bluuebunny/crossref_metadata_2025_split huggingface dataset:
Über Pyridinium‐N‐phenolat‐Betaine und ihre Verwendung zur Charakterisierung der Polarität von Lösungsmitteln, XVIII. Synthese und UV/Vis‐spektroskopische Eigenschaften eines negativ solvatochromen Pyridinium‐N‐thiophenolat‐Betainfarbstoffs
Authors: Reichardt Christian , Eschner Michael 
Published: July 2007

Pyridinium N‐Phenoxide Betaines and Their Application for the Characterization of Solvent Polarities, XVIII. – Synthesis and UV/Vis Spectroscopic Properties of a Negatively Solvatochromic Pyridinium N‐Thiophenoxide Betaine DyeSynthesis and UV/Vis spectroscopic properties of the negatively solvatochromic, relative to 1 homomorphic, thiobetaine dye 2 are described. The new thiobetaine 2 exhibits an even larger negative solvatochromism and thermochromism than the standard betaine dye 1, which has been used to establish an empirical scale of solvent polarity, the so‐called ET(30) scale. Surprisingly, there exists a linear correlation between the ETO(30) values of 1 and the ETS(30) values of 2 for both aprotic and protic solvents, despite of the fact that sulfur is usually known to act as worse hydrogen‐bond acceptor than oxygen. Possible reasons for this extraordinary behaviour of 2 are discussed. In contrast to 2, the sulfo‐substituted betaine dye 4 does not exhibit any solvatochromism.
Conversion of oleic acid to 17‐ and 18‐substituted stearic acid derivatives by way of the „acetylene zipper”︁
Authors: Augustin Kim E. , Schäfer Hans J. 
Published: July 2007

AbstractStearolic acid (2) was prepared from oleic acid (1) and converted to 4, 5, and 7 by way of the „acetylene zipper”︁ reaction. Compounds 5 and 7 were transformed to the (ω – 1) ketones 8 and 9 and dimerized by way of the Glaser coupling reaction to 11 and 12. At daylight, 12 polymerizes to a blue polymer.
Synthetic microbial chemistry, XXIV. Synthesis of antibiotic 1233A, an inhibitor of cholesterol biosynthesis
Authors: Mori Kenji , Takahashi Yoshio 
Published: July 2007

AbstractA synthesis of 1233A [(2E,4E,7R,2′R,3′R)‐11‐[3′‐(hydroxymethyl)‐4′‐oxo‐2′‐oxetanyl]‐3,5,7‐trimethyl‐2,4‐undecadienoic acid (1a)] was achieved by employing (R)‐2‐hydroxymethyl‐3‐butenyl acetate (2a) and (R)‐citronellic acid (3) as chiral building blocks. The former was prepared by lipase‐mediated asymmetric hydrolysis of the corresponding diacetate.
Benzyl (R)‐ and (S)‐2‐tert‐butyl‐5‐oxo‐oxazolidine‐3‐carboxylate for convenient preparation of D‐ and L‐threonine analogs from aldehydes
Authors: Blaser Denis , Seebach Dieter 
Published: July 2007

AbstractLithium enolates of (R)‐ or (S)‐oxazolidinones 1 (specified in the title) are generated with lithium hexamethyldisilazanide (LHMDS) in THF at −75°C and added to aliphatic or aromatic aldehydes (products 2–18 of hydroxyalkylation, yields mostly over 80%, diastereoselectivities usually over 98%; Scheme 2). The adducts can be cleaved to give threonine analogs (19–32) under salt‐free conditions (H2/Pd‐C, then H2O and evaporation of the solvents, Scheme 3). In some cases, the primary adducts may cyclize with elimination of benzyl alcohol to give bicyclic carbamates 33 which, in turn, can be hydrolyzed to 5‐substituted trans‐2‐oxo‐1,3‐oxazolidine‐4‐carboxylic acids 34 (Scheme 4). – The essentially complete threo selectivity of the coupling step is proved by NMR spectroscopy and by chemical correlations. The stereochemical course of the reaction is opposite to that observed with carbocyclic enolates; possible reasons for this behavior are discussed (Scheme 5). – The starting material rac‐1, prepared from glycine, pivalaldehyde and benzyl chloroformate, is readily resolved by chromatography on preparative scale by using the stationary phase Chiraspher® and a Prepbar® system (Scheme 1); the undesired enantiomer may be recycled by thermal racemization (heating at reflux in CH3CN for 8 h).
Condensation of diglycolic acid dichloride with polyglycols, 5. An improved synthesis of cyclic polyether‐esters by cyclization
Authors: Erk Cakil 
Published: July 2007

AbstractAn improved synthesis of oligocyclic (ether‐ester)s by cyclization condensation of polyglycols with diglycolic acid dichloride in benzene/pyridine or dioxane/pyridine is reported.
Untersuchungen an 1,3‐Thiazinen, 44. Neuartige Umlagerungsreaktion von 3,3′‐Carbonylbis(tetrahydro‐2H‐1,3‐thiazin‐2‐thion) und 3,3′‐Carbonylbis(2‐thiazolidinthion)2)
Authors: Hanefeld Wolfgang , Von Gösseln Hans Joachim 
Published: July 2007

Investigations of 1,3‐Thiazines, 44. – Novel Rearrangement of 3,3′‐Carbonylbis(tetrahydro‐2H‐1,3‐thiazine‐2‐thiozine) and 3,3′‐Carbonylbis(2‐thiazolidinethione)2)2‐Thioxo‐1,3‐thiazine and ‐thiazolidine derivatives react with phosgen yielding N,N′‐carbonylbis(heterocycles) 3, 9, 11, 12. With excess of phosgen 3 and 9 gave a novel rearrangement to the 3,5‐bis(ω‐chloroalkyl)‐2,6‐dithioxo‐perhydro‐1,3,5‐thiadiazin‐4‐ones 8 and 10.
Short and stereoselective synthesis of (±)‐ibogamine via a Vinylsulfone intermediate, IV
Authors: Herdeis Claus , Hartke‐Karger Claudia 
Published: July 2007

AbstractIbogamine (11b) was synthesized starting from the vinyl sulfone 3. Addition of organocuprate reagents to 3 furnished 2a–d with high stereoselectivity. Only products from the syn addition of the cuprate reagents could be detected. Functional group transformations provided 7a,b the key intermediates for the synthesis of (±)‐21‐noribogamine (11a) and (±)‐ibogamine (11b).
Synthesis of rac‐allocoronamic acid hydrochloride
Authors: Marco José L. , Sánchez Belén , Fernández M. Dolores , Bernabé Manuel 
Published: July 2007

AbstractA new method is reported for the synthesis of rac‐allocoronamic acid hydrochloride (5), from the readily available oxazolone 1 via the 1,3‐dehydro amino acid derivative 2, diazomethane addition, photolysis and acid hydrolysis.
Studies on Isocyanides and Related Compounds. Synthesis of Oxazole Derivatives via the Passerini Reaction
Authors: Bossio Ricardo , Marcaccini Stefano , Pepino Roberto 
Published: July 2007

AbstractThe reaction between arylglyoxals (1), cyclohexyl isocyanide, and aromatic carboxylic acids (2) affords N‐cyclohexyl‐2‐acyloxy‐3‐aryl‐3‐oxopropionic amides (3) which can be cyclized to N‐cyclohexyl‐2,4‐diaryl‐5‐oxazolecarboxamides (4).
Bausteine von Oligosacchariden, IC. Darstellung von synthetischen Antigenen der inneren Core‐Region von Lipopolysacchariden durch Copolymerisation mit Acrylamid
Authors: Paulsen Hans , Wulff Achim , Brenken Mathias 
Published: July 2007

Building Units of Oligosaccharides, IC. – Preparation of Synthetic Antigens of the Inner Core Region of Lipopolysaccharides by Copolymerisation with AcrylamideBesides L‐α‐D‐Hepp‐OAll (5), the following allyl glycosides with oligosaccharide structures of the inner core region of lipopolysaccharides have been synthesized: L‐α‐D‐Hepp‐(1→7)‐L‐α‐D‐Hepp‐OAll (19), L‐α‐D‐Hepp‐(1→3)‐L‐α‐D‐Hepp‐OAll (26), L‐α‐D‐Hepp‐(1→5)‐α‐Kdop‐OAll (31), L‐α‐D‐Hepp‐(1→5)‐β‐Kdop‐OAll (34), L‐α‐D‐Hepp‐(1→5)‐[α‐Kdop‐(2→4)]‐α‐Kdop‐OAll (48) and L‐α‐D‐Hepp‐(1→5)‐[α‐Kdop‐(2→4)]‐β‐Kdop‐OAll (39). All these compounds have been coupled with cysteamine to the spacer‐elongated derivatives 54b – 60b and finally converted into the acryloyl compounds 54c – 60c. The copolymerisation of 54c – 60c with acrylamide gave the polymers 54d – 60d, containing the above mentioned oligosaccharides as haptens in an antigenic form.
Synthesis of allopurinol and 4‐amino‐1H‐pyrazolo[3,4‐d]pyrimidine N1‐ and N2‐(β‐D‐arabinofuranosides)
Authors: Seela Frank , Winter Holger 
Published: July 2007

AbstractAllopurinol and 4‐amino‐1H‐pyrazolo[3,4‐d]pyrimidine N1‐and N2‐(D‐arabinofuranosides) have been synthesized. Nucleobase anion glycosylation of 4‐methoxy‐1H‐pyrazolo[3,4‐d]‐pyrimidine (7) with the α‐D‐arabinofuranosyl chloride 6a proceeds stereoselectively and affords the N1‐(β‐D‐nucleoside) 8 as the main product (43% yield) together with the N2 isomer 10 (25% yield). The formation of the α anomer 9 (6% yield) results from the β‐D‐arabinofuranosyl chloride 6b being formed upon chlorination of the nitrobenzoate 5. Compounds were deprotected (11–13) and subjected to nucleophilic displacement reactions affording allopurinol and 8‐aza‐7‐deazaadenine N1‐and N2‐(arabinonucleosides) 1b, 2b, 3, and 4b. The anomeric configuration and the position of glycosylation have been established by 1D 1H‐NOE difference spectroscopy. Compound 3 has proved to be a substrate of adenosine deaminase with a half‐life 100‐fold longer than that of ara‐A.
An efficient synthesis of R3Si(CH2)n‐substituted acetylacetone derivatives
Authors: Urbaniak Wlodzimierz , Schubert Ulrich 
Published: July 2007

AbstractAn efficient synthesis of R3Si(CH2)3CH[C(O)Me]2 3 [R = Me, OR′] is described. The reaction of R3Si(CH2)3Cl 2 with the sodium of potassium salt of acetylacetonate (1) and 0.8–2 equivalents of NaI of KI in DMF, DMSO or NMP as a solvent gives the C‐ and O‐alkylation products R3Si(CH2)3CH[C(O)Me]2 3 and R3Si(CH2)3OC(Me)CHC(O)Me 4 in a 3:1 ratio and a 60–70% total yield. For R3SiCH2CH[C(O)Me]2 selectivity and yields are lower.
Synthesen mit aliphatischen Dialdehyden, XLV. Substituierte Glutaconaldehyd‐Derivate durch Vilsmeier‐Addition an 1‐Methoxy‐1‐buten‐3‐in, 1‐Methoxy‐1‐penten‐3‐in und 1‐(Dimethylamino)‐1‐buten‐3‐in und deren Reaktionen mit einigen Nucleophilen
Authors: Nolte Christian , Schäfer Gerhard , Reichardt Christian 
Published: July 2007

Syntheses with Aliphatic Dialdehydes, XLV. – Substituted Glutaconaldehyde Derivatives by Vilsmeier Addition to 1‐Methoxy‐1‐buten‐3‐yne, 1‐Methoxy‐1‐penten‐3‐yne, and 1‐(Dimethylamino)‐1‐buten‐3‐yne and Their Reactions with Some Nucleophiles3‐Halogeno‐substituted unsymmetrical pentamethinium salts 5, 7, 8, and 10 as well as 3‐halogeno‐substituted symmetrical vinamidinium salts 6, 9, and 11 are synthesized by addition of suitably substituted Vilsmeier reagents to 1‐methoxy‐1‐buten‐3‐yne (1). Analogous Vilsmeier additions to 1‐methoxy‐1‐penten‐3‐yne lead to 3‐halogen‐2‐methyl‐substituted unsymmetrical pentamethinium salts 13 and 14. Symmetrical 3‐methoxy‐and 3‐methylthio‐substituted vinamidinium salts 15 and 16 are observed by appropriate Vilsmeier additions to 1‐(dimethylamino)‐1‐buten‐3‐yne (4). Further 3‐substituted unsymmetrical and symmetrical pentamethinium salts are obtained by nucleophilic substitution at the C‐3 position of these salts, leading to 19–27. The [C4 + C1] pathway to 3‐substituted glutaconaldehyde derivatives represents a useful completion to their synthesis.
Natural Product Chemistry, 147. Synthesis of some coumarin derivatives
Authors: Reisch Johannes , Herath H. M. T. Bandara , Bergenthal Dieter , Kumar N. Savitri 
Published: July 2007

AbstractTwo naturally occurring coumarins, dihydrosuberenol (5) and (E)‐O‐ethylsuberenol (6), and another possible natural product (E)‐O‐methylsuberenol (7), were synthesized from (E)‐suberenol (1). The treatment of 1 with HBr gave the new menthadienediylbis(coumarin) 8.
Enantioselective synthesis of (S)‐(+)‐2‐tridecanol acetate, an aggregation pheromone component of Drosophila mulleri
Authors: Enders Dieter , Plant Andrew 
Published: July 2007

AbstractThe enantioselective synthesis of (S)‐(+)‐2‐tridecanol acetate [(S)‐6] (ee = 93.5%), an aggregation pheromone of Drosophila mulleri, is described. Key steps are the α‐alkylation of the propiophenone SAMP‐hydrazone (S)‐2 (de ≥ 96%) and the Baeyer‐Villiger reaction of the ketone (S)‐4.
Synthesis of [13C]‐ and [2H]betulin for biological transformations
Authors: Tietze Lutz F. , Heinzen Horacio , Moyna Patrick , Rischer Matthias , Neunaber Horst 
Published: July 2007

AbstractSelective acetylation of 1 at C‐28 afforded the monoacetate 2, which was oxidized to the 3‐oxo compound 8. H,D exchange at C‐2 in 8 followed by reduction with LiAlH4 led to [2‐2H]‐betulin (5). Reduction of 8 with NaBD4 or LiAlD4 yielded [3‐2H]betulin (6) besides different amounts of the respective 3α‐hydroxy compound 7. For the introduction of a CD2 or 13CH2 unit at C‐29 betulin diacetate 4 was ozonolyzed to give the known compound 10, which was treated either with CD2Br2, Zn, and TiCl4 in THF to yield the [29‐2H2] compound 11 or with [13C]methyltriphenylphosphonium iodide and potassium tert‐butoxide to afford the [29‐13C]‐labeled compound 11. Solvolysis of 11 and 13 with methanol and potassium carbonate afforded the desired compounds [29‐2H2]betulin (12) and [29‐13C]betulin (14).
Totalsynthese von Thymosin β4, 1. Klassische Synthese des Fragments [11–19] von Thymosin β4
Authors: Kapurniotu Afroditi , Voelter Wolfgang 
Published: July 2007

Total Synthesis of Thymosin β4, 1. – Conventional Synthesis of the Fragment [11–19] of Thymosin β4As part of the total synthesis of thymosin β4 two synthetic pathways for the synthesis of the thymosin β4 fragment [11–19] are described. The side‐chain functions are protected by tert‐butyl and the α‐amino residues by Z groups. As temporary protection of the carboxyl function the phenyl ester is successfully used.
Preparation of (R)‐ and (S)‐2‐alkyl‐2‐amino‐3‐(methylamino)propanoic and other 2,3‐diaminoalkanoic acid derivatives from a chiral imidazoline
Authors: Pfammatter Elmar , Seebach Dieter 
Published: July 2007

Abstractt‐Butyl 2‐t‐butyl ‐3‐methyl‐4‐oxo‐1‐imidazolidinecarboxylate (Boc‐BMI, 1) is deoxygenated (→3), reductively carboxylated (→10, 11), converted to an imidazolinedicarboxylate 31 and subjected to a 1,2‐carbonyl‐group transposition (→34), The new chiral building blocks thus obtained are used to synthesize derivatives of (i) 1,2‐ethylenediamines (type4–11), of diaminopropanols (8, 16– 18) via the lithiated carbamate F, (ii) of 2‐alkyl‐2,3‐diaminopropanoic acid (20–26, 30) via the enolate H, (iii) of higher 2,3‐diaminoalkanoic acids (see 32, 33) via the Michael acceptor 31, and (iv) of simple α‐(methylamino) acids (type 35) via the enolate of 34. A number of free α,β‐diaminocarboxylic acids with a tertiary stereogenic center in the αposition is prepared (37–39). Some of these diamino acids are cyclized to β‐lactams (41–43) bearing an alkyl and a phenylsulfonylamido group in the 2‐position.
Enantioselektive Terpensynthesen durch Diels‐Alder‐Reaktion von 1‐(1‐Arylalkoxy)‐2‐methyl‐1,3‐butadien mit Isopren
Authors: Zadel Guido , Rieger Rainer , Breitmaier Eberhard 
Published: July 2007

Enantioselective Terpene Syntheses by Diels‐Alder Reaction of 1‐(1‐Arylalkoxy)‐2‐methyl‐1,3‐butadiene with IsopreneThe (R)‐ and (S)‐1‐(1‐arylalkoxy)‐2‐methyl‐1,3‐butadienes 6 undergo [4 + 2] cycloadditions with excess isoprene (7) under pressure to yield not only the expected (4S,6R)‐ and (4R,6S)‐trans‐carveol (8) with up to 96% e.e. but also up to 40% of (R)‐ and (S)‐limonene (9) with up to 93% e.e. Asymmetric induction is proposed to arise from a transition state involving definite π stacking of one molecule of isoprenyl ether and two molecules of isoprene.
Ceramides from Urtica dioica roots
Authors: Kraus Rupert , Spiteller Gerhard 
Published: July 2007

AbstractIn methanolic extracts of stinging nettle roots (Urtica dioica) a special class of ceramides was detected. These ceramides contain a double bond in position 8 of the sphingoid base. With the typical amidic linkage the amino group of the sphingoid base (2‐amino‐1,3,4‐trihydroxy‐8‐octadecene) is either connected to an unbranched fatty acid with 20 – 25 carbon atoms or to a 2‐hydroxy fatty acid with the same chain length. Both classes of ceramides were separated from each other by thinlayer chromatoraphy. The members of each class were further separated as trimethylsilyl derivatives by gas chromatography. The structures of the ceramides were determined by mass, NMR and IR spectroscopy combined with hydrolysis experiments.
Tetra‐meso‐methylenporphyrinogene
Authors: Otto Christiane , Breitmaier Eberhard 
Published: July 2007

Tetra‐meso‐methyleneporphyrinogensWhile usual methods of carbonyl alkenylation such as the Wittig reaction fail when applied to xanthoporphyrinogens 1, methylenation of xanthoporphyrinogens 1 to tetra‐meso‐methyleneporphyrinogens 3 occurs with methyllithium in low to moderate yields.
Solanum alkaloids, 121. Partial Synthesis of the Steroid Alkaloids Teinemine, 22‐Isoteinemine, Etioline, and 25‐Isoetioline
Authors: Quyen Le Thi , Ripperger Helmut , Schreiber Klaus 
Published: July 2007

AbstractThe rare 16α‐hydroxylated steroid alkaloids teinemine [(22S,25S)‐22,26‐epiminocholest‐5‐ene‐3β,16α‐diol, 8], 22‐isoteinemine [(22R,25S)‐22,26‐epiminocholest‐5‐ene‐3β,16α‐diol, 10], etioline [(25S)‐22,26‐epiminocholesta‐5,22(N)‐diene‐3β,16α‐diol, 12], and 25‐isoetioline [(25R)‐22,26‐epiminocholesta‐5,22(N)‐diene‐3β,16α‐diol, 21] are synthesized from the abundant spirosolane alkaloids tomatid‐5‐en‐3β‐ol [(25S)‐22βN‐spirosol‐5‐en‐3β‐ol, 1] and solasodine [(25R)‐22αN‐spirosol‐5‐en‐3β‐ol, 15], respectively. The crucial stages of these syntheses are the conversions of 1 or 15 into the N‐protected (22S,25S)‐, (22R,25S)‐, and (22S,25R)‐22,26‐epimino‐3β‐hydroxycholest‐5‐en‐16‐ones 6, 7, and 18 as well as their reductions with sodium/ 2‐propanol to the 16α‐hydroxy compounds teinemine (8), 22‐isoteinemine (10), and (22S,25R)‐22,26‐epiminocholest‐5‐ene‐3β,16α‐diol (19), respectively. By treatment with sodium methanolate the N‐chloro derivatives 9 and 11 of 8 and 10 afford etioline (12). In an analogous manner, the N‐chloro derivative 20 of 19 is converted into 25‐isoetioline (21).
Selektive enzymatische Schutzgruppenabspaltungen: Der n‐Heptylester als Carboxylschutzgruppe in der Peptidsynthese
Authors: Braun Peter , Waldmann Herbert , Vogt Walter , Kunz Horst 
Published: July 2007

Selective Enzymatic Removal of Protecting Groups: n‐Heptyl Esters as Carboxy Protecting Functions in Peptide SynthesisAmino acid heptyl (Hep) esters are accessible as generally crystalline hydro tosylates 3 from the amino acids by azeotropic esterification with 1‐heptanol in high yields. They can be condensed with Z‐, Boc‐, and Aloc‐protected amino acids to give the dipeptides 7–9 in the presence of 1‐ethoxycarbonyl‐2‐ethoxy‐1,2‐dihydroquinoline (EEDQ). From the fully protected dipeptides the N‐terminal protecting groups are cleaved by chemical methods without affecting the Hep esters. On the other hand, the heptyl esters can be hydrolyzed under mild conditions (pH = 7.0, 37°C) and with high yields by means of a lipase from Rhizopus niveus without attacking the N‐terminal urethane groups or the peptide bonds.
1H‐NMR spectra of all diastereomeric nitroalditols with a chain length up to C7, obtained from aldoses by the Fischer‐Sowden reaction
Authors: Köll Peter , Brandenburg Heinz , Seelhorst Willi , Stenns Claudia , Kogelberg Heide 
Published: July 2007

AbstractThe 1H‐NMR spectra of all diastereomeric alditols with a terminal nitro group up to a chain length of seven carbon atoms (31 compounds) have been recorded at 500 MHz in D2O. In most cases, a complete first‐order analysis has been performed. The spectra show systematic correlations with those of the parent alditols. Despite a special situation around the nitromethyl group no severe deviations of preferred conformations in solution from those of the parent alditols have been observed.
Pheromone synthesis, CXXV. Synthesis of the four possible stereoisomers of 3,7‐dimethylnonadecane, the female sex pheromone of Agromyza frontella Rondani
Authors: Mori Kenji , Wu Jiang 
Published: July 2007

AbstractThe synthesis of the four possible stereoisomers of 3,7‐dimethylnonadecane (1) has been achieved by starting from the enantiomers of methyl 3‐hydroxy‐2‐methylpropanoate (2) and (R)‐(+)‐citronellic acid (3).
Synthese langkettiger Benzo‐ und Naphthochinonaldehyde als Substrate für bakterielle Luciferasen
Authors: Jockers Half , Schmid Rolf D. , Rieger Hagen , Krohn Karsten 
Published: July 2007

Synthesis of Long‐Chain Benzo‐ and Naphthoquinonealdehydes as Substrates of Bacterial LuciferasesThe naphthoquinones 1 and 2 and the benzoquinones 28 and 29 have been alkylated with long‐chain‐functionalized aliphatic carboxylic acids 3–10 using the method of Torssell. The functional groups (COOH, OH, CHCH2) of the coupling products have been transformed into aldehyde groups affording quinoid aliphatic aldehydes with chain lengths ranging from C8 to C15. The quinoid aldehydes with an optimal chain length ranging from C9 to C11, especially the C9 aldehydes 27 and 31, were shown to be effective substrates of the bacterial luciferases from Vibrio harveyi and Photobacterium fischeri.
1,2,4‐Dithiazoliumsalze als Ausgangsstoffe für Pyrimidinderivate mit Oxo‐, Thioxo‐ oder Aminofunktion in 4‐Stellung
Authors: Briel Detlef 
Published: July 2007

Synthesis of Pyrimidine Derivatives Having Oxo, Thioxo or Amino Functions at Position 4 from 1,2,4‐Dithiazolium SaltsThe (thioaroylamido)acrylonitriles 2, obtained by reaction of 1,2,4‐dithiazolium salts 1 with ethyl cyanacetate, undergo ring transformation reactions by reaction with ammonium acetate, primary and secondary amines and form the pyrimidines 7–9. A possible mechanism for these reactions is discussed.
An unusual synthesis of tetrakis (trifluoromethyl)tetrathiafulvalene
Authors: Müller Harald , Lerf Anton , Fritz Heinz P. 
Published: July 2007

AbstractTetrakis(trifluoromethyl)tetrathiafulvalene (5) was formed in a phase‐transfer‐catalyzed unusual one‐step reaction by basic cleavage and subsequent alkylation of 1,3,4,6‐tetrathiapentalene‐2,5‐dione (thiapendione) (1) with 2,3‐dichlorohexafluoro‐2‐butene. As an example of the normal course of this reaction the synthesis of 4,5‐(ethylenedithio)‐1,3‐dithiol‐2‐one (3) is described.
Ein neues Butenolid aus Conyza bonariensis
Authors: Sanz Juan Francisco , Marco Juan Alberto 
Published: July 2007

A New Butenolide from Conyza bonariensisExtraction of aerial parts of Conyza bonariensis and chromatographic separation yielded the new butenolide 1, together with the acetylenic compounds trans‐lachnophyllum lactone (2) and cis‐lachnophyllum methyl ester (3), and the germacrane alcohol 4.
Chemie und Stereochemie der Iridoide, XV. Eine effiziente Synthese enantiomerenreiner (−)‐Specionin‐Analoga aus peracetylierten Iridoidglucosiden Kristall‐ und Molekülstruktur von (−)‐3′‐Methoxyspecionin
Authors: Weinges Klaus , Neuberger Karl , Schick Hartmut , Reifenstahl Uwe , Irngartinger Hermann 
Published: July 2007

Chemistry and Stereochemistry of Iridoids XV. – An Efficient Synthesis of Enantiomerically Pure (−)‐Specionin Analogs from Peracetylated Iridoid Glucosides. – Crystal and Molecular Structure of (−)‐3′‐MethoxyspecioninWhen peracetylated iridoid glucosides are submitted to hydroxymercuration and reduction with zinc the glucoside bond is cleaved exclusively. The aglycones can be regio‐ and stereoselectively transformed into specionin analogs. An example is the preparation of crystalline (−)‐3′‐methoxyspecionin (3b) from hexaacetyl‐6‐O‐vanilloylcatalpol (1d), which is readily available in larger quantities. The stereochemistry of 3b was determined by X‐ray crystallographic analysis.
Functionally substituted vinyl carbanions, 43. Convenient transformation of hexopyranosides into α‐methylene δ‐lactone derivatives
Authors: Kast Jürgen , Hoch Monika , Schmidt Richard R. 
Published: July 2007

AbstractTreatment of glycopyranosyl phenyl sulfoxides 2ah, 1, 2bh, 1 with two equivalents of lithium diisopropylamide provides directly the C‐2‐lithiated glycal intermediates 3aAh, 1, 3bAh, 1 which, on reaction with formaldehyde as electrophile, furnish the 2‐hydroxymethyl derivatives 4ah, 1 and 4bh, 1, respectively. These compounds are transformed at elevated temperature and by acid catalysis directly into the α‐methylene‐δ‐lactones 5a, b. Correspondingly, from 2ah, 1 and methyl chloroformate as electrophile the 2‐methoxycarbonyl derivatives 6h and 61, respectively, are obtained. Treatment of 6h, 1 with Raney nickel leads to 2‐methoxycarbonyl‐substituted glycal 7 containing a β‐alkoxyacrylate moiety which again can be directly β‐C‐lithiated as demonstrated by the introduction of deuterium at C‐1.