bluuebunny/crossref_metadata_2025 huggingface dataset:
The behaviour of some derivatives of 1,2,4‐triazine toward organomagnesium halides
Authors: Mustafa Ahmed , Mansour Abdel Kader , Zaher Hussein Abdel Azim
Published: January 2005

6‐Phenyl‐3,5‐dioxo‐2,3,4,5‐tetrahydro‐1,2,4‐triazine 1, 3‐oxo‐5,6‐diphenyl‐2,3‐dihydro‐1,2,4‐triazine 3, 3,5,6‐triphenyl‐1,2,4‐triazine 4, and 3‐chloro‐5,6‐diphenyl‐1,2,4‐triazine 8, react with phenylmagnesium bromide. The reactions involved are represented by scheme A. Compound 3 reacts with o‐ and/or p‐methoxyphenylmagnesium bromide to give compounds believed to have structures like 10 and 11 respectively. Compound 1 reacts with methylmagnesium bromide and with benzylmagnesium chloride to give products believed to have structures like 12 a, b.
Reactions with 2‐thiazolin‐5‐ones. III. The behaviour of 4‐Arylazo‐2‐alkoxy‐2‐thiazolin‐5‐ones toward amines and Grignard reagents
Authors: Harhash Abdel Hamid , Elnagdi Mohamed Hilmy , Hafez Ebtisam Abdel Aziz
Published: January 2005

Treatment of 4‐arylazo‐2‐alkoxy‐2‐thiazolin‐5‐ones 4a–f with glycine or phenylhydrazine effects their conversion into 1‐aryl‐5‐alkoxy‐1 H‐1,2,4‐triazole‐3‐carboxylic acid derivatives 5a–j, with the loss of hydrogen sulfide. On the other hand, the reaction of the 2‐ethoxy (4a–c) and the 2‐isopropyloxy (4g–i) derivatives with strong basic amines involves the loss of an alkyl mercaptan to yield the N‐substituted amines 7d–j of 1‐aryl‐Δ2‐1,2,4‐triazolin‐5‐one‐3‐carboxylic acids. The 2‐benzyloxy derivatives 4d–f react with the same reagents to give the N‐substituted amides 2a–g of 1‐aryl‐Δ2‐1,2,4‐triazolin‐5‐thione‐3‐carboxylic acids, with the loss of benzyl alcohol.

Hetero‐ring opening of 4, followed by recyclisation, occurs upon treatment with ethyl or phenyl magnesium halides to yield the triazolinethione derivatives 13 a–c.
The Behaviour of Some 4‐Hydroxy‐1‐thiocoumarins toward amines and phenylhydrazine
Authors: Asker Wafia , Elnagdi Mohamed Hilmy , Fahmy Sherif Mohamed
Published: January 2005

Acetylation of 4‐hydroxy‐1‐thiocoumarin 1 b in the presence of phosphorus oxychloride yields the 3‐acetyl derivative 2, which condenses with aromatic aldehydes to give the corresponding 3‐cinnamoyl derivatives 3 a–e, and yields 3‐arylazo‐4‐hydroxy‐1‐thiocoumarins 4 a–d upon treatment with aromatic diazonium salts.

Whereas treatment of 1 b with primary amines results in the formation of 4‐substituted amino derivatives 5 a–c, 3‐acetyl‐4‐hydroxy‐1‐thiocoumarin 2 reacts with the same reagents to yield the 3‐α‐alkyliminoethyl derivatives 7 a–c.

Treatment of 1 b with phenylhydrazine affords the 4‐phenylhydrazine derivative 5 d. On the other hand, 2 reacts with the same reagent to yield a mixture of the phenylhydrazone 9 and the pyrazolo‐1‐thiocoumarin 10.
Structural isomers in the perkin reaction. II. Products of interaction of 4‐bromophthalic anhydride with phenylacetic acids and some of their reactions
Authors: Islam A. M. , Hannout I. B. , Souka L. M. , Naser A. M. , El‐Maghraby A. A. , Islam I. E.
Published: January 2005

Isomeric bromobenzalphthalides of type 1 were obtained by condensation of 4‐bromophthalic anhydride with phenylacetic acids. Isomeric benzalphthalimidines of type 6–11 were also prepared and some of their reactions discussed.
Dienoligomerisierung. VII. Palladiumkomplexkatalysierte Dimerisierung und Telomerisierung von Butadien im alkoholischen Medium
Authors: Beger J. , Reichel H.
Published: January 2005

Bei der Umsetzung von Butadien in Gegenwart von homogen gelösten Katalysatorsystemen aus Palladium(II)‐acetylacetonat und verschiedenen Verbindungen des dreiwertigen Phosphors bilden sich bei Anwesenheit von Alkoholen Gemische aus n‐Octatrienen‐(1,3,7), 1‐Alkoxyoctadien‐(2‐t,7) und wenig 3‐Alkoxyoctadien‐(1,7). Es wird die Abhängigkeit der Zusammensetzung des Produktgemisches von den zugesetzten Komplexliganden, Alkoholen und weiteren Versuchsparametern, wie Molverhältnissen und Temperatur untersucht. Durch kinetische Verfolgung der Reaktion werden das Geschwindigkeitsgesetz und die Aktivierungsparameter erhalten.
MO‐Berechnungen an Heterocyclen. IX. π‐Elektronenstruktur und UV‐Spektren von [1,2‐b]‐ sowie [1,2‐c]‐anneliertem Acenaphthothiophen und N‐Methyl‐acenaphthopyrrol
Authors: Scholz M. , Walzel E. , Hofmann H.‐J.
Published: January 2005

Nach der PPP‐Methode werden einige Grundzustandseigenschaften und die Elektronenspektren der Titelverbindungen untersucht.

Aus den Elektronendichten lassen sich nur bedingt Reaktivitätsvoraussagen treffen. Die aus den Bindungsordnungen berechneten Bindungslängen sind im Naphthalingerüst bei allen Verbindungen gleich denen im Fluoranthen. Im heterocyclischen Ring dagegen treten beträchtliche Unterschiede in Abhängigkeit von Art und Stellung des Heteroatoms auf.

Die UV‐Spektren können durch die Rechnungen gut interpretiert werden. Die gelbe Farbe der Heterocyclen mit C1h‐Symmetrie, die durch eine Absorptionsbande um 400 nm verursacht wird, entspricht einem 2‐1′‐Übergang (Perimetermodell: 1A → 1Lb‐Übergang). In den Verbindungen mit C2v‐Symmetrie liegt dieser Übergang sehr dicht am 1‐1′ (1A → 1La)‐Übergang unterhalb 360 nm.
13C‐NMR‐Spektroskopische Untersuchungen der Elektronenstruktur von einfachen Polymethinen. 13C‐Chemische Verschiebungen, 13C‐H‐Kopplungs‐konstanten und Eu(DPM)3‐Verschiebungseffekte
Authors: Radeglia R.
Published: January 2005

Die 13C‐NMR‐chemischen Verschiebungen δ einfachster Polymethine der allgemeinen Formel
equation image
werden mitgeteilt und mit entsprechenden π‐Elektronendichten (PPP–Näherung) korreliert. Die 13C‐H‐Kopplungskonstanten J(CH) der Polymethinfragmente CH werden in Zusammenhang mit dem ladungsinduzierten Alternieren der CCC‐Bindungswinkel innerhalb der Polymethinkette diskutiert. Die bei Merocyaninen durch Zusatz vom Verschiebungsreagenz Eu(DPM)3 hervorgerufenen Veränderungen der 13C‐chemischen Verschiebungen werden auf eine Überlagerung von Pseudokontakt‐ und Kontaktwechselwirkung zwischen den 13C‐Kernen der Polymethinkette und dem assoziierten paramagnetischen Europiumkomplex zurückgeführt.
Aufklärung der Molekülstruktur von Rohölinhaltstoffen durch NMR‐Spektroskopie. I. Struktur der Isoparaffine des Rohöls
Authors: Deutsch K. , Jancke H. , Zeigan D.
Published: January 2005

Es wird eine Zuordnung der 13C‐Resonanzen der Paraffine der Roherdölfraktionen zu entsprechenden C‐Atomen möglicher Strukturelemente vorgenommen. Daraus ergeben sich neue Informationen über die Struktur der Isoparaffine des Erdöls.
Organoarsen‐Verbindungen. XXV. Synthese und Reaktionen von 1.3‐Azarsolidin‐2‐thionen
Authors: Tzschach A. , Heinicke J.
Published: January 2005

Sekundäre 2‐Amino‐äthylarsine, RAs(H)CH2CH2NMR′, reagieren mit CS2 zu den 1.3‐Azarsolidin‐thionen. Unter geeigneten Bedingungen sind dabei auch die Ammoniumsalze der 2‐Arsinoäthyl‐dithiocarbamate als primäre Reaktionsprodukte isolierbar. Die 1.3‐Azarsolidin‐2‐thione reagieren mit elektrophilen Agentien am Schwefelatom, wobei 2‐Alkylthio‐ bzw. 2‐Organostannylthioazarsoline sowie 1.3.‐Azarsolidin‐2‐one zugänglich sind.
Allgemeine Synthese 1‐substituierter Pyrazolidone‐(3) durch nucleophile Grignard‐Addition an carbonylstabilisierte Azomethinimine
Authors: Dorn Helmut , Graubaum Heinz
Published: January 2005

An das C‐6‐Atom carbonylstabilisierter Azomethinimine 1 lassen sich Alkyl‐, Aralkyl‐ oder Arylreste mit Hilfe von Grignard‐Verbindungen in THF nucleophil addieren. Diese neue, allgemeine Synthese 1‐substituierter Pyrazolidone‐(3) 8 verläuft mit hoher Ausbeute. Die C‐6‐Substitution wird durch eindeutige Synthesen und NMR‐spektroskopisch bewiesen. Die Grignard‐Addition verläuft, wie an der NMR‐spektroskopisch nachgewiesenen Bildung von diastereomeren 1‐substituierten Pyrazolidonen‐(3) 8 aus C‐4‐substituierten 1 gezeigt wird, nicht stereospezifisch.
Über α‐substituierte Phosphonate, XX. Untersuchungen zur C‐N‐Umlagerung bei Aminomethan‐bis‐und ‐tris‐phosphorylverbindungen
Authors: Gross H. , Brennecke L. , Costisella B.
Published: January 2005

Versuche zur Darstellung von Aminomethan‐bis‐phosphorylverbindungen des Typs 5, 9 bzw. 13, also mit einer NH‐Funktion am Methin‐Kohlenstoffatom führen unabhängig vom Syntheseweg stets unter C‐N‐Wanderung eines Phosphorylrestes zu N‐phosphorylierten Aminomethanphosphonsäureestern 6, 10/11 bzw. 14. Der Ablauf dieser Umlagerung wird an charakteristischen Beispielen untersucht.
Darstellung und Koordinationsverhalten von 2‐Acylmethylen‐thiazolidinen
Authors: Spitzner R. , Dill G. , Schroth W. , Hennig H. , Jamil K. M.
Published: January 2005

Es wird die Reaktion von 2.2‐Dichlorvinyl‐ketonen mit 2‐Aminoäthylmercaptan beschrieben. Die dabei als Hauptprodukt gebildeten 2‐Acylmethylen‐thiazolidine werden hinsichtlich ihrer Komplexbildung gegenüber zweiwertigen Metallionen untersucht. Die dargestellten Neutralchelate von Cu2+, Ni2+, Co2+, Pd2+, Zn2+ besitzen [N2O2]‐Koordination, wie aus analytischen, spektroskopischen und magnetochemischen Befunden hervorgeht.
Lösungsmittelinduzierte Elektronenstrukturänderungen bei negativ solvatochromen Farbstoffen
Authors: Wähnert M. , Dähne S.
Published: January 2005

Die chemischen Verschiebungen des Protonenresonanzspektrums von negativ solvatochromen Farbstoffen hängen von der Polarität des verwendeten Lösungsmittels ab, wobei die Differenzen der chemischen Verschiebungen benachbarter Protonen mit zunehmender Polarität abnehmen. Dies deutet auf eine lösungsmittelinduzierte Veränderung der Elektronenstruktur von einem mehr polymethinähnlichen Zustand in unpolaren Lösungsmitteln in Richtung auf einen polyenähnlichen Zustand in polaren Lösungsmitteln hin.
Zur Chemie aktivierter Vinylhalogenide. Synthese und Reaktionsverhalten von 3‐(β‐Chlor‐vinyl)‐acrylnitrilen
Authors: Liebscher Jürgen , Hartmann Horst
Published: January 2005

In einer einfachen Reaktionsfolge, ausgehen von Arylmethylketonen 8 und Formamidchloriden 2 sind über arylsubstituierte β‐Chlor‐vinyl‐methinimmoniumsalze 4 und Umsetzung dieser mit substituierten Cyanessigsäure‐Derivaten 9 3‐(β‐Chlor‐vinyl)‐acrylnitrile 7 zugänglich, die ihrerseits sehr glatt mit nucleophilen Partnern, wie aliphatischen und aromatischen Aminen, Natriumsulfid, Natriumthiosulfat oder Dithiocarbaminaten sowie Alkalihydroxiden reagieren. Dadurch lassen sich eine Anzahl zum Teil neuartiger Verbindungen bzw. Verbindungstypen, wie 3‐(β‐Amino‐vinyl)‐acrylnitrile 10 bzw. 19, substituierte 3‐(β‐Mercapto‐vinyl)‐acrylnitrile 24, 3‐(β‐Hydroxy‐vinyl)‐acrylnitrile 14, 1,2‐Dihydro‐2‐imino‐pyridine 12 und 2‐Amino‐pyridiniumsalze 13, 2‐Amino‐pyryliumsalze 15, 2‐Pyridone 17, 2‐Imino‐2H‐thiopyrane 26 und 2‐Amino‐thiopyrylium‐salze 18, gewinnen. Ihre Entstehung verdanken sie der hohen Reaktivität sowie dem ambidenten Reaktionsverhalten der 7, für das auf der Basis einfacher MO‐Betrachtungen eine plausible Erklärung gegeben wird.

Zur Charakterisierung der neu dargestellten Verbindungen werden spektroskopische Daten sowie einige chemische Reaktionen angeführt.
Synthesen von 2,5‐disubstituierten Thiophenen aus 1‐Chlor‐propenyliden‐(3)‐immoniumsalzen und Schwefel‐Nucleophilen
Authors: Liebscher Jürgen , Hartmann Horst
Published: January 2005

Ausgehend von aus Formamidchloriden und substituierten Acetophenonen 6 erhältlichen 1‐Chlor‐propenyliden‐(3)‐immoniumsalzen 3 werden durch Umsetzung mit Thioglykolsäurederivaten bzw. substituierten Benzylmercaptanen 4 5‐substituierte Thiophen‐2‐carbonsäure‐Derivate bzw. 2‐Aryl‐thiophene 5 synthetisiert. Derartige Thiophene 5 werden außerdem durch Reaktion der β‐(N‐Pyridinium)‐vinylaldehyde 7 mit Thioglykolsäureester 4 bzw. von β‐Dimethylamino‐vinylthioketonen 8 mit Halogenmethylenverbindungen 9 erhalten. Die Thiophencarbonsäure‐Derivate 5 lassen sich mit o‐substituierten Anilinen 11 zu stark fluoreszierenden Benzazolylthiophen‐Derivaten cyclisieren.
Kristallin‐flüssige Aldoximester
Authors: Weissflog W. , Schubert H.
Published: January 2005

Die Acylierung aromatischer Aldoxime mit Benzoylchloriden ergibt Benz‐aldoxim‐benzoate. Durch den Einbau geeigneter geradkettiger Substituenten in 4‐ und 4′‐Stellung konnte eine neue Substanzklasse mit kristallin‐flüssigen Eigenschaften erschlossen werden. An mehreren Reihen 1–6 wurde der Einfluß verschiedener Flügelgruppen auf das mesomorphe Verhalten und dadurch bedingte Anomalien im Verlauf von Klärpunktskurven untersucht.
Tautomere 3‐Acetyltetramsäurederivate – 1H/13C‐NMR‐Untersuchung
Authors: Zschunke A. , Donau R. , Böttger U.
Published: January 2005

Tautomeric 3‐Acetyltetramic Acid Derivatives –1H/13C‐n.m.r.‐Investigation

The molecular structure of 1,5,5‐trimethyl‐3‐acetyltetramic acid (I) and its Schiffbases with ethylendiamin (II) and 1,3‐diaminopropan‐2‐ol (III) is described by an equilibrium of four tautomers. The solvent dependence of the equilibrium is attributed to the strength of the intramolecular hydrogen bond. The higher proton affinity of the Schiff‐bases (II and III) in comparison with the ketone (I) should be responsible for the faster equilibration of II and III.
Substituenteneffekte auf die CC‐Bindungsstärke. IX. Thermolabilität der 2,3‐Di(N,N‐dialkylamino)‐bernsteinsäure‐diethylester
Authors: Schulze Rainer , Beckhaus Hans‐Dieter , Rüchardt Christoph
Published: January 2005

Substituent Effects on the Strength of CC‐Bonds. IX. Thermolability of 2,3‐Di(N,N‐dialkylamino)‐diethyl‐succinates

The title compounds meso and D, L 3a–c have been prepared from R,R′NCH2‐COOEt (5), R,R′ = CH3 (a), C2H5 (b) and i‐C3H7 (c), by lithiation followed by oxidation with I2. The thermolysis of 3 above 140°C in solution generates the radicals 1, which could be detected by e.s.r. Kinetic measurements are performed in the presence of a phenylthiol as a scavenger and the activation parameters are determined. – The steric acceleration of the cleavage reaction is separated using the correlation ΔG≠(300°C) = a Ds + b, whereby the strain values Ds = Hs (3) – 2 Hs (1)) are taken from force field calculations. The obtained strain free barrier to dissociation b = 37.4 kcal/mol is considerably lower than the value for the thermolysis reaction of tetraalkyl ethanes (b = 66.2kcal/mol [17]). The decrease of the activation enthalpy (ΔΔH≠ = 35.4kcal/mol) is mainly caused by stabilisation of 1 compared to sec. alkyl radicals; heats of formation of meso‐3a and 5a support this conclusion.

Furthermore, the decrease of bond strength in 3 by the two geminal capto‐dative substituents exceeds the sum of the effect of one ester group (ΔΔH≠ = 4kcal/mol [19]) and one amino group (ΔΔH≠ = 9.5kcal/mol, drawn from the thermolysis of 1,2‐(N,N‐Dimethylamino)‐1,2‐diphenyl‐ethane (4) by about 4 kcal/mol.
Synthese 2‐substituierter 1H‐Benz[e][1,4]oxazepin‐5‐one
Authors: Sicker Dieter
Published: January 2005

Synthesis of 2‐Substituted 1 H‐Benz[e][1,4]oxazepin‐5‐ones

An approach to the hitherto unknown class of 1H‐benz[e][1,4]oxazepin‐5‐ones is given based on reduction and cyclization of appropriate acyclic ortho‐nitro compounds as starting materials. Thus, some 2‐substituted derivatives (3a–i) were synthesized by catalytic hydrogenation of acyl 2‐nitrobenzoates (1a–i) to yield the corresponding anthranilic acid esters (2a–i), which were subsequently cyclized in polyphosphoric acid at elevated temperature. The behaviour of esters 1a–i towards spontaneous intramolecular reductive cyclization is discussed in comparison to that of similar educts leading to sixmembered heterocycles as shown by former results.
Studies on the Oxidation of Phenyl Cycloalkanes by tertiary hydroperoxides
Authors: Pritzkow Wilhelm , Suprun Vladimir Ya. , Voerckel Volkmar
Published: January 2005

During the thermal decomposition of cumene hydroperoxide at about 125°C in phenyl cycloalkanes as solvents, the solvents are attacked, preferably at the tertiary CH bonds. Up to 70% (with regard to the decomposed hydroperoxide) of oxidation products of the phenyl cycloalkanes are obtained. The main oxidation products are the corresponding 1‐phenyl cycloalkanols, but relatively large amounts of phenyl alkyl ketones with the same number of carbon atoms are also formed, probably via a further oxidation of the 1‐phenyl cycloalkanols.
The synthesis of Pyrido[1,4]thiazinones
Authors: Dunn A. D. , Norrie R.
Published: January 2005

Both 2 and 4 halogenated 3‐aminopyridines react thermally with α‐mercapto esters and amides to afford pyrido[2,3‐b] and pyrido[4,3‐b] [1,4]thiazinones. N‐alkylation and oxidation of the products were investigated.
13C‐NMR‐spektroskopische Untersuchung einfach substituierter Flavyliumsalze
Authors: Gruner M. , Hartmann H. , Czerney P. , Hultzsch R.
Published: January 2005

13C‐N.M.R. Spektroscopical Studies on Simply Substituted Flavylium‐Salts

On a series of differently substituted flavyliumsalts 1‐3 their 13C‐NMR‐chemical shifts and their 1J(13CH) coupling constants were recorded and compared with results received by means of semiempirical PPP calculations and using LFE relationships. Both the experimental and theoretical results exhibit concordantly a characteristic alternate electron distribution along the conjugated π‐system of the compounds studies and reveal the distinct influence of donor and acceptor substituents on the electron distribution in both the benzopyrylium and the aryl moiety of the flavylium salts studied.
Electrosynthesis of Conducting Polyanisidine in biphasic media
Authors: Munaff G. A. , Omer Shua'a , Zutshi K.
Published: January 2005

The electrochemical polymerization of anisidine, a soluble conducting polymer has been studied in the two phase media. One phase comprises of a non‐polar solvent containing the monomer and the other a polar medium containing some added electrolytes. The process of electropolymerization has been catalyzed by FeCl3 as the suitable supporting electrolyte. Polyanisidine was obtained in moderate yields with the highest Rp of 0.0296% per hour and a maximum polymerization efficiency of 59.50 × 10−2 mol/faraday. These materials show great potential for applications to areas such as molecular electronic devices, batteries and chemically modified electrodes and sensors. The soluble polymer was analyzed using a variety of common experimental techniques including infrared spectroscopy, proton magnetic resonance spectroscopy and gel permeation chromatography. The conductivity determined by using a classical two‐probe technique displays a value in the range of 10−7 to 2.3 Ω−1 cm−1. The observations and experimental results suggest a cationic polymerization mechanism.
Reaktionen von Dithiocarbamidsäure‐ und Thiokohlensäureestern mit Heterokumulenen
Authors: Dölling Wolfgang , Sperk Katrin , Augustin Manfred
Published: January 2005

Reactions of Dithiocarbamates and Thiocarbonates with Heterocumulenes

3,3‐Bis(alkylthio)‐2‐dialkylaminothiocarbonylthioacrylonitriles 3–5 are obtained by dithiocarboxylation reaction of N,N‐disubstituted S‐cyanomethyl dithiocarbamates 1a‐c in NaH/THF at −15°C followed by alkylation. Treatment of N,N‐dimethyl‐S‐methylthiomethyl dithiocarbamate 6 with CS2/2 n‐BuLi in THF at − 55°C gives N,N‐dimethyl S‐[1,2,2‐tris(alkylthio)‐vinyl]dithiocarbamates 7a‐c. Phenylisothiocyanat reacts with S‐alkoxycarbonylmethyl‐O‐alkyl thiocarbonates 8a, b in the presence of t‐BuOK/dry DMF to yield 4‐subst. 2‐oxo‐3‐phenyl‐1,3‐thiazoline‐5‐carboxylates 11a‐e.
Furylvinylhalogenide. XI. Reaktionen von ß‐(5‐Nitrofur‐2‐yl)‐ß‐chlor‐β‐cyanacrylsäure‐derivaten mit Enaminen
Authors: Vieth Siegfried , Jähnisch Klaus
Published: January 2005

Furylvinylhalides. XI. Reactions of β‐(5‐Nitrofur‐2‐yl)‐β‐chloro‐α‐cyanoacrylic Acid Derivatives with Enamines

Enamines are vinylated by β‐(5‐nitrofur‐2‐yl)‐β‐chloro‐α‐cyanoacrylic acid derivatives 2 yielding push‐pull‐dienes 3, 4 or 6. Acidic ring closure of 3 leads to pyridin‐2‐ones 7 or chromen‐2‐ones 8, respectively.
Synthese von Pyrazolo[3,4‐b]chinolinen aus 4‐Aroyl‐5‐chlor‐pyrazolen
Authors: Hennig L. , Müller T. , Grosche M.
Published: January 2005

Synthesis of Pyrazolo[3,4‐b]quinolines from 4‐Aroyl‐5‐chloropyrazoles

The reaction of 4‐aroyl‐5‐chloro‐3‐methyl‐1‐phenyl‐pyrazoles 1 with an excess of 3‐ or 4‐substituted and 3,4‐disubstituted anilines 2 gives pyrazolo [3,4‐b]quinolines 4a‐k. Information about the reaction mechanism was obtained by the isolation of the intermediate product 3e. In some cases it was possible to isolate subsequent products 41‐p. The reaction of 1a with 5‐amino‐3‐methyl‐1‐phenyl‐pyrazole (5) gives a bispyrazolopyridine derivative 6.
On the Reaction of Chloroglyoximes with Aryl Isocyanates
Authors: Witek S. , Czekański T. , Kaczmarek A.
Published: January 2005

Reaction of chloroglyoxime 1 with aryl isocyanates yielded monocarbamates 3, and chlorooxime functional group was unchanged. The 1,3‐cycloaddition of nitrile N‐oxides generated from 3 to methyl methacrylate gave isoxazole derivatives 5. Compounds 5 were also obtained by carbamoylation of 3‐formyl‐4‐hydro‐5‐methyl‐5‐methoxycarbonylisoxazole oxime 6.

The selectivity of chloroglyoxime carbamoylation and the poor reactivity of chlorooxime group is general. Examples, involving another oximes and their halogeno derivatives are given.
The diastereofacial selectivity of the addition of various 1‐metalated 1‐heptynes to substituted cyclopentanecarbaldehydes. – The use of 1‐titanated 1‐heptyne for the construction of the alkyl side chain of Prostaglandins
Authors: Djadchenko Marina A. , Pivnitsky Kasimir K. , Mahrwald Rainer , Schick Hans
Published: January 2005

A highly diastereoselective addition of 1‐heptyne to substituted cyclopentanecarbaldehydes is one of the indispensable prerequisites to the construction of the (S)‐3‐hydroxy‐1(E)‐octenyl side chain of prostaglandins by palladium(II)‐catalyzed [3,3]‐sigmatropic rearrangement of allylic acetates. It was found that 1‐titanated 1‐heptynes afford the Cram product at best with a diastereofacial selectivity of 92.5%. The corresponding lithium and magnesium compounds are less diastereoselective.
Thermisch initiierte Addition von Alkanen an Alkene. V. Addition von Cyclohexan an Oct‐1‐en in einer freien Radikalkettenreaktion unter überkritischen Bedingungen
Authors: Metzger Jürgen O.
Published: January 2005

Thermal Addition of Alkanes to Alkenes. V. Addition of Cyclohexane to 1‐Octene in a Free Radical Chain Reaction at Supercritical Fluid Conditions

Alkanes can be added to alkenes in a thermally initiated free radical chain reaction (“ane reaction”). Kinetic and mechanistic studies on the addition of cyclohexane (1) to 1‐octene (2) (molar ratio = 100:1) at 330−450°C and pressures of up to 300 bar have been performed in a high pressure ‐ high temperature flow apparatus (“HP‐HT” apparatus). The free radical chain is initiated by comproportionation of1and2to give alkyl radicals6and7. Addition of cyclohexyl radical6to alkene2and competing abstraction of an allylic hydrogen atom from2give radicals7aand8, respectively. Subsequent stabilization of the radicals7aand8by hydrogen abstraction from1yields the addition product cyclohexyloctane (3) and isomerized octenes (4), respectively. The relative rate of addition and isomerization can be controlled by pressure and temperature. The regioselectivity of the addition reaction was also measured.
Untersuchungen zur Ringspaltung 4‐(4‐nitrophenylazo)‐substituierter Pyrazolidin‐3,5‐dion‐Derivate
Authors: Waldheim G. , Möhrle H. , Rüdiger S.
Published: January 2005

Studies on Ring Cleavage of Some 4‐(4‐Nitrophenylazo)‐substituted Pyrazolidine‐3,5‐dione‐Derivatives

Continuing to previous investigations the ring cleavage of the pyrazolidine compounds 3 and 7 is studied under the influence of KOH and CH3ONa. Due to the different substitution of atoms of the heterocyclus this reaction was expected to result in at least two isomeric compounds. Actually this assumption was only confirmed for 3. So the reaction of 3 with CH3ONa yields a mixture of four isomers (4a‐4d) with 4a as main product. On the other hand, when 7 is treated with CH3ONa or KOH only one product is formed. With regard to the great structural similarity of the possible isomers, mass spectroscopy proved to be the best test of whether the ring cleavage occurs between C‐3 and C‐4 or C‐4 and C‐5 of the heterocyclus.
Some New Heterocyclic Sulphonates with potential antimicrobial activity
Authors: Habib O. M. O. , Moawad E. B. , Badawy D. S. , Mansour F. A.
Published: January 2005

4‐(Phenylhydrazono‐4′‐benzenesulphonato)‐3‐methyl‐2‐pyrazolin‐5‐one (2) was prepared by treating 4‐(4′‐hydroxyphenylhydrazono)‐3‐methyl‐2‐pyrazolin‐5‐one (1) with benzenesulphonyl chloride. Heating 2 with acetic anhydride, chloroacetyl chloride and benzenesulphonyl chloride afforded the N‐acetyl (3), N‐chloroacetyl (4) and O‐benzenesulphonyl (5) derivatives, respectively. 2 reacted with benzenesulphonyl chloride under cooling conditions to give the N‐benzenesulphonyl derivative (6). 2 undergoes Mannich reaction to give the N‐Mannich base (7). Reaction of 2 with formaldehyde in methanol afforded the N‐hydroxymethyl derivative (8) which undergoes condensation with ethyl acetoacetate, ethyl cyanoacetate and malononitrile to give compounds 9, 10 and 11 respectively. The antimicrobial activity of these products against gram‐positive (+ve), gram‐negative (−ve) bacteria and fungi was screened. They showed potential bactericidal activity and some of them exhibited high fungicidal activity.
Reaction of 3H, 6H‐1, 2‐Dithiolo[4,3‐c]1,2‐dithiole‐3, 6‐dithione with primary aliphatic amines
Authors: Fanghänel E. , Laube U. , Kordts B. , Richter A. M.
Published: January 2005

The reaction of 3H,6H‐1,2‐dithiolo[4,3‐c]1,2‐dithiole‐3, 6‐dithione (1) with primary aliphatic amines (8a,b) gives 3H,6H‐3,6‐bisalkylimino‐1,2‐dithiolo[4,3‐c]1,2‐ dithiole (9a,b), 3H,3‐N‐alkylamino‐5‐N‐alkylthiocarbamido‐1, 2‐dithiolium‐4‐thiolate (10a,b) and 3H,3‐N‐alkylimino‐4‐alkylamino‐5‐N‐alkylthiocarbamido‐1,2‐dithiole (11a,b). The compounds 9‐11 can be formed from one another. The compounds 10a,b react with nickel chloride to the stable complexes 14a,b. In basic medium 10 gives the salt of 3H,3N‐alkylthiocarbamido‐1,2‐dithiole‐4‐thiolate 15, which reacts with methyl iodide to 3H,3N‐alkylimino‐5‐N‐alkylthiocarbamido‐4‐methylthio‐1,2‐dithiole 16.
Large‐Scale Synthesis of Mammalian Gonadoliberin without protection of side‐chain functions
Authors: Masiukiewicz Elzbieta , Rzeszotarska Barbara
Published: January 2005

A simple, Large‐scale preparation of mammalian gonadoliberin was elaborated using classical solution methods without protecting side‐chain functions. At the final stage, a hexapeptide segment was condensed with the corresponding tetrapeptide and the obtained decapeptide was purified by a single chromatographic procedure on silica gel. The total efficiency of the whole synthesis and the purity of the product amounted to 34% and 98.3%, respectively.
Photochemistry of Acylazides V. Sensitization of decomposition of p‐trimethylsilylbenzoylazide (TSBA)
Authors: Abraham W. , Siegert St. , Buck K. , Csongar Ch. , Helmstreit W. , Grummt U.‐W.
Published: January 2005

The sensitized decomposition of p‐trimethylsilylbenzoylazide by aromatic ketones benzophenone, thioxanthone and 4,4′‐bis(dimethylamino)benzophenone (Michler's ketone) and by diphenylanthracene and pyrene was investigated.

Excited benzophenone acts as producer of solvent radicals which attack the TSBA forming the substituted benzamide. Only short chain lengths are observed in the case of cyclohexane as solvent.

Michler's ketone, diphenylanthracene and pyrene sensitize the decomposition of TSBA via electron transfer processes forming the substituted phenylisocyanate beside primary and secondary amides. The product ratio is dependent on the solvent properties.

Reaction mechanisms are proposed which are founded on time resolved and stationary measurements of transient intermediates and quantum yields.
Produkte der Decarboxylierung photochemisch dargestellter Indencarbonsäure‐Derivate
Authors: Schuster C. , Bendig J.
Published: January 2005

Products of the Decarboxylation of Photochemically prepared Indenecarboxylic Acid Derivatives.

4‐(2‐Diazo‐1‐oxo‐1, 2‐dihydro‐naphthalen‐5‐sulfonyl‐oxy)‐benzophenone (NQD‐BP) was photolyzed to form 4‐(3‐carboxy‐indene‐7‐sulfonyl‐oxy)‐benzophenone (ICA‐BP). This was decarboxylated base‐catalysed in ethanol leading to 4‐(indene‐4‐sulfonyl‐oxy)‐benzophenone (4) and 4‐(indene‐7‐sulfonyl‐oxy)‐benzophenone (5). The indene isomers were separated by means of preparative HPLC and their structure was determined using n.m.r., mass, i.r. and u.v. spectroscopy.
Push‐pull‐Butadiene. XII. Darstellung von Hetrocyclen aus 2,6‐Bis[bis(alkylthio)methylen]cyclohexylidenmalononitrilen
Authors: Peseke K. , Heide G. , Feist H. , Michalik M.
Published: January 2005

Preperations of Heterocycles by using of 2,6‐Bis[bis(alkylthio)methylene]cyclohexylidenemalononitriles.

2,6‐Bis[bis(alkylthio)methylene]cyclohexylidenemalonitriles 1 react with alkanethioles to give 1,3‐bis(alkylthio)‐5‐[bis(alkylthio)methylene]‐5,6, #7,8‐tetrahydro‐isoquinoline‐4‐carbonitriles 2. Treatment of 1 with hydrogen bromide yields 4,6,7,9‐tetrakis(alkylthio)‐2,3‐dihydro‐5,8‐diaza‐phenalenes 3. On the other hand, 1 can be converted with bromine to 6,9‐bis(alkylthio)‐4,7‐dibromo‐2,3‐dihydro‐5,8‐diaza‐phenalenes 5. However, the reaction of 1 and N‐bromosuccinimide afforded 2,6‐bis[bis(alkylthio)methylene]‐3‐bromo‐cyclohexylidenemalononitriles 8.
Flüssigkristalline 4,6‐O‐(n‐Alkyliden)‐D‐glucopyranosen
Authors: Thiem Joachim , Vill Volkmar , Miethchen Ralf , Peters Dietmar
Published: January 2005

Liquid‐crystalline 4,6‐O‐(n‐Alkylidene)‐D‐glucopyranoses.
Folgeprodukt aus Sulfonamiden. XI. Synthesen mit 2‐Chlor‐benzensulfonamid
Authors: Hans M. , Gulube A. , Dehne H.
Published: January 2005

Subsequent Products of Sulphonamides. XI. Syntheses with 2‐Chloro‐benzenesulphonamide.
Synthese von Δ16‐17(Trialkylstannyl)steroiden aus 17‐Ketosteroiden. II
Authors: Schweder Bernd , Uhlig Egon
Published: January 2005

Syntheses of Δ16‐17(Trialkylstannyl)steroids from 17‐Ketosteroids. II.

The oxidation of the hydrazones of 17‐ketosteroids by iodine yields Δ16‐17‐iodosteroids (2, 4). Starting with 2 or 8 (the 3‐tetrahydropyranylether of 4) and lithium(tribu‐tyl)stannate, Δ16‐17(tributylstannyl)steroids (5, 9) are synthesized. The reaction is catalyzed by electronrich complexes of nickel and palladium. In the course of side reactions Δ16‐olefines (6, 10) and the „dimers”︁ 7 and 11, the products of a cross coupling of the Δ16‐17‐iodosteroids, and the Δ16‐17‐tributylstannylsteroids are obtained. The mechanisms of these side reactions and the influence of the solvent (THF, HMPA) are discussed.

The tributylstannylsteroids are to be used as intermediates for the syntheses of steroid hormones from the 17‐ketosteroids.
Massenspektroskopie von Thiogibberelllnen
Authors: Voigt D. , Adam G.
Published: January 2005

Mass Spectroscopy of Thiogibberellins.

The results of the positive ion (electron impact, desorption electron impact, low voltage electron impact, positive ion desorption chemical ionization, — EI, DEI, LEI, PIDCI), as well as negative ion (electron attachment — EA) mass spectra of 4 different types of thio gibberellins 6–9 are compared, and the fragmentation pathways are discussed.
Oxdation of Styrene and its analogues with hydrogen peroxide activated by organoseleniun compounds
Authors: Kubicz Elżbieta , Młochowski Jacek , Syper Ldwik
Published: January 2005

Some organoselenium compound (1) were tested as catalysts for the oxidation of styrene to phenyloxirane (2) with hydrogen peroxide. Bis(2, 4‐dinitrophenyl) diselenide (12) was found most effective. A convenient method for the synthesis of phenyloxirane and its polysubstituted analogs was elaborated.
Synthesen neuer Chinolon‐Chemotherapeutika. V [5] Methodische Untersuchungen zur Synthese von Chinoloncarbonsäuren
Authors: Jordis Ulrich , Sauter Fritz , Burkart Michael , Henning Hans‐Georg , Gelbin Anke
Published: January 2005

Synthesis of Novel Quinolone‐Chemotherapeutics. V. Methodical Investigations on the Synthesis of Quinolone Chemotherapeutics.

The synthesis of 6, 7‐dihalogen‐N‐ethyl‐4‐oxo‐l, 4‐dihydroquinoline‐3‐carboxylic acids (3a, b) from 3, 4‐dihalogen‐anilines is a three‐step processes: (a) N‐ethylation, (b) reaction with ortho formic ester and Meldrum's acid, (c) intramolecular cyclization. An increase of the total yields in comparison with known methods is mainly connected with the third step. Here the Meldrum's method allows reactions in solution at temperatures ≥ 100°C. With application of special Lewis acids the 6, 7‐dihalogen‐substituted products are formed in relatively high yields (6, 7‐difluoro‐l‐ethyl‐4‐oxo‐1, ‐4‐dihydro‐quinoline‐3‐carboxylic acia (3a): 71%; 7‐chloro‐6‐fluoro‐1 ‐ethyl‐4‐oxo‐1, 4‐dihydro quinoline‐3‐carboxylic acid (3b): 60%) without impurities of the corresponding 5, 6‐dihalogen substituted isomers. Anhydrides (5) of 4‐oxo‐1, 4‐dihydro‐quinolone‐3‐carboxylic acids with dibromo and difluoro‐boric acid were synthesized and shown to facilitate the aromatic nucleophilic substitution. The kinetics of two reactions (5a → 6 and 3b → 7) were determined and relative reaction rates established.
Ultraschall‐induzierte Synthese von Trlmethylsilylessigsäuresilylestern
Authors: Nietzschmann Eckhart , Böge Olaf , Tzschach Alfred
Published: January 2005

Ultrasound‐induced Synthesis of Trimethylsilylacetic Acid Trimethylsilylester.

The reaction of bromoacetic acid trimethylsilylester with zinc in presence of chlorotrimethylsilane is promoted by sono‐waves. The trimethylsilylacetic acid trimethylsilylester could be obtained in high yield. Different products are observed in presence of dichloro dimethylsilane. Mechanical aspects are discussed.
Funktionallsierung von lodprazolen mit D‐Glucopyranose bzw. mit Aminoalkoholen
Authors: Randow H. , Miethchen R.
Published: January 2005

Functionalisation of Iodopyrazoles with D‐Glucopyranose and with Aminoalcohols, Respectively.

3, 4, 5‐Triiodo‐pyrazole (1a) and 3, 4‐diiodo‐5‐methyl‐1 H‐pyrazole (1 b) were silylated with hexamethyldisilazane without isolation of the N‐trimethylsily derivatives and than glucosilated to give the β‐N‐nucleosides 2a and 2b, respectively, with 2, 3, 4, 6‐tetra‐O‐acetyl‐α‐D‐glucopy‐ranosylbromide or ‐fluoride in the presence or absence of SnCl4. The corresponding deacetylated derivatives 3 a–b can be easily obtained by treatment of 2 a–b with sodium methanolate in methanol. Furthermore, 1 a and 1 b as well as 3(5)‐methoxycarbonyl‐4‐iodo‐1‐H‐pyrazole (1 c) were alkylated with methyl bromoacetate‐acetate to form the corresponding pyrazole‐1‐yl‐methylacetates 4 a–c. These compounds could be amidated by short heating with N‐methylglucamine and 1‐amino‐propane‐2, 3‐diol (isoserinol), respectively, in methanol to form the corresponding amides 5 a–c and 6 a–c. The diamide 7 c was prepared bylongtime heating of 4 c with excess isoserinol in n‐propanol.
Reactions of acylium salts with aryl nitriles. A convenient Synthesis of Aryl Substituted bis‐ and tris‐1, 3, 5‐oxadiazinium salts
Authors: Al‐Talib Mahmoud , Tashtoush Hasan , Al‐Omari Mohammad
Published: January 2005

Bis‐l, 3,5‐oxadiaziniumalkanes (5a–u) and tris‐1, 3, 5‐oxadiaziniumbenzene (6a–d) were prepared from the reaction of diacylium and triacylium salts with aryl nitrites, respectively. All new compounds are fully characterized by spectroscopic methods and elemental analysis.
Zur Reaktion von atomarem Wasserstoff mit 1‐Olefinen
Authors: Gebhardt J. , Scherzer K.
Published: January 2005

About the Reaction of Atomic Hydrogen with 1‐Olefines.

Chemical activated reaction paths of the C2C8‐l‐olefines, initiated by atomic hydrogen, have been studied using an isothermal flow‐system (298 K, 130 Pa) with electrical discharge. In the reaction mixtures homologeous series of 1‐olefines and n‐alkanes were found which are identical with those of cycloolefine systems described previously [1, 2]. The reactions of the 1‐olefines are analysed and discussed in detail and compared to the cycloolefine reactions.
On the Spin Trapping off Sulfur Dioxide Anion‐Radicals (.SO2−) by nitrones
Authors: Rehorek Detlef , Dubose Coit M. , Janzen Edward G.
Published: January 2005

.SO2− radicals react with nitrones to form the anion of the corresponding spin adduct. Addition of mild oxidants generates the spin adduct of .SO2−, the e.p.r. spectrum of which exhibits additional hyperfine splitting.
Investigations on the synthesis of Dimethylbenzodiazepinium Tetrahalogenometalate Complexes
Authors: Steinborn Dirk , Dung Pham Gia , Sedlak Ursula
Published: January 2005

o‐Phenylenediamine and acetylacetone react with MCl2 (M = Fe, Co) to give dimethylbenzodiazepinium tetrahalogenometalate complexes [dmb]2[MCl4]1, but in the presence of NiCl2 only [dmb]Cl is obtained. The complexes [dmb]2[MX4] (M = Fe, Co, Ni; X = Cl, Br) have been prepared by the reaction of MX2 with [dmb]X and in the case of nickel also by metathetical reaction of tetrahalogenoniccolat complexes with [dmb][BPh4]. All complexes described have been characterized by elemental analysis, magnetic measurement and spectroscopically.
Synthese von 2‐aminosubstituierten 4,5‐Dihydro‐1,3‐thiazolen
Authors: Richter C. , Hobert A. , Meisner W. , Schulze K.
Published: January 2005

Synthesis of 2‐Amino‐Substituted 4,5‐Dihydro‐1,3‐thiazoles.

The reaction of 2‐substituted 4‐methallylthiosemicarbazides 1 with carbonyl compounds catalyzed by weak acids gives thiosemicarbazones 2 and 1,2,4‐triazolidine‐3‐thiones 3. By contrast under strong acidic conditions the reaction occurs by electrophilic cyclisation with participation of the methallyl and thiono groups, and 4,5‐dihydro‐1,3‐thiazoles 5 are formed after neutralisation. The electrophilic cyclisation of N‐methallyl substituted thioureas 6 and 1,4‐disubstituted thiosemicarbazides 7 is also described.
Substituierte Alkinyle als axiale Liganden an häminähnlich gebundenem Eisen(III) ‐ Einordnung in eine spektrochemische Serie
Authors: Jäger E.‐G. , Hähnel H. , Klein H.‐F. , Schmidt A.
Published: January 2005

Substituted Alkinyles as Axial Ligands at Hemine Like Bound Iron(III) ‐ Incorporation into a Spectrochemical Series.

Substituted lithium alkynyles LiCCR (R = tBu, Ph, p‐ClC6H4, Me3Si, iPr3Si, Ph3Si) react with the hemine like macrocyclic iron(III) complex 6,13‐di(ethoxycarbonyl)‐5, 14‐dimethyl‐1, 4, 8, 11‐tetraazatetradeca‐4,6,12,14‐tetraenato[2−]iron(III)‐iodide (formula 2;) in tetrahydrofuran to form anionic low‐spin di‐adducts [fe(CCR)2]−. The incorporation of the alkynyles into a spectrochemical series of the axial ligands (studied by the sharp equatorial‐ligand‐to‐metal CT absorption band) results in the wavelength‐sequence (nm): OH− (≈︁ 510) « N3− (≈︁ 625) < tBuCC− (664) < NH3 (666) < PhCC− (692) < PhNH2 (695) < Me3SiCC− (698) < SCN− (713) < Ph3SiC  C− (716) < CN− (739) < 4‐picoline (759) < pyridine (765) < nicotinamide (776) < methylnicotinat (788) < pyrazine (798) and points to a significant π‐acceptor ability of the silyl substituents.
Photometrische Untersuchungen zum Übergang der Dianionen in Trianionen von o,ó‐Dihydroxyazofarbstoffen und zur Assoziatbildung mit kationaktiven Tensiden in diesem pH‐Bereich
Authors: Sagaster Hans‐Rainer , Röbisch Gerhard
Published: January 2005

Photometric Investigations in Transition of the Dianions in the Trianions of o,ó‐Dihydroxyazodyes and to the Forming of Associates with Cationic Surfactants in this pH‐range.

In transition of the dianions in the trianions of the investigated dyes take place preferred the deprotonation of the tautomeric form A12− by forming of the equilibrium H ⇄ A3−. The addition of cationic surfactants to the dye solution caused the increase of the pKa3‐values of the dyes. That proved among other things the formation of associates is dye and cationic surfactants determined composition.
Dreikomponentenreaktionen. XX. Methoxymercurierung von Cyclohexa‐1,4‐dienen
Authors: Beger J. , Thomas B. , Vogel T. , Lang R.
Published: January 2005

Three Component Reactions. XX. Methoxymercuration of Cyclohexa‐1,4‐dienes.

The methoxymercuration of several cyclohexa‐1,4‐dienes leads to insoluble mixtures of mono‐ and bismercuricompounds 2–4 and 5–7. After reduction with NaBH4/NaOH mixtures of methoxycyclohexenes and bismethoxycyclohexanes result. The result of capillary gaschromatographic analyses and n.m.r. spectra allow a semiquantitative evaluation of the reaction pathways.
β‐Oxocarbonsäuren durch Carboxylierung von Enaminen
Authors: Frenzel Ralf , Domschke Günther , Mayer Roland
Published: January 2005

β‐Oxocarboxylic Acids by Carboxylation of Enamines.
Acidität und thermodynamische Metallkomplexstabilität von Arylsulfonylthioharnstoffen
Authors: Schlebe Andrea , Tschwatschal Frank , Dietze Frank , Thomas Philipp
Published: January 2005

Acidity and Thermodynamical Metal Complex Stability Constants of Arylsulfonylthioureas.
Zur Synthese von Polyfluoralkylestern der Fluorsulfonyl‐difluoressigsäure und der α‐Trifluormethylfluoressigsäure
Authors: Hass D. , Holfter H. , Schönherr M. , Zahm E. , Storek W.
Published: January 2005

On the Synthesis of Polyfluoroalkylesters of Fluorosulfonyl‐difluoroacetic Acid and α‐Trifluoromethylfluoroacetic Acid.
An update to the Baker–Strehlow–Tang vapor cloud explosion prediction methodology flame speed table
Authors: Pierorazio Adrian J. , Thomas J. Kelly , Baker Quentin A. , Ketchum Donald E.
Published: January 2005

The Baker–Strehlow–Tang vapor cloud explosion (VCE) blast load prediction methodology uses flame speed as a measure of explosion severity. In previous publications, guidance has been presented for selecting flame speeds as a function of congestion, confinement, and fuel reactivity. These recommended values were based on empirical data available from the literature. Over the last 5 years, a series of medium‐scale VCE tests have been conducted through a joint industry program to better understand vapor cloud explosions and to allow a more accurate definition of the flame speed applicable to a given combination of congestion, confinement, and fuel reactivity. These tests have demonstrated that the previously published flame speeds are not conservative for all configurations for the case of no confinement (3‐D flame expansion). This paper provides an overview of the tests along with an update to the flame speed table where the previously published guidance was not conservative. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005
p‐Hydroxyphenylpyruvate dioxygenase inhibitor‐resistant plants
Authors: Matringe Michel , Sailland Alain , Pelissier Bernard , Rolland Anne , Zink Olivier
Published: January 2005

The enzyme p‐hydroxyphenylpyruvate dioxygenase (HPPD) catalyzes the formation of homogentisic acid, the aromatic precursor of plastoquinone and vitamin E. HPPD is the specific target of several herbicide families: isoxazoles, triketones and pyroxazoles. Its inhibition results in the depletion of the plant plastoquinone and vitamin E pools, leading to bleaching symptoms. These herbicides are very potent for the selective pre‐ and in some cases post‐emergence control of a wide range of broadleaf and grass weeds in maize and rice. Their herbicidal potential raised interest in the development of highly resistant transgenic crops. This goal was first achieved by over‐expression of a bacterial HPPD in crop plants, and an increased level of resistance was obtained by using a mutant enzyme. A second strategy based on bypassing HPPD in the production of homogentisate was then developed. Recently, a third strategy of resistance based on the increase of p‐hydroxyphenylpyruvate substrate flux has been developed. This was achieved by the introduction of the yeast prephenate dehydrogenase gene (PDH) into transgenic plants already overexpressing HPPD. In addition to a high level of herbicide resistance, a massive accumulation of vitamin E, mainly tocotrienols, was observed in leaves of the transgenic HPPD‐PDH plants. Copyright © 2004 Society of Chemical Industry
Zur Konzentrationsabhängigkeit der Dissoziation und der Aktivität bei Verbindungsbildung in Mischphasen Mit 2 Abbildungen
Authors: Metzger G. , Sauerwald F.
Published: January 2005

In homogenen binären Systemen, in denen Verbindungen AmBnsich im Gleichgewicht mit ihren Dissoziationsprodukten sowie überschüssigem A oder B befinden, werden die Dissoziationsgrade berechnet und die Art ihrer Konzentrationsabhängigkeit von der Verbindungsformel festgestellt. Dasselbe wird für die Aktivitäten berechnet.
Über die Oxyde des Cers. III
Authors: Brauer G. , Holtschmidt U.
Published: January 2005

Die Geschwindigkeit der Reduktion von Cerdioxyd zu Cersesquioxyd wird erhöht, wenn dem Ceroxyd kleine Mengen an Lanthanoxyd, Neodymoxyd, Uranoxyd oder Terbiumoxyd homogen zugemischt werden. Aus dem verschiedenen Ausmaß der Reaktionsbeschleunigung bei den einzelnen Zusätzen können Rückschlüsse auf den Reduktionsmechanismus gezogen werden. Darin müssen die mit dem Wertigkeitswechsel der beteiligten Metallionen verbundenen Ele ktronenübergänge eine entscheidende Rolle spielen. Die Reaktionsschichten haften wahrscheinlich fest auf dem Ausgangsmaterial.
Röntgenuntersuchung des Systems KClTlCl
Authors: Brauer G. , Müller R.
Published: January 2005

Wie nach der verschiedenen Kristallgitterstuktur von KCl und TlCl zu erwarten ist, bilden diese beiden Salze — entgegen früher veröffentlichten Angeben — keine lückenlose Reihe von Mischkristallen. Jedoch vermag jedes der beiden Salze das andere zu einem geringen Betrage von einigen Molprozent in fester Lösung aufzunehmen.
Alkinyloverbindungen von Übergangsmetallen. II. Alkinylokomplexe von Nickel
Authors: Nast R. , Vester K. L.
Published: January 2005

Durch Umsetzungen von Alkalisalzen des Acetylens, Propins und Phenylacetylens mit Hexammin‐nickel(II)‐rhodanid in flüssigem Ammoniak werden Komplexe des Typs Me2[Ni(CCR)4] isoliert (Me = K, Na; R = H, CH3, C6H5). Leitfähigskeitmessungen in flüssigem Ammoniak bzw. Aceton beweisen die Elektrolytnatur dieser Verbindungen, durch magnetische Messungen werden sie als Durchdringungskomplexe charakterisiert.

Die Analogie dieser „Alkinylokomplexe”︁ zu den Cyanokomplexen wird durch die in flüssigem Ammoniak durchführbare Reduktion K2[Ni(CCH)4] + 2 K → K4[Ni(CCH)4 unterstrichen, die zur Isolierung eines pyrophoren, diamagnetischen Kalium‐tetraäthinyloniccolat (O) führt].
Die Geschwindigkeit der Rückwandlung von bestrahltem festem Nitropentamminkobalt(III)‐chlorid
Authors: Adell Birger
Published: January 2005

Wenn eine dünne Schicht von reinem, gelbem Nitropentamminkobalt(III)‐chlorid hinter einer Glasplatte während etwa drei Monate der Einwirkung von Sonnenlicht ausgesetzt wird, so entsteht eine rötliche Verbindung, die dann im Dunkeln wieder die ursprüngliche gelbe Farbe der Schicht annimmt. Die Dunkelumwandlung wird extinktiometrisch bei 20° C verfolgt und verläuft wie eine Reaktion erster Ordnung. Die Geschwindigkeitskonstante (3,3 ± 0,15) · 10−3 h−1 (dekadische Logarithmen) fällt mit derjenigen (3,3 ± 0,1) · 10−3 h−1 zusammen, die früher für die Isomerisation

in festem Zustande gefunden wurde. Es wird deshalb geschlossen, daß das Nitropentamminkobalt(III)‐chlorid unter dem Einfluß der Lichtenergie wahrscheinlich in die isomere Nitritoverbindung übergeht und daß diese sich dann im Dunkeln in das Nitrosalz rückwandelt.
Untersuchungen über Chromoxydhydrat. V. Konduktometrische Untersuchung der Fällung von Chromhydroxyd
Authors: Narain Tewari Swarup , Ghosh Satyeshwar
Published: January 2005

Es wird die Leitfähigkeit von CrCl3‐Lösungen nach Zugabe wechselnder Mengen von Natronlauge in Abhängigkeit von der Temperatur untersucht. Die Leitfähigkeit sinkt nach Zugabe kleiner Mengen an Natronlauge stark ab. Dieser Effekt ist auf die Neutralisation der durch Hydrolyse des CrCl3 in Lösung gebildeten Salzsäure, also auf den Ersatz von H3O+‐ durch Na+‐Ionen zurückzuführen, wobei sich gelöstes basisches Salz bildet. Die Hydrolyse der CrCl3‐Lösung nimmt mit steigender Temperatur zu.