bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaktionen von Bleitetraacetat mit alicyclischen Alkoholen, III. Cyclopropyl‐ und Cyclobutylcarbinole. 18. Mitteilung über Reaktionen mit Bleitetraacetat
Authors: Lj. Mihailović M. , Čekovié Ž. 
Published: December 2004

AbstractWhen treated with lead tetraacetate, cyclopropylcarbinol and cyclopropylmethylcarbinol do not give β‐fragmentation products resulting from the intermediate formation of cyclopropyl radicals; however, cyclopropylmethylcarbinol affords a small amount of a fragmentation product which arises from CαCβ bond cleavage involving removal of a methyl radical. In contrast, cyclobutylcarbinol undergoes β‐fragmentation in 18% yield with formation of both the unrearranged cyclobutyl acetate and the rearranged cyclopropylmethyl acetate. These results suggest the following order of increasing radical stability: cyclopropyl < methyl < cyclobutyl, whereas the isolation of the isomeric fragmentation acetates in the lead tetraacetate reaction of cyclobutylcarbinol represents further evidence that in the β‐fragmentation process the initially produced carbon radical fragment is in major part oxidized to the corresponding carbonium ion before final product formation.
Fluoreszierende Stoffe aus Drosophila melanogaster. 14. Mitteilung [1]. Eine Synthese des Biopterins
Authors: Viscontini M. , Provenzale R. 
Published: December 2004

Abstract2,4,5‐Triamino‐6‐oxo‐1, 6‐dihydropyrimidin wird mit 1‐(Benzylphenylhydrazino)‐5‐desoxy‐L‐ribulose in wässrigem Methanol unter N2 kondensiert. Die Mischung der gebildeten Tetrahydropterine wird zu den entsprechenden Pterinen oxydiert, wobei die polyhydroxyalkylierte Kette teilweise abgespalten wird. Diese Pterine stellen eine Mischung von Biopterin, wenig seines 7‐Isomeren und viel Pterin sensu stricto dar. Aus dieser Mischung lässt sich reines Biopterin durch Chromatographie an Dowex 1 × 8 gewinnen. Das synthetische und das aus Drosophila melanogaster isolierte Biopterin sind völlig identisch.
Le blocage de la lysine par la réaction de MAILLARD. I. Synthèse de N‐(désoxy‐1‐D‐fructosyl‐1)‐ et N‐(désoxy‐1‐D‐lactulosyl‐1)‐L‐lysines
Authors: Finot P. A. , Mauron J. 
Published: December 2004

AbstractThe authors describe a specific method for the preparation of Nϵ‐(1‐deoxy‐D‐fructosyl)‐L‐lysine, Nα‐(1‐deoxy‐D‐fructosyl)‐L‐lysine, their formyl derivatives, and Nα‐formyl‐ϵ‐(1‐deoxy‐D‐lactulosyl)‐L‐lysine, as well as Nα, Nϵ‐di‐(1‐deoxy‐D‐fructosyl)‐L‐lysine. After purification by cation‐exchange chromatography using volatile pyridine‐acetic acid or pyridine‐formic acid buffers, these compounds are obtained in the pure state. By thin‐layer chromatography and paper electrophoresis these lysine derivatives can be rapidly separated and identified.
Die Oxydation von Alkoholen mit Bleitetraacylaten; Einfluss der Acylreste bei der thermischen Reaktion
Authors: Heusler K. 
Published: December 2004

AbstractThe competitive thermal oxidation of a 6β‐hydroxy steroid (to a 6β, 19‐ether) and the thermal oxidative decarboxylation of various carboxylic acids by lead4+ was investigated. The alcohol oxidation is faster than acetate and benzoate oxidation, about as fast as the oxidative decarboxylation of higher primary carboxylic acids (propionic, butyric acid), and much slower than the oxidative decarboxylation of secondary and tertiary carboxylic acids.
δ1‐p‐Menthen‐9‐al, ein Bestandteil des bulgarischen Rosenöls
Authors: Ohloff G. , Giersch W. , Schulte‐Elte K. H. , Kovats E. sz. 
Published: December 2004

AbstractAls einer der Bestandteile des riechenden Prinzips vom bulgarischen Rosenöl wurde (+)‐δ1‐p‐Menthen‐9‐al erkannt. Seine Stereochemie wurde zusammen mit einer Reihe verwandter Verbindungen festgelegt. 2, 8 und 10 besitzen danach die 4 R, 8 R‐Konfiguration, während die Chiralitätszentren der Verbindungen 3, 9 und 11 mit 4 R, 8 S bezeichnet werden müssen. Demzufolge konnte für 4, 5, 12 und 14 die 8 R‐, für 6, 7, 13 und 15 die 8 S‐Konfiguration abgeleitet werden.
Struktur der Marsectobiose. Desoxyzucker, 46. Mitteilung
Authors: Saner A. , Allgeier H. 
Published: December 2004

AbstractMarsectobiose (1), a disaccharide isolated from Marsdenia erecta R. Br., is shown to be 4‐O‐(3‐O‐methyl‐6‐deoxy‐β‐D‐glucopyranosyl)‐3‐O‐methyl‐2, 6‐dideoxy‐D‐arabinohexose.
Über 1, 5‐Diphenyl‐2, 3, 6, 7‐tetrahydro‐1H, 5H‐pyrazolo[1, 2‐a]pyrazole(2, 6‐Diphenyl‐1, 5‐diazabicyclo[3, 3, 0]octane)
Authors: Wagner‐Jauregg Th. , Zirngibl L. , Demolis A. , Günther H. , Tam S. W. 
Published: December 2004

AbstractThe synthesis of a 1, 5‐diphenyl perhydro‐pyrazolo‐[1, 2‐a] pyrazole (IV) (m. p. = 170–171°) by LiAlH4‐reduction of its 3, 7‐dioxo derivative Va, one of the stereoisomers of V, is described. Va was obtained in small yield by the reaction of cinnamic acid with its hydrazide or with hydrazine. It proved to be identical with the compound obtained previously by interaction of cinnamic acid hydrazide with iodine which in the literature erroneously had been described as N, N′‐dicinnamoyl hydrazine. This hydrazine now was obtained by bis‐acylation of hydrazine with cinnamoyl chloride.In Va the extremely low NMR. absorption of the tertiary protons at ρ = 4,6 ppm is probably due to the spatial grouping magnified image with the proton situated in the deshielding region of the carbonyl group.Previously, another tertiary proton with a very low NMR. absorption at ρ = 4,85 ppm has been observed in the «bisimide M», the main criss‐cross addition product of one mole benzaldazine and two moles of N‐(n‐butyl)‐maleinimide. A stereostructure for bisimide M is now proposed, which is a hybrid between those of the bisimides L and H.
Cyclopentadienyl‐Metallverbindungen. 1. Zusammenhang zwischen Stabilität und Dissoziationsenergien von Metall‐Kohlenstoffbindungen in M5H5‐Komplexen
Authors: Egger Kurt W. 
Published: December 2004

AbstractThe existence and thermal stability of CH(3) M(σC5H5) compounds has been viewed in terms of the bond dissociation energies involved, which predict the two‐center covalent two‐electron metal‐σC5H5 bond to be ∼30 kcal/mole less stable than the parent metal‐CH3 bond. The available experimental data are shown to be consistent with this prediction. Electron donating ligands can lead to stable two‐center diene‐type covalent metal‐C5H5 bonds, even where the two‐electron σ‐bond would not be stable. With the exception of group IIB, transition metals are not capable of forming stable metal‐σC5H5 complexes.
Die Hydrolyse des Ga3+‐Ions; potentiometrische Untersuchungen in 3m NaClO4 bei 60°C
Authors: Gamsjäger H. , Aeberhard K. , Schindler P. 
Published: December 2004

AbstractThe hydrolysis of the ion Ga3+ has been investigated at 60°C by potentiometric titrations in a sodium perchlorate medium of the constant ionic strength 3 m. Solutions of various total gallium concentrations B were alkalified by means of a coulometric technique. The concentrations h of the free hydrogen ions were measured with the aid of a glass electrode. From the experimental data, Z, the average number of OH bound per Ga was calculated. The mathematical analysis of the curves Z(logh)B is consistent with the following formulation of the hydrolysis reactions

with log*βl = log k0 kl = −1,7 − 11,55 l.
Kristallstruktur von Cadmium‐Kupfer‐Hydroxidnitrat, CdCu3 (OH)6 (NO3)2·H2O
Authors: Oswald H. R. 
Published: December 2004

AbstractThe crystal structure of cadmium copper hydroxide nitrate, CdCu3 (OH)6 (NO3)2 · H2O, has been determined from three dimensional single crystal X‐ray data.One single elementary cell of the compound has to be of triclinic symmetry, but as either the crystal is built up from such triclinic domains grown together regularly at angles of 120 degrees, or the nitrate groups of the whole crystal are distributed statistically over three possible orientations standing at 120 degree angles respectively to each other, the structure can also be described in the hexagonal system: a = 6.522 ± 0.005 Å, c = 7.012 ± 0.006 Å, space group D – P 3 m 1, cell content one formula unit.Mixed layers (00.1) of Cu and Cd atoms are embedded between layers consisting of the OH groups and one oxygen atom per nitrate group. The nitrate groups extend with their trigonal plane nearly perpendicular to the layers (00.1) and connect them by hydrogen bridges between the remaining two oxygen atoms and OH groups of the next layer. The Cd atoms are coordinated octahedrally by six equidistant OH groups, and the Cu atoms have a strongly distorted octahedral (4 + 2) coordination with four OH groups and two nitrate oxygens. Thermogravimetric measurements allowed to distinguish the crystal water molecule from variable amounts of excess water. The hydrogen bonds between OH groups and nitrate oxygen atoms and the deformation of the nitrate groups were confirmed by infrared spectra.
Die Struktur des KNCS‐Komplexes von Nonactin
Authors: Dobler M. , Dunitz J. D. , Kilbourn B. T. 
Published: December 2004

AbstractThe macrotetrolide antibiotic nonactin forms a crystalline complex with KNCS. The crystals are orthorhombic, a = 20.17, b = 15.55, c = 15.33 Å, space group Pnna (D,h) with four molecules per unit cell. The crystal structure has been determined with the help of direct methods and refined by full‐matrix least‐squares analysis of three‐dimensional diffractometer data. The K+ ion is surrounded by four O‐atoms from tetrahydrofurane rings (K+ … O, 2.81–2.88 Å) and by four carbonyl O‐atoms (K+ … O, 2.73–2.81 Å) in approximately cubic 8‐coordination. The observed conformation of the 32‐membered ring of the macrotetrolide has approximate S4(4)‐symmetry and can be described as resembling the seam of a tennis ball with K+ at the centre of the ball and with methyl substituents and methylene groups of the tetrahydrofurane rings on the outside. The constitution and configuration of nonactin, as reported on the basis of chemical studies [10], is confirmed by the present analysis. Some implications of the structure are discussed.
Ungesättigte Zucker. Eine milde Sulfonat‐β‐Eliminierung bei Aminohexopyranosiduronat‐Derivaten
Authors: Kiss J. , Burkhardt F. 
Published: December 2004

AbstractSubstituted 2‐deoxy‐2‐acylamino‐4‐O‐methanesulfonyl‐hexopyranosiduronates yield, by mild alkaline mesylate (a, e)‐β‐elimination, the corresponding 4,5‐unsaturated 4‐deoxyhexopyranosiduronates VIII. This type of aminosugars proved to be the cyclic enol‐ether acetal form of the 2,4‐dideoxy‐2‐acylamino‐hexos‐5‐ulosuronates. The structural principle of the latter can be found e.g. in neuraminic acid.These 4,5‐unsaturated 4‐deoxy‐acylamino‐hexopyranosiduronates give by reduction with NaBH4 the corresponding 4,5‐unsaturated 2,4‐dideoxy‐2‐acylamino‐hexopyranosides IX (with an endocyclic double bond on the glycosidic C atom 5).The isomeric 5,6‐unsaturated 2,6‐dideoxy‐2‐acylamino‐hexopyranosides XVI (with an exocyclic double bond) are furthermore synthesized according to the method of HELFERICH [14] by elimination of a molecule of HI from the corresponding 2,6‐dideoxy‐2‐acylamino‐6‐iodo‐4‐O‐acylhexopyranoside derivatives XV.The ring stability of the two types of isomeric unsaturated hexopyranosides mentioned (bearing respectively an exo‐ and an endocyclic 5‐enol‐ether linkage) has been examined. In accordance with the stability principle of BROWN [16] – on the base of our preliminary experimental indications – the hexopyranosides with endocyclic double bond have been shown to be more stable than those with an exocyclic double bond: the latter (1) decompose slowly at 20°; (2) the α‐glycosidic linkage is very easily split by dil. acetic acid at 20° within a few hours, giving 2, G‐dideoxy‐2‐acyl‐amino‐D‐xylo‐hcxofuranos‐5‐ulose derivatives XX. On the other hand, the hcxopyranosides with endocyclic double bond show in the mass spectrometer, besides other fragmentations, a retro‐dien decomposition.Some data on the NMR. spectra (100 and 220 MHz) of the above isomeric unsaturated acylamino‐hexopyranosides (and hexopyranosiduronates, resp.) are furnished. The ORD./CD. spectra of the 4,5‐unsaturated 2,4‐dideoxy‐2‐acylamino‐hexopyranosiduronates, which have two «COTTON centres», have been measured.
Recherches sur la formation et la transformation des esters LXXXIII [1]. Réactions de condensation et/ou de phosphorylation, en solution aqueuse, de divers composés organiques à fonctions OH, COOH, NH2, ou autres, à l'aide de polyphosphates linéaires ou cycliques
Authors: Rabinowitz Joseph 
Published: December 2004

AbstractAmino acids and other derivatives are condensed in aqueous solutions in the presence of linear or cyclic polyphosphates (or other anhydrides of P acids). The best results are obtained in slightly alkaline media (pH 7.5 to 9.5). The reaction, which has been studied at 70°C and at room temperature, proceeds with relative ease even at room temperature. In the case of the cyclic polyphosphates, trimetaphosphate gave the best results as compared with tetra‐ and hexametaphosphate, and among the linear polyphosphates used the yields grew with the average length of the chain.The significance of this method of condensation as a general method and also in the context of chemical evolution is discussed.The author suggests that one of the pathways leading to the peptide bond formation involves the intermediate formation of aminoacyl phosphates or polyphosphates by the nucleophilic attack of the carboxylate group of the amino acid on the phosphorus of a linear or cyclic POP bond, giving rise to the labile mixed anhydride, and subsequent nucleophilic attack of the amino nitrogen of a molecule of the amino acid, or of the aminoacyl phosphate already produced, on the C of the mixed anhydride with displacement of phosphate or polyphosphate and formation of a peptide bond. Other pathways may also involve the intermediate formation of phosphoramidates which may result from the reaction of amino groups (or ammonia) with trimetaphosphate in alkaline medium.Linear and cyclic polyphosphates (which are known to be phosphorylating agents of the OH (alcoholic) function in aqueous solutions at pH's above 7) phosphorylate serine, ethanolamine and threonine in aqueous solutions at pH 8–10 with yields up to 25%.
Strom‐Spannungs‐Zeit‐Beziehungen bei der Bildung metallischer Monoschichten
Authors: Schmidt E. 
Published: December 2004

AbstractDer bei der Bildung einer Metallmonoschicht fliessende Polarisationsstrom setzt sich aus einem durch die Depolarisatoradsorption bedingten, der zeitlichen Änderung der Oberflächenkonzentration des Mez+‐Ions proportionalen Nettostrom und einem depolarisatorunabhängigen Grundstrom zusammen. Es werden Beziehungen zwischen Nettostrom, Elektrodenpotential und Versuchszeit diskutiert, die sich unter der Annahme quasistatischer, diffusionskontrollierter und diffusions‐durchtritts‐kontrollierter Mez+‐Adsorption ergeben.
Sur quelques réactions par décharge électrique dans les systèmes phosphine‐eau, phosphine‐eau‐ammoniac et phosphine‐eau‐ammoniac‐méthane
Authors: Rabinowitz Joseph 
Published: December 2004

AbstractElectric discharge reactions in the systems PH3 + H2O, PH3 + H2O + NH3 and PH3 + H2O + NH3 + CH4 have been studied.In the system PH3 + H2O, they produce polyphosphines (insoluble in water) and hypophosphorous, phosphorous and orthophosphoric acids.In the system PH3 + H2O + NH3, besides the above products, hypophosphate, pyrophosphate, polyphosphates and possibly polyhyphosphates are also present.In the system PH3 + H2O + NH3 + CH4, besides all the above inorganic P compounds, organic phosphorus derivatives such as aminoalkyl phosphates and aminoalkanephosphonates are also formed, as well as other non‐phosphorus containing organic products (amino acids, ethanolamine, etc.). The presence of phosphine (or its transformation products), seems to promote condensation reactions in this system since the ratio of amino acids found after hydrolysis (in 6N HCl) to amino acids found before hydrolysis is greater in this system. than in the system (CH4+ H2O+ NH3)iiot containing phosphine.
Contribution à la connaissance des o‐menthols et des o‐menthones (carquéjanols et carquéjanones) ‐ 1ère communication
Authors: Ferretti‐Alloise Maria‐Giulia , Jacot‐Guillarmod André , Naves Yves‐René 
Published: December 2004

AbstractThe mixture of carquejanols obtained from carquejol of carqueja oil has been converted in ketones. The alkohols obtained respectively by hydrogenation on Pt(O2), by lithium‐aluminiumhydride reduction and by Meerwein‐Ponndorf‐Verley reaction have been separated by vapour phase chromatography. The ketones obtained from the Beckmann oxidation of the alkohols has been identified as carquejanone and isocarquejanone by application of the Auwers‐Skita rule.
Die Bildung von Hexahydro‐1,2,4,5‐tetrazinderivaten bei der Reaktion von Aldehyden mit Hydrazin
Authors: Skorianetz W. , Sz. Kováts E. 
Published: December 2004

AbstractThe cristalline reaction products of acetaldehyde and some of its higher straight chain homologues with one equivalent of hydrazine are shown to be 3, 6‐dialkyl‐hexahydro‐1, 2, 4, 5‐tetrazines (1) which can be oxidized to the corresponding 3, 6‐dialkyl‐1, 2, 4, 5‐tetrazines.
Zur Thermodynamik der Metallcarbonate. 4. Mitteilung. Potentiometrische Untersuchungen am System Mn2+CO2H2O
Authors: Gamsjäger H. , Kraft W. , Schindler P. 
Published: December 2004

AbstractThe solubility and the complex equilibria in the system Mn2+‐CO2‐H2O have been investigated at 25°C in solutions of the constant ionic strength 3 M (Na)ClO4. From experimental data the following values for equilibrium constants and Gibbs free energies of formation are deduced:

A predominance area diagram for the system Mn2+‐H2‐CO2(g)‐H2S(g) including MnCO3(ppt.), α‐MnS and Mn2+ is given.
Protonierung von Amino‐ und Hydroxypyrimidinen NMR‐Spektren und Strukturen der Mono‐ und Dikationen
Authors: Wagner R. , Von Philipsborn W. 
Published: December 2004

AbstractProton‐NMR. spectra of amino‐ and hydroxypyrimidines including biologically important bases have been measured in four solvents: CF3COOH, CF3COOHSO2, FSO3H and FSO3HSbF5–SO2 at 27° and −55°C. In CF3COOH mono‐cations are formed, whereas in FSO3H and FSO3HSbF5–SO2 double protonation occurs. In each case the structures of the protonated species are derived from the chemical shifts of CH, NH and OH protons and proton‐proton spin coupling constants. A combination of the measurements described leads to a complete assignment of all proton resonances of the protonated pyrimidines. This approach is also recommended for the structural determination of heterocyclic compounds.
Die Photoelektron‐Spektren von Chlor‐, Brom‐ und Jodcyan. Vorläufige Mitteilung
Authors: Heilbronner E. , Hornung V. , Muszkat K. A. 
Published: December 2004

AbstractThe four bands which have been observed in the photoelectron‐spectra of the cyanogen halides CICN, BrCN and ICN (region from 10 to 20 eV) have been assigned to the following states:

.
Über Pyrrolizidinchemie. 9. Mitteilung. Synthese von 1‐Hydroxy‐7‐oxo‐5,6‐dihydropyrrolizin
Authors: Viscontini M. , Bühler H. 
Published: December 2004

AbstractDas 1, 4‐Dioxa‐7‐azaspiro [4, 4]nonan (I) addiert eine Molekel von α‐Chloracrylsäure‐methylester unter Bildung von 3‐[1, 4‐Dioxa‐7‐azaspiro [4, 4] nonyl‐(7)]‐2‐chlor‐propionsäure‐methylester (II). Dieses Produkt wird mit Polyphosphorsäure zu III deketalysiert, das mit Natriumäthylat zu 1‐Hydroxy‐7‐oxo‐5, 6‐dihydropyrrolizin (IV), unter gleichzeitiger HCl‐Abspaltung, cyclisiert wird. Das unerwartet sehr beständige Produkt wird beschrieben und mit Isomaltol, einem Isologen der Furan‐Reihe, verglichen.
Das Phenylcarbamylchlorid‐Phenylisocyanat‐Gleichgewicht in Chlorbenzol
Authors: Konecny Jan 
Published: December 2004

AbstractThe equilibrium constant for the reaction C6H5NHCOCl = C6H5NCO + HCl in chlorobenzene solution is K = 0.14 mole/kg at 70°. The approximate values of the enthalpy and the entropy of the reaction are ΔH0 = 12 kcal and ΔS0 = 31 cal/deg.
Über Oxidhydroxide des vierwertigen Mangans mit Schichtengitter 2. Mitteilung: Mangan (III)‐manganat (IV)
Authors: Giovanoli R. , Stähli E. , Feitknecht W. 
Published: December 2004

AbstractThe preparation and probable structure of managanese (III)‐manganate (IV) Mn7O13, 5H2O (a0 = 2,84, c0 = 7,27 Å) and manganous (II)‐manganate (IV) Mn7O12, 6H2O are described. Both consist of platelets. Digesting in diluted HNO3 leads to γ‐MnO2 (nsutite). Manganese (III)‐manganate (IV) is much less stable than the sodiummanganese (II, III)‐manganate‐(IV) described earlier and looses water easily when heated or in vacuo. Water loss results in breaking down of the double layer lattice, and the product is only two‐dimensionally ordered, producing only prism reflections on the X ray diagramm. Heating results in a continuous transition to the two‐dimensionally ordered phase, then to a finely divided and very disordered γ‐MnO2, and eventually to a finely divided and disordered β‐MnO2 (pyrolusite). The transition is topotactical so far, but further heating produces δ‐Mn2O3 without obvious topotactical relations to the earlier products. The so‐called ‘δ‐MnO2’ (birnessite) appears to be a family of finely divided and very disordered varieties of such manganates (IV) with part of the Mn3+ substituted by Mn4+. Since such products usually contain remarkable amounts of alkali ions, they are rather varieties of the earlier described sodiummanganese (II, III)‐manganate (IV). A provisional explanation of the streaking in the electron diffractions of these manganate (IV). A provisional explanation of the streaking in the electron diffractions of these manganates (IV) is given. With respect to these results the so‐called ‘δ‐MnO2’ can no longer be attributed to the true manganese dioxides.
Über eine ungewöhnliche Cyclisationsreaktion bei der Umsetzung von (+)‐Epoxy‐α‐dihydrojonon mit Hydrazinhydrat
Authors: Ohloff G. , Uhde G. 
Published: December 2004

Abstract(+)‐Epoxy‐α‐dihydroionone (2) is formed completely stereospecifically from (+)‐α‐ionone (1). Under the conditions of the Wharton reaction this epoxide gives the expected isomeric allyl alcohols 4 and 5 and, surprisingly, the bicyclic allyl alcohol 3. The structure and absolute configuration of the reaction products have been established. A common intermediate for the formation of compounds 3, 4 and 5 is probably the vinyl anion C.
Synthese und Fragmentierung von 4‐Halogen‐ und 4‐Tosyloxy‐chinuclidinen. Chinuclidinreihe, 9. Mitteilung
Authors: Grob C. A. , Kostka K. 
Published: December 2004

AbstractThe synthesis and fragmentation of 4‐chloro‐, 4‐iodo‐ and 4‐tosyloxy‐quinuclidine are described.
Contribution à l'étude de la mésomérie, VIII [1] Système formé de deux atomes à deux électrons et de n atomes à un électron chacun
Authors: Klement O. , Portmann J. 
Published: December 2004

AbstractUne simplification des calculs dans le cadre de la méthode de mésomérie, analogue à celle indiquée dans [1], est présentée pour un système à deux atomes bivalents et n atomes mono‐valents.
Autoxydation von CuI‐Komplexen IV Der Einfluss der mehrzähnigen Komplexbildner Histamin, Histidin, Carnosin und Histidylhistidin
Authors: Zuberbühler A. 
Published: December 2004

AbstractThe autoxidation of the CuI‐complexes with the chelating ligands histamine, histidine, carnosine, and histidylhistidine has been studied spectrophotometrically using a stopped flow setup. The reaction of these complexes is in general very rapid compared with the reactions of complexes of unidentate ligands studied earlier. It seems that for rapid autoxidation the formation of a CuII‐like quadricoordinated transition state must be easy, and when the same number of similar ligand atoms are bound in the cuprous complex sterical factors seem to play an important role.
Fluxional Isomerism in a Prebullvalene Lactone
Authors: Von Philipsborn W. , Altman J. , Babad E. , Bloomfield J. J. , Ginsburg D. , Rubin M. B. 
Published: December 2004

AbstractA prebullvalene lactone exhibits fluxional isomerism in solution. Analysis of proton NMR. spectra at 100 MHz and 220 MHz together with variable temperature studies show that the species existing in solution are 7, 8 and 9.