bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steroids, XLII. Configurational analysis of 3‐methoxy‐16‐methylestra‐1,3,5(10)‐trien‐17‐ol derivatives
Authors: Meskó Eszter , Schneider Gyula , Dombi György , Zeigan Dieter 
Published: July 2007

AbstractThe four possible isomers of 16‐hydroxymethyl‐3‐methoxyestra‐1,3,5(10)‐trien‐17‐ol 5a, 6a, 7a, 8a were converted into the corresponding 16‐methyl analogues 4a, 11a, 12a, 13a, which were characterized from their 1H‐ and 13C‐NMR spectra. The results permit a configurational correlation with 16‐methyl derivatives reported in the literature.
Marine Bakterien, II. Synthese cyclischer und sterisch gehinderter Pseudiline
Authors: Pudleiner Heinz , Laatsch Hartmut 
Published: July 2007

Marine Bacteria, II. — Synthesis of Cyclic and Steric Hindered PseudilinesFor structure‐activity studies, various derivatives of pentabromopseudiline (1) were synthesized with distorted (3a) or hetero‐cis‐arranged rings (30c). The pyrrole 30c was accessible by Paal‐Knorr cyclization of the 4‐keto aldehyde 25d, which was obtained in a 5‐step synthesis starting from 18.
Synthesis of 2‐alkyl‐3‐vinyloxaziridines as potential antitumor agents
Authors: Said Samy B. , Młochowski Jacek , Skarżewski Jacek 
Published: July 2007

AbstractA convenient method for the synthesis of previously unknown oxaziridines having unsaturated substituents at the 3‐position (3a–k) is based on the selective oxidation of the imino group of α,β‐unsaturated aldimines 2 with m‐chloroperbenzoic acid. The title compounds and 2‐tert‐butyl‐3‐(phenylethynyl)oxaziridine (3k) exhibit potent activity against experimental tumor cells in vitro.
Ein 1,5‐Diazabicyclo[3.3.0]octa‐2,7‐dien aus Acetylendicarbonsäure‐dimethylester und einem 3,5‐Dihydro‐4H‐1,2,3‐triazol‐4‐on
Authors: Quast Helmut , Meichsner Georg , Regnat Dieter , Banert Klaus , Peters Eva‐Maria , Peters Karl , von Schnering Hans Georg 
Published: July 2007

A 1,5‐Diazabicyclo[3.3.0]octa‐2,7‐diene is Formed from Dimethyl Acetylenedicarboxylate and a 3,5‐Dihydro‐4H‐1,2,3‐triazol‐4‐oneThe 3,5,5‐trialkyl‐3,5‐dihydro‐4H‐1,2,3‐triazol‐4‐one 1 and dimethyl acetylenedicarboxylate (2) react slowly at 50°C in a 1 : 1 ratio to afford a 40% yield of a deep red crystalline product C18H24N2O8. 1H‐, 13C‐ and 15N‐NMR spectra and an X‐ray diffraction analysis prove the structure 6 for the red product.
Functionally substituted vinyl carbanions, 40. Synthesis of the basic structure of ezomycin A
Authors: Maier Sibylle , Preuss Rainer , Schmidt Richard R. 
Published: July 2007

AbstractDirect 1‐C‐lithiation of the readily available 2‐phenylsulfinyl‐D‐galactals 3h, 1 leads to reactive intermediates, which on reaction with glyoxal monodiethyl acetal as electrophile yield compounds 7. Subsequent O‐benzylation of the unprotected hydroxy group, removal of the phenylsulfinyl group with Raney nickel, and diastereospecific 3‐hydrogen and 4‐hydroxy transfer provide a convenient entry into functionalized C‐β‐D‐galactopyranosides or 3,7‐anhydrooctoses 11, respectively. Acid‐catalyzed deacetalization and furanose formation with acetic anhydride/pyridine affords 3,7‐anhydrooctofuranoses‐(1,4) 14. The O‐acetylated D‐erythro‐L‐talo isomer (R)‐17 reacts with the cytidine derivative 18, leading to the ezomycin A basic structure 4.
Synthesis of gibberellin A29 β‐D‐glucosides and β‐D‐glucosyl derivatives of [17‐13C,T2]gibberellin A5, A20, and A29
Authors: Schneider Gernot , Schreiber Klaus , Jensen Einar , Phinney Bernard O. 
Published: July 2007

Abstract2‐O‐GA29β‐D‐glucopyranoside (1e) and 13‐O‐GA29, β‐D‐glucopyr‐anoside (1h) were synthesized from GA29 methyl ester (1b). Their structures were confirmed by 1H NMR and GC‐MS. Likewise, [17‐13C,T2]‐labelled 1e and 1h could be obtained. From [17‐13C,T2]GA20 (2a) and [17‐13C,T2]GA5 (3a) the 13‐O‐GA β‐D‐[6‐D2]glucopyranosides [17‐13C,T2;6′‐D2]‐2d and [17‐13C,T2;6′‐D2]‐3d, and the β‐D‐glucopyranosyl esters [17‐13C,T2;6′‐D2]‐2f and [17‐13C,T2;6′‐D2]‐3f were synthesized. The labelled compounds were characterized by HPLC and GC‐MS.
Synthesis and reactions of biginelli compounds, 3. Unexpected formation of nitriles from reactions of 6‐(dibromomethyl)‐1,2,3,4‐tetrahydro‐2‐oxo‐5‐pyrimidinecarboxylates with sodium azide
Authors: Kappe C. Oliver 
Published: July 2007

AbstractThe action of sodium azide on (dibromomethyl)pyrimidines 2a and 8a leads to the nitriles 3a and 9, whereas the 1‐methyl derivatives 2b and 8b afford the geminal diazides 7 and 10. The nitriles 3a, b add another mole of azide to give the tetrazoles 4a, b. The palladium‐catalyzed decomposition of azide 5, obtained from bromide 6 by treatment with sodium azide, yields nitrile 3a.
Neopentylierung von Phenolen und Hydrochinonen
Authors: Quast Helmut , Schulze Johannes 
Published: July 2007

AbstractNeopentylation of phenol, the hydroquinones 6 as well as the hydroquinone diacetates 8 by means of neopentyl iodide in diethylene glycol dimethyl ether in the presence of cesium carbonate affords high yields of the neopentyl ethers 2a and 7, respectively. Even sterically hindered hydroquinones and hydroquinone diacetates, e.g. 6e and 8c, d, are smoothly converted to the neopentyl ethers 7c–e.
Photochemische Bildung von Heteromethylencyclopropanen, 20. Diastereomere 3,3,5,5‐Tetraalkyl‐3,5‐dihydro‐4H‐pyrazol‐4‐one
Authors: Quast Helmut , Jakobi Harald , Seiferling Bernhard 
Published: July 2007

Photochemical Formation of Heteromethylenecyclopropanes, 201)). – Diastereomeric 3,3,5,5‐Tetraalkyl‐3,5‐dihydro‐4H‐pyrazol‐4‐onesThe dibromo ketones (u/1)‐8b react with sodium azide to afford the α,α′‐diazido ketones (u/1)‐9b, which are reduced to the diastereomeric α,α′‐diamino ketones (u/1)‐11b. The hydrochlorides of the latter are separated through fractionating crystallization yielding pure (1)‐11b · 2 HCl (d.e. >99%) and (u)‐11b · 2 HCl having d.e. of 60%. Oxidation of (u)‐11b and (1)‐11b with sodium hypobromite produces the 4‐pyrazolones cis‐6b (d.e. = 60%) and trans‐6b (d.e. >99%), respectively. The mixture of cis‐and trans‐6b is reduced with sodium tetrahydridoborate to the diastereomeric alcohols cis,cis‐, cis,trans‐, and trans,trans‐5, which exhibit separation factors of α = 1.08 and α = 1.15, respectively, in the HPLC on silica gel. The diastereomeric alcohols are separated on large scale (d.e.'s >99%) by means of cyclic medium‐pressure chromatography (silica gel/ petroleum ether/ethyl acetate). Swern oxidation of cis,cis‐5 and trans,trans‐5 produces high yields of cis‐6b, while cis,trans‐5 affords trans‐6b. Both ketones possess d.e.'s >99%.
2,6‐Epoxy‐3‐benzoxocin‐4‐ol‐Derivate durch zweifache intramolekulare Halbacetalbildung
Authors: Wünsch Bernhard , Bauschke Gerd 
Published: July 2007

2,6‐Epoxy‐3‐benzoxocin‐4‐ol Derivatives by Double Intramolecular Formation of HemiacetalsWith dilute HCl the hydroxydialdehyde derivatives 10a‐c are cyclised to give the tricyclic hemiaccetals 6a–c. This double intramolecular formation of hemiacetals succeeds well, if R in 10 is not hydrogen; if R = H an equilibrium betwen 5a and 6a is observed. The 1H‐NMR data of 6 and 17 support the chair conformation of the 1,3‐dioxane ring bearing an equatorial substituent (OH, OAc) in position 4.
Tartraldehydes, 4. Synthesis of D‐ and L‐rhodinose
Authors: Herczegh Pál , Kovács Imre , László Attila , Dinya Zoltán , Sztaricskai Ferenc J. 
Published: July 2007

AbstractStarting from tartraldehyde derivatives 1 and 2, we prepared the title compounds 6 and 7 via a Wittig‐type chain elongation, protection of the formyl group, simultaneous reduction of the double bond and reductive desulfurization of the dithioacetal function as well as hydrolytic removal of the acetal‐type protective groups.
Konsequenzen einer Einschränkung des Porphyrin‐π‐Systems: Versuche zur Synthese des Bakteriophins und Chlorophins
Authors: Bohusch Michael , Flitsch Wilhelm , Kneip Heinz‐Gerd 
Published: July 2007

Consequences of a Diminution of the Porphyrin π‐System: Attempted Syntheses of Bacteriophin and ChlorophinA report is given on a synthesis of bacteriophin (1) from 2,5‐disubstituted pyrrole derivatives. Spectroscopic properties of 1 resemble those of octaethylbacteriochlorin. Starting from 2,2‐dipyrrylmethane and 2‐(2‐aminoethyl)pyrrole the chlorophin derivative 6 has been obtained.
The mechanism of formation of 3H,9H‐Pyrano[3,4‐b]indol‐3‐ones from 3‐indolalkanoic acids
Authors: Medio‐Simon Mercedes , Erfanian‐Abdoust Houshang , Pindur Ulf 
Published: July 2007

AbstractThe mechanism of the formation of 1‐methyl‐3H,9H‐pyrano[3,4‐b]indol‐3‐one (4) from the corresponding 3‐indolacetic acid 1 is discussed. The suggested mechanism is substantiated by the isolation of a stable intermediate 2 and its transformations in the presence of acetic anhydride and/or Lewis acids.
Totalsynthese von (±)‐Bonellin‐dimethylester
Authors: Montforts Franz‐Peter , Schwartz Ulrich Manfred 
Published: July 2007

Total Synthesis of (±)‐Bonellin Dimethyl EsterBonellin (1) is the green sex‐differentiating pigment ofBonellia viridis, a marine animal widely distributed in the Mediterranean Sea. Bonellin dimethyl ester (rac‐2), has been synthesized from the four monocyclic building blocks6, 7, 8b, 10and the selectively cleavable malonic ester9by an highly convergent synthetic concept.
Diterpenoid total synthesis, XXIX. Synthesis of (±)‐14‐deoxystypoldione, an analogue of the marine natural product stypoldione
Authors: Mori Kenji , Koga Yasuo 
Published: July 2007

Abstract(±)‐14‐Deoxystypoldione (2) has been synthesized by starting from geranylacetone. The key step was the construction of the spirobenzofuran moiety by an intramolecular Michael addition (15 → 16). (−)‐Stypoldione is the ichthyotoxic and cytotoxic metabolite of the tropical brown alga Stypopodium zonale (Lamouroux) Papenfuss.
Structural variations of N‐acetylneuraminic acid, 23. Synthesis of 2‐deoxy‐2Heq‐sialic Acid analogues structurally varied at C‐4
Authors: Hartmann Michael , Zbiral Erich 
Published: July 2007

Abstract2‐Deoxy‐2‐Heq‐N‐acetylneuraminic acid (1a) has been shown to be a versatile mimic for sialosyl 2‐α‐glycosides to study the hemagglutinin‐sialic acid interaction. Starting with a 4‐oxo derivative of 2‐deoxy‐2‐Heq‐sialic acid, we obtained the 4‐C‐methylax and 4‐C‐methyleq derivatives 4 and 5 as a separable mixture. The derivative 4 was formed as a single product by using tributoxymethylzirconium. The 4‐C‐methylene derivative 10 was formed by treatment of the ketone with Cp2ZrCl2/Zn/CH2I2. Catalytic hydrogenation of the exo‐methylene compound 10 yielded the two 4‐deoxy‐4‐C‐methyl diastereomers 13 and 14. All above‐mentioned derivatives could be transformed into the unprotected 4‐branched 2‐deoxy‐2‐Heq‐sialic acids 7, 9, 12, 16, and 18. 2‐Deoxy‐2Heq‐4‐oxosialic acid (21) was synthesized by a different pathway.
Acetogenic isoquinoline alkaloids, XXI. An atropisomer‐differentiating reaction for the chemical analysis of axial chirality and its computational investigation: Proof of the stereostructure of dioncophylline A
Authors: Bringmann Gerhard , Jansen Johannes R. , Busse Holger 
Published: July 2007

AbstractA chemical method for the unambiguous elucidation of axial chirality in naphthylisoquinoline alkaloids such as dioncophylline A (1a) is described. It involves synthetic connection of the stereogenic axis to be investigated with the stereocenters present in the same molecule. The resulting macrocyclic ansa compound 7c is formed in high yield, yet exclusively for only one of the two atropodiastereomers (4c), the other isomer (4b) does not cyclize at all. This cyclization behavior fully confirms the stereostructure 1a of dioncophylline A, as postulated by us earlier. For an interpretation of the striking atropisomer specificity of this ring closure reaction, computer‐assisted theoretical investigations on the molecular geometries and thus thermodynamical properties of both of the imaginable cyclization products 7b/c have been performed by using force‐field (MM2, MMX) and semiempirical methods (AM1). The optimized structures show the obtained macrocycle 7c to be a nonstrained, stable compound, whereas the other possible product 7b (which definitely is not formed) should be severely distorted.
Preparation of enantiomerically pure pyrazolines by an enantioconvergent process
Authors: Bosum‐Dybus Annegrit , Neh Harribert 
Published: July 2007

AbstractDerivatization of insecticidally active rac‐pyrazoline 2 with (1S)‐(−)‐camphanic acid chloride led to the separable diastereomers 3a and 3b. Regioselective cleavage to the enantiomerically pure pyrazolines 2a and 2b was achieved under mild conditions. Diastereomer 3b was transformed into diastereomer 3a by crystallization under equilibrating conditions making the overall process enantioconvergent.
Secondary metabolites by chemical screening, 10. Glycerinopyrin, a novel metabolite from Streptomyces violaceus
Authors: Schönewolf Monika , Grabley Susanne , Hütter Klaus , Machinek Reinhard , Wink Joachim , Zeeck Axel , Rohr Jürgen 
Published: July 2007

AbstractGlycerinopyrin (1) was detected by chemical screening as a new metabolite from Streptomyces violaceus. Its structure was elucidated by chemical and spectroscopical methods as (2S)‐ 2,3‐dihydroxypropyl 1‐hydroxy‐4‐methyl‐2‐pyrrolecarboxylate.
Synthese des Thiophosphatidylcholins und seiner Analogen
Authors: Młotkowska Barbara , Markowska Anna 
Published: July 2007

Synthesis of Thiophophatidylcholine and Its AnaloguesSynthesis of thiophatidylcholine 5, its phosphonothionate 7 and phosphonate 9 analogues are described. A novel facile rearrangement of 2‐(2,3‐distearoyloxypropylthio)‐1,3,2‐dioxaphospholane (3) into 2‐(2,3‐distearoyloxypropyl)‐1,3,2‐dioxaphospholane 2‐sulfide (6) was observed by 13P‐NMR spectroscopy.
Synthese des Morphan‐Gerüstes aus 4‐Acetamidocyclohexanon
Authors: Teuber Hans‐Joachim , Tsaklakidis Christos 
Published: July 2007

Synthesis of the Morphane Skeleton from 4‐Acetamidocyclohexanone4‐Acetamidocyclohexanone (1) was substituted via the enamine 2 to yield the estermaids 3a and 4. By means of sodium hydride the cis isomer of the acetal 3b could be cyclized to give the 2‐azabicyclo[3.3.1]nonane (morphane) 5.
Studies on isocyanides and related compounds. – Synthesis and cyclization of N‐substituted 1‐isocyano‐1‐cycloalkanecarboxamides
Authors: Bossio Ricardo , Marcaccini Stefano , Paoli Paola , Papaleo Sandro , Pepino Roberto , Polo Cecilia 
Published: July 2007

AbstractThe Ugi four‐component condensation between cycloalkanones, isocyanides, and ammonium formate affords N‐substituted 1‐formylamino‐1‐cycloalkanecarboxamides 1 which are dehydrated to give the corresponding isocyanides 2. Compounds 2 are cyclized with arylsulfenyl thiocyanates to 1,3‐diazaspiro‐2‐thiones 4 and 5. A series of 1,3‐diazaspiro[4,5]dec‐1‐en‐4‐ones 7 is prepared by cyclizing 2c–j with butyllithium. The structures of these compounds are confirmed by means of IR, 1H‐NMR, and X‐ray analysis.
Regioselectivity of the amination of some 3‐nitropyridines by liquid ammonia/potassium permanganate
Authors: Woźniak Marian , Barański Andrzej , Szpakiewicz Barbara 
Published: July 2007

Abstract3‐Nitropyridine and some of its derivatives are aminated in a liquid ammonia solution of potassium permanganate to the corresponding 2‐ and (or) 4‐ and (or) 6‐amino compounds. Quantumchemical calculations for a few 3‐nitropyridines suggest that the experimentally observed regioselectivity of the amination is controlled by Coulombic interaction.
Gezielte Funktionalisierung des Pimarangerüstes, I. – Oxidationsreaktionen
Authors: John Michael , Rudolph Sabine , Haslinger Ernst 
Published: July 2007

Directed Functionalization of the Pimarane Skeleton, I. – Oxidation ReactionsSelective oxidation of dextropimaric acid (2) using different reagents, e.g. H2SeO3, pyridine–SO3, air etc., is described. The structures of the products have been determined by spectroscopic methods. The 1H‐ and 13C‐NMR resonances of all compounds have been assigned.
Chemie und Stereochemie der Iridoide, XVI. EPC‐Synthese von (−)‐Hypnophilin
Authors: Weinges Klaus , Iatridou Helene , Dietz Uwe 
Published: July 2007

Chemistry and Stereochemistry of Iridoids, XVI. – EPC‐Synthesis of (−)‐HypnophilinThe synthesis of enantiomerically pure (−)‐hypnophilin (27) from (6R,7R)‐(−)‐7‐hydroxy‐3‐oxabicyclo[4.3.0]non‐1‐en‐9‐one (1) is described. 1 was obtained in 93% yield from catalpol, which is readily available from the aqueous sodium carbonate extract of Picrorhiza kurrooa (Scrophulariaceae). The specific rotation, MS, 1H‐ and 13C‐NMR data of synthetic (−)‐hypnophilin were identical with those of the natural product.
Stereoelectronically controlled cyclization reactions on the way to peri‐fused tetrahydropyrazolo[1,5‐a]pyridines as aza analogs of ergoline partial structures
Authors: Gmeiner Peter , Sommer Josef 
Published: July 2007

AbstractThe synthesis of the 3‐substitued tetrahydropyrazolopyridin‐4‐ylalkyl iodides 7a, 7b, 8a and 8b as well as their behavior towards anionic cyclization conditions have been investigated. An (enol endo)‐exo‐tet‐type ring closure only proceeds when a seven‐membered ring is annulated (9b, 10b). Otherwise, treatment of the β‐keto ester 7a with NaH results in O‐alkylation to yield the stereoelectronically favored (Z)‐enol ether 13a, which can be isomerized to the thermodynamically more stable (E) isomer 13b. Various attemps to achieve ring closure of the methyl ketone 8a failed; instead, β‐elimination is observed. Annulation of a six‐membered carbocycle is acchieved when the triester 17 is treated by a Dieckmann condensation to give the tricyclic products 18 and 19.
New umbelliferone sesquiterpene ethers from roots of Ligularia persica
Authors: Marco Juan Alberto , Sanz Juan Francisco , Yuste Alberto , Rustaiyan Abdolhossein 
Published: July 2007

AbstractAn extract of roots of Ligularia persica yielded thirteen umbelliferone sesquiterpene ethers, among them the new ones ligupersin A (11) and ligupersin B (13).
Synthese von N‐Acetyl‐D‐ und ‐L‐glucosamin, cis‐3,5‐Cyclohexadien‐1,2‐diol als Baustein für die Gewinnung modifizierter Hexosen
Authors: Lehmann Jochen , Moritz Andreas 
Published: July 2007

Synthesis of N‐Acetyl‐D‐ and ‐L‐glucosamine, cis‐3,5‐Cyclohexadiene‐1,2‐diol as Building Block for the Preparation of Modified HexosesSix‐membered, unsaturated carbocycles are versatile starting materials for the preparation of a large variety of modified hexoses. This is exemplified by the synthesis of N‐acetylglucosamine 12 as a racemate from cis‐3,5‐cyclohexadiene‐1,2‐diol (1), which can be obtained by microbial oxidation of benzene. In this special case D‐ and L‐N‐acetylglucosamine could be differentiated by enzymatic D‐galactosylation of the former.
Darstellung und Untersuchung eines neuen Diacetylens mit Nitroxylradikal‐Endgruppen
Authors: Dulog Lothar , Lutz Sabine 
Published: July 2007

Synthesis and Characterization of a New Diacetylene with Terminal Nitroxyl Radical GroupsThe new diacetylene 4 was prepared from 4‐isocyanato‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl (2) and 2,4‐hexadiyne‐1,6‐diol (3). The diacetylene 4 could not be polymerized by irradiation or thermal treatment, but decomposition and loss of paramagnetic properties was observed. A new synthesis of isocyanate 2 is also described.
Synthesis of bicyclic imidazole, 1,2,4‐triazole and 1,3,5‐triazine derivatives from N‐cyanolactam 2‐imines
Authors: Pätzel Michael , Bohrisch Jörg , Liebscher Jürgen 
Published: July 2007

AbstractN‐Cyanolactam 2‐imines 1 are versatile NCNC building blocks for the synthesis of partially saturated bicyclic compounds. Reactions with acidic methyl halides, hydroxylamine O‐sulfonic acid, and phenyl isocyanate afford bicyclic imidazole (4), 1,2,4‐triazole (6), and 1,3,5‐triazine (8) derivatives, respectively.
Mehrstufige Redoxsysteme, LVII. Quartärsalze pyridinsubstituierter 1,3,5‐Triazine – eine neue Klasse zwei‐ bis vierstufiger, reversibler Redoxsysteme
Authors: Gries Willi‐Kurt , Günther Erhard , Hünig Siegfried 
Published: July 2007

Multi‐Step Redox Systems, LVII. – Quaternary Salts of Pyridyl‐Substituted 1,3,5‐Triazines – A New Class of Two‐ to Four‐Step Reversible Redox SystemsThe synthesis of 1,3,5‐triazines 3–5a–e substituted by one to three 4‐pyridinium rings [N‐substituents Me, Et, Benzyl, CH2C(O)NMe2, CH2CO2C(O)OEt] is described. According to voltammetric data 3–5 constitute a new type of redox systems with reversible electron transfer in two to four separate steps. Reduction by zinc or sodium amalgam in acetonitrile produces coloured stable solutions of radicals (SEM).
Asymmetric synthesis of bicyclic amino acid derivatives by Aza‐Diels‐Alder reactions in aqueous solution
Authors: Waldmann Herbert , Braun Matthias 
Published: July 2007

AbstractDerivatives 7–10 and 13–16 of methyl and ethyl 2‐azabicyclo[2.2.1]heptane‐3‐carboxylates are synthesized by Aza‐Diels‐Alder reactions of chiral iminium ions, formed in situ from glyoxylic acid and chiral amines, with cyclopentadiene. Whereas the heterodienophiles derived from phenylglycinol and esters of sterically more demanding amino acids fail to undergo asymmetric cycloadditions, with alanine methyl ester and (R)‐1‐phenylethylamine hydrochoride the cycloadducts are formed in yields of 15 and 52%, respectively, reaching de values of up to 90:10 for the exo isomers.
Synthese von disubstituierten Cyclopropa[c]pyranosiden aus 2,3‐Epoxy‐4‐triflat‐pyranosiden
Authors: Zaman Fakhar , Fatima Ayjaz , Voelter Wolfgang 
Published: July 2007

Synthesis of Disubstituted Cyclopropa[c]pyranosides from 2,3‐Epoxy‐4‐triflate‐pyranosidesReaction of benzyl 2,3‐anhydro‐4‐O‐trifluoromethylsulfonyl‐β‐L‐ribopyranoside (1) and benzyl 2,3‐anhydro‐4‐O‐trifluoromethylsulfonyl‐α‐D‐ribopyranoside (4) with malonic acid derivatives yields, via the carbanions, the cyclopropa‐monosaccharides 3 and 6. The ester residues attached to the cyclopropane moiety can be saponified to give the corresponding acids which can be coupled to new carbohydrate amino acid derivatives of type 9 which are of biological interest in different immunological assays.
Photochemische Studien, 61. Photoisomerisierung von Digitoxin in kristallinem Zustand
Authors: Ekiz‐Gücer Nurten , Reisch Johannes 
Published: July 2007

Photochemical Studies 61. – Photoisomerization of Digitoxin in Crystalline StateUV irradiation of digitoxin (1) in the crystalline state yields as major photoisomerization product 3β‐[O‐β‐D‐digitoxopyranosyl‐(1→4)‐O‐β‐D‐digitoxopyranosyl‐(1→4)‐O‐β‐D‐digitoxopyranosyloxy]‐14,20ξ‐epoxy‐5β‐cardanolide (2).
Chemie und Stereochemie der Iridoide, XVII. Palladium‐katalysierte Substitution an Hexaacetylaucubin
Authors: Weinges Klaus , Ziegler Hans Jürgen 
Published: July 2007

Chemistry and Stereochemistry of Iridoids, XVII. – Palladium‐Catalysed Substitution of HexaacetylacubinAcetoxy groups, in allylic position, can be replaced by nucleophiles in a palladium‐catalysed reaction. The reaction of hexaacetylaucubin (2) with piperidine or benzylamine regioselectively gives the crystalline, N‐containing iridoidglucosides 3 and 4. With the anion of diemethyl malonate, 5 was obtained along with the byproduct 7. Adding triethylammonium formate as a hydride donor, then the reaction gives 6; a reaction mechanism is discussed.
Produkte des reduktiven Abbaus von α‐(Acyloxy)plasmalogenen aus Rindergewebe‐Lipiden mit LiAlH4
Authors: Lutz Arnulf , Knörr Walter , Spiteller Gerhard 
Published: July 2007

Products of Reductive Degradation of α‐(Acyloxy)plasmalogens from Bovine Tissue LipidsIf bovine tissue lipids are treated with LiAlH4, two types of unexpected products are detectable: 1‐Acetylglycerols (homologs of compound 2) and α‐hydroxylated glycerol acetals (homologs of compounds 7 and 8). This fact was assumed to indicate the presence of α‐(acyloxy)plasmalogens 1, an up to now unknown class of mammalian tissue lipids. To confirm this assumption, the model compound 6 possessing an enol ether‐enol acetate structure was synthesized and teated with LiAlH4. Corresponding derivatives of 1‐acylglycerols 2 as well as α‐hydroxylated glycerol acetals 7 and 8 were produced, thus confirming the existence of α‐(acyloxy) plasmalogens 1 in tissue of natural origin. They are detectable by GC and GC/MS after conversion of free hydroxy groups with diazomethane/silica gel into the corresponding methyl ether derivatives.