bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tetrathiafulvalene. VIII. Ethylenverbrückte polymere Tetrathiafulvalene
Authors: van Hinh Le , Schukat G. , Fanghänel E. , Libera L. 
Published: December 2004

Tetrathiafulvalenes. VIII. Ethylene‐bridged Polymer TetrathiafulvalenesSyntheses and properties of ethylene‐bridged polymer tetrathiafulvalenes are described. These polymers react with bromine, iodine or tetracyanoquinodimethane to form the radical cation salts, whose electrical conductivity are estimated by means of powder compactions. The polymer radical cation salts have a higher conductivity than the polymer TTF (σRT max. 10−5 Ω−1cm−1). The differences in the conductivity between polymer TTF‐cationhalides and polymer TTF‐TCNQ‐salts are small.
Die Bestimmung der isosteren Adsorptionswärme von n‐Butan an den Zeolithen NaX und NaY
Authors: Stach H. , Fiedler K. , Scholtyssek P. , Schirmer W. 
Published: December 2004

Isosteric Heat of Adsorption of n‐Butane on Zeolites NaX and NaYUsing the technique of measuring isosteres the equilibria of adsorption of n‐butane on zeolites NaX and NaY were investigated. From the isosteres the heats of adsorption were calculated. Although the differences between the enthalpies are small the zeolithe with higher electrostatic field in the cavity always shows larger heats of adsorption. These differences are explained assuming an adsorption of the n‐butane molecules at (or near) Na+‐cations in SIII position (which are found only in NaX‐zeolites).
Der kristallin‐flüssige Zustand als Kriterium zur Konstitutionsermittlung von Derivaten tautomeriefähiger heterocyclischer Systeme. II. Kristallin‐flüssige Thiobenzoesäure‐pyridazinyl‐(3)‐ester
Authors: Zaschke H. , Hyna C. 
Published: December 2004

The Liquid Crystalline State as a Criterion in Determination of Structure. II. Crystalline Liquid Thiobenzoic Acid Pyridazinyl‐(3)‐estersThe synthesis of subst. thiobenzoic acid‐S‐esters of 3‐mercapto‐1H‐pyridazinethione‐(6) 1, of subst. 6‐phenyl‐3‐mercapto‐pyridazines 3 and of 6‐alkoxy‐3‐mercapto‐pyridazines 7 is described. The liquid crystalline properties of these esters are discussed.
Zur Analytik von Kohlenwasserstoffen mit Hilfe der Massenspektrometrie. VII. Der elektronenstoßinduzierte Zerfall von cis‐Bicyclo(n.2.0)‐alkanen
Authors: Herzschuh R. , Epsch K. 
Published: December 2004

Analysis of Hydrocarbons by Means of Mass Spectrometry. VII. The Fragmentation of Bicyclo(n.2.0)alkanes by Electron ImpactThe mass spectra of cis‐bicyclo(n.2.0)alkanes (n = 3–6) are characterized by small intensities of molecular ions and large intensities of (MC2H4)+‐ions. The stability of M+ and the main fragmentations are a function of the ring size of the second ring.
Dienoligomerisierung. XV. Palladiumkomplexkatalysierte Telomerisierung von Butadien mit Aminen und Dimerisierung in Gegenwart von Ketoximen
Authors: Beger J. , Meier F. 
Published: December 2004

Diene Oligomerization. XV. Palladiumcomplexcatalyzed Telomerization of Butadiene with Amines and Dimerization in the Presence of KetoximesButadiene reacts with primary or secondary amines and with the homogeneous catalytic system bis‐acetylacetonatopalladium‐(II)/triphenylphosphine to form 1‐amino‐octa‐2,7‐dienes. The rate and the selectivity of the reaction increase in presence of cocatalysts as triarylphosphates instead of triphenylphosphine and if the reaction proceeds in a protic media — in alcohols, water or lower carboxylic acids. A number of 1‐aminoocta‐2,7‐dienes were prepared. If oximes act as organic nitrogen compounds, only n‐octa‐1,3,7‐triene is selectively formed. Schiff' bases aldolisate under the conditions of the reaction.
The comparative kinetics of tungstate and molybdate ions catalysed Epoxidation of Crotonaldehyde by Hydrogen Peroxide
Authors: Ahmad Iftikhar , Yusuf Hafiz M. 
Published: December 2004

Die Konkurrenzkinetik der wolframat‐ und molybdationenkatalysierten Epoxidierung von Crotonaldehyd durch WasserstoffperoxidDie Konkurrenzkinetik der Epoxidierung von Crotonaldehyd durch Wasserstoffperoxid in Gegenwart von Natriumwolframat oder Natriummolybdat wird untersucht.Natriumwolframat ist ein wirksamerer Katalysator bei der Umsetzung von Crotonaldehyd in 2,3‐Epoxybutyraldehyd. Die Reaktion ist bezüglich Substrat und Katalysator 1. Ordnung, bezüglich Wasserstoffperoxid 0. Ordnung.Ein mit den gefundenen Abhängigkeiten übereinstimmendes Geschwindigkeitsgesetz wird aufgestellt.
Vinyloge Acylverbindungen. XIX. Vinyloge Acylgruppenwanderung am 2‐Aminophenol. Ein Beitrag zum Isomerisierungsmechanismus gemischter Diacylderivate des 2‐Aminophenols
Authors: Fischer Gerhard W. 
Published: December 2004

Vinylogous Acyl Compounds. XIX. Vinylogous Acyl Group Migration in 2‐Aminophenol. A Contribution to the Isomerization Mechanism of Mixed Diacyl Derivatives of 2‐AminophenolStarting with 2‐acylaminophenols 5 and 2‐(2‐acylvinylamino)‐phenols 6 the N‐acyl O‐acylvinyl derivatives 7 of 2‐aminophenol and their N‐acylvinyl O‐acyl isomers 8 were prepared and characterized. These vinylogous acyl compounds are able to isomerize in the same manner as simple O,N‐diacylated 2‐aminophenols 3 and 4, which under suitable conditions easily rearrange to give a dynamic equilibrium 3 ⇌ 4. Contrary to 3 and 4, however, the isomerization of 7 and 8 can be followed directly by spectroscopic methods, so that vinylogs of this type are useful model systems for studying acyl group migrations in 2‐aminophenol. Kinetic measurements show that the mutual rearrangement of 7 and 8 is a reversible general based catalyzed reaction, being first order with respect to substrate and catalyst. The isomerization of the N‐acetyl derivatives 7a–h as well as the N‐benzoyl derivatives 7i–p results in strictly linear HAMMETT correlations with positive reaction constants ϱ. In the case of 7a–h the equilibrium constant K and the forward and reverse velocity constants k1 and k2 (including activation parameters) could be determined. The kinetic investigations and additional nonkinetic experiments indicate that the catalyst acts as proton acceptor and not — as hitherto supposed — as acyl group transferring nucleophile. Based on the findings an isomerization mechanism for mixed diacyl derivatives of 2‐aminophenol is suggested.
Untersuchungen zum UV/Vis‐Spektralverhalten von Azofarbstoffen. IV. Zum Einfluß von Lösungsmitteln auf die Farbbande von Azobenzenen
Authors: Mustroph H. , Epperlein J. 
Published: December 2004

Studies on UV/VIS Absorption Spectra of Azo Dyes. IV. Solvent Effects on the Visible Absorption Band of AzobenzenesSolvent effects on \documentclass{article}\pagestyle{empty}\begin{document}$ \begin{array}{*{20}c} \sim \\ {\nu _{\max } } \\ \end{array} $\end{document} values of substituted azobenzenes are studied and correlated with solvent polarity parameters. Poor correlations of \documentclass{article}\pagestyle{empty}\begin{document}$ \begin{array}{*{20}c} \sim \\ {\nu _{\max } } \\ \end{array} $\end{document} values with functions of ϵ and n of solvents are found. A comparison of spectral data with the ET scale shows a much poorer correlation. The correlation with the ET values are significantly better if the protic solvents are excluded. The best of the tested relationships was found with the empirical solvent parameters π*. Values of S in the equation \documentclass{article}\pagestyle{empty}\begin{document}$\begin{array}{*{20}c} \sim \\ {\nu _{\max } } \\\end{array} = {\rm S}\pi ^{\rm *} {\rm + }\begin{array}{*{20}c} \sim \\ {\nu 0} \\\end{array}, $\end{document} depend on the dye structure. It is found a relationship between S and the difference of quantum chemical calculated dipol moments in the first exited singlet (μ(S1)) and in the ground state (μ(S0)) of the dyes.
Substituierte 1,4,2‐Dithiazolin‐3‐yliden‐aroylacetonitrile
Authors: Dehne H. , Krey P. 
Published: December 2004

Substituted 1,4,2‐Dithiazoline‐3‐ylidene‐aroylacetonitrilesA convenient method for the preparation of new 2,5‐disubst‐1,4,2‐dithiazoline‐3‐ylidene‐aroylacetonitriles 4 is presented. The compounds 4 are formed during reaction of substituted thioacetamides 1 with α‐bromo‐α‐thiocyanatoketones 2. The mechanism of formation as well as the mass and i.r.‐spectra of the synthesized compounds are discussed.
Amines as Dehalogenating Agents. IV. Hydrocarbons, N‐bornyl‐ and N‐isobornylaniline formation in the reaction between 3‐bromocamphor and N‐methylaniline
Authors: Giumanini Angelo G. , Musiani Marco M. 
Published: December 2004

Amine als Dehalogenierungsreagenzien. IV. Kohlenwasserstoff‐, N‐Bornyl‐ und N‐Isobornylanilinbildung bei der Reaktion zwischen 3‐Bromcamphor und N‐MethylanilinN‐Methylanilin (4) reagiert bei 200°C im Vergleich zu N,N‐Dimethyl‐anilin entweder mit 3‐Bromcamphor (2) oder Camphor (3) zu den Kohlenwasserstoffen, Camphen 5 und Tricyclen 6 und N‐Bornylanilin (exo‐endo‐Isomers 7). Bei der Reaktion mit 3 ist Säurekatalyse not‐wendig. Untersuchungen zum Mechanismus erlauben es, anzunehmen, daß Camphoranil 8 ein gemeinsames Zwischenprodukt für alle Produkte und 4 der H‐Donator in den Reduktionsstufen ist, auf der Grundlage von kinetischen und stereochemischen Beweisen und unabhängigen chemischen Experimenten.
Zur Polymerisation des Ethylens mit Vanadium(III)amid
Authors: Radwan F. , Ulbricht J. 
Published: December 2004

Polymerization of Ethylene with Vanadium(III)amideBy addition of AlEt3, AlEt2Cl or AlEtCl2 to V(NPh2)3 · THF · 0,5 Dx. the polymerization of ethylene under normal conditions is started with increasing rate. The influence of the concentration of the catalyst components, the monomer concentration and the ageing time of the catalytic system on the rate is studied.
Transformation of chloromethylbenzaldehydes into corresponding (2‐nitroalkenyl‐1) benzyl chlorides or acetates. III
Authors: Grobelny Damian , Witek StanisłAw 
Published: December 2004

Zur Umwandlung von Chlormethylbenzaldehyden in die entsprechenden (2‐Nitroalk‐1‐enyl) benzylchloride bzw. AcetateUnter den bekannten Methoden zur Darstellung von β‐Nitrostyrenen wurde der günstigste Weg für die Synthese von (2‐Nitroalk‐1‐enyl)‐derivaten des Chlormethylbenzaldehydes 1 gesucht.Die besten Resultate erhält man durch Umsetzung der Aldehyde 1a–c zu den Schiff′schen Basen 2a–c und nachfolgende Kondensation der Verbindungen 2a–c mit Nitroalkanen in Essigsäure bei Raumtemperatur.Bei höheren Temperaturen liefern diese Umsetzungen die (2‐Nitroalk‐1‐enyl)benzylacetate der Struktur 7–10. Die Struktur des Ausgangsaldehydes 1 bestimmt die Geschwindigkeit dieser Reaktion.Ein möglicher Mechanismus sowie die 1H‐NMR‐Spektren der erhaltenen Verbindungen werden diskutiert.
Über die IR‐Spektren kurzkettiger aliphatischer Trimethylbetainamide. IR‐spektroskopische Untersuchungen über β‐Homobetainamid, γ‐Butyrobetainamid und die Konglomeratbildung beim kristallinen razemischen Carnitinamid
Authors: Lorenz Irmgard 
Published: December 2004

The Infrared Spectra of Some Low‐molecular Aliphatic Amides with Quaternary Nitrogen Infrared Spectroscopical Investigations of β‐Homobetaine Amide, γ‐Butyrobetaine Amide and the Conglomerate from D‐ and L‐Carnitine AmideThe infrared absorption spectra of β‐homobetaine amide, γ‐butyrobetaine amide D,L‐, D‐ and L‐carnitine amide in KBr‐discs were recorded in the frequency range from 400 cm−1 to 4000 cm−1. Assignments of the characteristic group frequencies have been proposed. In crystallized state D,L‐carnitine amide forms a conglomerate from D‐ and L‐carnitine amide, but no chemical compound because of the identity of the infrared spectra obtained from the three optical isomeric carnitine amides.
Über die Bildung von Radikalen bei der Photolyse von 4‐N, N‐Dialkylaminobenzendiazoniumtetraphenylboraten
Authors: Rehorek Detlef , Marx Jörg 
Published: December 2004

On the Formation of Radicals during the Photolysis of 4‐N, N‐Dialkylaminobenzene Diazonium TetraphenylboratesThe photolysis of 4‐N, N‐dialkylaminobenzene diazonium tetraphenylborates 1–11 in dichloromethane proceeds by an electron transfer between ion pairs forming radicals as primary products. Using e.s.r. spin trapping technique arenediazo, phenyl, 4‐N, N‐dialkylamino phenyl and substituted cyclohexadienyl radicals could be detected.
Kristallin‐flüssige 1,3,4‐Thiadiazole. I. Biphenyl‐ und terphenylanaloge 1,3,4‐Thiadiazole
Authors: Dimitrowa K. , Hauschild J. , Zaschke H. , Schubert H. 
Published: December 2004

Liquid Crystalline 1,3,4‐Thiadiazoles. I. Biphenyl‐ and Terphenyl Analogous 1,3,4‐ThiadiazolesThe synthesis of disubstituted 1,3,4‐ and 1,2,4‐thiadiazoles and 1,3,4‐oxadiazoles is described and their melting and clearing points are investigated. The influence of the heterocyclic ring system on the formation of crystalline liquid phases is discussed.
Zur Rolle von EDA‐Komplexen bei kationischen Polymerisationen. VIII. Zur Charge‐Transfer‐Wechselwirkung von bπ‐Donatoren mit organischen Kationen in Lösung
Authors: Heublein G. , Spange St. 
Published: December 2004

On the Role of EDA‐complexes in Cationic Polymerization. VIII. The Charge‐Transfer‐Interaction of bπ‐Donors with Organic Cations in SolutionThe interaction of 25 aromatic bπ‐donors with organic cations of the type (RC6H4)3 C⊕X⊖ (R = CH3, C(CH3)3, OCH3, H, Cl, I, NO2; X = BF4⊖, AsF6⊖, SbCl6⊖, FeCl4⊖) is investigated by means of u.v.‐spectroscopy. The influence of the dissociation on the charge transfer energy will be discussed. With the decreasing concentration of the salt the charge transfer band is hardly shifted at longer wave length. The charge transfer energy can be described as a linear function of structural parameters (i.e. σp of R; Ip of the donor and reciprocal radius of the anions, respectively).The influence of the solvent is dependent on both the donicity and dielectric factors.
Diels‐Alder‐Reaktionen. VIII. Kinetische Untersuchungen zur Bildung und zur Pyrolyse von Tetracyclo[6.2.1.13.6.02.7]dodec‐4‐en
Authors: Moll K. K. , Ramhold K. , Zimmermann G. , Pohle Ch. 
Published: December 2004

Diels‐Alder‐Reactions. VIII. Kinetic Investigations of the Formation and the Pyrolysis of Tetracyclo [6.2.1.13.6.02.7]‐dodec‐4‐enThe formation of tetracyclo[6.2.1.13.6.02.7]dodec‐4‐ene by codimerisation of cyclopentadiene with bicyclo[2.2.1]hept‐2‐ene between 60 and 140°C in the liquid phase and the inverse reaction by gas phase pyrolysis between 240 and 300°C were studied kinetically. The activation parameters were determined.
Zur Reduktion von 1,3‐Thiaziniumsalzen; Synthese von 6,6′‐Bi‐1,3‐thiazinylen und 6,6′‐Bi‐1,3‐thiazinylidenen
Authors: Rüttinger H. H. , Spitzner R. , Schroth W. , Matschiner H. , Ziebig R. 
Published: December 2004

On the Reduction of 1,3‐Thiazinium Salts; Synthesis of 6,6′‐Bi‐1,3‐Thiazinyls and 6,6′‐Bi‐1,3‐Thiazinylidenes1,3‐Thiazinium perchlorates 1 are linked together in a reaction with zinc powder or at a cathode forming 6,6′‐bi‐1,3‐thiazinyls 3. This reaction proceeds via radical intermediates 2. Evidence of the existence of the very short‐lived radicals is given by means of ring‐disk‐voltammogrammes as well as by electrochemical luminescence excitation. The 6,6′‐bi‐1,3‐thiazinyls 3 undergo the reverse fission at a platinum anode resulting in thiazinium salts 1, whereas the dehydrogenation by chloranile yields the violet 6,6′‐bi‐1,3‐thiazinylidenes 6.
Neue Hybridinsuline mit synthetisch sequenzveränderten B‐Ketten
Authors: Lossf G¨︁nter , Stange Hans , Naumann Wolfgang , Bilk Lothar 
Published: December 2004

New Hybrid Insulins with Synthetically Sequence‐Modified B‐chainsThe shortened and modified insulin‐B‐chain sequences B 4–30 (Ala 4) 1, B 4–27 (Ala 4, Ala 27) 2, B 1–27 (Ala 9, Ala 10, Ala 27) 3, B 4–27 (Ala4, Ala 9, Ala 10, Ala 27) 4 and B 4–27(Ala 4, Val 6, Ala 9, Ala 10, Ala 27) 5(1) were synthesized in protected form, converted by deprotection and oxidative sulfitolysis into the S‐sulfonates and combined with native insulin‐A‐chain‐S‐sulfonate to the corresponding hybrid insulins 6–10.The biological activities indicate that distinct simplifications of the sequence in the region of the B‐chain are tolerated relatively well.
Zur Oligomerisierung von Cycloolefinen in Gegenwart zirkonhaltiger Katalysatorsysteme
Authors: Bittrich H.‐H. , Bittrich R. , Sass L. , Zirz P. , Reich P. , Zimmermann G. 
Published: December 2004

On the Oligomerization of Cyclic Alkenes in the Presence of Zirconium‐containing Catalytic SystemsIn connection with investigations on olefin metathesis we studied the reaction of cyclic olefins C5C8 and C12 in the presence of zirconium‐containing catalytic systems in the homogeneous liquid phase.The influence of different zirconium compounds on the reaction run off and on the distribution of the reaction products was examined in the presence and the absence of Lewis acids.The reaction products could be separated and identified by a combination of distillation, chromatographical, chemical and spectrometrical methods. The results show that under the conditions mentioned a metathetic polymerization and a normal olefin oligomerization take place simultaneously.
Desaktivierungsverhalten von Arenen und Heteroarenen. XXXII [1]. Zum Einfluß von endo‐ und exocyclischer Substitution auf das reversible Dimerisierungsverhalten von Anthracen
Authors: Bendig J. , Buchwitz W. , Fischer J. , Kreysig D. 
Published: December 2004

Deactivation Behaviour of Arenes and Heteroarenes. XXXII. The Influence of Endo‐ and Exocyclic Substitution on the Reversible Dimerization Behaviour of AnthracenesThe kinetic and thermodynamic values of the reversible photodimerization of 17 endo‐ and exocyclic substituted anthracenes are presented and discussed on the basis of the potential correlation diagram. The deactivation kinetics of the partial steps of photodimerization (excimer formation, transition into the pericyclic state, dimer formation) is influenced in dependence on the type and the place of substitution. From the determined partial values the interpretation of the integral behaviour is possible.A relationship between the enthalpy of dimer formation, thermal stability and quantum yield of dimer formation is obtained. The sum of the quantum yields of forward and back reaction is 1 with the exception of derivatives substituted by heavy atoms and in the case of fluorescent excimers, respectively. With that the model of the common pericyclic transition state is confirmed.
UV‐Vis‐spektroskopische Eigenschaften 3,5‐disubstituierter 1,3,4‐Oxadiazolin‐2‐imine. II. Fluoreszenzeigenschaften und Dipolmomente von Grund‐ und Anregungszustand
Authors: Bendig Jürgen , Kreysig Dieter , Sauer Erika , Just Manfred 
Published: December 2004

The U.V.‐vis‐spectroscopic Properties of 3,5‐disubstituted 1,3,4‐Oxadiazoline‐2‐imines. II. Fluorescence Properties and Dipol Moments of the Ground and the Excited StateWith increasing polarity of the solvent the fluorescence maxima of 3,5‐disubstituted 1,3,4‐oxadiazoline‐2‐imines are shifted to longer wavelengths. In alcohol, Stokes shifts are in the range of 8 · 105 m−1. The dipol moments of the molecules in the excited state (determined in terms of the Onsager theory) are different from those of the ground state. The differences are competible with the push‐pull effect of the substituents and its influence on the polarity of the oxadiazoline‐imine system. The kinetic parameters of the fluorescence (quantum yields, rate constants, decay times) correlate with Hammett's substituent constants. Iod‐ and nitroaryl substituted compounds as well as some of the o‐substituted phenyl derivatives show specific deactivation processes like predissociation and others.
MO‐LCAO‐calculations on polymethines. XIII. Spectral Effects Resulting from the Cyclization of Cyanine Chains
Authors: Fabian J. 
Published: December 2004

MO‐LCAO‐Berechnungen an Polymethinen. XIII. Spektrale Effekte infolge einer Cyclisierung der PolymethinketteCyclisierung von Streptopolymethinen zu aromatischen oder heterocyclischen Ringen führt entweder zu einer bathochromen oder hypsochromen Verschiebung der Farbbande. Nach PPP‐Berechnungen werden die spektralen Effekte durch die Einelektronen‐MO‐theorie richtig wiedergegeben, ausgenommen einige erste Vertreter der untersuchten vinylogen Reihen. Molekülorbital‐ und Konfigurationsanalyse stützen die Brauchbarkeit des Polymethinkonzeptes. Das alternative Konzept substituierter Aromaten ist jedoch dann überlegen, wenn spektrale Charakteristika iso‐π‐elektronischer Strukturen verschiedener Serien verglichen werden.
MO‐Berechnungen an Heterocyclen. XXV. Zur Elektronenstruktur des Pyridin‐N‐Oxids
Authors: Scholz Manfred 
Published: December 2004

MO‐Calculations on Heterocycles. XXV. On the Electronic Structure of Pyridin‐N‐OxideMO calculations with different levels of sophistication (ab initio, HAM/3, INDO‐, CNDO‐ and PPP‐typ) are reported. The eigenvalues of the different methods are correlated with the experimentally known assignment of the PE spectrum on the basis of HeI/HeII intensities.The pattern of the PE spectrum and also the large dipole moment make this compound a very useful test molecule for quantumchemical calculations. Comments are made concerning the calculation of dipole moments within the point charge model especially in the PPP‐approximation.
Massenspektren donator‐substituierter 4‐Diphenylphosphinyl‐trans‐stilbene
Authors: Alder Lutz , Gloyna Dieter 
Published: December 2004

Mass Spectra of Donor Substituted 4‐Diphenylphosphinyl StilbenesThe electron impact induced fragmentation of six donor substituted diphenylphosphinyl stilbenes 1a–f have been determined. In general, independent fragmentation of the diphenylphosphinyl group and the donor substituent was found. Interaction between both substituents can be observed by the formation of ions with quinonoide structure and the loss of CO from the [M‐1]‐ion of the methoxy derivatives. Only few stilbene‐typical ions have been observed.
Geschützte Aminooxazoline der Arabinose und Ribose
Authors: Cech D. , König J. , Köppel H. , Möller S. , Herrmann G. 
Published: December 2004

Protected Aminooxazolines of Arabinose and RiboseThe reaction of D‐arabinose or D‐ribose with cyanamide afforded 2‐amino‐1,2‐oxazolines 1 which were treated with dihydropyran or ethylvinylether. In the presence of PTS the 3′,5′‐di‐THP‐ or 3′,5′‐di‐O‐ethoxyethyl‐D‐arabino‐(ribo)‐furo‐[1′,2′:4,5]‐2‐oxazolines 2 and 3 could be isolated as useful intermediates for the preparation of nucleosides.When the 2‐aminooxazolines are treated with benzyloxycarbonylchloride or its p‐substituted derivatives the N‐3 atom of the oxazoline ring is preferentially substituted. Under these conditions the exocyclic amino function is always replaced and 2‐oxo‐3‐benzyloxycarbonylderivatives 4 are obtained; only traces of the corresponding 2‐aminoderivatives 5 are formed. Treatment of 4 with acetic anhydride, benzoylchloride, and benzoylcyanide, respectively, results in the 3′‐, 5′‐di‐O‐acyl derivatives 6. Mild hydrolysis of the benzyloxycarbonyl group with trifluoroacetic acid yields the 3′,5′‐di‐O‐acyl‐D‐arabino‐(ribo)‐furo‐[1′,2′:4,5]‐2‐oxooxazolidines as further intermediates for the synthesis of nucleosides.
Stereochemistry of Diastereomeric 3‐Dialkylaminopropanols and O‐Derivatives
Authors: Spassov S. L. , Avramova P. D. , Palamareva M. D. 
Published: December 2004

Stereochemie von diastereomeren 3‐Dialkylaminopropanolen und entsprechenden O‐DerivatenErythro‐ und threo‐3‐Dialkylamino‐1‐phenyl(1‐ethyl)‐2‐methyl‐1‐propanole 1a–c, 2a, b wurden durch fraktionierte Umkristallisation bzw. Säulenchromatographie über Kieselgel oder Aluminiumoxid isoliert. Weiterhin wurden die diastereomeren O‐Derivate 3–8 erhalten. Eine erythro‐threo‐Isomerisation wurde mit Säuren durchgeführt. Die relativen Konfigurationen und bevorzugten Konformationen wurden durch 1H‐NMR‐ und IR‐Spektroskopie bestimmt.