bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemisch‐spezifische Kopplung von Adrenocorticotropin‐ und Angiotensin‐II‐Derivaten an Polymerträger für die Affinitätschromatographie
Authors: Fauchère Jean‐Luc , Pelican Giatgen‐Mario 
Published: December 2004

Specific covalent attachment of adrenocorticotropin and angiotensin II derivatives to polymeric matrices for use in affinity chromatographyThe purpose of this investigation was to prepare polymer‐supported forms of adrenocorticotropin and angiotensin II with unique points of covalent attachment and presumably low rates of hormone detachment, making them potentially useful for affinity chromatography. Conventional chemical synthesis provided the peptides cysteinyl‐ACTH (5–24) ([4‐cysteine]‐adrenocorticotropin‐(4‐24)‐heneikosipeptide) and cysteinyl‐angiotensin II amide ([I‐Nα‐cysteinyl‐asparagine,5‐valine]‐angiotensin II). Strategies were devised to bind these hormone derivatives either in the protected form to polyacrylamide or in the deprotected form to sepharose beads. The obtained high degree of matrix substitution suggests a general applicability of these methods.
The Crystal and Molecular Structures of Two Acid‐Catalysed Rearrangement Products of Taxochinon
Authors: Weber Hans Peter , Petcher Trevor J. , Hensch Marcel , Eugster Conrad Hans 
Published: December 2004

AbstractDie Strukturen von zwei säurekatalysierten Umlagerungsprodukten von Taxochinon (1) wurden kristallographisch bestimmt: Die eine Verbindung stellte sich als ein 20 (10 → 9) abeo‐Abietan (2) heraus, die andere als ein achirales Phenalenon (3). Die Abietanverbindung, C20H26O3, kristallisiert in der Raumgruppe P212121 mit 4 Molekeln in der Zelle und wurde mit 879 signifikanten Reflexionen bis R = 0,032 verfeinort. Die Phenalenonvervindung, C20H22O2, KRISTALLISIERT IN DER rAUMGRUPPE p21/c mit 12 Molekeln in der Zelle und wurde mit 1823 signifikanten Reflektionen bis R = 0,058 verfeinert.
Aza‐2‐diènes‐1,3. 2. Synthèse et structure d'un ylure d'azométhine stable
Authors: Fleury Jean‐Pierre , Schoeni Jean‐Paul , Clerin Daniel , Fritz Hans 
Published: December 2004

2‐Aza‐1,3‐dienes. 2. Synthesis and Structure of a Stable Azomethine‐ylid.Thermal treatment of 2‐(2′‐cyano‐2′‐methoxycarbonyl)methylide‐amino‐1‐morpholino‐cyclohexene results in the formation of a stable isomere. Its azomethine‐ylid structure is demonstrated from the spectroscopic data (UV., IR., 1H‐ and 13C‐NMR.). 1,3‐dipolar cycloaddition reactions of this ylid leads to spiropyrrolines.
Piperaceae Alkaloids: Part III. Synthesis of N‐isobutyl‐11‐(3,4‐methylenedioxyphenyl)‐undeca‐2,4,6‐trans, trans, trans‐trienoic amide and N‐isobutyl‐11‐(3,4‐methylenedioxyphenyl)‐undeca‐2,8,10‐trans, trans, trans‐trienoic amide (piperstachine)
Authors: Viswanathan Narayanan , Balakrishnan Venkatachalam , Joshi Balawant S. , von Philipsborn Wolfgang 
Published: December 2004

AbstractN‐Isobutyl‐11‐(3, 4‐methylenedioxyphenyl)‐undeca‐2,4,6‐trans, trans, trans‐trienoic amide (II) and N‐isobutyl‐11‐(3,4‐methylenedioxyphenyl)‐undeca‐2,8,10‐trans, trans, trans‐trienoic amide (III), two of the three possible structures of the alkaloid piperstachine, have been synthesized. Compound (III) has been found to be identical with piperstachine. The 1H‐ and 13C‐NMR. spectra of the compound (II) are discussed.
Photoelectron Spectra of Vicinal Tricarbonyls
Authors: Bischof Peter , Gleiter Rolf , Hofmann Peter 
Published: December 2004

AbstractThe He I photoelectron spectra of tetramethylcyclopentane‐1,2,3‐trione 1, 4,4,6,6‐tetramethylcyclohexane‐1,2,3‐trione 2, bicyclo[1.2.3]octane‐2,3,4‐trione 3, bicyclo[2.2.3]nonane‐2,3,4‐trione 4 and anhydrous ninhydrine 5 are presented. The assignment of the first two bands is discussed using semiempirical calculations together with a qualitative band shape analysis. It is shown that the first two bands in 1 to 4 are due to the ionization of an electron from lone pair combinations of the 2p‐oxygen orbitals.
Über einen neuen Zugang zu Imidazolen, sowie deren Verwendung zur Synthese von Purinen und 4,6‐Dihydro‐1,2‐dimethyl‐8‐phenylimidazo[4,5‐e]‐1,4‐diazepin‐5(1H)‐on
Authors: Edenhofer Albrecht 
Published: December 2004

AbstractA novel route to imidazoles and their use for the synthesis of purines and 4,6‐dihydro‐1,2‐dimethyl‐8‐phenylimidazo[4,5‐e]‐1,4‐diazepin‐5(1H)‐on.Recently it has been shown [2] that pyrimidines are available from Thorpe‐Ziegler cyclization of the appropriate dinitriles. As an extension of this work, a novel route to imidazoles has been developed. It has been demonstrated that these imidazole derivatives are valuable intermediates for the synthesis of purines by application of standard procedures. The use of these imidazoles has enabled the preparation of some derivatives not accessible by other methods.
Die Struktur einer stabilen dipolaren Verbindung aus 2,2‐Dimethyl‐3‐dimethylamino‐2H‐azirin und Benzoylisothiocyanat. Vorläufige Mitteilung
Authors: Schmid Ursula , Heimgartner Heinz , Schmid Hans , Schönholzer Peter , Link Helmut , Bernauer Karl 
Published: December 2004

AbstractStructure of a Stable Dipolar Compound from 2,2‐Dimethyl‐3‐dimethylamino‐2H‐azirine and Benzoylisothiocyanate.Benzoylisothiocyanate and 2,2‐dimethyl‐3‐dimethylamino‐2H‐azirine (1) react to given the dipolar compound 4,4‐dimethyl‐2‐thiazolin‐5‐dimethylimminium‐2‐benzcarboxamidate (2), whose structure has been proved by X‐ray analysis. Compound 2, upon addition of water, yields the thiourea derivative 3, whereas by acid catalyzed hydrolysis the thiazolinone derivative 4 is formed. The dipolar structure 2 is also existent in organic solvents like dimethylsulfoxide or chloroform.
Über Reaktionen oxygenierter Kobalt(II)‐Komplexe. V. Reaktivität diastereoisomerer μ‐Peroxo‐μ‐hydroxo‐dikobalt(III)‐Ionen
Authors: Zehnder Margareta , Mäcke Helmut , Fallab Silvio 
Published: December 2004

On Reactions of oxygenated Cobalt(II) Complexes. V. Reactivity of diastereoisomeric μ‐peroxo‐μ‐hydroxo‐dicobalt(III) IonsThe kinetics of dissociation of μ‐peroxo‐μ‐hydroxo‐dicobalt(III) chelates have been reinvestigated using a stopped flow technique. The binuclear cations [(trien)Co(O2, OH) Co(trien)]3+, [(tren)Co(O2, OH)Co(tren)]3+ and [(en)2Co(O2, OH)Co(en)2]3+ dissociate on acidifying to Co2+ and the protonated ligand and up to 100% of the bound O2 is evolved. The dissociation is H+‐catalyzed and first order in complex. The observed rate constants at pH 2 are in the range of 10−3 to 10−1 s−1 (20°). They depend not only on the nature of the ligand and on ligand configuration but also on the diastereoisomeric structure of the binuclear cation.In the case of trien there are 8 possible chemically different isomers. On oxygenation of Co(trien)2+ in dilute solution 3 of those isomers seem to be formed preferentially. Their rate constants are separated over a factor of 50. For [(en)2 Co(O2, OH)Co(en)2]3+ there exist a meso form and a chiral structure. On oxygenation of Co(en)22+ in dilute solution the meso form and the racemate are formed to about equal amounts. The racemate dissociates about 5 times slower. Of the 3 possible achiral isomers of [(tren)Co(O2, OH)Co(tren)]3+ one is formed stereoselectively by oxygenation in solution.
Anwendung von Ringerweiterungen zur Herstellung von rac‐Muscon und Exalton®
Authors: Karpf Martin , Dreiding André S. 
Published: December 2004

Application of Ring Expansions for the Preparation of rac‐Muscone and Exaltone®4,6‐Undecamethylene‐2‐pyrone (8), prepared from 1‐morpholino‐cyclododec‐1‐ene (7) according to Hünig et al., was saponified and decarboxylated to a mixture of the 3‐methyl‐cyclotetradecenones 11, 12, 13 and 14, which was hydrogenated to 3‐methyl‐cyclotetradecanone (3). Similarly, 4,6‐dodecamethylene‐2‐pyrone (16) was prepared from 1‐morpholino‐cyclotridec‐1‐ene (15) and ketene, saponified to a mixture of the 3‐methyl‐cyclopentadecenones 19, 20, 21 and 22 and the latter hydrogenated to rac‐muscone (6).The ratios of the four regio‐ and stereoisomers in the above mentioned two mixtures of 3‐methyl‐cycloalkenones were derived from the 1H‐NMR.‐spectra.From the reactions of the enamines 7 and 15 were also isolated small amounts of 4,5‐decamethylene‐ (9) and 4,5‐undecamethylene‐6‐methyl‐2‐pyrone (17) respectively. Saponification and partial decarboxylation of 9 lead to (2‐acetyl‐cyclododec‐1‐enyl)‐acetic acid (23) and methyl‐(2‐methyl‐cyclododec‐1‐enyl)‐ketone (24), the latter possessing an incense‐like odor.The keton homologation method of Mock & Hartman (reaction of alkanones with diazoacetic ester in the presence of triethyl oxonium fluoroborate, followed by saponification and decarboxylation) was applied three times in succession, starting with cyclododecanone (1). This furnished, after the first stage, the cyclotridecanone (4) required for the above described synthesis of rac‐muscone (6) and, after the third stage, cyclopentadecanone (5 = exaltone®).Application of this reaction to 2‐methyl‐cyclododecanone (28) resulted in a low yield of 2‐methyl‐ (30) and 3‐methyl‐cyclotridecanone (31) in the ratio of 2:1.
The Radical Anion of 2,7‐Diazapyrene, a Change in Orbital Sequence on Protonation
Authors: Bruhin Jürg , Gerson Fabian 
Published: December 2004

AbstractESR.‐spectra are reported for the radical anion I · Θ of 2,7‐diazapyrene (I), along with those for the radical cations I(2H) · ⊕ and I(2 CH3) · ⊕ of 2,7‐dihydro‐2,7‐diazapyrene and its 2,7‐dimethyl‐derivative, respectively. In contrast to the analogous radical ions of 4,4′‐bipyridyl (II) and other previously studied diazaaromatic compounds, there is a striking change in the 14N and proton coupling constants on going from the radical anion I · Θ to the radical cations I(2H) · ⊕ and I(2 CH3) · ⊕. This change can be rationalized in terms of the HMO model of the pyrene π‐system. A reversal in the energy sequence of the lowest antibonding orbitals is predicted upon an increase in the absolute value of the Coulomb integral for the azasubstituted π‐centres, such an increase simulating the enhanced electronegativity of the azanitrogen atoms 2 and 7 on protonation.
The Radical Ions of Benzo[b]biphenylene, a Test for HMO Models of Biphenylene and its Derivatives
Authors: Gerson Fabian , Martin William B. , Sondheimer Franz , Wong Henry N. C. 
Published: December 2004

AbstractESR.‐spectra are reported for the radical anion and the radical cation of benzo[b]‐biphenylene (III). Comparison of the proton coupling constants (aHμ) for III · ⊖ and III · ⊕ with π‐spin populations (ϱμ), calculated by the McLachlan procedure, permits a lower limit of 0.77 to be set for the parameter κ = β′/β where β′ represents a reduced value of the HMO integral for the two essentially single bonds linking the benzene with the naphthalene π‐system. The differences in the aHμ values for III · ⊖ and III · ⊕ are substantially larger than those generally found for the two corresponding radical ions of alternant, purely benzenoid hydrocarbons, but they closely parallel the analogous differences observed for the radical anion and the radical cation of biphenylene.
ESR.‐Studies of Nonalternant Radicals Structurally Related to Phenalenyl
Authors: Gerson Fabian , Jachimowicz Joanna , Murata Ichiro , Nakasuji Kazuhiro , Yamamoto Kagetoshi 
Published: December 2004

AbstractThe radical anion and the radical cation of azuleno[1,2,3‐cd]phenalene (III) have been investigated by ESR. spectroscopy, along with the radical anion of 2‐phenylazulene (IV). Also studied has been the neutral radical obtained by one‐electron reduction of cyclohepta[cd]phenalenium‐cation (VI⊕). Assignment of the proton coupling constants for the radical ions III. ·⊖, III ·⊕ and IV·⊕, and the radical VI · is supported by comparison with the ESR. spectra of specifically deuteriated derivatives III‐d5 ·⊖, III‐d5 ·⊕, IV‐d2 ·⊖ and VI‐d1′. The experimental results are in full accord with qualitative topological arguments and predictions of HMO models. Whereas the radical anion III ·⊖ exhibits α‐spin distribution similar to that of IV ·⊖the corresponding radical cation III ·⊕ and the neutral radical VI · are related in this respect to phenalenyl (V·). It is noteworthy that oxidation of III by conc. H2SO4 yields a paramagnetic species (IIIa ·⊕) which has a similar – but not an identical – structure as the radical cation III ·⊕ produced from III with AlCl3 in CH3NO2.
Biosynthesis of cytochalasans. Part 5. The Incorporation of Deoxaphomin into Cytochalasin B (Phomin)
Authors: Robert Jean‐Louis , Tamm Christoph 
Published: December 2004

AbstractRadioactive deoxaphomin (1) which was obtained by feeding [4′‐3H, U‐14C]‐L‐phenylalanine to cultures of Phoma sp. (S298) was shown to be well incorporated into cytochalasin B (phomin) (2). The results demonstrate that 1 is an immediate biogenetic precursor of 2.
A New Synthesis of β‐Lactams
Authors: Prasad Kapa K. , Petrzilka Theodor 
Published: December 2004

AbstractEs wird eine neue Synthese von β‐Lactamen durch Umsatz von 4‐Alkylazlactonen mit acyclischen Iminen beschrieben. Mit einem cyclischen Imin wird dagegen ein Imidazolin‐Derivat erhalten.
Incorporation of Sulfur Dioxide into the Products of Reaction of Schiff Bases with Halo‐ or Alkylthio‐ketenes in Liquid SO2. Preliminary communication
Authors: Belluš Daniel 
Published: December 2004

AbstractA simple ‘three‐component‐reaction’ between halo‐ or alkylthio‐ketenes, Schiff bases and sulfur dioxide, yielding 4‐oxo‐1,3‐thiazolidine‐1,1‐dioxides 4 in one step, is presented.
C‐Glucuronides, a Novel Type of Drug Metabolites
Authors: Richter Wilhelm J. , Alt Karl O. , Dieterle Walter , Faigle Johann W. , Kriemler Hans‐Peter , Mory Hans , Winkler Tammo 
Published: December 2004

AbstractThe structure elucidation of C‐β‐glucuronides of sulfinpyrazone (Anturan®) and phenylbutazone (Butazolidin®) by spectroscopic means is reported. These conjugates represent a novel type of drug metabolites.
Photochemical Reactions. V. [1] Photo‐oxidation of 17 β‐acetoxy‐4‐aza‐androst‐5‐en‐3‐one
Authors: Abelló F. , Boix José , Gómez José , Morell José , Bonet Juan‐Julio 
Published: December 2004

AbstractThe photo‐oxidation of the title compound (1) is described. The isolated products are the result of a [2 + 2] oxygen addition to the olefinic double bond of the enamide.
Spiropyrannes benzoxathioliques‐1,3 photochromes: Synthèse et étude des cinétiques de décoloration thermique
Authors: Appriou Pierre , Garnier Francis , Guglielmetti Robert 
Published: December 2004

AbstractNous avons synthétisé une série de spiropyrannes benzoxathioliques par un processus en deux étapes: obtention de perchlorates styryliques en milieu acide par condensation simultanée de trois substrats intermédiaires, puis cyclisation en milieu basique. Un mécanisme est proposé.Ces spiropyrannes benzoxathioliques sont photochromes et nous avons étudié la cinétique de décoloration thermique ainsi que l'absorption visible de leurs photomérocyanines. Des observations comparables à celles enregistrées en série benzodithiolique nous ont amenés ici encore à envisager une structure de type quinonique pour la mérocyanine.
Stereoselektivität diastereogener CC‐Verknüpfungen II Eine Carben/Carbenoid‐Kaskade und «Hypermechanismen»
Authors: Schlosser Manfred , Spahić Bojana , Van Chau Le 
Published: December 2004

Stereoselectivity of Diastereogenic CC‐Linking Reactions II. A Carbene/Carbenoid‐Cascade and «Hypermechanisms»In a systematic study four pairs of dihalocarbene precursors were treated with methyllithium in the presence of 2‐methyl‐2‐pentene. Each pair was made up of a tetrahalomethane and a trihalomethane, namely CCl4 vs. CHCl3, CCl3F vs. CHCl2F, CCl2F2 vs. CHClF2 and CClF3 vs. CHF3. Since all the tetrahalomethanes reacted exclusively by chlorine/lithium exchange and all the trihalomethanes by hydrogen/lithium exchange, each pair gave rise (at least formally) to an identical ‘carbenoid’. Two different carbenoids may always undergo elimination of LiCl or LiF and thus collapse generating the same carbene.A comparison of the product composition (ratios of straight‐forward cycloaddition vs. consecutive substitution reactions, ratios of diastereoisomers) reveals more or less marked, but always significant discrepancies in the outcome of ‘carbene‐convergent’ as well as ‘carbenoid‐convergent’ reactions.
Die Thermolyse von 2,2,6,7‐Tetramethyl‐1,7 ‐epidioxybicyclo[4.3.0]non‐8‐en
Authors: Skorianetz Werner , Ohloff Günther 
Published: December 2004

Thermolysis of 2,2,6,7‐Tetramethyl‐1,7‐epidioxybicyclo[4.3.0]non‐8‐ene.Dye‐sensitized photooxygenation of the cyclopentadiene derivative 1 gives three products: the peroxide 2a and the monocyclic ketones 5 and 8. 5 and 8 are probably formed by rearrangement of the unstable peroxide 2b. Thermolysis of 2a gives, besides 5 and 8, the furylketone 9 and the cyclooctenone derivative 10. The structures of the new compounds have been established by means of spectroscopic methods and chemical transformations. A reaction mechanism for the formation of 5, 8, 9 and 10 from 2a is proposed. Irradiation of 10 leads to the two diastereoisomeric trans cyclooctenones 12a and 12b.
Neue Ambra‐Riechstoffe durch photochemische Reaktionen von 15, 16‐Dinorlabd‐8(20)‐en‐13‐on. Photochemische Reaktionen. 84. Mitteilung
Authors: Ohloff Günther , Vial Christian , Wolf Hans Richard , Jeger Oskar 
Published: December 2004

New Ambra Odorants by Photoreactions of 15, 16‐Dinorlabd‐8(20)‐en‐13‐one.UV.‐irradiation of 15,16‐dinorlabd‐8(20)‐en‐13‐one (1) led to the fragmentation product 4 and its photo‐cyclisation product 5. Ethers 6 and 7 and the βγ‐unsaturated alcohols 8 and 10 were formed via ketone 9, a double bond isomer of 1. The olfactory properties of the photo‐products are described.
Photochemische Reaktionen. 85. Mitteilung [1]. Zur Photochemie von α, β‐Epoxy‐eucarvon
Authors: Frei Bruno , Wolf Hans Richard 
Published: December 2004

Photochemistry of α,β‐epoxy‐eucarvone.On π,π*‐excitation (λ = 254 nm) 4 isomerizes to the bicyclic ketoaldehyde 5; on n,π*‐excitation (λ ⩾ 280 nm) 4 gives 5, the β,γ‐unsaturated ketone 6, the enone 7 and the cyclobutanone 8. Scission of the (C—C)‐bond of the oxirane 4 would give the dihydrofurane e, which could isomerize to the ketoaldehyde 5. On the other hand, 4 is assumed to isomerize to the β,γ‐unsaturated aldehyde c, which could yield 6 and 7 by photodecarbonylation. The cyclo‐butanone 8 is shown to be a photoisomer of the ketone 6.Furthermore, eucarvol (18) rearranges by a thermal [1,5]‐H‐shift to dihydro‐eucarvone (20); on UV.‐irradiation 18 gives the bicyclic isomers 27 and 28.
The Chemical Ionization of Organic Compounds. 1st Communication. Linear alkenes with six to nine carbon atoms
Authors: Houriet Raymond , Gäumann Tino 
Published: December 2004

AbstractThe chemical ionization spectra of linear alkenes have been measured using H2O, CH4 or CD3OD as ionizing gas. In the case of 1‐heptene the dependence of spectra on pressure, temperature and repeller field strength has been measured and is discussed.
Azidiniumsalze. 17. Mitteilung [1]. Azidiniumsalze und Triazatrimethincyanine substituierter Benzimidazole
Authors: Balli Heinz , Maul Rudolf 
Published: December 2004

Azidinium Salts and Triazatrimethinecyanines of Substituted Benzimidazoles.1‐Äthyl‐2‐chlor‐5‐X‐benzimidazole (X  H, CH3, CH3O, CF3, Cl, COOC2H5, NO2) werden hergestellt und durch Triäthyloxonium‐tetrafluoroborat in 1,3‐Diäthyl‐2‐chlor‐5‐X‐benzimidazolium‐tetrafluoroborate übergeführt, die in Methanol mit Natriumazid eine nukleo‐phile Substitution zu 1,3‐Diäthyl‐2‐azido‐5‐X‐benzimidazolium‐tetrafluoroboraten erfahren. Letztere werden durch Natriumazid in Dimethylformamid in Bis‐(1,3‐diäthyl‐5‐X‐benzimidazol‐2)‐triazatrimethincyanin‐tetrafluoroborateumgewandelt. UV./VIS.‐Daten der Farbsalze in Methanol werden diskutiert.
The Derivation of Inductive Substituent Constants from pKa Values of 4‐Substituted Quinuclidines. Polar effects. Part I
Authors: Grob Cyril A. , Schlageter Markus G. 
Published: December 2004

AbstractThermodynamic pKa‐values have been determined for 38 4‐substituted quinuclidinium perchlorates. They are remarkably sensitive to the polar effect of the substituent and cover a range of 3.63 pKa units. Furthermore, they vary linearly and almost equally with temperature since the contribution of the TΔS° term to the free energy of ionization is relatively small and constant. The magnitude of the polar effect of the 4‐cyano group varies with the solvent and appears to depend on its ability to form hydrogen bonds to the substituent rather than its dielectric constant.New inductive substituent constants σIq are derived from the pKa values. Their correlation with known inductive constants is only fair or unsatisfactory, especially as regards the relative order of hydrogen and the alkyl groups. The discrepancies can be ascribed mainly to the different models used to derive the substituent constants.
Syntheses of (2R, 4′R, 8′R)‐α‐Tocopherol and (2R, 3′E, 7′E)‐α‐Tocotrienol
Authors: Scott John W. , Bizzarro Fred T. , Parrish David R. , Saucy Gabriel 
Published: December 2004

AbstractReaction of trimethyl‐hydroquinone with methyl vinyl ketone in acidic methanol gave rac.‐2‐methoxy‐2,5,7,8‐tetramethyl‐chroman‐6‐ol (8). This acetal was converted in four steps to rac.‐(6‐hydroxy‐2,5,7,8‐tetramethyl‐chroman‐2‐yl)acetic acid (13). Acid 13 was readily resolved with α‐methyl‐benzylamine to give the (S)‐enantiomer 14. Treatment of the unwanted (2 R)‐isomer with acid regenerated 13, thus leading to an efficient use of this compound. Employing a side chain derived from phytol, 14 was converted to (2R, 4′R, 8′R)‐α‐tocopherol (1d, ‘natural’ vitamin E). A reaction sequence from 14 involving two highly stereoselective Claisen rearrangements has provided the first total synthesis of (2R,'E,7′E)‐α‐tocotrienol (2d).
Migration du groupe éthoxycarbonyle dans la transposition de Wagner‐Meerwein
Authors: Phan Trung Hieu , Dahn Hans 
Published: December 2004

Ethoxycarbonyl group migration in the Wagner‐Meerwein rearrangement.13 β‐Hydroxy‐esters have been treated with P2O5 in benzene at 80°. Olefin‐forming dehydration, when possible, was found to be the main reaction. When this is excluded, tertiary or benzylic hydroxy‐esters react in a manner most easily explained by migration of the COOEt group, thus avoiding the formation of α‐carbonyl‐carbenium ions. On the other hand, in primary hydroxy‐esters (incapable of direct olefin formation), phenyl and methyl groups migrate in preference to COOEt, indicating in this case a concerted reaction.
Peptidsynthese: Verfolgung der Abspaltung von Benzylschutzgruppen mittels 1H‐NMR.‐Spektroskopie
Authors: Monnier Vincent M. 
Published: December 2004

Peptide synthesis: The following of the cleavage of benzyl protecting groups with 1H‐NMR. spectroscopy.In spite of the great number of signals 1H‐NMR. spectroscopy can be used to demonstrate the presence or absence of oxygen bound benzyl groups in protected viz. deprotected peptides.
Komplexbildung von Ionophoren vom Typ der Dioxakorksäurediamide mit Alkali‐ und Erdalkaliionen. Stabilitätskonstanten in Äthanol
Authors: Kirsch Norbert N. L. , Simon Wilhelm 
Published: December 2004

Complex Formation of Ionophores of the Dioxaoctane Dicarboxylic Acid Diamide Type with Alkali and Alkaline Earth Cations. Stability Constants in Ethanol.Stability constants are reported for two noncyclic, neutral ionophores in interaction with alkali and alkaline earth metal cations in ethanol. The ligands studied give high selectivity of alkaline earth in respect to alkali metal cations when used in liquid membrane electrodes.