bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Relationship between C6H5N Isomers. Pyrolysis of isatins
Authors: Wentrup Curt 
Published: December 2004

AbstractThe pyrolysis of methyl isatins is described. Examination of the toluidines formed by elimination of 2 CO followed by H‐abstraction indicates that 1H‐benzazirines (12) are inter‐mediates. The interconversion of 1H‐ and 1aH‐benzazirine (15) is not detectable. 1‐Phenyl‐benzotriazole does not give a benzazirine intermediate.
Die vermutliche Struktur der Anodendroside. Glykoside und Aglykone, 331. Mitteilung
Authors: Lichti H. , von Euw J. , Stöckel K. , Polonia J. , Reichstein T. 
Published: December 2004

AbstractFive crystalline compounds (anodendrosides) have been isolated from Anodendron paniculatum (Roxb.)A. DC. (Apocynaceae). They represent glycosides containing unusual sugars. Tentative structures for anodendroside‐A (155), −E1 (3), −E2 (84), −F (144) and −G (115) are now presented. These structures are based on UV., IR., but mostly on high resolution mass spectra. NMR.‐spectra could be performed with A, O‐acetyl‐E2 and O‐acetyl‐G, which are in good agreement with the suggested structures. The unusual methylendioxy group postulated in the sugar moiety of A, E1 and E2 was also established by chemical methods, yielding approximately 1 Mol. equiv. of formaldehyde after acid hydrolysis of anodendroside‐E2.
Coleon D, ein Diterpen aus Coleus aquaticus Guercke mit trans‐A/B‐6,7‐Dioxostruktur
Authors: Rüedi P. , Eugster C. H. 
Published: December 2004

AbstractColeon D, C20H26O6 a new orange red diterpenoid hydroquinone has been isolated from the yellow glands on the leaves and inflorescences of Coleus aquaticus Guercke (Labiatae). Its structure has been determined as 11,12,14,16‐tetrahydroxy‐5α‐abieta‐8,11,13‐trien‐6,7‐dion (1) Therefore it is a tautomer of Coleon C (2). Coleon D is the precursor of Coleon C.
Nachweis von Desacetylakuammilin und 10‐Methoxy‐desacetylakuammilin in Vinca minor L. 147. Mitteilung über Alkaloide
Authors: Savaskan S. , Kompiš I. , Hesse M. , Schmid H. 
Published: December 2004

AbstractThe two indole alkaloids desacetylakuammiline (2) and 10‐methoxy‐desacetylakuammiline (4) were shown to occure in the upper parts of the small periwinkel Vinca minor L. The structure of the hitherto unknown 10‐methoxy‐desacetylakuammiline was established on the bases of chemical, spectroscopic and o.r.d. evidence.
Composés d'addition des halogénures de niobium(V) et de tantale(V). VII. Composés du chlorure de niobium(V) avec l'oxytrichlorure et l'oxytribromure de phosphore
Authors: Bünzli J. C. , Merbach A. 
Published: December 2004

AbstractThe adducts NbCl5 · OPCl3 and NbCl5 · OPBr3 are observed in chloroform solution by 31P‐NMR spectroscopy. The enthalpy and entropy of activation for the exchange reaction between bulk and coordinated OPCl3 are found equal to 17 ± 3 kcal/mole and 18 ± 10 cal/°mole. The stability of NbCl5 · OPCl3 is compared on a semi‐quantitative basis to the stability of other adducts NbCl5 · OPR3 (R = Br, OMe, NMe2).
Anil‐Synthese. 8. Mitteilung. Über die basenkatalysierte Umsetzung von 2‐(p‐Tolyl)‐7‐aryl‐benzo[1, 2‐d:3, 4‐d′]bis‐triazolen mit Anilen aromatischer Aldehyde
Authors: Siegrist A. E. 
Published: December 2004

Abstract2‐(p‐Tolyl)‐7‐aryl‐benzo[1, 2‐d:3, 4‐d′]bis‐triazole und 2, 7‐Di‐(p‐tolyl)‐benzo[1′2‐d:3, 4‐d′]bis‐triazole können mit Anilen aromatischer Aldehyde in Gegenwart von Dimethylformamid und Kaliumhydroxid in 2‐(Stilben‐4‐yl)‐7‐aryl‐ bzw. 2, 7‐Di‐(stilben‐4‐yl)‐benzo[1′2‐d:3, 4‐d′]bis‐triazole übergeführt werden («Anil‐Synthese»).
Ein neuer Süßstoff aus der Indolreihe
Authors: Hofmann A. 
Published: December 2004

AbstractThe synthesis of 3, 4‐dehydro‐2‐(3‐indolylmethyl)‐1‐methyl‐piperidine‐4‐carboxylic acid, a new dulcifiant of the indole series being twice as sweet as saccharine, is described.
Ein Kobalt(II)‐Corrin‐Komplex als reversibler Sauerstoffträger. Eine ESR.‐spektroskopische Untersuchung
Authors: von Zelewsky A. 
Published: December 2004

AbstractThe diamagnetic crystalline Jodo‐Co(II)‐cobyrinicacid‐heptamethylester dissolves in benzene or toluene forming solutions which contain the monomeric paramagnetic complex unit. From anisotropic ESR.‐parameters, measured in frozen solutions, follows a ground state configuration (dxz,dyz)4(dxy)2(dz2)1 for the Co(II). The unpaired electron is highly delocalized to the axially coordinated iodide ion, giving rise to a strong hyperfine coupling with the iodine nucleus. The complex forms in a very fast and completely reversible reaction a 1:1 adduct with molecular oxygen in toluene solutions below ca. 280° K. ESR.‐parameters of the oxygen adduct are presented and discussed. Thermodynamic data for the formation reaction of the adduct are estimated.
Extraction liquide‐liquide par des esters alkylphosphoriques. I. Extraction de l'yttrium par l'acide di‐(2‐éthylhexyl)phosphorique
Authors: Brunisholz G. , Hirsbrunner W. , Roulet R. 
Published: December 2004

AbstractThe extraction of macro‐amounts of Yttrium from solutions of nitric and perchloric acids by di‐(2‐ethylhexyl)phosphoric acid has been studied. The extraction of Yttrium is more effective from the perchloric medium and takes place by two mechanisms: an ion‐exchange reaction Y3+/H+ at low concentrations and a solvatation reaction at high concentrations of Yttrium. The stability constant of the mononitratocomplex YNO has been estimated.
Ringerweiterung in organischen Molekeln unter Elektronenbeschuss: Die massenspektrometrische Fragmentierung von 2,3‐dicarbalkoxy‐spiro‐cyclopropan‐1, 9′‐fluorenen
Authors: Richter Wilhelm J. , Braun André M. 
Published: December 2004

AbstractRing Expansion of a three‐ to a five‐membered cyclic structure in conjunction with loss of a carbalkoxy radical from the molecular ions is postulated for a series of 2,3‐dicarbal‐koxy‐spiro‐cyclopropane‐1,9′‐fluorenes. Initial rupture of the strained spiro‐cyclopropane system with destruction of the distinct molecular geometry is inferred from virtually identical spectral patterns of, cis‐ and trans‐isomers, whereas reclosure of the ‘open’ intermediate to a cyclopentadiene ring can be deduced from the secondary decomposition of the resulting (M–COOR) fragments. These latter ions exhibit loss of the second carbalkoxy group together with a hydrogen atom of unusual positional origin (1′ or its equivalent 8′) to form a pair of neutral species, ROH and CO. Since the ejection of hydrogen from aromatic positions can be taken as evidence of rearomatisation in the course of substitution, this origin is liable to mark the site of the new ring junction and thus to reflect the size of the enlarged cyclic moiety.
Thermische Zerfallsreaktionen von Nitroverbindungen in Stosswellen. II: Dissoziation von Nitroäthan
Authors: Glänzer Klaus , Troe Jürgen 
Published: December 2004

AbstractA shock wave study of the thermal decomposition of nitroethane in excess Ar at temperatures 900 < T < 1350 K and total concentrations of 4,5 · 10−6 < [Ar] < 3 · 10−4 mol cm−3 showed that the CN‐bond fission

is the primary reaction step. This unimolecular reaction could be observed in its transition region near the high pressure limit. The derived rate constants are k∞ = 1015.9 exp (–57 kcal mol−1/RT) s−1 for the high pressure and k0/[Ar] = 1018.0 exp (‐36 kcal mol−1/RT) cm3 mol−1 s−1 (at T ≃ 1100–1200 K) for the low pressure limit.The observed concentration profiles of C2H5NO2 and NO2 permitted to conclude on the subsequent decomposition of the ethyl radical

This reaction was found to be in the fall‐off range under the applied conditions.
Aktivierungsanalytische Bestimmung von Spurenelementen in Blei durch Computerauswertung der Ge(Li)‐γ‐Spektren
Authors: Schubiger August , Wyttenbach Armin 
Published: December 2004

AbstractDie aktivierungsanalytische Bestimmung von Spurenelementen in Blei durch Computerauswertung der Ge(Li)‐Spektren ergibt gute und reproduzierbare Resultate. Das entwickelte Verfahren ist sehr allgemein und schnell und lässt sich auch auf andere Probleme anwenden.
cis‐trans Isomerization of bis(Dialkylsulfide)Dihaloplatinum(II) Complexes in Solution
Authors: Roulet Raymond , Barbey Claude 
Published: December 2004

AbstractThe equilibrium energetics and the kinetics of cis‐trans isomerization of some bis(dialkylsulfide)dihaloplatinum(II) complexes have been examined by 1H‐NMR. spectroscopy. The isomers are stable in chloroform but each form isomerizes to an equilibrium mixture when free dialkylsulfide is added. The cis to trans process is endothermic and the position of the equilibrium is markedly dependent on the nature of the donor atoms and of the solvent. The rate of isomerization of Pt(Me2S)2Cl2 is first order in complex and in Me2S. The isomerization proceeds by a double displacement mechanism as it is shown that the tris(dimethylsulfide)chloroplatinum(II) cation is an isolable intermediate of the reaction. When free Me2S is added to trans‐Pd(Me2S)2Cl2, isomerization does not occur and one observes instead a fast ligand exchange. Its mechanism is the usual associative one for substitutions in square planar d8complexes.
Photoreduktion von 2‐phenylchinoxalin mit Alkoholen und Aminen
Authors: Baumann Niklaus 
Published: December 2004

AbstractA mechanistic and kinetic analysis of the photoreduction of 2‐phenylquinoxaline (I) to 3‐phenyl‐1,2‐dihydroquinoxaline (II) in the presence of alcohols and amines is described. It is concluded that the reduction in alcohols proceeds exclusivly over an excited singlet state I (S1), probably of mixed n‐π*, π‐π* configuration. The triplet state which is also populated (ϕ;isc = 0.62) shows π‐π* configuration but remains inactive. A calculated pKa* 6.2 of I (S1) by means of a. Förster‐cycle, makes a mechanism which includes a first step photoprotonation of I (S1), followed by formation of semiquinone type radicals very probable.In the presence of amines the formation of II proceeds exclusively via the first excited triplet state of I. The calculated rate constants are strongly dependent on the solvent polarity and on the ionisation potentials of the amines. This demonstrates clearly the importance of a charge‐transfer mechanism. It is also shown that once the charge‐transfer from the amine to I (T1) has occurred, physical quenching by electron backtransfer is of no importance. At high amine concentration I (S1)‐quenching is observed.
Oxidation – Reduction Reactions of Tetrachloroaurate(III) Anion with Triphenyl Derivatives of Group V Elements
Authors: Roulet Raymond , Lan Nguyen Quang , Mason W. Roy , Fenske Gerald P. 
Published: December 2004

AbstractThe reduction of the tetrachloroaurate (III) anion by L (L = PPh3, AsPh3, SbPh3) is quantitative in non‐aqueous solution. The products are the gold(I)‐complexes AuClL (L = AsPh3, SbPh3) and Au(PPh3)+2 together with the corresponding oxidation product LCl2. Kinetic studies show that the reactions are first order in AuCl−1 and L. In addition a path independent of PPh3 was found in dichloromethane. These data are interpreted in terms of mechanisms which involve reduction of AuCl−4 to AuCl−2 followed by equilibrium formation of AuClL for L = AsPh3 and SbPh3. For PPh3, the data are consistent with a chloride replacement by PPh3 to give AuCl3 PPh3, which is followed by a rapid reduction by a second mole of PPh3. Equilibrium formation constants are reported for several Au(I) complexes.
Über die spektrale Sensibilisierung von Zinkoxid: II. Anomales Sorptionsverhalten von o, o′‐Dihydroxyazofarbstoffen und Entladungskinetik des damit sensibilisierten Zinkoxids
Authors: Baumeler Rudolf , Rys Paul , Zollinger Heinrich 
Published: December 2004

AbstractThe first acidity constants (pK1) and the zinc complex formation constants (pKzn) of 9 dyes of the type 1‐(2‐hydroxy‐4′‐X‐5′‐Y‐phenylazo)‐2‐naphthol 1 were measured potentiometrically. The sorption behaviour of these dyes on zinc oxide in toluene demonstrates that first a Langmuir‐type pseudo‐equilibrium of the dye with a monomolecular edge‐on adsorption (11) can be observed. The more acidic the dyes, the more is this equilibrium disguised by a faster dissolution of zinc ions from the surface to form (practically irreversibly) the polymeric 1:1 zinc‐dye complex 10. This complex is detectable in electron micrographs. The discharge kinetics of dye‐sensitized zinc oxide‐binder layers in the dark and under irradiation by visible light (10 interference filters) was determined. Substituents X and Y have no detectable influence on the intrinsic discharge kinetics; however, they influence the formation of the polymer complex 10 which is contrast to 11 is not a good sensitizer.
Controlled Allylic Transformations via the Meisenheimer Rearrangement
Authors: Rautenstrauch Valentin 
Published: December 2004

AbstractDescribed are synthetic sequences which effect allylic transformations I and II. Sequence I involves (1) conversion of a primary allyl alcohol into the corresponding N, N‐dimethyl‐amine oxide, (2) [2,3]‐rearrangement to give an N, N‐dimethylhydroxylamine and (3a) reduction to give the ‘rearranged’ secondary or tertiary allyl alcohol [e.g. 36 → 35 → 37 → 40]. Sequence II involves the same steps (1) and (2), followed by (3b) N‐methylation of a secondary N, N‐dimethyl‐hydroxylamine and (4) Hofmann elimination to give a vinyl ketone [e.g. 11 → 12 → 13 → 14 → 15].
Surface Chemistry of Polymers the Influence of Thermal and Chemical Treatments on the Surface Properties of Polyvinylchloride
Authors: Jeanneret C. , Stoeckli H. F. 
Published: December 2004

AbstractThe influence of thermal and chemical treatments (tetrahydrofuran and dioxane) on the adsorption properties of polyvinylchloride is investigated by gas chromatographic methods. It is shown, that heating to the glass‐transition temperature has an erasing effect. Methanol was used as the main molecular probe.
Diterpenoid Hydroquinones from Coleus Somaliensis (S. Moore): Coleons H, I, and K
Authors: Moir Michael , Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

AbstractAus den Blättern und Stengeln von Coleus somaliensis (S. Morre) wurden die Diterpen‐Hydrochinone H, I und K (Coleone H, I und K) isoliert und ihre Struktur aufgeklärt. Coleon H ist 3α‐Acetoxy‐6,11, 12, 14, 16 (oder 17)‐pentahydroxy‐abieta‐5,8,11,13‐tetraen‐7‐on (2). Coleon I ist vermutlich das entsprechende A/B‐trans‐6,7‐Diketon 5. Coleon K ist 16,17‐Diacetoxy‐3α, 11, 12, 14‐tetrahydroxy‐abieta‐8,11,13‐trien‐6,7‐dion (6). Es sind die höchst hydroxylierten Coleone, die bisher aufgefunden worden sind.
Diterpenoids from coleus somaliensis (S. Moore): Coleons G, and J
Authors: Moir Michael , Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

AbstractAus den Blättern und Stengeln von Coleus somaliensis (S. Moore) wurden die farblosen, tetracyclischen Diterpene Coleon G (C22H28O6) und Coleon J (C20H26O5) isoliert und vor allem aus Spektren (einschliesslich 270‐MHz‐1H‐ und 13C‐NMR.) für sie die Strukturen 2 und 1 abgeleitet. Wir fassen sie als Abietanderivate auf mit einer aus der oxydierten Isopropylgruppe entstandenen spiro‐Methylcyclopropan‐cyclohexendion‐Struktur. Sie enthalten zudem anstelle der geminalen Methylgruppen an C(4) eine α‐ständige Methyl‐ an C(3) und eine exocyclische Methylengruppe an C(4).
Dérivés C‐glycosyliques. XV Vinylogues d'homo‐C‐glycosides. Communication préliminaire
Authors: Tronchet Jean M. J. , Campanini Marie‐Thérèse , Denoyelle Josiane , Zumwald Jean‐Bernard 
Published: December 2004

Abstract1,2‐O‐Isopropylidene‐3‐O‐methyl‐α‐D‐xylo‐pentodialdo‐1,4‐furanose and its 3‐O‐benzyl analog have been reacted with pyridinyl‐3‐methylenetriphenylphosphorane and benzimidazolyl‐2‐methylenetriphenylphosphorane. The unsaturated sugars so obtained are vinylogs of homo‐C‐glycosides whose conformation is easily determined. They constitute useful model compounds for pharmacologic studies.
Gleichgewichte der Protonenaddition an 1, 1‐Bis‐(4′, 4″‐dimethylaminophenyl)‐äthylen in Methanol und in Dimethylsulfoxid
Authors: Bernasconi Claude F. , Iijima Toshiro , Koch Werner , Wakae Masao , Zollinger Heinrich 
Published: December 2004

AbstractThe first and second proton addition equilibrium constants of 1,1‐bis‐(4′, 4″‐dimethylaminophenyl)‐ethylene (1) have been measured by the spectrophotometric method in methanol and in dimethylsulfoxide. Defined as acid dissociation constants of the mono‐ and diprotonated adduct they are: K1 (CH3OH) = 8.3 (± 0.9) · 10−6M, K2 (CH3OH) = 1.22 (± 0.06) · 10−4M, K1 (DMSO) = 2.3 (± 0.9) · 10−3M, K2 (DMSO) ≥ 1M. The evaluation of the electronic and the NMR. spectra demonstrates that the equilibrium of the two monoprotonated tautomers 2 (methyl‐carbenium ion) and 3 (ammonium ion) is, in methanol to about 96% on the side of the ammonium ion (tautomeric equilibrium constant K23 = [3]/[2] ≅ 23). The tautomer 2 cannot be detected in dimethylsulfoxide. The possible causes of these solvent effects are discussed.
Drei neue Mutterkornalkaloide aus saprophytischen Kulturen von Claviceps paspali Stevens et Hall. 77. Mitteilung über Mutterkornalkaloide [1]
Authors: Tscherter Hans , Hauth Hartmut 
Published: December 2004

AbstractFrom saprophytic cultures of a strain of Claviceps paspali Stevens et Hall, which produces as main metabolite 6‐methyl‐Δ8,9‐ergolen‐8‐carboxylic acid, three new alkaloids of the clavine type were isolated. One is a dihydro derivative of setoclavine, the two others, which are named paspaclavine and paliclavine, represent new structural types.
Pyrolyse du Diméthylidène‐2, 3‐oxa‐7‐bicyclo[2.2.1]heptane
Authors: Vogel Pierre , Hardy Michèle 
Published: December 2004

AbstractBenzocyclobutene 10 and 3‐oxabicyclo [3.2.0]hepta‐1, 4‐diene 11 are formed by gas‐phase pyrolysis of the title compound 9. The results are discussed with reference to the estimated reaction parameters. It is found that the activation due to oxygen in 9 is relatively weak in comparison to its effect on the reactivity of oxaquadricyclanes 1.
The stereochemistry of fragmentation products formed in the lead tetraacetate and related oxidations of alcohols. Part. I. β‐fragmentation of cis‐and trans‐4‐t‐Butylcyclohexanemethanol
Authors: Mihailovič Mihailo Lj. , Bošnjak Jovan , Čeković Živorad 
Published: December 2004

AbstractThe stereochemistry of β‐fragmentation products formed in the oxidation of cis‐and trans‐4‐t‐butylcyclohexaanemethanol with lead tetraacetate and with lead tetraacetate‐metal chloride combinations, under various reaction conditions, has been investigated, and the results compared with those obtained, under similar conditions, in the oxidative decarboxylation of cis‐and trans‐4‐t‐butylcyclohexanecarboxylic acid with the same reagents. It was found that all four substrates afford, under comparable conditions, identical cis‐trans proportions of the respective fragmentation products, and that, therefore, so far as steric course is concerned, both the initial homolytic and subsequent heterolytic processes involved in the lead tetraacetate fragmentation reaction are independent of the nature and configuration of the starting material.
Use of Dimethylsilyl Ethers for Characterizing Primary Aliphatic Alcohols: A comparison of mass spectrometric fragmentation of di‐ and trimethylsilyl derivatives
Authors: Richter Wilhelm J. , Hunnemann Don H. 
Published: December 2004

AbstractMass spectral fragmentation patterns of dimethylsilyl (DMS) ethers of primary unbranched, branched, and secondary unbranched aliphatic alcohols in the C5 to C10 range are compared with those of the corresponding trimethylsilyl (TMS) derivatives. Unlike their TMS analogues, DMS ethers of primary alcohols exhibit pronounced rupture of the CC bond adjacent to the oxygen atom within the alkyl moiety (loss of an alkyl radical R) in marked preference to cleavage within the silyl substituent (loss of CH3). Within this class of compounds, complementary preparation of DMS derivatives can therefore be used to establish or to confirm the site, and thus the primary nature of the hydroxyl group, whereas preparation of TMS ethers may be of advantage in deducing molecular size. For the derivatives of secondary alcohols this diagnostically useful difference in fragmentation behaviour is not observed.
Transpositions de doubles liaisons de terpènes bicycliques catalysées par des bases
Authors: Ferro Alberto , Naves Yves‐René 
Published: December 2004

AbstractThe displacements of double bonds and dehydrogenation by basic catalysts are examined by analogy with the preceding studies on p‐menthenes and p‐menthadienes [1] with bicyclic terpenes: α‐ and β‐pinenes, sabinene and 3‐carene.
Azidiniumsalze. 11.Mitteilung [1]. Struktur‐Reaktivitäts‐Beziehungen in Serien quartärer N‐Heteroaromaten: Polarographische Untersuchungen an heterocyclischen Azidiniumsalzen
Authors: Hellrung Bruno , Balli Heinz 
Published: December 2004

AbstractDie polarographischen Halbstufenpotentiale von neun Azidiniumsalzen mit verschiedenem Heterocyclus wurden in wässeriger, gepufferter Lösung und in Sulfolan bestimmt. Die Messergebnisse in den beiden Lösungsmitteln werden miteinander und mit σHet‐Konstanten [1] [3] verglichen. – Die Korrelation der Halbstufenpotentiale mit den σHet‐Konstanten ist unbefriedigend. Messergebnisse und Korrelationen werden diskutiert.
Adducts of Niobium(V) and Tantalum(V) Halogenides. IX. Relative stability of the adducts of the chlorides and bromides with some dialkylchalcogenides
Authors: Good René , Merbach André E. 
Published: December 2004

AbstractThe relative stability of adducts formed by Nb(V) and Ta(V) pentachlorides and bromides with some dimethylchalcogenides and nitriles has been determined by 1H‐NMR. in dichloromethane at − 60°. The stabilities are explained in terms of the HSAB principle and Jørgensen's symbiotic effect. A good correlation exists between the ionisation potential of the valence p orbital of the chalcogen atom in the ligand and the logarithm of the relative stability of the adduct formed with a given acid.
Synthese von 1,6‐Trimethylen‐3‐methoxycarbonyl‐4‐methyl‐2‐pyridon
Authors: Fuhrer Walter , Hobi Reinhard , Pfaltz Andreas , Schneider Peter 
Published: December 2004

AbstractThe reaction sequences shown in schemes 3 and 4, represent a new method for the synthesis of a substituted pyridone‐system, starting from a vinylogous amide or thioamide and malonic ester.
Utilisation d'ylides du phosphore en chimie des sucres. XX. Synthèse de sucres acétyléniques et réarrangment d'intermédiaires carbénoïdes. Communication préliminaire
Authors: Tronchet Jean M. J. , Gonzalez Alberto , Zumwald Jean‐Bernard , Perret Françoise 
Published: December 2004

AbstractTwo novel methods for the synthesis of terminal acetylenic sugars, both involving a chain extension by one carbon unit, are described. In the first procedure, an aldehydo‐sugar is treated with dibromomethylenetriphenyl‐phosphorane, then with n‐butyllithium and finally with water. The second method involves an one‐step reaction between an aldehydo‐sugar and dimethyl diazomethylphosphonate. The acetylenic sugars obtained are valuable synthetic intermediates for the preparation of heterocyclic C‐nucleosides by 1,3‐dipolar cycloaddition reactions and some examples of syntheses of this type are described. Treatment of keto‐sugars with dimethyl diazomethylphosphonate led to an intermediate carbenoid species which reacted by insertion into a CH bond in one case and underwent nucleophilic attack by a methoxy group in a second case.
Der massenspektrometrische Zerfall von Tetralin‐Derivaten Beitrag zur massenspektrometrischen Retro‐Diels‐Alder Reaktion
Authors: Heimgartner Heinz , Weibel Peter A. , Hesse Manfred 
Published: December 2004

AbstractThe mass spectral decomposition of the 1‐tetralol derivatives 2, 3 and 4 in view of the retro Diels‐Alder reaction is investigated, for which deuterated derivatives, high resolution data and metastable peaks were used. By these studies it follows that the decyclisation reaction on ring A possesses the character of a retro Diels‐Alder reaction only in some part. The main mass spectral degradation is forced by the substituents placed thereon.