybenzyl (Tmob) group is very suitable for temporary protection of the aminosulfonyl group of S‐cysteine‐ and homo‐S‐cysteinesulfonamides. Both the introduction and removal of the Tmob‐protecting group can be achieved in high yields. 2‐Aminoethyl derivatization of the aminosulfonyl group of S‐cysteine‐ and homo‐S‐cysteinesulfonamides has been carried out, and various derivatives useful for peptide synthesis with Z, Boc and Fmoc as Nα‐protecting groups have been prepared. In all cases, a racemic mixture of S‐cysteine‐ or homo‐S‐cysteinesulfonic acid has been used and subsequent enantiomer resolution has been achieved by treatment with Bacillus subtilis alkaline protease.
New Studies and a Reinvestigation on [4+2] Cycloadditions of (−)‐Thebaine: Asymmetrical Diels‐Alder Reactions with a Conformationally Fixed Chiral Diene
Authors: Pindur Ulf , Keilhofer Diana 
Published: July 2007

AbstractSome novel Diels‐Alder reactions of the opium alkaloid (−)‐thebaine (1) as an electron‐rich diene and a reinvestigation of its reactions with cyclic and acyclic dienophiles are described. The π‐facial selectivity has been studied on the basis of structural analyses of the cycloadducts. Some related results on [4 + 2] cycloaddition reactions of 1‐methoxy‐1,3‐cyclohexadiene (11) are also reported.
Studies on Ketoses, 7 – 5‐(α‐D‐Glucosyloxymethyl)furfural: Preparation from Isomaltulose and Exploration of Its Ensuing Chemistry
Authors: Lichtenthaler Frieder W. , Martin Dierk , Weber Thomas , Schiweck Hubert 
Published: July 2007

AbstractAn effective, practical, large‐scale adaptable procedure has been developed to selectively dehydrate the fructose portion of isomaltulose [glucosyl‐α(1→6)‐fructose] (6): heating in DMSO in the presence of a strongly acidic ion‐exchange resin generates α‐D‐glucosyloxymethylfurfural (“α‐GMF”, 3), isolable in yields up to 70%. A variety of ensuing reactions have been exploited concerning the generation of products with industrial application profiles such as aldol‐type additions to the dicyanovinyl (16), nitrovinyl (20), and benzoylvinyl (21) derivatives, or to the polymerizable unsubstituted vinyl compound (25) and the GMF‐acrylic acid (22). Oxidation to GMF‐carboxylic acid (11) and reductive amination to GMF‐amine 8 can be carried out without affecting the hydroxyl groups in the glucosyl portion; esterification of 11 with long‐chain alcohols and N‐acylation of 8 with fatty acid chlorides provide novel surfactants in which hydrophilic and hydrophobic parts of the molecule are separated by a heteroaromatic spacer.
Synthese, Struktur und Reaktionen von α‐Campholenepoxiden
Authors: Schulze Klaus , Habermann Anne‐Kathrin , Uhlig Holger , Weber Lutz , Kempe Rhett 
Published: July 2007

Synthesis, Structure and Reactions of α‐Campholenic EpoxidesThe epoxidation of α‐campholenic compounds 3, 4 is described, besides the rearrangement of the epoxides 5 and 6 into the hydroxy‐β‐campholenic system 7, 8, the reduction to the tertiary alcohols 11a, 12a, the alkylation reaction to 11b and 12b and the conversion of 7 into the diketone 10 are reported. The stereochemistry and the odour of the new compounds are also described.
Synthesis and Reactions of Pyridinethiones
Authors: Köditz Jens , Rudorf Wolf‐Dieter , Hartung Helmut , Heinemann Frank 
Published: July 2007

AbstractThe push‐pull systems 1 and 7 undergo regioselective cyclization with cyanothioacetamide 2 leading to pyridinethiones 3 and 8. Subsequent S‐alkylation affords the alkylthio derivatives 5 and 10. Thieno[2,3‐b]pyridines 6 and 11 are formed by using an α‐CH‐acidic halogen compound as alkylating agent, followed by Thorpe‐Ziegler reaction. The cyano group in 6d and 11d can be converted into an imidazoline ring by treatment with 1,2‐diaminoethane hydrate and carbon disulfide. Structures are supported by spectral data as well as by X‐ray analysis of 5d.
Diterpenoid Total Synthesis, XXX. Synthesis of the Racemic Form of Tripterifordin, a Novel Anti‐HIV Diterpene Lactone from Tripterygium wilfordii
Authors: Mori Kenji , Aki Shinji 
Published: July 2007

AbstractThe pentacyclic diterpene ketone (±)‐3, which had been prepared by a total synthesis from naphthalene, was methylenated and hydrated to give (±)‐tripterifordin [(±)‐1], the racemate of a new kaurane‐type diterpene lactone with anti‐HIV activity recently isolated from the roots of Tripterygium wilfordii.
Antibiotics from Gliding Bacteria, LIV. Isolation and Structure Elucidation of Soraphen A1α, a Novel Antifungal Macrolide from Sorangium cellulosum
Authors: Bedorf Norbert , Schomburg Dietmar , Gerth Klaus , Reichenbach Hans , Höfle Gerhard 
Published: July 2007

AbstractFrom the myxobacterium Sorangium cellulosum, strain So ce26, a novel group of highly active antifungal metabolites was isolated. Large‐scale production of the basic compound soraphen A1α (1) was achieved by fermentation in the presence of the adsorber resin XAD‐16, extraction and crystallization. The 18‐membered macrolide structure of 1 was determined by spectroscopic methods. X‐ray crystal structure analysis revealed the absolute configuration of the ten asymmetric centers. According to proton coupling constants and difference NOE measurements the solution conformation in CDCl3 and [D6]DMSO is very similar to that in the crystal structure.
Chemie und Stereochemie der Iridoide, XIX. Zwei einfache EPC‐Synthesen mit chemischem Beweis der absoluten Konfiguration von (+)‐Mitsugashiwa‐Lacton aus (S)‐(−)‐Citronellol und Aucubin
Authors: Weinges Klaus , Ziegler Hans Jürgen , Maurer Wolfgang , Schmidbauer Stefan B. 
Published: July 2007

Chemistry and Stereochemistry of Iridoids, XIX. – Two Straightforward EPC Syntheses with Chemical Evidence of Absolute Configuration of (+)‐Mitsugashiwa Lactone from (S)‐(−)‐Citronellol and AucubinEnantiomerically pure (+)‐Mitsugashiwa lactone (9) was prepared in eight steps from (S)‐(−)‐citronellol (1), whereas only four steps were required for the conversion of hexaacetylaucubin (10) into 9. Both starting materials are readily available in large quantities. The synthesis of 9 from 1 establishes the absolute configuration at C‐7 in 9. Conversely, the synthesis of 9 from 10 confirms the absolute configuration at C‐4a and C‐7a in 9.
Strukturaufklärung eines Azadirachtinderivates aus dem Marrangobaum Azadirachta excelsa durch NMR‐Spektroskopie
Authors: Kalinowski Hans‐Otto , Ermel Klaus , Schmutterer Heinrich 
Published: July 2007

NMR Spectroscopically Structure Elucidation of an Azadirachtin Derivative from the Marrango Tree Azadirachta excelsaThe structure of marrangin, a new limonoid from the Marrango tree Azadirachta excelsa (Jack), has been established as 3 by 1D‐ and 2D‐1H and 13C‐NMR spectroscopy.
Regio‐ and Stereoselective Reduction of 3,5‐Disubstituted 3a,6a‐Dihydro‐4H‐pyrrolo[3,4‐d]isoxazole‐4,6(5H)‐diones with Sodium Borohydride
Authors: Konopíková Marta , Fišera L'Ubor , Prónayová Nada , Ertl Peter 
Published: July 2007

AbstractThe reduction of condensed imides 1 with sodium borohydride proceeds regio‐ and stereoselectively to yield the hydroxylactams 2, 3 and 4. AM1 calculations of the reactants and products reveal that the regiochemistry of the reductions seems to be controlled by both electronic and steric effects. The regio‐ and stereoselectivity of the reductions are dramatically improved by the presence of magnesium perchlorate. This is interpreted in terms of a chelate complex formation between the carbonyl group, isoxazoline oxygen atom and magnesium ion. The presence of p‐toluenesulfonic acid (p‐TsOH) also improves the regioselectivity, but lowers the chemoselectivity.
Synthesis and Application of a New Fluorescein Derivative for Fluorescent Labelling of Oligonucleotides and as a Novel Tool for Non‐radioactive DNA Sequencing
Authors: Holletz Torsten , Möller Uwe , Knaf Andrea , Reinhardt Richard , Cech Dieter 
Published: July 2007

AbstractThe synthesis of 4(5)‐(bromomethyl)fluorescein, which can be used as its 3′,6′‐dibenzoyl derivative 7 for the labelling of nucleosides is described. Pyrimidine nucleosides such as 3′‐and/or5′‐protected 2′‐deoxyuridine and thymidine are labelled by 7 at N3 of the heterocyclic base. The resulting base‐labelled 3′‐benzoyl‐5′‐dimethoxytrityl nucleosides may, on the one hand, be converted, after cleavage of the protective dimethoxytrityl group, into the 5′‐phosphoramidite 11 by normal phosphorylation; on the other hand, 5′‐triphosphates 13 are prepared by phosphorylation with 2‐chloro‐4H‐1,3,2‐benzodioxaphosphorin‐4‐one and pyrophosphate. The phosphoramidites 11 were sucessfully used for the fluorescent labelling of oligonucleotides during automatic DNA synthesis. The oligonucleotides can be used as primer in automatic non‐radioactive DNA sequencing. The 5′‐triphosphates 13 are potential substrates for DNA polymerases or terminal transferase.
Absolute Configurations of Three Naturally Occurring Acetylenic Spiroacetal Enol Ethers
Authors: Wurz Gerald , Hofer Otmar , Sanz‐Cervera Juan F. , Marco J. Alberto 
Published: July 2007

AbstractThe absolute configurations of three 6,7‐oxygenated acetylenic spiroacetal enol ethers were determined by using the kinetic method of Horeau. The results were confirmed by the circular dichroism of the compounds in correlation with the corresponding 6,7‐epoxide.
Amphiphilic Carbohydrate‐based Mesogens, IX. Mesogenic 4‐O‐Alkyl‐D‐glucoses via Methyl 4,6‐O‐Alkylidene‐D‐glucopyranosides
Authors: Dahlhoff Wilhelm V. , Riehl Klaus , Zugenmaier Peter 
Published: July 2007

AbstractThe 4,6‐O‐alkylidene derivatives (hexylidene–decylidene, 2a–e) are prepared by condensation of methyl α‐ or β‐D‐glucopyranoside 1 with alkanals in the presence of pyridinium tosylate. O‐diethylborylation of 2 gives 3 which are allowed to react firstly with bromodiethylborane and subsequently with sodium triethylhydroborate to yield methyl 4‐O‐alkyl‐D‐glucopyranosides 5 after deborylation. Acid hydrolysis of 5 gives mesogenic 4‐O‐alkyl‐D‐glucopyranoses 6a–e. The amphiphilic 6 exhibit the smectic A liquid crystalline phase on melting.
Terpenes and Terpene Derivatives, XXXII. New Cadinene and Bisabolene Derivatives from the Essential Oil of Pulicaria gnaphalodes
Authors: Weyerstahl Peter , Wahlburg Hans‐Christian , Marschall Helga , Rustaiyan Abdolhossein 
Published: July 2007

AbstractFrom the essential oil of Pulicaria gnaphalodes growing near Tehran some new cadinene derivatives were isolated. The structures of 1,8‐oxidocadin‐4‐enes (6, 7, epimers at C‐10), 1(10),4‐cadinadien‐8α‐ol (1), 4,10(14)‐cadinadien‐ and 4,10(14)‐muuroladien‐8‐ols (2–5) could be verified by their 1H‐ and 13C‐NMR spectra. Furthermore, the 8α‐epimer 9 of the known α‐copaen‐8β‐ol (10), (Z)‐γ‐curcumen‐12‐ol (13a) and the esters (Z)‐13b–e could be identified.
Synthese und konformative Flexibilität von 4,9‐Dihydroindolo[3,2‐d][1,2,4]triazolo[4,3‐a]benzazepinen
Authors: Kunick Conrad 
Published: July 2007

Synthesis and Conformational Flexibility of 4,9‐Dihydroindolo[3,2‐d][1,2,4]triazolo[4,3‐a]benazepinesHerrn Prof. Dr. P. Nickel zum 60. Geburtstag gewidmet
Indolotriazolobenzazepines 6 are prepared by cyclisation of thiolactam 4 with acylhydrazides 5. The influence of the 1‐ substituent on the barrier of ring inversion of the new ring system 6 is studied by dynamic 1H‐NMR spectroscopy.
Ringtransformationen heterocyclischer Verbindungen, VI. 3‐Nitrobenzonitrile aus 2,4,6‐Triarylpyryliumsalzen und Nitroacetonitril
Authors: Zimmermann Thomas , Pink Maren 
Published: July 2007

Ring Transformations of Heterocyclic Compounds, VI. – 3‐Nitrobenzonitriles from 2,4,6‐Triarylpyrylium Salts and Nitroacetonitrile2,4,6‐Triarylpyrylium salts 1 react with nitroacetonitrile in the presence of sodium acetate, triethylamine, triethylamine/acetic acid or piperidine acetate to give 3‐nitrobenzonitriles 2. In the course of this 2 6‐[C5 + C] pyrylium ring transformation a nitro group is shifted to C‐3 of the benzene ring formed. Structural elucidation of the reaction products 2 is based on an X‐ray structure determination of the methoxyphenyl derivative 2c.
Derivate des Imidazols, VII. 2,3‐Dihydro‐1,3,4,5‐tetramethyl‐2‐methylen‐1H‐imidazol als Kupplungsreagens. Die Kristallstruktur von Bis(1,3,4,5‐tetramethyl‐2‐imidazolyl)methylium‐iodid
Authors: Kuhn Norbert , Bohnen Hans , Kratz Thomas , Henkel Gerald 
Published: July 2007

Imidazole Derivatives, VII. – 2,3‐Dihydro‐1,3,4,5‐tetramethyl‐2‐methylen‐1H‐imidazole as Coupling Reagent. The X‐ray Structure of Bis(1,3,4,5‐tetramethyl‐2‐imidazolyl)methylium Iodide2,3‐Dihydro‐1,2,3,4‐tetramethyl‐2‐methylen‐1H‐imidazole (1) reacts with 1,3,4,5‐tetramethyl‐2‐(methylthio)imidazolium iodide (4) in the presence of pyridine to give bis(1,3,4,5‐tetramethyl‐2‐imidazolyl)methylium iodide (5) which is also formed by the reaction of 4 and methyl lithium in the ratio 2:3. The X‐ray structure of 5 is reported.
Stereoselective Synthesis of Alcohols, XLIII. Asymmetric Induction on the Intramolecular Allylboration Reaction of (8‐Oxo‐2‐octenyl)boronates
Authors: Hoffmann Reinhard W. , Sander Thomas 
Published: July 2007

AbstractThe cyclization of (8‐oxo‐2‐octenyl)boronates having methyl substituents in the chain linking the two functional groups proceeds with complete simple diastereoselectivity and with induced diastereoselectivity of 85 to > 98% to give methylsubstituted 2‐vinylcyclohexanols.
Stereoselective Synthesis of Alcohols, XLIV. Cyclization of Benzyloxy‐substituted (8‐Oxo‐2‐octenyl)boronates
Authors: Sander Thomas , Hoffmann Reinhard W. 
Published: July 2007

AbstractThe cyclization of (8‐oxo‐2‐octenyl)boronates having benzyloxy substituents in the chain linking the two functional groups gives benzyloxy‐substituted 2‐vinylcyclohexanols. High asymmetric induction is found for the 4‐ or 6‐benzyloxy‐(Z)‐octenylboronates 12a and 12c, whereas cyclization of the other isomers studied proceeded in a stereorandom fashion. Possible reasons for this unexpected behavior are discussed.
Cholesteno‐Indole, I – Synthese von 1′H‐5α‐Cholest‐2‐eno[3,2‐b]indolen
Authors: Samu János , Botyánszki János , Duddeck Helmut , Snatzke Günther 
Published: July 2007

Cholesteno Indoles, I. – Preparation of 1′H‐5α‐Cholest‐2‐eno[3,2‐b]indoles1′H‐5α‐Cholest‐2‐eno[3,2‐b]indole (1a), the corresponding N‐methyl, N‐acetyl, and N‐formyl compounds 1b–d, as well as the respective methoxy derivatives 2b–5d have been synthesized as model compounds for intended CD investigations. Application of the Fischer indole synthesis afforded the compouds 1a–5a which were N‐methylated to 1b–5b, N‐acetylated to 1c–5c, and N‐formylated to 1d–5d.
Studies on Isocyanides and Related Compounds. A Facile Synthesis of Imidazo[1,5‐a]imidazoles
Authors: Bossio Ricardo , Marcaccini Stefano , Pepino Roberto 
Published: July 2007

AbstractThe Ugi four‐component condensation between 1,1‐diethoxy‐2‐isocyanoethane (2), cycloketones 1, amine hydrochlorides 4, and potassium thiocyanate (3a) or selenocyanate (3b) affords spiroimidazoles 5, which are cyclized to spiroimidazo[1,5‐a]imidazole‐5‐thiones (or selenones) 6.
Bildung von Enolether‐Epoxiden durch Einwirkung von (9S,10E,12Z)‐Hydroperoxyoctadecadiensäure auf Plasmalogene
Authors: Scheick Cordula , Spiteller Gerhard 
Published: July 2007

Formation of Enol Ether Epoxides by Reaction of (9S,10E,12Z)‐Hydroperoxyoctadecadienoic Acid with Plasmalogens(9S,10E,12Z)‐Hydroperoxyoctadecadienoic acid (8a) oxidizes enol ethers (e.g. 2 and neutral plasmalogens 3) under physiological conditions (pH = 6.6, room temperature). The reaction products, unstable enol ether epoxides 9a and 10a, react as recently demonstrated with methanol to α‐hydroxyaldehyde dialkyl acetals 11a or with 1,2‐ethanedithiol to 2‐(α‐hydroxyalkyl)dithiolans 13a which can be detected by GC/MS after trimethylsilylation. If [18O2]‐(9S,10E,12Z)‐hydroperoxy‐octadecadienoic acid (8b) is used instead of 8a one atom of 18O is incorporated into the enol ether epoxide and found in the α‐hydroxy group of the aldehyde derivatives 11 and 13.
Plasmalogenepoxide als biologische Vorstufen von α‐Hydroxyaldehyden
Authors: Dudda Angela , Spiteller Gerhard 
Published: July 2007

Plasmalogen Epoxides as Biological Precursors of α‐HydroxyaldehydesCell damage produces hydroperoxides which in turn are able to oxidize plasmalogens 1 to plasmalogenepoxides 2. These are masked α‐hydroxyaldehydes, which can be detected after appropriate derivatization. The detected α‐hydroxyaldehydes could also be generated during the preparation procedure of tissue. Experiments carried out with 18O2 demonstrate no incorporation of 18O2 in α‐hydroxyaldehydes. Consequently, they are already present in tissue. – Further experiments proved that α‐acyloxyplasmalogens 3, recently suggested to be the source of α‐hydroxyaldehydes[1,2], do not occur in tissue.