bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intramolekulare Chinhydrone. III. Farbe und Charge‐transfer‐Wechselwirkungen
Authors: Heberer H. , Hartung H. , Lukowczyk B. , Schubert H. 
Published: January 2005

AbstractDie intensive Farbe der kristallinen intramolekularen Chinhydrone 2a–o hängt von der Kernsubstition und der unsymmetrischen Brückenstruktur ab. Lösungen sind nur gelb gefärbt. Nach den Ergebnissen röntgenkristallographischer, IR‐ und UV/VIS‐spektroskopischer Untersuchungen bilden 2a–o inter‐, aber keine intramolekularen CT‐Komplexe.
Ionische und radikalische Dediazonierungen von Aryldiazoniumsalzen: Ein Beispiel für wellenlängenabhängige Photoreaktionen
Authors: Becker H. G. O. , Hoffmann Gerda , Israel G. 
Published: January 2005

AbstractDie Photolyse von p‐substituierten Benzoldiazonium‐tetrafluoroboraten in Methanol bzw. Äthanol/Acetonitril liefert bei Einstrahlung in die Absorptionsmaxima der Diazoniumsalze (313 nm) höhere Mengen an ionisch entstandenen Dediazonierungsprodukten (ArOR und ArF), als nach der für Elektronenübertragungen gültigen Beziehung ΔG*=E(Donor) − E) − Ehv erwartet wird. Bei Wellenlängen > 330 nm oder in Gegenwart des auch bei 313 nm absorbierenden Donors Pyren werden dagegen überwiegend Reduktionsprodukte (die entsprechenden aromatischen Kohlenwasserstoffe) gebildet. Die Verhältnisse werden an Hand der von Salem u.a. entwickelten Symmetrievorstellungen erörtert. Es ergibt sich, daß die photochemische Dediazonierung von Aryldiazoniumsalzen wahrscheinlich aus dem schwingungsangeregten Grundzustand heraus erfolgt und demzufolge in einigen Fällen ähnliche Produktverhältnisse liefert wie die Thermolyse.
The Polarographic Behaviour of Benzylidenebenzhydrazide in Solutions of Varying pH. Effect of hydrolysis on the reduction mechanism
Authors: Issa I. M. , Temerk Y. M. , Zuhri A. Z. Abu 
Published: January 2005

Das polarographische Verhalten des Benzylidenbenzhydrazides in Lösung in Abhängigkeit vom pH‐Wert. Der Effekt der Hydrolyse auf den ReduktionsmechanismusDas polarographische Verhalten des Benzylidenbenzhydrazides (BBH) in Lösung wurde durch Änderung des pH‐Wertes innerhalb des Konzentrationsbereiches 1 · 10−4 bis 1 · 10−3 mol untersucht. Die Polarogramme bestehen im sauren Medium jeweils aus einer Welle. Die Stufenhöhe nimmt mit steigendem pH‐Wert ab. Bei pH 8.6 tritt eine zweite Welle auf. Diese nimmt in der Höhe zu, bis ein konstanter Wert im alkalischen Medium erreicht wird.Der Effekt des pH‐Wertes auf den Grenzstrom und E1/2 sowie auf den Reduktionsmechanismus werden diskutiert. Die kinetischen Parameter werden bestimmt.
Sydnon‐äthylene. III. Chemische Reaktionen elektronisch angeregter 4‐Styryl‐sydnone
Authors: Neumann Bernd‐Michael , Henning Hans‐Georg , Gloyna Dieter , Sauer Joachim 
Published: January 2005

Sydnone Ethylenes. III. Chemical Reactions of Excited 4‐Styryl‐sydnonesDependent on the character of the substituents in the photo reactions of 4‐styryl sydnones Z/E‐isomerism competes with CO2‐elimination. Excited p‐nitrostyryl sydnones exhibit a relatively strong degradation of the bond order in the CC region. Their quantum yields of Z/E‐isomerism are therefore much higher than those of compounds with p‐substituents of lower acceptor effect. In these compounds the cleavage of the sydnone ring with elimination of carbon dioxide is favoured especially if a methyl group is in 3‐position of the sydnone.
Some Reactions with 2‐Arylmethylene‐3,4‐dihydro‐1(2H)‐naphthalenones
Authors: Moustafa A. H. , Shams N. A. , Zahran R. H. , Eweiss N. F. 
Published: January 2005

Einige Reaktionen mit 2‐Arylmethylen‐3,4‐dihydro‐1(2H)‐naphthalin‐onen2‐Arylmethylen‐3,4‐dihydro‐1(2H)‐naphthalin‐one 1a–f und N‐Methylcyanoacetamid reagieren in Gegenwart von Ammoniumacetat zu den 1,4‐Cyclo‐Addukten, 4‐Aryl‐3‐cyano‐5,6‐dihydronaphthalino[1,2‐b]pyridin(1‐methyl)‐2‐onen 2a–f und 4‐Aryl‐5, 6‐dihydronaphthalino‐[1,2‐b]pyridin(1‐methyl)‐2‐onen 3a–f; nur im Falle der Verbindung 1c entsteht noch α‐Cyano‐β‐(1‐oxo‐3,4‐dihydronaphth‐2‐yl)‐β‐(4‐methoxyphenyl)‐N‐methyl propionamid 4c. Setzt man N‐aralkyl und N‐arylsubstituierte Cyanoacetamide ein, erhält man die entsprechenden Addukte 5a–f und 6a–f.
Zur Molekülverknüpfung mit Schwefelchloriden. VI. Die Reaktion von Dichlorsulfan mit Thiocarbamidsäureestern
Authors: Mühlstädt M. , Widera R. 
Published: January 2005

Molecule Linkage by Sulfur Chlorides. VI. The Reaction of Sulfur Dichloride with Thiocarbamic Acid EstersSulfur dichloride reacts with thiocarbamic acid esters to form aminoacyl trisulfides. The reaction of sulfur dichloride with unsaturated thiocarbamic acid esters yields heterocycles of the 2‐thiazolidinon and 3‐dithiazinon type.
Die basen‐initiierte Umlagerung von Trialkyl‐(2‐methylalk‐2‐enyl)‐ammoniumjodiden
Authors: Dietrich W. , Schulze K. , Mühlstädt M. 
Published: January 2005

The Base Promoted Rearrangement of Trialkyl‐(2‐methyl‐2‐alkenyl)‐ammonium IodidesIt is not possible to distinguish between a [1, 2] – or a [3, 2]‐rearrangement by shift of the allyl group in the Stevens rearrangement of trialkylallyl‐ and trialkylmethallylammonium salts. It has been found by γ‐alkyl substitution in the methallyl group of trialkyl‐methallyl‐ammonium salts that the [3,2]‐rearrangement by shift of these unsaturated groups exclusively or mainly takes place depending on the choosen base system.
Verwendung von 2‐Furaldehyd für die Synthese von selbstlöschenden Polyurethanwerkstoffen
Authors: Lesiak T. , Marzec K. 
Published: January 2005

New Utilization Possibility of Furfural for the Synthesis of Self‐Extinguishing Polyurethane ResinsA new method for the conversion of furfural into heptane‐1, 4‐diol, 3, 5‐dichloroheptane‐1, 4‐diol as well as 3, 5‐dibromoheptane‐1, 4‐diol is presented, and the possibilities of applying of two last alcohols for the syntheses of self‐extinguishing polyurethane resins are discussed. In addition, a method for the preparation of ethyl 3, 5‐dichloro‐4‐keto‐ and 3, 5‐dibromo‐4‐ketoheptanoate is described.
Synthese von Substanz P und acylierten Teilsequenzen
Authors: Bienert M. M. , Köller Gy. , Wohlfeil R. , Mehlis B. , Bergmann J. , Niedrich H. , Kraft R. 
Published: January 2005

Synthesis of Substance P and of Acylated Partial SequencesSubstance P undecapeptide has been synthesized by the stepwise procedure and via condensation of the fragments 1–4 and 5–11. Formation of pyrrolidone carboxylic acid‐ and S‐tert. butyl peptides was observed. Gln(Mbh)‐containing sequences have been synthesized but were not useful for fragment condensation due to there low solubility. Additionally, some derivatives have been prepared by acylation of the C‐terminal pentapeptide. Reaction with trifluoracetic acid anhydride resulted in the formation of substituted 5‐amino‐oxazole derivatives as detected by mass spectrometric investigation.
Oxidative Kupplung CH‐acider Verbindungen mit p‐Phenylendiaminen. IV. Massenspektrometrische Untersuchungen an 4‐substituierten 1‐Hydroxy‐2‐naphthoesäure‐Derivaten
Authors: Mann G. , Wilde H. , Herzschuh R. , Lehmann J. , Lepom P. 
Published: January 2005

Oxidative Coupling of CH‐acid Compounds with p‐Phenylenediamines. IV. Mass Spectrometric Investigations of 4‐Substituted 1‐Hydroxy‐2‐naphthoic‐acid Derivatives.Mass spectrometric fragmentations of 4‐substituted 1‐hydroxy‐N‐3′, 5′‐(dimethoxy‐carbonyl)phenyl‐2‐naphthalene carboxamides and derivatives of 1‐hydroxy‐2‐naphthoic acid and 4‐bromo‐1‐hydroxy‐2‐naphthoic acid have been determined. All compounds undergo a characteristic fragmentation. The most important primary process is amide cleavage and hydrogen rearrangement. The relation of the primary fragments which compete for the charge depends on the substituents of the active methylene group and of the amide. The mass spectra permit determination of structure, purity and stability of the substituted colour couplers.
Halogenlipide. III. Alkyl‐glyceryl‐ether‐Analoga
Authors: Brachwitz H. , Langen P. , Otto A. , Schildt J. 
Published: January 2005

Halogenolipids. III. Alkyl Glyceryl Ether AnaloguesSynthesis of the halogeno analogues of alkyl glycerol ether, 3‐fluoro‐1‐O‐hexadecyl‐(octadecyl)‐propane‐1, 2‐diol, 2‐fluoro‐1‐O‐hexadecyl(octadecyl)‐propane‐1, 3‐diol, 2‐chloro‐1‐O‐hexadecyl‐propane‐1,3‐diol and 3‐fluoro‐2‐O‐hexadecyl‐propane‐1,2‐diol, which are of interest as potential cytostatic agents, is described.
Zur Acylierbarkeit des Phosphorylsauerstoffs. I. Acyloxyphosphoniumsalze aus Hexamethylphosphorsäuretriamid und Carbonsäurederivaten
Authors: Teichmann H. , Auerswald Ch. , Engelhardt G. 
Published: January 2005

On the Acylation of the Phosphoryl Oxygen. I. Acyloxyphosphonium Salts from HMPT and Carboxylic Acid DerivatesAcylation equilibria with participation of acyloxyphosphonium ions exist in solutions of HMPT and carboxylic chlorides, or anhydrides, respectively, as can be shown by 31P‐n.m.r. after trapping the counter ion with SbCl5. Moderately stable acyloxyphosphonium salts have been isolated for the first time by acylation of HMPT. In the alternative reaction of (Me2N)3P with CCl4 and carboxylic acids, acyloxyphosphonium salts are formed only after prolonged reaction times, due to the stability of the intermediate chlorotris‐(dimethylamino)‐phosphonium ion.
Elektronische und sterische Substituenteneinflüsse auf die UV/VIS‐Absorptionsspektren der Phenylfulgidisomeren
Authors: Ilge H.‐D. , Drawert Ch. , Sühnel J. , Paetzold R. 
Published: January 2005

Electronic and Steric Substituent Influences on the U.V./VIS‐Absorption Spectra of Phenylfulgide IsomersThe u.v./vis spectral data of a large number of phenylfulgides (E‐, Z‐, E‐E‐, E‐Z‐, Z‐E‐, Z‐Z‐isomers, 1.8a‐dihydronaphthalenes) are presented. An increase of the number of phenyl rings as well as substitution of the phenyl rings cause correlatable bathochromic spectral shifts. Steric influences became obvious by introducing methyl groups, by coplanarization of phenyl groups and in the series of isomers. By means of PPP calculations shifts in position and/or intensity of absorption bands are ascribed to the substituent effects.The calculated band polarization of E(E‐E)‐isomers are in agreement with the results of polarization spectra in oriented liquid crystal mesophases. The polarization spectra allow the assignment of the longwave absorption band to the S2 ← S0 and S1 ← S0 electronic transitions for E‐E‐Isomers with a C2v‐symmetry.
Synthese von 2,7,12,17‐Tetraoxa‐teranaphtho‐(1,2‐f h f′h′)‐dispiro[8.0.8.1]‐nonadecan‐ein Vertreter des[8.0.8.1] Dispiran‐Typs
Authors: Jamrozik Janusz 
Published: January 2005

Synthesis of 2,7,12,17‐Tetraoxa‐tetranaphtho‐(1,2‐fhf′h′)‐dispiro[8.0.8.1]‐nonadecanes‐An Example of [8.0.8.1] DispiranesIn einer früheren Mitteilung[1] wurden Dispiran‐Systeme beschrieben, welche Repräsentanten der Klasse [6.0.6.1] waren. Die Synthesen dieser Dispirane erfolgten durch Kondensation des 1,1,2,2‐Tetrakis(brommethyl)cyclopropans mit 1,2‐Diolen,in die gegenseitige Lage der funktionellen Gruppen jedesmal fixiert und genau bestimmt war. Gegenstand der vorliegenden betrachtungen sind Versuche, eine Synthese des [8.0.8.1]‐Dispirans auf ähnlichem Wege, wenn auch unter Verwendung labiler Diphenole auszuarbeiten. Zu diesem Zweck wurden zwei reaktive Diphenole mit extrem verschiedenen Rotationsmöglichketen um die Einfachbindung gewählt.
Konfiguration und Thermochromie von Benzoinhydrazon‐Derivaten
Authors: Timpe H.‐J. , Müller U. , Schütz R. 
Published: January 2005

Configuration and Thermochromic Properties of Benzoine Hydrazone DerivativesZ‐Benzoine aroylhydrazones (2a–d), E‐benzoinephenylether phenylhydrazone (4) and E‐benzoinephenylether p‐chlorobenzoylhydrazone (5), respectively, are produced by acid‐catalyzed reaction of benzoine and corresponding hydrazone derivatives. The configuration of these new compounds are proved by their u.v.‐spectra and n.m.r.‐spectra data. In comparison to the Z‐isomers, the E‐isomers possess a hypsochromically shifted electron transition. In the n.m.r.‐spectra the Z‐isomers can be detected by a downfield N–H‐signal. Only the aroylhydrazones 2 have thermochromic properties in methanolic solutions, based on a geometrical E/Z‐isomerization. The kinetic and thermodynamic data of this reaction agree with an inversion mechanism.
Zur Struktur neuartiger Thiatriazinsysteme
Authors: Teller M. , Fischer E. , Martin D. , Graubaum H. 
Published: January 2005

Structure of New Systems of ThiatriazinesDepending on the nucleophilicity of exocyclic nitrogen in 2‐guanidino‐benzimidazole‐1‐carbimidic esters and 1‐carbamides cyclization with N‐sulfinyl amines leads to new 3‐amino‐1λ4, 2,4,6‐thiatriazino[2,3‐a]benzimidazole‐1‐oxide‐5‐carbimidic esters (3), 1‐oxide‐5‐carbamides (5) and 3‐(4‐chlorphenylamino)‐1‐toluene‐sulfonylimino‐1λ4,2,4,6‐thiatriazino[2,3‐a]benzimidazole‐5‐carbimidic ester (7).
α‐substituierte Phosphonate. 47. PC‐Spaltungen bei geminalen Trisphosphorylverbindungen
Authors: Gross H. , Costisella B. 
Published: January 2005

α‐Substituted Phosphonates. 47. Splitting of PC‐Bonds from Trisphosphoryl CompoundsHexaethyldimethylaminomethyl‐trisphosphonate (2a) reacts with HCl or trimethylsilylbromid/water by splitting off one phosphoryl group, giving dimethylaminomethyl‐bisphosphonic acid (7). The result of methylation of 2a depends on the reagent: with methyliodide one phosphoryl group is split off, and the ammonium salt 11a is formed, while with methyl toluene sulfonate or dimethylsulfate the expected quarternary ammonium salts 10b or 10c are formed. One phosphoryl group of 10c is split off under acidic as well as alkalinous conditions: acidic hydrolysis gives the bisphosphonic acid 15, while under alkalinous conditions the known ylid 16 is formed.
Synthese und Elektronenanregungsspektren tetrakis(dialkylamino)phenylsubstituierter Nickel‐Dithiolenchelate
Authors: Freyer Wolfgang 
Published: January 2005

Synthesis and Electronic Absorption Spectra of Tetrakis(dialkylamino)phenyl Substituted Nickel DithiolenesNickel dithiobenziles with four dialkylamino groups (1a, b) have been synthesized from the correspondent 4,4′‐bis‐(dialkylamino)‐benzil (2a, b) or 4,4′‐bis‐(dialkylamino)‐benzoin (3b). Such compounds show the lowest transition energy ever observed for any dithiolene complex. The absorption maximum depends strongly on solvent polarity and can be shifted in the range 1000 to 1450 nm.
UV‐VIS‐ und IR‐spektroskopische Untersuchungen an N‐substituierten 4‐Amino‐7‐nitrobenz‐2,1,3‐oxadiazolen
Authors: Heberer H. , Matschiner H. 
Published: January 2005

UV‐VIS‐ and IR‐Spectroscopic Studies with N‐Substituted 4‐Amino‐7‐nitro‐benzofurazansStarting from spectra of parent substance benzofurazan the influence of different functional groups (NO2, OH, NH2, NHAlk, NAlk2, NHAr, NArAlk) in 4‐ and (or) 7‐position on the shape of spectra and the intensity of individual bands was examinated. It was tried to assign spectral bands to defined absorptions in the u.v./vis and i.r. range. The long‐wave band in the solution‐VIS‐spectra of N‐substituted 4‐amino‐7‐nitrobenzofurazans was identified as a charge‐transfer band. By the use of constants α, β, and π* by Kamlet and Taft the influence of different properties of solvents was correlated with band shifts in the UV/VIS range. A qualitative correlation was found between \documentclass{article}\pagestyle{empty}\begin{document}$ \bar \nu _{{\rm max}} $\end{document} of the long‐wave band in the VIS‐spectra, the polarographic half wave potential E 1/2 and the sum of polar substituent constants Σσ* of Taft. These proportions were plotted in a three‐dimensional diagram.
Isomerisierung von (Z)‐But‐2‐en‐1,4‐diol zu 4‐Hydroxybutyraldehyd in Gegenwart von Palladium‐(O)‐komplexen mit tert. Phosphin‐ und tert. Phosphitliganden
Authors: Seddig B. , Alm J. 
Published: January 2005

AbstractDie Isomerisierung von (Z)‐But‐2‐en‐1,4‐diol 1 zu 4‐Hydroxybutyraldehyd 2 bzw. dessen cyclischem Halbacetal, 2‐Hydroxytetrahydrofuran 3, wurde bereits von REPPE [1] als Nebenreaktion bei der Hydrierung von But‐2‐in‐1,4‐diol mit einer Reihe heterogener Hydrierkatalysatoren beobachtet. Spätere Arbeiten zur gezielten Darstellung von 2 nutzten vorzugsweise vergiftete Nickelkatalysatoren, erreichten aber nur unbefriedigende Ausbeuten [2–4].
Phosphinites of carbohydrates as chiral ligands for asymmetric synthesis catalysed by complexes. IV. Influence of the solvent and the structure of cationic 4,6‐0‐benzylidene‐2,3‐0‐bis(diphenylphosphino)‐D‐hexopyranoside‐rhodium(I) chelates on enantioselectivity in Hydrogenation of Dehydroamino Acid Derivatives
Authors: Selke Rüdiger 
Published: January 2005

AbstractCationic rhodium(I)‐chelates of 4,6‐benzylidene‐2,3‐0‐bis(diphenylphosphino)‐D‐hexopyranosides bearing axial 0‐functions, as for instance manno‐ 5 and galactopyranosides 4c, 4d or α‐D‐glycopyranosides, show lower enantioselectivity in the hydrogenation of dehydroamino acid derivatives than chelates of the all‐equatorial phenyl 4,6‐0‐(R)‐benzylidene‐2,3‐0‐bis(diphenylphosphino)‐β‐D‐glucopyranoside 3d (abbreviated Ph‐β‐glup). Complexes of the galactopyranosides 4c and 4d give an abnormal decrease of enantiomeric excess with the prochiral dehydroamino acid 1c in contrast to the analogous substrate ester 1d. In hydrogenations with [Rh(Ph‐β‐glup)(COD)] A as precatalyst various weak coordinating anions A⊖ do not produce differences in % ee, and the solvent effect remains low. However, an analogous chelate of the methyl α‐anomer bisphosphinite Me‐α‐glup 3a gives rise to inversion of the optical induction using benzene as solvent.
1,2,3‐Triazabutadiene XXI [1]. Zur Bestimmung des Oberflächenpotentials und des relativen pH‐Wertes in der Sternregion anionischer Mizellen unter Verwendung von 1‐(4′‐Chlorphenyl)‐3‐(3‐methylbenzthiazolinyliden‐(2))‐triazen als Sonde
Authors: Fanghänel E. , Ortmann W. 
Published: January 2005

1,2,3‐Triazabutadienes. XXI. Determination of the Electrical Surface‐potential and of the Relative pH Value in the Stern Region of Anionic Micelles by using 1‐(4′‐Chlorphenyl)‐3‐(3‐methylbenzthiazolinyliden‐(2))‐triazene as ProbeThe title triazene is insoluble in water but it can be solubilized in the Stern region of micelles. It is used as pH indicator for the Stern region of anionic micelles. The relative pKs‐values for the triazene are determined in anionic micellar solutions of different detergents. The electrical potential at the surface of the charged micelles is calculated using the value of SDS‐micelles for calibration. The dependence of the electrical potential and the pH value in the Stern region on the structure of the detergents is discussed.
Transformation von Uridin‐ zu Cytidinderivaten durch selektive Aminierung
Authors: Krug A. , Schmidt S. , Lekschas J. , Lemke K. , Cech D. 
Published: January 2005

Transformation of Uridine Derivatives into Cytidines via Selective AminationThe synthesis of some 5‐fluorosubstituted cytidine 2 derivatives via amination of corresponding uridine derivatives 1 is described. 5‐Substituted 4‐tetrazolo pyrimidinone derivatives 5 are key intermediates in the procedure. The method used is extended to other fluorinated starting materials, e.g. fluorinated uridinedinueleotides 7 or 2′‐deoxy‐2′‐fluorouridine 9. The fluoro containing products are easily available by fluorination with elemental fluorine or hydrogene fluoride.
Pyryliumverbindungen. 44 [1]. 2‐(2‐Hydroxy‐3‐oxo‐cycloalk‐1‐enyl)‐2H‐thiopyrane aus 2,4,6‐Triaryl‐thiopyryliumsalzen und Cycloalkan‐1,2‐dionen
Authors: Zimmermann T. , Fischer G. W. , Olk B. 
Published: January 2005

Pyrylium Compounds. 44. 2‐(2‐Hydroxy‐3‐oxo‐cycloalk‐1‐enyl)‐2H‐thiopyranes from 2,4,6‐Triarylthiopyrylium Salts and Cycloalkane‐1,2‐diones2,4,6‐Triarylthiopyrylium salts 5 react with cyclopentane‐1,2‐dione (2a) or cyclo‐hexane‐1,2‐dione (2b) in the presence of an appropriate acid binding agent (e.g. sodium acetate, piperidine acetate, triethylamine/acetic acid, triethylamine) to give the hitherto unknown 2‐(2‐hydroxy‐3‐oxo‐cycloalk‐1‐enyl)‐2H‐thiopyranes 6. – The structure of the novel compounds was established by n.m.r., i.r. and u.v. spectroscopic methods.
Zur reversiblen Umwandlung von 3‐Diethylamino‐5‐phenyl‐1,2,4‐dithiazolium‐halometallaten in Metallchelate der 3‐(Thio)benzoyl(thio)harnstoffe
Authors: Hartung J. , Rosenbaum K. , Beyer L. , Losada J. , Fernandez V. 
Published: January 2005

About the Reversible Conversion of 3‐Diethylamino‐5‐phenyl‐1,2,4‐dithiazoliumhalometallates into Metal Chelates of 3‐(Thio)benzoyl(thio)ureasRedox reactions of 3‐diethylamino‐5‐phenyl‐1, 2,4‐dithiazolium halometallates 1a‐e and metal chelates (M = CuII (2 A), CoII (2 C), NiII (2 F)) of 3‐thiobenzoylthioureat was studied by cyclic voltammetry. 1 are converted by reduction into 2. The mechanism of the oxidation of 2 A, C, F into 1a, d, e is dependent on the central ion.On formation of 1 a from copper(II) chelates of 3‐benzoylthiourea 3 A by means of thionylchloride as well as by electrochemical oxidation 3‐benzoylureas 4 A are formed as sideproducts.
Zur Stereochemie von N,N′‐Bis‐[3‐(o‐ethoxyphenoxy)‐2‐hydroxy‐propyl]‐ethylendiamin
Authors: Kristen H. , Wrubel F. , Widuwild H. , Lücke L. 
Published: January 2005

Stereochemistry of N,N′‐Bis‐[3‐(o‐ethoxyphenoxy)‐2‐hydroxy‐propyl]‐ethylendiamineN,N′‐Bis‐[3‐(o‐ethoxyphenoxy)‐2‐hydroxy‐propyl]‐ethylene diamine (5), synthesized from racemic 1,2‐anhydro‐3‐O‐(o‐ethoxyphenyl)‐glycerol (1) and ethylene diamine (2) or N,N′‐dibenzyl ethylene diamine (3) crystallized in two fractions with different melting points. Both of these analytically pure products gave identical two spot tl‐chromatograms on achiral phases. Attempts were made to resolve the mixtures which proved to consist of configurative but not constitutive isomers. Optically pure products were synthesized from chiral precursors.
Reactions of 2‐arylhydrazones of 1,2,3‐triketones with 1,2‐diaminoethane. I. Synthesis and spectral characterization of 6‐arylazo‐2,3‐dihydro‐1H‐1,4‐diazepines and 3,10‐diarylazo‐4,9‐dimethyl‐5,8‐diaza‐3,9‐dodecadiene‐2,11‐diones
Authors: Opozda Ewa , Śledziewska Ewa 
Published: January 2005

AbstractReactions of 3‐arylhydrazones of 2,3,4‐pentanetrione (1a–1e) and 2‐arylhydrazones of 1,3‐diphenyl‐1,2,3‐propanetrione (1f–1l) with 1,2‐diaminoethane have been studied. It was found, that 3‐arylhydrazones of 2,3,4‐pentanetrione react with 1,2‐diaminoethane with formation of 6‐arylazo‐2,3‐dihydro‐1,4‐diazepines (2a–2e) or the diarylazo derivatives of 4,9‐dimethyl‐5,8‐diaza‐3,9‐dodecadiene‐2,11‐dione (3a–3e). Analogous reactions of 2‐arylhydrazones of 1,3‐diphenyl‐1,2,3‐propanetrione yielded exclusively the derivatives of dihydrodiazepine. The structure of obtained products has been elucidated on the basis of i.r., m.s. and 1H‐n.m.r. spectra.
The Alkali Metal Reduction of Trimethoxybenzenes in hydrocarbon solvents
Authors: Dubis Alina T. , Morzycki Jacek W. , Poplawski Janusz 
Published: January 2005

AbstractA series of trimethoxybenzenes was subjected to reduction in hydrocarbon solvents. 1,2,3‐Trimethoxybenzene (1) and 1,2,4‐trimethoxybenzene (2) underwent selective demethoxylation in high yields, whereas the 1,3,5‐substituted isomer 3 proved resistant to the reduction conditions. The reactions mechanism involves the fission of a methoxyl radical from an initial radical anion. The accompanying side‐reactions, i.e. demethylation and deoxygenation, may be suppressed by the addition of n‐butanol as a proton source.
Strukturelle Abwandlungen an N‐Acetylneuraminsäure. 22 [1]. Zur Umsetzung von Methyl‐5‐acetamido‐7,8‐anhydro‐4‐O‐t‐butyldimethylsilyl‐3,5‐didesoxy‐D‐glycero‐ und L‐glycero‐β‐D‐galakto‐nonulopyranosidonsäure‐methylester mit Bis‐imidazolylthiocarbonat
Authors: Zbiral E. , Brandstetter H. H. 
Published: January 2005

Structural Variations on N‐Acetylneuraminic Acid. 22 On the Reaction of Methyl[5‐Acetamido‐7,8‐anhydro‐4‐O‐t‐butyldimethylsilyl‐3, 5‐dideoxy‐D‐glycero‐and‐L‐glycero‐β‐galacto‐2‐nonulopyranosid]onate with DiimidazolylthiocarbonateThe title compounds 1 and 3 are transformed with diimidazolylthiocarbonate into the cyclic 8(S),9(O)‐dithiocarbonatosialic acid derivatives 2 and 4 as well as into a mixture of the cyclic 8(S),9(O)‐monothiocarbonato derivatives 5a and 5b, which turned with acetanhydride pyridine to the corresponding 4‐O‐t‐butyldimethylsilyl‐7‐O‐acetyl‐ and 4,7‐di‐O‐acetyl derivatives 5c and 5d.