bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aromastoffe der roten Passionsfrucht. Zwei neue Edulanderivate
Authors: Winter Max , Schulte‐Elte Karl H. , Velluz Alain , Limacher Josef , Pickenhagen Wilhelm , Ohloff Günther 
Published: December 2004

Aroma Constituents of the Purple Passion Fruit. Two New Edulan DerivativesThe isolation of (2R*, 4S*, 4aS*, 8aS*)‐4,4a‐epoxy‐4,4a‐dihydroedulan (1), and (2R*, 3S*, 8aS*)‐3‐hydroxyedulan (2), two new constituents of the purple passion‐fruit (Passiflora edulis SIMS), is reported.Racemic epoxide 1 was synthesized by oxidation of edulan 6 with peracidic acid, and racemate of alcohol 2 was obtained by reduction of ketone 7, one of the chromic acid oxidation‐products of edulan 6.
Réactions de germylènes avec divers oxirannes et le thiiranne. Mise en évidence de germanones et germathiones intermédiaires. Communication préliminaire
Authors: Barrau Jacques , Bouchaut Marsan , Lavayssiere Hélène , Dousse Gabriel , Satgé Jacques 
Published: December 2004

AbstractComplexed dialkylgermylenes R2GeNR3 or R2GePy react with oxiranes or thiirane and lead to dialkylgermanone and germathione via germaoxetanes or germathiacyclobutane. The formation of germadioxolanes or germadithiolane finally observed arises from condensation of dialkylgermanone (or germathione) on oxiranes (or thiirane).
Notiz zur Synthese von rac. cis‐ und trans‐2‐Nor‐abscisinsäure
Authors: Kienzle Frank 
Published: December 2004

Note on the synthesis of rac. cis‐ and trans‐nor‐abscisic acidThe synthesis of the 2‐nor‐analogues of cis‐ and trans‐abscicic acid is described.
Additionsreaktion von 3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirin mit Phenylisothiocyanat
Authors: Schmid Ursula , Heimgartner Heinz , Schmid Hans 
Published: December 2004

Reaction of 3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirine with Phenyl IsothiocyanateIn contrast to the reactions of 3‐dimethylamino‐2,2‐dimethyl‐2H‐azirine (1a) with various isothiocyanates, leading to thiazoline derivatives, the reaction of 1a with phenyl isothiocyanate at room temperature gives 5,5‐dimethyl‐3‐phenyl‐Δ1‐imidazolin‐4‐dimethyliminium‐2‐thiolate (9, Scheme 2). The structure of 9 is deduced from spectral data and reactions of this zwitterionic compound (Schemes 2 and 4).
Photolyse des 3‐Phenyl‐2, 1‐benzisoxazols und einiger seiner Derivate in Bromwasserstoffsäure
Authors: Giovannini Edgardo , De Sousa Bernardo F. S. E. 
Published: December 2004

Photolysis of 3‐phenyl‐2, 1‐benzisoxazole and some derivatives in hydrobromic acidThe behaviour of 3‐phenylanthranils (3‐phenyl‐2, 1‐benzisoxazoles) towards photolysis in hydrobromic acid differs greatly from that in hydrochloric and sulfuric acid. Thus, reduction and substitution products are obtained. The formation of the reduction products involves hydrogen abstraction by a nitrenium ion species in the triplet state and that of the substitution products can be attributed to a subsequent SE‐bromination.
Secondary 2‐Norbornyl Cation Intermediates Substituted at C(5) and C(7) by Electron‐withdrawing Groups. Addition of fluorosulfuric acid to unsaturated norbornane derivatives
Authors: Quarroz Daniel , Vogel Pierre 
Published: December 2004

AbstractLow temperature (−130° to −110°) addition of exo‐norborn‐5‐en‐2‐ol (7) to excess HSO3F in SO2CIF yielded a mixture of exo‐5‐(fluorosulfonyloxy)‐exo‐2‐ and endo‐2‐norbornylhydroxonium ions (9+10) under kinetic control that was different from the mixture of 9+10 obtained by addition of endo‐norborn‐5‐en‐2‐ol (8) to HSO3F under kinetic control. These mixtures differed from the mixture of 9+10 observed at higher temperature (−80° to −60°) (thermodynamic control). Addition of 3‐nortricyclanol (23) or exo‐2, 3‐epoxynorbornane (24) to HSO3F at ‐−120° ± 10° yielded a mixture containing the exo‐2‐(fluorosulfonyloxy)‐anti‐7‐ and syn‐7‐norbornylhydroxonium ions (26+27) as major adducts. Qualitative rates of the isomerization of 26+27 to the more stable ions 9+10 and of the isomerization 9 ⇄ 10 were evaluated. The solvolysis of 9+10 in HSO3F yielded the exo‐2, exo‐5‐ and exo‐2, endo‐5‐norbornanediyl bis (fluorosulfates) (21+22). Norbornadiene and quadricyclane added 2 equivalents of HSO3F and furnished kinetically a mixture of exo‐2, anti‐7‐ and exo‐2, syn‐7‐norbornanediyl bis (fluorosulfates) (36+37) as major adducts. The latter 36+37 were isomerized into a kinetic mixture of the more stable isomers 21+22. The rates of these isomerizations were compared. The use of DSO3F and (exo‐2‐D)‐norborn‐5‐en‐2‐ol (15) confirmed that heterolyses of the fluorosulfates were responsible for the observed isomerization; elimination‐addition processes occurred but much more slowly. The results are interpreted in terms of substituted classical and σ‐bridged secondary 2‐norbornyl cation intermediates. It appears that the electron withdrawing substituents FSO3 and H2O+ (HO) destabilize the σ‐bridged 2‐norbornyl cation more at C(5) than C(7). If the σ‐bridged ions 5‐Z substituted at C(5) by Z = FSO3 or H2O+ (HO) are transition states in the isomerization of the corresponding classical ions 3‐Z, 4‐Z, the free enthalpy difference between the ‘non‐classical’ σ‐bridged ion and the classical ions is not higher than the energy barrier to the quenching of the latter intermediates by FSO in HSO3F/SO2CIF.
Syntheses and Absolute Configuration of (E)‐ and (Z)‐α‐Bisabolenes
Authors: Delay Franç , Ohloff Günther 
Published: December 2004

AbstractStereospecific syntheses of (E)‐ and (Z)‐α‐bisabolenes have made revision of the configuration of natural (+)‐α‐bisabolene from Opoponax oil necessary. 13C‐NMR. spectroscopy has been used for the differentiation of these isomers.
Synthesis, Opiate Receptor Binding and Analgesic Activity of Enkephalin Analogues
Authors: Pless Janos , Bauer Wilfried , Cardinaux Francis , Closse Annemarie , Hauser Daniel , Huguenin René , Roemer Dietmar , Buescher Heinz‐Hermann , Hill Ronald Charles 
Published: December 2004

AbstractThe synthesis and biological testing of analogues of Met‐enkephalin, a recently discovered opioid peptide from mammalian brain, are described. Testing involved determination of affinity constants for an opiate receptor site and of analgesic potency in the tail‐flick test in mouse. The effects on opioid activity of modifying various parts of the enkephalin molecule are discussed. Tyr‐D‐Ala‐Gly‐MePheMet (O)‐olThe ending ‐ol added to the symbol of an amino acid designates the aminoalcohol obtained by reduction of the α‐carboxyl group of the amino acid.
(FK 33‐824), which was highly active in these tests, was subsequently selected for clinical testing.The use of two complementary models ‐ in vitro binding studies and in vivo test for analgesia ‐ for the assessment of biological activity in the evaluation of analogues is explained.
The Synthesis and Reactions of Dialkyl 1‐Vinylvinyl‐Phosphates
Authors: Kienzle Frank , Rosen Perry 
Published: December 2004

Abstract3,4‐Dichlorobutanone reacts with trialkyl phosphites to give dialkyl 1,3‐butadien‐2‐yl phosphates. Their structures were determined by spectroscopic methods and various chemical reactions.
Totalsynthese von natürlichem α‐Tocopherol. 2. Mitteilung. Aufbau der Seitenkette aus (−)‐(S)‐3‐Methyl‐γ‐butyrolacton
Authors: Schmid Max , Barner Richard 
Published: December 2004

Total Synthesis of Natural α‐TocopherolA short and efficient route to optically pure (+)‐(3 R, 7 R)‐trimethyldodecanol (14) is demonstrated, 14 serving as side chain unit in the preparation of natural vitamin E. The synthesis of 14 is based on the concept of using a single optically active C5‐synthon of suitable configuration and functionalization to introduce both asymmetric centres in 14. (−)‐(S)‐3‐Methyl‐γ‐butyrolacton (1) and ethyl (−)‐(S)‐4‐bromo‐3‐methylbutyrate (2), respectively, is used in a sequence of either two Grignard C,C‐coupling reactions 5 → 8 and 12 → 13 or two Wittig reactions 17a → 18 and 20 → 21 to achieve this goal. 14 is converted to (2 R, 4′R, 8′R)‐α‐tocopherol (= vitamin E) by coupling with a chroman unit in known manner. Optical purity of products and intermediates is established.
ipso‐Substitution with Sodium‐N‐alkyl‐(p‐nitrobenzene)sulfonamide. A novel anionic rearrangement
Authors: Müller Paul , Phuong Nguyen‐Thi Minh 
Published: December 2004

AbstractReaction of N‐benzyl‐N, N‐di‐(p‐nitrobenzene)sulfonamide (3) with NaCN/HMPA at 140° affords N‐benzyl‐p‐nitroaniline (4). The same product is obtained upon heating of the sodium salt of N‐benzyl‐(p‐nitrobenzene)sulfonamide (5). The transformation 5 → 4 is believed to proceed via an anionic episulfonyl compound 6.
Selective Hydrogen Chloride Elimination from Primary Chlorides Induced by the Fluoride Anion. Anchimeric participation of the chloromethyl group in the heterolytic opening of an epoxide. Stereospecific syntheses of 5,6‐bis (methylidene)‐syn‐2‐norbornen‐7‐ol and 5,6‐bis (methylidene)‐endo‐3‐chloro‐exo‐2‐norbornanol
Authors: Chollet André , Hagenbuch Jean‐Pierre , Vogel Pierre 
Published: December 2004

AbstractSyntheses of the alcohols10and18, and the corresponding ketones11and19are presented.Endo‐5,exo‐6‐bis (chloromethyl)‐endo‐3‐chloro‐exo‐2‐norbornanol (16) andendo‐5‐(bromomethyl)‐exo‐6‐(chloromethyl)‐endo‐3‐chloro‐exo‐2‐norbornanol (17) were obtained by HCl‐ and, respectively, HBr‐addition toendo‐5,exo‐6‐bis (chloromethyl)‐exo‐2, 3‐epoxynorbornane (5). TheWagner‐Meerweinrearrangement was precluded in these reactions probably because of the formation of a relatively stable chloronium ion15arising from the participation of the 1,4‐chlorine atom of theendo‐5‐chloromethyl group in the heterolytic ring opening of the epoxide5.The ‘naked’ fluoride anion (excess CsF in DMF or KF in DMF with 18‐crown‐6‐ether) permitted the selective elimination of 2 equivalents of HCl from16and yielded the chlorohydrin‐diene18.
Minecosid und Verminosid, zwei neue Iridoidglucoside aus Veronica officinalisL. (Scrophulariaceae)
Authors: Sticher Otto , Afifi‐Yazar Fatma Ü. 
Published: December 2004

Minecoside and verminoside, two new iridoid glucosides from Veronica officinalis L. (Scrophulariaceae)Two new esters of catalpol, minecoside (1) and verminoside (3), have been isolated from Veronica officinalis L. The structures of 1 and 3 have been determined on the basis of the spectral data as 6‐isoferuloylcatalpol and 6‐caffeeoylcatalpol, respectively.
Absorption and Fluorescence Studies on Neutral and Cationic Isoalloxazines
Authors: Visser Antonie J. W. G. , Müller Franz 
Published: December 2004

AbstractThe electronic properties of a variety of methylated isoalloxazine derivatives have been investigated with absorption and fluorescece techniques (Table 1). The spectral effects of methyl substitution at different positions in the isoalloxazine ring are interpreted in terms of different bond orders between the C‐atoms of the methyl groups and of the aromatic ring. Methyl groups at C(6) or C(9) induce quenching of the fluorescence and shortening of the lifetime whereas a methyl group at C(7) has an opposite effect. The quenching effect might be due to strain in the molecular framework caused by the methyl groups.The lowest energy levels of the isoalloxazine cations are shifted to higher energy as compared to the neutral isoalloxazines. Apart from these shifts the trends in spectral behaviour upon methylation are similar to those observed for the neutral isoalloxazine (cf. Table 2). The fluorescence of the isoalloxazine cations is strongly quenched in auqeous solution and their lifetime much shortened. These observations indicated that there is substantial interaction between the charged fluorophore and the water dipoles and that this interaction produces efficient radiationless deactivation of the first excited singlet state.
Structure of Globularidin: An Unusual Iridoid Glucoside from Globularia alypumL.
Authors: Chaudhuri Ratan Kumar , Sticher Otto 
Published: December 2004

AbstractA novel iridoid glucoside, named globularidin, lacking the typical double bond between C(3) and C(4), has been isolated from the whole plant of Globularia alypum by the combination of open column‐ and high‐performance liquid chromatography. The structure of this compound was established by chemical transformation and spectral data.
15N‐NMR. and 31P‐NMR. Studies of palladium and platinum complexes
Authors: Motschi Herbert , Pregosin Paul S. , Venanzi Luigi M. 
Published: December 2004

Abstract15N‐NMR. parameters for the complexes trans‐[MCl2 (15NH2 (CH2)5CH3)L] are reported; M = Pt, Pd, L = PBu, PMePh2, P (p‐CH3C6H4)3, AsBun3, AsMePh2, As (p‐CH3C6H4)3, NH2 (CH2)5CH3 and (for Pt) C2H4. For both metals, the NMR. parameters depend on the trans‐influence of the ligand L. The values 1J (195Pt, 15N) vary from 138 to 336 Hz and can be shown to correlate with the values 1J (195Pt, 31P) in the complexes trans‐[PtCl2 (PBu)L]. There is a linear relation between the 15N chemical shifts in the complexes of the two metals. The reactions of the complexes sym‐trans‐[M2Cl4L2], M = Pd, Pt, L = a tertiary phosphine or arsine, with neutral ligands are described. 195Pt‐, 31P‐ and 13C‐NMR. data are reported.
Synthèse et désamination enzymatique des C‐hydroxyméthyl‐3′‐ et C‐méthyl‐3′‐β‐D‐xylofurannosyl‐9‐adénines
Authors: Tronchet Jean M. J. , Tronchet Jeannine F. 
Published: December 2004

Synthesis and enzymatic deamination of 3′‐C‐hydroxymethyl‐ and 3′‐C‐methyl‐β‐D‐xylofuranosyl‐9‐adeninesThe title compounds have been prepared by classical synthetic steps after having optimized the nature of the blocking groups. Both nucleosides were found to be substrates of adenosine aminohydrolase which proved that C(3′)‐branched‐chain sugar nucleosides can be deaminated when the branched‐chain is exo (trans relative to the base) if a suitably disposed hydroxy group is available on the endo side of the furanose ring.
Kinetische Betrachtung der Verteilung von elektrisch neutralen Ionophoren zwischen einer Flüssigmembran und einer wässerigen Phase
Authors: Oesch Urs , Simon Wilhelm 
Published: December 2004

Kinetic Study of the Distribution of Electrically Neutral Ionophores between a Solvent Polymeric Membrane and an Aqueous PhaseThe kinetic behaviour of a series of ligands in the transfer from a solvent polymeric membrane into a stirred aqueous phase was investigated and compared with theoretical kinetic models. It was found that the transfer of ligands with low lipophilicity was controlled by the diffusion in the membrane phase, and that of ligands with high lipophilicity was controlled by the exchange reaction at the phase boundary and/or the diffusion through the unstirredNernstdiffusion layer. The diffusion coefficients in the membrane decrease drastically on increase of the content of the polymer in the membrane and are nearly independent of the size and lipophilicity of the ligand, whereas the overall transfer coefficient through the boudary region does not depend on the polymer content but decreases with increasing lipophilicity of the ionophore.
Photooxygenation of 3,3‐dialkylsubstituted allyl alcohols. Occurrence of syn preference in the ene addition of 1O2 at E/Z‐isomeric allyl alcohols
Authors: Schulte‐Elte Karl H. , Muller Bernard L. , Pamingle Hervé 
Published: December 2004

AbstractDye‐sensitized photooxygenation (1O2‐reaction) of the symmetrically 3,3‐dialkyl‐substituted allyl alcohols 1–6 (A, Table 1) and the E‐ and Z‐isomers of the 3‐methyl‐3‐alkylsubstituted allyl alcohols 7–11 (A1, Table 2) has been studied. The α, β‐epoxyaldehydes B and B1 and the β‐hydroperoxy‐homoallyl alcohols C, C1 and D1 were practically the sole oxygenation products formed. The rate and selectivity of the 1O2 additions were found to be markedly dependent on the degree of substitution (i.e. H‐availability) at the allyl position which is Z‐orientated to the carbinol group. The allyl alcohols with a Z‐3‐methyl group, 1 and the E‐isomers of 7 to 10, showed practically the same reactivity towards 1O2 and formed only the two oxygenation products of type B1 and C1 (ratio close to 60:40). In contrast, the allyl alcohols with a Z‐3‐methylene group, 2 and the Z‐isomers of 7 to 9, reacted more slowly with 1O2 and yielded all the three possible products B1, C1 and D1 in a very different ratio of ∼ 80:10:10. However, from both the E‐ and Z‐isomers of the alcohols 7 to 10 the formations of the two oxygenation products were always strongly favoured (85–100%) which result from 1O2 additions at the disubstituted side of the double bond. This behaviour is thus completely analogous to that of the corresponding trisubstituted olefins previously studied [1]The same side‐specific selectivity in 1O2 ene additions to several E/Z‐isomeric and deuterium‐labelled olefins has also been described recently by C.M. Stephenson et al. [2] (we thank Dr. V. Rautenstrauch and Prof. C.W. Jefford for informing us about this work). The similar behaviour of enol ethers, which react with 1O2 preferentially at the RO‐substituted side, had been observed earlier by C.S. Foote et al. [3] and extended to numerous derivatives by J.M. Conia et al. [4] [5].
and follows a new selection rule, termed syn‐preference [1], in the ene addition of 1O2.
Thermische Cyclisierung von α‐Alkinonen zu 2‐Cyclopentenonen
Authors: Karpf Martin , Dreiding André S. 
Published: December 2004

Thermal Cyclization of α‐Alkynones to 2‐CyclopentenonesGas phase thermolysis at 600–740° of substituted 1‐pentyn‐3‐ones (α‐alkynones), which are easily prepared by acylation of trimethylsilyl acetylenes, leads to substituted 2‐cyclopentenones. The intramolecular formation of a new C, C‐bond between an acetylenic and a non‐activated carbon atom is accompanied by a [1,2]‐migration of one of the substituents at the triple bond. This novel ‘‐alkynone cyclization’ reaction may be explained by postulating an alkylidene carbene intermediate which inserts into a C,H‐bond five carbon atoms away at the non‐acetylenic part of the ketone. Several examples demonstrate that the α‐alkynone cyclization offers a simple tool for the preparation of certain monocyclic, bicyclic and spiro compounds containing a 2‐cyclopentenone moiety.
The Synthesis of [4‐Carboranylalanine, 5‐Leucine]‐Enkephalin (Including an Improved Preparation of t‐Butoxycarbonyl‐L‐o‐carboranylalnine, New Derivatives of L‐Propargylglycine, and a Note on Melanotropic and Opiate Receptor Binding Characteristics)
Authors: Fauchère Jean‐Luc , Leukart Othmar , Eberle Alex , Schwyzer Robert 
Published: December 2004

AbstractThe title compound, an analogue of [Leu5]‐enkephalin with L‐o‐carboranylalanine replacing L‐phenylalanine in position 4, was prepared by fragment condensation. The analogue has a 3‐fold higher affinity for rat brain opiate receptors in the [3H]naloxone competition assay than natural [Leu5]‐enkephalin. Like [Leu5]‐enkephalin and Na‐acetyl‐[Leu5]‐enkephalin, the N‐terminal tripeptide fragment, H · Tyr‐Gly‐Gly · OH, had no melanotropic activity in the Rana pipiens frog skin assay.A convenient, direct synthesis of methyl t‐butoxycarbonyl‐L‐propargylglycinate is described, and the 13C‐NMR. spectra of L‐o‐carboranylalanine recorded. The procedure was extended to the preparation of BOC · Car‐Leu · OMe from BOC · Pra‐Leu · OMe. A number of new propargylglycine derivatives are reported.
(Perhalogenmethylthio)heterocyclen. X. Säurekatalysierte Substitutionen an (Perchlorfluormethylthio)pyrrolen und deren agrobiologische Wirkung
Authors: Dorn Silvia , Eggenberg Peter , Gerstenberger Michael R. C. , Haas Alois , Niemann Ulrich , Zobrist Peter 
Published: December 2004

(Perhalomethylthio)heterocycles. XIX. Mitt.: s. [1].

.
Acid‐catalyzed substitutions on (perchlorofluoromethylthio)pyrroles and their agro‐biological activities
In the presence of C4F9SO3H the (perhalomethylthio)pyrroles 1a–c react with Cl3−nFnCSCl (n = 1–3) to give mixtures of the 2,5‐ and 2,4‐disubstituted pyrroles 2a–f and 3a–h. 2a and 3a react with CF3SCl (catalyst CF3SO3H) yielding 2,3,5‐tris (trifloromethylthio)pyrrole (4a), which under similar conditions reacts further to give 2,3,4,5‐tetrakis (trifluoromethylthio)pyrrole (5). As a by‐product during the conversion of 3a to 4a 2,3,4‐tris (trifluoromethylthio)pyrrole (4b) is formed. The pyrroles 2a, 4a and 5 form the mercury salts 6a–c; compound 5 yields also a silver salt 7. The 1H‐ and 19F‐NMR. spectra are discussed and the agro‐biological properties of the compounds investigated.
Heterocyclisch anellierte Derivate des Strychnins: Imidazo‐, Oxazolo‐ und (1,3‐Dioxolo)strychnine
Authors: Edenhofer Albrecht , Arnold Wolf 
Published: December 2004

Heterocyclic anellated derivatives of strychnine: Imidazo‐, oxazolo‐ and (1,3‐dioxolo)strychnineThe synthesis of imidazo‐, oxazolo‐ and dioxolo‐strychnine derivatives, anellated at the 2,3‐position of the aromatic nucleus is described. The spectroscopic properties of these compounds and of some intermediates are given.
Conversion of Natural (S)‐Bulbocapnine into Two (Ring A)‐Substituted Derivatives of (R)‐Apomorphine
Authors: Greecke Max , Borer René , Brossi Arnold 
Published: December 2004

Abstract(6aR)‐1,2‐(Methylenedioxy)aporphine‐10, 11‐diol (8) and (6aR)‐aporphine‐1, 1, 10, 11‐tetrol (16) have been prepared from natural (S)‐bulbocapnine (4). For both compounds, the partial synthesis included racemic intermediates which have been resolved into their enantiomers. Both compounds 8 and 16 showed dopaminergic activity in rats, although to a lower extent than (R)‐apomorphine (1) itself.
Etude en série triazénique. IV. Synthèse et réactivité d'aryl‐3‐(diméthyl‐3,4‐isoxazolyl‐5)‐1‐triazènes et d'arylazo‐4‐diméthyl‐3,4‐isoxazolones‐5
Authors: Siv Chhan , Vernin Gaston , Metzger Jacques 
Published: December 2004

Synthesis and reactivity of 3‐aryl‐1‐(3,4‐dimethyl‐5‐isoxazolyl)‐triazenes and 4‐arylazo‐3,4‐dimethylisoxazol‐5‐onesAccording to the experimental conditions and the nature of the substituents on the aromatic ring, aryldiazonium salts react with 5‐amino‐3,4‐dimethylisoxazole (3) leading to either 3‐aryl‐1 (3,4‐dimethyl‐5‐isoxazolyl)‐triazenes (1A) or 4‐arylazo‐3,4‐dimethylisoxazol‐5‐ones (4). Analyses of the products resulting from thermal decomposition of these triazenes in aromatic substrates and in DMSO and their behaviour in acidic medium show that it is essentially the arylazo form 1B which is reactive.
The Configuration of Naturally Occurring Iridoid Glucosides at C(6) and C(8): A Complementary Assignment Aid by 13C‐NMR. Spectroscopy
Authors: Chaudhuri Ratan K. , Afifi‐Yazar Fatma Ü. , Sticher Otto 
Published: December 2004

AbstractEvidence is presented which demonstrates that 13C‐NMR. spectroscopy can be used with confidence in evaluating the configuration of R1R2CHOH centers at C(6) and C(8) of iridoid glucosides.
Dérivés d'énose‐ et d'ynosephosphonates et composés voisins. Communication préliminaire
Authors: Tronchet Jean M. J. , Bonenfant Alain P. , Pallie Kemal Deen , Habashi Ford 
Published: December 2004

Derivatives of enose‐ and ynosephosphonates and related compounds. Preliminary communicationThe gem‐dibromo terminal enoses 1 and 7 are convenient sources of glycosylacetylenes which upon reaction with phosphorus electrophiles gave the phosphorusbearing acetylenic sugars 4, 5 and 8. Compounds 5 and 8 underwent cycloaddition reactions leading to isoxazolyl‐C‐glycosides 6 and 9 respectively. The nitroolefinic sugar derivative 11 gave upon bromination‐dehydrobromination the first example of a new kind of potentially useful synthetic intermediates, the gem‐bromonitroenose 12. The enosephosphonate 13 was also prepared from 11. The diglycosylhydroxylamine 18 represents another type of phosphorus‐bearing acetylenic sugar derivative. Some 1H‐ and 13C‐NMR. data relative to the new types of phosphorus‐containing sugar derivatives synthesized are given.