bluuebunny/crossref_metadata_2025 huggingface dataset:
Die Endgruppenverteilung und der Zusammenhang zwischen den Molekulargewichtsverteilungsfunktionen von Oligomeren und daraus hergestellten Polymeren
Authors: Entelis S. G. , Evreinov V. V. , Romanov A. K. , Sarynina L. I.
Published: January 2005

Die physikalisch‐mechanischen und die physikochemischen Eigenschaften von Polymeren, die aus reaktionsfähigen Oligomeren erhalten werden, hängen wesentlich von der Funktionalität und der Verteilung der relativen Molekülmassen der als Ausgangsmaterial dienenden Vorpolymeren ab.

Die Absorptionschromatographie ermöglicht es, den relativen Gehalt an di‐ und monofunktionellen sowie funktionslosen Makromolekülen im Oligomeren zu bestimmen und ihre präparative Trennung durchzuführen.

Für die Bestimmung der Verteilung der relativen Molekülmassen empfiehlt sich die Gelchromatographie.

Es wird ein Verfahren zur Berechnung der Massen‐ und Zahlenfunktion der Verteilung der relativen Molekülmassen von Oligomeren aus gelchromatographischen Angaben vorgeschlagen.

Die analytische Form der Verteilungsfunktion des Endpolymeren als Ergebnis der Transformation der Verteilungsfunktion des Ausgangsoligomeren kann theoretisch nach einem von Bamford vorgeschlagenen Verfahren gewonnen werden.

Für den Fall der nichtumkehrbaren Polykondensation eines polydispersen unimodalen Vorpolymeren mit einem bifunktionellen Monomeren wurden analytische Ausdrücke erhalten, die es ermöglichen, die Änderung der Verteilungsfunktion während des Prozesses zu beschreiben und die endgültige Verteilungsfunktion des Polykondensats zu erhalten.

Zur Überprüfung der theoretischen Annahmen wurde experimentell die Reaktion von Diisocyanaten mit Polyesterdiolen untersucht.
Polarographic Study of Thio‐acetic Acid
Authors: Kumar A. , Tiwari S. K.
Published: January 2005

The polarographic behaviour of thio‐acetic acid (RSH) at dropping mercury electrode (d.m.e.) has been investigated in presence of KNO3 in the pH range 2–10.5 at 30.0 ± 0.2°C in 50% alcoholic medium at 0.2 M ionic strength. Well defined anodic waves were obtained at all pH values in the concentration range studied. At pH < 2.2 and > 10.5 ill defined anodic waves were obtained. The effect of pH, concentration of RSH, temperature, drop time and alcohol on the wave characteristic and the mechanism of the reaction occurring at the surface of the mercury drop have been studied in detail. A small prewave was also observed at pH 9.1 and 10.5, which has been assigned adsorption characteristics. The reversibility of the reaction mechanism was confirmed by a number of methods. The wave is diffusion controlled and reversible involving one electron transfer process:

Mathematical and experimental evidence shows that the anodic wave of RSH at. d.m.e. does not correspond to formation of (RSSR) but to a mercury compound RSHg according to the above equation. The diffusion coefficient and temperature coefficient for (30–45°C) of id at pH 4.0 and 9.1 have been found to be 1.698; 1.965 × 10−6 cm2/sec and 1.08%; 1.20% per degree respectively. The dissociation constant pKa was found to be 4.25 by the plot of E1/2 vs. pH. The linearity of id with RSH concentrations provides a rapid and precise method for the determination of RSH down to 0.2 mM.
Reactivity of the exocyclic double bond in 4‐arylidene‐2‐phenyl‐2‐imidazolin‐5‐ones toward organomagnesium compounds. I
Authors: Asker Wafia , Hamid Harhash Abdel , Kassab Nazmi Abdel Latif
Published: January 2005

4‐Arylidene‐2‐phenyl‐1‐substituted‐2‐imidazolin‐5‐ones 1a–d react with organomagnesium compounds, in ether at room temperature, to yield, as the main isolable products, the 4‐disubstituted‐methyl derivatives 2a–h. On the other hand, 1a–d react with phenylmagnesium bromide in a boiling ether‐benzene mixture to give, among the reaction products, 2a–d and the 4‐diarylmethylene derivatives 3a–d. Spectral data of 2 and 3 are discussed.

Treatment of the GRIGNARD products 2a–c with formaldehyde and piperidine or morpholine effects aminomethylation at C‐4 with the formation of the MANNICH bases 6a–f.
Synthesen mit Brenzcatechincarbonat
Authors: Ohme R. , Preuschhof H.
Published: January 2005

Durch Umsetzung von Brenzcatechincarbonat 1 mit Alkoholen, Aminen und Hydrazinen werden Kohlensäureester, Urethane, Harnstoffe, Semicarbazide und Carbohydrazide hergestellt. Durch thermische Zersetzung von N‐Alkyl‐carbamidsäure‐(2‐hydroxyphenyl)‐estern 6 werden Alkylisocyanate gewonnen.
Bildung und Zersetzung von 4‐Methoxy‐semicarbaziden
Authors: Ohme R. , Preuschhof H.
Published: January 2005

Die Darstellung von 4‐Methoxy‐semicarbazid 2 und 4‐Methyl‐4‐methoxy‐semicarbazid 7 wird beschrieben. Beide Verbindungen werden durch verdünnte Natronlauge unter Stickstoffentwicklung zersetzt, wobei Methanol und Formiat gebildet werden. Der Mechanismus wird diskutiert.
Fragmentierung von N‐Chlor‐azocarbonamiden
Authors: Ohme R. , Preuschhof H.
Published: January 2005

Phenylazocarbonamide liefern nach N‐Chlorierung mit tert.‐Butylhypochlorit in Chloroform in einer Fragmentierungsreaktion kristallines Phenyldiazoniumchlorid 4 in hoher Ausbeute. Auch N‐Chlor‐cyclohexyl‐azocarbonamid ist fragmentierbar.
Hydroximsäurederivate. IV. 3‐Acyl‐1,2,4‐oxadiazole aus N‐Acyl‐ und N‐Äthoxycarbonyl‐α‐amino‐ketonen
Authors: Brachwitz Hans
Published: January 2005

In der Umsetzung von N‐Acyl‐ und N‐Äthoxycarbonyl‐α‐aminoketonen 1 mit Nitrosierungsmitteln wurde eine neue Methode zur Darstellung von 3‐Acyl‐1,2,4‐oxadiazolen 3 gefunden. Als instabile Zwischenverbindungen sind die α‐Hydroximinoderivate von 1, die C,N‐Diacyl‐formamidoxime bzw. C‐Acyl‐N‐äthoxycarbonyl‐formamidoxime 2, anzunehmen, welche vermutlich aus den primär gebildeten N‐Nitrosoderivaten von 1 entstehen.
Zur Alkylierung des Ammoniaks und einiger seiner Derivate durch o‐Xylylendihalogenide
Authors: Dauth Ch. , Becker H. G. O.
Published: January 2005

Die Umsetzung von o‐Xylylendihalogeniden mit Ammoniak und einigen seiner Derivate (Benzylamin, N,N‐Diphenylhydrazin, Carbonsäurehydrazide, Harnstoff, Cyanamid) liefert Isoindolin 2, 2‐substituierte Isoindolin‐ und o‐Xylylendiaminderivate.

Eine neue Methode zur Darstellung von 2 aus o‐Xylylendihalogeniden und Cyanamid wird beschrieben.
Reactions of Asymmetric Bis‐(p‐alkoxyphenyl) ethylenes with dimethylaniline
Authors: Tadros Wadie , Sakla Alfy Bady , Awad Sami Bassili
Published: January 2005

1,1‐Bis‐[p‐methoxy(or ethoxy)phenyl]ethylene 1 gave in boiling dimethylaniline in the presence of hydrogen chloride or zinc chloride 1,1‐bis‐[p‐methoxy(or ethoxy)phenyl]‐1‐p‐dimethylaminophenylethane 2 1,1‐bis‐[p‐methoxy(or ethoxy)phenyl]ethane, 1,1‐bis‐[p‐hydroxyphenyl]‐ethane and bis‐[p‐dimethylaminophenyl]methane. The structure of the triarylethanes 2 was proven by synthesis.

The isomeric 1,1‐bis‐[p‐methoxy(or ethoxy)phenyl]‐2‐p‐dimethylaminophenylethane 6 was also synthesised.
α‐Aminochlormethylketone aus Aminosäuren und Peptiden als substratanaloge Inhibitoren der Leucinaminopeptidase
Authors: Fittkau Siegfried
Published: January 2005

Es wird die Synthese von α‐Amino‐chlormethylketonen 1, 2 aus Aminosäuren mit freier und N‐alkylierter Aminogruppe über die Diazoketone sowie die Darstellung der entsprechenden Aminosäurehydrazide 4 beschrieben. Durch Kupplung von N‐Acylaminosäuren mit α‐Amino‐chlormethylketonen und Abspaltung der Schutzgruppe wurden α‐Amino‐chlormethylketone von Peptiden mit freier N‐terminaler Aminofunktion (3) erhalten.

Es wird auf die Eigenschaften der Verbindungen und speziell die Instabilität der α‐Aminoketone eingegangen.
1‐Hydroxy‐2‐phenylazo‐anthracene aus 1,2‐Anthrachinon und Arylhydrazinen
Authors: Morgenstern J. , Tontscheff N. , Mayer R.
Published: January 2005

Die bisher unbekannten 1‐Hydroxy‐2‐phenylazo‐anthracene 1 sind in guten Ausbeuten durch Kondensation von 1,2‐Anthrachinon mit Arylhydrazinen zu erhalten. Die isomeren 1‐Phenylazo‐2‐hydroxy‐anthracene 5 lassen sich in Anlehnung an die Literatur durch Kupplung diazotierter Arylamine auf 2‐Hydroxy‐anthracen synthetisieren. Die Typen 1 absorbieren in Cyclohexan und DMF etwas längerwellig als die isomeren 5 und sind in DMF polarographisch insgesamt etwas leichter reduzierbar.
Darstellung und Reaktionen von 1‐Alkyl‐4‐amino‐5‐alkylmercapto‐s‐triazoliumsalzen
Authors: Becker H. G. O. , Nagel D. , Timpe H.‐J.
Published: January 2005

1‐Alkyl‐4‐amino‐s‐triazolthione‐(5) 2 werden durch Methyljodid am Schwefelatom zu den wenig beständigen 1‐Alkyl‐4‐amino‐5‐methylmercapto‐s‐triazoliumsalzen 3 methyliert. Analog reagiert Chloracetonitril. Dagegen entstehen mit α‐Halogenketonen 1,6‐disubstituierte s‐Triazolo[4,3,‐b] 1,3,4‐thiadiaziniumsalze 4.

Mit Basen wie Ammoniak, aliphatischen Aminen, Laugen oder Kaliumcarbonat ergeben die 1‐Alkyl‐4‐amino‐5‐methylmercapto‐s‐triazoliumsalze 3 1,5‐Dialkyl‐1,5‐H‐s‐triazolo‐[4,3‐b]‐s‐triazolo[4,3‐e] 1,2,4,5‐tetrazine 9, deren Bildung durch Deprotonierung von 3, Dimerisierung des entstandenen Amin‐N‐imins und Abspaltung von Methylmercaptan leicht erklärlich ist.

Es gelang nicht, die Amin‐N‐imine durch 1,3‐Dipol‐Addition abzufangen: mit Schwefelkohlenstoff/Alkali wird lediglich die Methylmercaptogruppe in 3 ersetzt.
Decarbonylation Kinetics of Formic Acid in Aqueous Sulphuric Acid Solutions
Authors: Ciuhandu G. , Dumitreanu A. , Simon Z.
Published: January 2005

Decarbonylation of formic acid in 46.6–80.2% (6.5–14.1 m) sulphuric acid was studied by driving CO out of the reaction medium by an air current followed by its photometrical determination with Ag‐Na‐sulphamoyl‐benzoate. The logarithm of the reaction rate constant increases straight with the acidity of the medium in the 6.5–12.6 M H2SO4 range. The data obtained argue in favour of a possible implication of a sulphuric acid molecule respectively hydrogensulphate ion in a rate controlling step.
Zum Substituenteneinfluß auf die Kationische Copolymerisation p‐substituierter Styrole
Authors: Heublein G. , Wondraczek R. , Hallpap P.
Published: January 2005

Unter Einhaltung standardisierter Reaktionsbedingungen wird die Empfindlichkeit der Monomerenreaktivitätsverhältnisse und der Durchschnittspolymerisationsgrade gegenüber Substituenteneinfluß bei der kationischen Copolymerisation nach folgenden beiden Beziehungen untersucht:equation image

Die Durchschnittspolymerisationsgrade erfahren dabei eine geringere Beeinflussung als das Verhältnis der relativen Reaktivitäten. Copolymere, in denen p‐Fluorstyrol enthalten ist, haben von den obigen Beziehungen stark abweichende Durchschnittspolymerisationsgrade.
Steroide. XLVI. Darstellung von 15.16.17‐trisubstituierten Steroiden durch Ringöffnung von 17β‐substituierten 15β.16β‐Epoxy‐östra‐1.3.5(10)‐trien‐3‐methyläthern
Authors: Ponsold K. , Schubert G.
Published: January 2005

Die Ringöffnung von 15β.16β‐Epoxy‐3‐methoxy‐östra‐1.3.5(10)‐trien‐17β‐ol 1a mit starken Nucleophilen erfolgt vorzugsweise am C‐16 unter Bildung der 16α‐substituierten 15β.17β‐Diole 2a—2f. Daneben wird 1a in geringem Umfang am C‐15 unter Bildung der 15α‐substituierten 16β.17β‐Diole 3a–3f und des Δ14‐16.17β‐Diols 5a gespalten. Die Strukturaufklärung erfolgt mit Hilfe der IR‐, 1H‐NMR‐ und Massenspektroskopie.
Immunsuppressiva‐Antigen‐Konjugate. VIII. Darstellung von 6‐Mercaptopurin‐Protein‐Konjugaten nach dem Azid‐Verfahren
Authors: Nuhn Peter , Schilling Ekkehard , Wagner Günther
Published: January 2005

Zur kovalenten Bindung von 6‐Mercaptopurinderivaten an Proteine wurde 6‐Carboxymethylmercaptopurin in Gegenwart eines wasserlöslichen Carbodiimids mit Humanserum‐albumin (HSA) und Rindergammaglobulin (RGG) umgesetzt. Unter diesen Reaktionsbedingungen konnten bei der Behandlung von HSA mit dem Carbodiimid elektrophoretisch nachweisbare Veränderungen beobachtet werden. Aus diesem Grunde wurde zur Darstellung weiterer Konjugate das Azid‐Verfahren eingesetzt, wobei die entsprechenden Mercaptopurinderivate mit Azidgruppierung aus den Hydraziden gewonnen wurden. Auf diese Weise wurden RGG‐ und HSA‐Konjugate ausgehend von 6‐Methylmercapto‐ bzw. 6‐Benzylmercapto‐purinyl‐(9)‐essigsäureazid dargestellt. Die erhaltenen Konjugate enthielten bis zu 4,2% kovalent gebundenes Mercaptopurin. Der Mercaptopuringehalt wurde spektrophotometrisch ermittelt. Purinyl‐(6)‐mercaptoessigsäurehydrazid ließ sich nicht zu einem Azid umsetzen.
3‐Amino‐furo[2.3‐b]pyridine
Authors: Gewald K. , Jänsch H. J.
Published: January 2005

Die 6‐substituierten 3‐Cyan‐pyridone‐(2) 1 reagieren mit α‐Halogen‐carbonylverbindungen zu 2‐Alkoxypyridinen 2, die in Gegenwart von Natriumalkoholat zu substituierten 3‐Amino‐furo[2.3‐b]pyridinen 3 cyclisieren. Aus dem 4.6‐Dimethyl‐3‐cyan‐pyridon‐(2) erhält man dabei Gemische der N‐ und O‐Alkylverbindungen, die bei der Cyclisierung 3‐Amino‐furopyridine 6 neben Indolizinonen 7 liefern. 3 eignet sich zur Darstellung von Pyridofuropyrimidinen 9.
Peptide. XXIII. Synthese von Bradykinin‐Analoga mit durch Norarginin modifizierter Sequenz
Authors: Arold H. , Gersch D.
Published: January 2005

Beschrieben wird die Synthese von drei Analoga des Bradykinins, in denen das Arginin in Position 1 oder 9 bzw. in beiden Positionen durch Norarginin ersetzt ist.
Aluminiumalkyle mit Heteroatomen. II [1]. Darstellung von Tris(3‐trimethylsilyl‐propyl)aluminium
Authors: Sonnek Georg , Reinheckel Heinz , Baumgarten Karl‐Günther
Published: January 2005

Tris(3‐trimethylsilyl‐propyl)aluminium 4 wird durch Disproportionierung und durch Olefinverdrängung im Kreislauf dargestellt. Der Reaktionsablauf wird mit Hilfe der IR‐ und NMR‐Spektroskopie untersucht.
Elektrosynthese von O,O‐Dialkyl‐vinylphosphonaten
Authors: Matschiner H. , Richter C.
Published: January 2005

Ausgehend von der Elektroreduktion der O,O‐Dialkyl‐2,2,2‐trichlor‐1‐hydroxyäthylphosphonate 1 wird über eine neue Synthesemöglichkeit für O,O‐Dialkyl‐2,2‐dichlorvinylphosphonate 2, O,O‐Dialkyl‐2,2,2,1‐tetrachloräthylphosphonate 3 und O,O‐Dialkyl‐2,2,1‐trichlorvinylphosphonate 4 berichtet.
Eine einfache Synthese des Cyclohexanon‐2‐carbonsäure‐amids sowie dessen Reaktionen
Authors: Bischoff Christian , Herma Hannelore
Published: January 2005

Bei Umsetzung von Cyclohexanon mit Harnstoff wird Verbindung 1 gebildet, die sich in guter Ausbeute zu Cyclohexanon‐2‐carbonsäureamid 2 spalten läßt. 2 reagiert mit Alkylhalogeniden unter C‐Alkylierung zu 6a—g, mit Aminen unter Bildung der Enamine 10a und 10b, mit Hydrazinen zu den Tetrahydroindazolonen 8a und 8b. Mit Alkali wird 2 zu Pimelinsäure gespalten. Analog zu 2 ließ sich aus Cyclopentanon bzw. Cycloheptanon Cyclopentanon‐2‐carbonsäureamid 3 und Cycloheptanon‐2‐carbonsäureamid 4 darstellen.
The Stobbe Condensation with Substituted Succinic Esters. Part III. A Synthesis of Benzofuran and Indole Derivatives
Authors: El‐Rayyes N. R. , Al‐Salman N. A.
Published: January 2005

The condensation of 1‐methyl‐pyrrolyl‐2‐carboxaldehyde with dimethyl methyl‐succinate in presence of sodium hydride gave predominantly the corresponding E‐half ester 1a. However, the condensation of either 1‐methyl‐pyrrolyl‐ or furan‐2‐carboxaldehyde with dimethyl phenylsuccinate using either the potassium t‐butoxide or sodium hydride method produced a stereoisomeric mixture of E‐ and Z‐half ‐esters. Cyclisation of the E‐half‐esters gave the corresponding benzofuran and indole derivatives 2; whereas their hydrolysis produced the E‐dibasic acids 6, which were converted to the corresponding anhydrides 7.
Sydnon‐äthylene. I Stereoselektive Darstellung von Sydnon‐äthylenen aus Sydnon‐aldehyden
Authors: Neumann Bernd‐Michael , Henning Hans‐Georg , Gloyna Dieter , Bandlow Margit
Published: January 2005

Sydnone lassen sich in 4‐Position nach VILSMEIER‐HAAK formylieren. N(3)‐Methyl‐ und N(3)‐(p‐Anisyl)‐sydnon‐(4)‐carbaldehyd werden mit Äthoxycarbonylmethan‐phosphonsäurediäthylester nach HORNER und mit verschiedenen Arylmethylphosphoniumsalzen nach WITTIG in Gegenwart starker Basen stereoselektiv olefiniert. Im letzteren Fall tritt besonders in Abwesenheit von Lithiumkationen eine Z‐Selektivität auf, die auf eine elektronische Wechselwirkung zwischen dem Sydnonring und dem aromatischen Substituenten des Phosphin‐ylids im ersten Reaktionsschritt zurückgeführt wird. Die Konfigurationsbestimmung der resultierenden Z‐ und E‐Sydnonäthylene erfolgt an Hand der 1H‐NMR‐ und IR‐Spektren.
Folgeprodukte halogenierter Aldehyde. VI [1]. Die Addition von Phosphorpentachlorid an Chloral
Authors: Schnell M. , Erfurt G. , Zinner H. , Michalik M.
Published: January 2005

1,2,2,2‐Tetrachloräthoxy‐phosphor‐tetrachlorid 1 erhält man durch Umsetzung von Chloral mit überschüssigem Phosphorpentachlorid in Tetrachlorkohlenstoff bei 35–40°C. Die Hydrolyse von 1 mit Wasser führt zum 1,2,2,2‐Tetrachloräthyl‐dichlorphosphat 2, die Reduktion mit weißem Phosphor zum 1,2,2,2‐Tetrachloräthyl‐dichlorphosphorit 3. Die Strukturen von 1, 2 und 3 werden durch IR‐ und NMR‐Spektren bestimmt.
Eine Ungewöhnliche Peroxidreaktion an einem Octahydrochinazolinon
Authors: Bischoff Christian
Published: January 2005

Bei Umsetzung der Titelverbindung 1 mit Wasserstoffperoxid oder Persäure wird 5a‐Hydroxy‐5‐oxo‐perhydro‐oxaziridino[3,2‐j]chinazolin‐2‐spirocyclohexan 2 gebildet. Verbindung 2 reagiert mit Natronlauge unter CC‐Spaltung zu dem zehngliedrigen Ringsystem 3. Durch Eisen(II)‐sulfat wird 2 in das cyclische Lactam 4 umgelagert. Sowohl aus 3 als auch aus 4 läßt sich unter Säureeinwirkung 5‐[Cyclohexan‐spiro‐2′‐(5′‐oxo‐Δ3′‐imidazolin‐4′‐yl)]valeriansäure 5 darstellen.
Kombinierte 13C‐ und dynamische 1H‐NMR‐Untersuchung der π‐Elektronenverteilung in NR2‐substituierten 4H‐Pyran‐4‐on sowie strukturanalogen Pyrylium‐ und N‐Methylpyridiniumsalzen
Authors: Kleinpeter E. , Spitzner R. , Peters A. , Schroth W. , Pihlaja K.
Published: January 2005

Combined 13C and Dynamic 1H‐n.m.r. Investigation of the π‐Electron Distribution in NR2‐Substituted Pyran‐4‐one, Analogous Pyrylium‐ and N‐Methylpyridinium Salts

The 13C chemical shifts of relevant carbon atoms and the barriers to rotation about the exocyclic partial C,N‐double bonds of a series pyrylium and pyridinium salts have been discussed with respect to the π‐electron distribution. Special polymethine cyanine‐like substructures were shown to control the electronic properties of the compounds studied. C4,N barriers to rotation, not obtained earlier due to symmetry reasons, were determined for different NR2‐substituents in 2,6‐positions.
Prostaglandins and prostaglandin intermediates. Part 26. A novel route to PGF2α using triisopropoxy‐hept‐1‐ynyl‐titanium as precursor for the β‐side chain
Authors: Mahrwald Rainer , Schick Hans , Pivnitsky Kasimir K. , Schwarz Sigfrid
Published: January 2005

The benzoylated Corey aldehyde 1a can be alkynylated with hept‐1‐ynyl‐triisopropoxytitanium in good chemical yield and high diastereoselectivity to the (R)‐alcohol 3c admixed with about 10% of the diastereomeric (S)‐alcohol 2c. Without removal of this admixture the (R)‐alcohol 3c was converted into PGF2α, which was easily separated from the accompanying 15‐epi‐PGF2α. The main steps of this reaction sequence involve the conversion of a propargylic alcohol into an (E)‐allylic alcohol and the palladium (II)‐catalyzed allylic rearrangement of its acetate. With hept‐1‐ynyllithium the trimethylsilyloxy aldehyde 1b affords the (S)‐alcohol 2c as the predominating product admixed with about 20% of the diastereomeric (R)‐alcohol 3c. Again, without removal of the admixture the (S)‐alcohol 2c was converted into known PGF2α intermediates via the palladium(II)‐catalyzed allylic rearrangement of the corresponding (Z)‐allyl alcohol.
Substituierte 2‐Amino‐thiazole aus α‐Thiocyanato‐acetophenonen und Dialkylaminen
Authors: Teller J. , Dehne H. , Zimmermann T. , Fischer G. W. , Olk B.
Published: January 2005

Substituted 2‐Amino‐thiazoles from α‐Thiocyanato‐acetophenones and Dialkylamines

α‐Thiocyanato‐acetophenones 1 react with dialkylammonium salts of weak acids (acetates, propionates, benzoates) to give 2‐dialkylamino‐4‐aryl‐thiazoles 4. As reaction medium aliphatic alcohols (methanol, ethanol), dipolar‐aprotic solvents (acetonitrile, dimethylformamide, dimethyl sulphoxide) or chlorinated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride) can be used. In comparison to known methods for the preparation of the thiazoles 4 the synthesis via α‐thiocyanato‐acetophenones 1 has the advantage of the simpler accessible starting compounds. – I.r., u.v., n.m.r. and mass spectroscopic data of the thiazoles 4 are reported.
Synthesis of Pyrimido[2,1‐b]thiadiazinium Salts and 3‐ Mercaptopyrazolo[1,5‐a]pyrimidines from 1‐Amino‐2(1H)‐pyrimidinthiones and α‐Haloketones
Authors: Liebscher Jürgen , Hassoun Ahmad
Published: January 2005

1‐Amino‐2(1 H)‐pyrimidinthiones 1 react with α‐haloketones 2 by S‐alkylation. Resulting 2‐carbonylmethylthiopyrimidinium salts 3 easily cyclise giving pyrimidothiadiazinium salts 4. When treated with base the latter suffer a ring contraction affording mercaptopyrazolopyrimidines 6 in high yields.
Nichtsteroidale Entzündungshemmer V. Basische Ester des Indometacins
Authors: Kappe Th. , Frühwirth F.
Published: January 2005

Non Steroidal Antiinflammatory Agents. V. Basic Esters of Indometacin

The reaction of diisopropylcarbodiimid 1a with ethanolamines 2a, b affords isoureas 3a, b which in turn react with indometacin 4 to yield the title compounds 6a, b. The noncatalyzed reaction of 1a, b with 4 (also in the presence of 2) leads to the ureido‐indometacines 8a, b.
Some reactions with ω‐bromoacetophenone: Synthesis of new Pyrazole, Pyrrole and Furan Derivatives
Authors: Abdelrazek Fathy M.
Published: January 2005

Phenacyl bromide 1 reacts with ethyl cyanoacetate 2 in presence of piperidine catalyst to afford the hexa‐2,4‐diene derivative 5. Ethyl phenacylcyanoacetate 3 was obtained by reaction of 1 with the sodium salt 6. Compound 3 reacts with hydrazines and trichloroacetonitrile to afford the pyrazoles 7a, b and the pyrroles 8 and 9, respectively. The reflux of 3 in acetic/sulphuric acid mixture afforded the furan derivatives 10 and 11.
The structure of the Cycloaddition products of C‐(2‐thenoyl)‐N‐arylmethanohydrazonyl bromides to some substituted olefins
Authors: Hassaneen Hamdi M. , Ead Hamed A. , Abdallah Magda A. , Nousa Hiyam A. H. , Nousa Hiyam A. H.
Published: January 2005

The cycloaddition of C‐(2‐thenoyl)‐N‐arylnitrilimines 2a, b to acrylic acid derivatives 3‐5, fumaric acid derivatives 9‐10, benzalmalononitrile 14 and N‐arylmaleimides 20 has been studied. Under thermal conditions these 1,3‐dipolar cycloadditions proceed with absolute regio‐chemistry to yield 5‐substituted‐2‐pyrazolines 6‐8, 11‐12, 16 and 21, respectively. The cycloadducts 11 and 16 lose hydrogen cyanide to give the corresponding pyrazoles 13 and 18, respectively.
Zur näheren Kenntnis des 1‐Camphenylsystems ‐ 1‐Camphenylverbindungen des Lithiums, Zinns und Quecksilbers
Authors: Schenke D. , Thiele K.‐H.
Published: January 2005

About the 1‐Camphenyl System – 1‐Camphenyl Compounds of Lithium, Tin and Mercury

1‐Camphenyl lithium, 1‐camphenyl isobutyl mercury an 1‐camphenyl triethyl tin were synthesized and characterized by their 13C n.m.r. spectra. The lithium compound contains σ,η1‐bonded allyl groups and suggests a weak interaction between the exocyclic double bonds and the metal atoms. The coupling constants 1J(199Hg‐13C) and 1J(119Sn–13C) in the spectra of the mercury and the tin compound allow to compare the donor strength of 1‐camphenyl anion with those of other carbanions.
Synthesis of Hydroxy Benzonitriles by heterogenous‐catalytical ammoxidation of the isomeric methoxytoluenes and their mixtures
Authors: Martin A. , French J. , Seeboth H. , Lücke B. , Fischer E.
Published: January 2005

In the synthesis of p‐hydroxybenzonitrile as a herbicide intermediate the nitrile formation is the most important reaction step. Possible feed compounds could be pure p‐cresole, cresole mixtures or OH‐protected cresoles like methoxy‐ or acetoxytoluenes. The ammoxidation of m‐ and p‐methoxytoluene and a m,p‐methoxytoluene‐mixture over vanadium‐titanium oxide catalysts has been investigated using flow reactors in a temperature range of 630–703 K. On comparable reaction conditions the conversion of pure compounds leads to a higher selectivity of p‐methoxybenzonitrile (approx. 70%, conversion 85 mol‐%) than that of the m‐compound (only 35%, conversion 45 mol‐%). For synthesis of the p‐nitrile the feedstock can be p‐methoxytoluene obtained by methylation of p‐cresole, but it is also possible to use a m,p‐methoxytoluene mixture obtained by methylation of an industrial cresole mixture. The ammoxidation of such a mixture affords a higher reactivity of the p‐isomer and p‐methoxybenzonitrile as the main reaction product, whereas m‐methoxytoluene remains unreacted for the most part. Generally, the results obtained show that an amount of approx. 79% of the converted p‐methoxytoluene was transformed into p‐methoxybenzonitrile, whereas the corresponding transformation into the m‐isomer was lower than 36%. An important part of the m‐isomer was degraded by oxidation towards CO, CO2 and HCN.
α‐Cyanothioacetamide and its derivatives in heterocyclic synthesis: Preparation of several new 4‐oxoquinazoline derivatives
Authors: Aziz M. A. Abdel , Daboun H. A. , Gawad S. M. Abdel
Published: January 2005

The reaction of α‐cyanothioacetamide (1) or its methylthio derivative (2) with anthranilic acid led to the formation of 3,4‐dihydro‐4‐oxoquinazolin‐2‐yl acetonitrile (3). 3 condensed with aromatic aldehydes to give arylidene derivatives (4a‐d) which could be prepared also via the reaction of 2‐thiocarbamoylcinnamonitriles (5a‐d) or their methylthio derivatives (6a‐d) with anthranilic acid. 3 reacted with cinnamonitrile derivatives (7a‐h) and (12a‐d) to yield pyrido‐[1,2‐a]‐quinazoline derivatives (10a‐h) and (15a‐d) which could also be prepared by the reaction of (4a‐d) with malononitrile (11a), benzoyl acetonitrile (11b) and ethylcyanoacetate (16), respectively.
Thermodynamic Proton Ionization Constants of some fluorinated β‐ketoesters in dioxane‐water mixtures. Influence of terminal group substitution
Authors: Shukla J. P. , Sharma R. S.
Published: January 2005

Thermodynamic proton ionization constants, TpKa, of methyl trifluoroacetoacetate (HMTAA), ethyltrifluoroacetoacetate (HETAA) and ethylpentafluoropropionylacetate (HEPPA) have been determined in 10–50% dioxane‐water mixtures at 25 and 35 ± 0.1°C applying an empirical pH correction for mixed aqueous‐organic media. The TpKa values are calculated by subjecting the experimental data to rigorous weighted least‐squares analysis. Further, a least‐squares extrapolation technique is applied to evaluate TpKa in pure water (0% dioxane). All the three ligands are weak monoprotonic acids with their TpKa between 6.0 and 9.0. Plots of TpKa with the reciprocal of the dielectric constants of the medium are not linear but plots of TpKavs. mole fraction of dioxane are linear at a given temperature. Values of standard free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) changes, associated with their ionization are also computed. Temperature, medium and substituent effects are briefly discussed.
Chemotherapeutic agents. XIX. Synthesis of [1,2,4]‐Triazoloquinazolinones and related compounds as antihypertensive agents
Authors: Ram V. J. , Srimal R. C. , Kushwaha D. S. , Mishra L.
Published: January 2005

A series of 1,2,4‐triazolo[4,3‐a]quinazolin‐5‐ones have been prepared to assess their therapeutic utility as CNS depressant, spasmolytic and hypertensive agents.
Studies on 1,3‐indandione: Synthesis of Fluorenones and Indeno(2,1‐c)pyridazine
Authors: Sofan Mamdouh A. , El‐Taweel Fathy M. , Elagamey Abdel Ghani A.
Published: January 2005

1,1‐Dicyanomethylene‐3‐indanone (2) reacted with cinnamonitriles 1a‐c to afford fluorenone derivatives 6a‐c. Compounds 6a‐c were also obtained when treating 2 with 1d‐f. The coupling of 2 with aromatic diazonium chlorides resulted in the formation of the hydrazones 8a‐c. 8a readily cyclized to indeno[2,1‐c]pyridazine (9a) in acidic medium. The action of 1d‐f on enaminone 3 was also studied.
Photoreduction of Methyleneblue by the two‐equivalent electron donor N‐methyl‐9‐phenylacridane and the use of the system for the spectrally sensitized dediazoniation of p‐N,N‐dimethylamino benzenediazonium tetrafluoroborate
Authors: Becker H. G. O. , Kohrs K.
Published: January 2005

The photoreduction of methyleneblue by N‐methyl‐9‐phenylacridane (ACH) is studied in acetonitrile by means of flash photolysis and quantum yields. In the first step, due to fast proton shift within the original electron transfer product protonated semi‐methyleneblue MBH.+ and the deprotonated donor radical (N‐methyl‐9‐phenylacridanyl radical AC·) are formed with a rate constant of 2×108 M−1 s−1. In this radical pair a second electron is transferred very fast from AC· to MBH.+ with a rate constant ke2 ≈︂ 1010 s−1 to form leuco‐methyleneblue and N‐methyl‐9‐phenyl‐acridinium salt (AC+). About 80% of the two‐equivalent reduction product, leuco‐methyleneblue, are formed within the first solvent cage during the flash. The maximum quantum yields of photoreduction approach φisc of MB+ as expected for a two‐equivalent reduction reaction.

The out‐of‐cage reaction consists of the known disproportionation of the protonated semi‐methyleneblue MBH.+ and its reduction by the N‐methyl‐9‐phenylacridanyl radical AC·. From the decay kinetics kred = 3×109 M−1 s−1 and kdis = 8×108 M−1 s−1 is derived.

The system sensitizes the dediazoniation of p‐N,N‐dimethylamino benzenediazonium tetrafluoroborate efficiently even at very low diazonium salt concentrations (Φ = 0.6).
Zur thermischen Cyclisierung und Aromatisierung von Hex‐1‐en‐5‐in
Authors: Remmler M. , Ondruschka B. , Vorwerk D. , Olk B. , Pola J. , Kubat P.
Published: January 2005

On the Thermal Isomerization and Aromatization of Hex‐1‐ene‐5‐yne

The gas phase conversion of hex‐1‐ene‐5‐yne induced by conventional hot‐wall pyrolysis, very low pressure pyrolysis (VLPP‐MS technique) and continuous‐wave CO2 laser‐photosensitized (SF6) pyrolysis was studied at 350–1100°C.

The pyrolysis experiments were performed in quartz reactors and the reaction products analyzed by capillary gas chromatography, mass and n.m.r. spectroscopy. The pattern of conversion suggested for all the processes involved a sequence of isomerizations (→hexa‐1,2,5‐triene→methylcyclopentenes), aromatization (into benzene via pentafulvene) and CC bond rupture (into propargyl and allyl radicals).

The formation of benzene is explained by reaction network with methylenecyclopentenes and methylcyclopentadienes as key intermediates.
Synthesis of Substituted Crown‐Ethers by radical addition of 18‐crown‐6
Authors: Zeleconok Ju. B. , Orlovskij V. V. , Zlotskij S. S. , Rachmankulov D. L.
Published: January 2005

An example of the synthesis of substituted crown‐ethers by radical addition reaction of 18‐crown‐6 (1) to several α‐olefins (2a‐e), cyclohexene (2f), vinyl butyl ether (2g), allyl alcohol (2h), trimethylvinylsilane (2i), diethylmaleate (2j) and formaldehyde (2k) in the presence of a peroxide initiator was studied.

The dependence of the yield of the addition product upon reaction conditions was also investigated.
Reduction of Long Chain and Bulky Carboxylic Esters by sodium tetrahydroborate
Authors: Giumanini Angelo G. , Tubaro Franco
Published: January 2005

Methyl esters of long chain fatty acids as well as esters with functional (OH) and/or bulky substituents in alpha position and in the OR moiety may be effectively reduced with an excess of sodium tetrahydroborate at moderate temperature in dioxane‐water without catalysts. The reaction has been applied to the reduction of a pool of triglycerides of natural origin (virgin olive oil) in order to obtain a mixture of the acyl residues reduced to the corresponding alcohols without any structural or configurational modification. They, no matter which was the advancement of the reaction, seemed to reproduce quite well the overall acyl composition, as shown by GC‐MS analysis: the feasibility of such quantitative analysis may be extended, in order to obtain confirmatory evidences, on the component identifications and to perform specific separations, to the corresponding chlorides, hydrocarbons and trimethylsilylethers.
Substituent effect on “Ring‐Chain” tautomerism of 1,2,3,4‐Tetrahydro‐s‐tetrazines
Authors: El‐Abadelah M. M. , Hussein A. Q. , Abushamleh A. S.
Published: January 2005

Methylhydrazones (III) of aromatic aldehydes and ketones react with nitrile imines (II) to give 1,2,3,4‐tetrahydro‐s‐tetrazines IV (1‐9) which exhibits “ring‐chain” tautomerism in solution. The extent of this tautomerism is dependent both on steric and electronic effects of substituent groups at C‐3 and C‐6 ring carbons.
Preparation and characterization of 1,5‐Diacyl‐2,4‐dioxohexahydro‐1,3,5‐triazines with Higher Acyl Groups
Authors: Hofmann Jörg , Just Gerhard , Pritzkow Wilhelm
Published: January 2005

The title compounds were prepared from 2,4‐dioxohexahydro‐triazine (DHT) and the corresponding acid chlorides in the presence of sulphuric acid. They are active acylating agents against piperidine in dioxane as the solvent. Only the diacyl derivatives of DHT with acyl chain lengths up to C6 react with aqueous solutions of sodium perborate forming the corresponding peroxy acids.
Synthese und spektroskopische Untersuchung von 3‐substituierten 1‐(1,3‐Diarylpropan‐1‐on‐3‐yl)‐1‐methoxy‐thioharnstoffen
Authors: Gerd Weber Fritz , Richter Claudia , Schultz Andreas , Köppel Hubert
Published: January 2005

Synthesis and Spectroscopical Investigation of 3‐Substituted 1‐(1,3‐Diarylpropan‐1‐on‐3‐yl)‐1‐methoxy‐thioureas.
Synthese von 1,3,4‐Thiadiazol‐derivaten
Authors: Tschierske C. , Girdziunaite D.
Published: January 2005

Synthesis of 1,3,4‐Thiadiazol Derivatives.
Reaktionen von 4‐Chlormethyl‐1,3‐dioxolanen mit schwefel‐ und stickstoffhaltigen Nucleophilen
Authors: Zlotskij S. S. , Rol'nik L. S. , Kabibulin I. R. , Rachmankulov F. D. L. , Timpe H.‐J.
Published: January 2005

Reactions of 4‐Chloromethyl‐1,3‐dioxolanes with Sulfur and Nitrogen Containing Nucleophiles.
Acyllerung von N‐(2, 6‐Dimethylphenyl)‐α‐alaninmethylester mit sp‐hybridisierten Kohlensäurederlvaten
Authors: Martin D.
Published: January 2005

Acylation of N‐(2, 6‐Dimethylphenyl)‐α‐alanine Methylester with sp‐hybridized Carbonic Acid Derivatives.

The title compound 5 reacts with isocyanates and isothiocyanates to yield the substituted imidazolidinones 7 and 8, respectively, whereas with chlorosulfonyl isocyanate the open chained urea 9 is formed. Cyanation of 5 takes place with phenyl cyanate and cyanogene bromide. Consecutive reactions of the primary products are described.
Nitriles in heterocyclic synthesis: Synthesis of pyrazolo[1, 5‐a] pyrimidine, pyrazolo[1, 5‐c][1, 2, 4]triazine and pyrazolo[4, 3‐e][1, 2, 4]triazine derivatives
Authors: Ali Elagamey Abdel Ghani , El‐Taweel Fathy Mohamed Abdel‐Aziz
Published: January 2005

5‐Amino‐3‐phenylpyrazole (1) reacted with enaminonitriles 2a–c to afford the pyrazolopyrimidines 5a, b and the 5‐substituted aminopyrazole 8. 5a reacted with arenediazonium chlorides and benzaldehyde to give 6 and 7 respectively. Also, o‐hydroxyacetophenone afforded the fused pyrazole derivative 9 on treatment with 1. Enaminonitrile 3 coupled with 11 and arenediazonium chlorides to give 12 and 13 respectively. Cyclization of 13a, b afforded the pyrazolotriazines 15a, b.
Nitriles in organic synthesis: The Reaction of Cinnamonitriles with cyclohexanone and acetylacetone
Authors: El‐Sakka I. A. , El‐Kousy S. M. , Kandil Z. E.
Published: January 2005

The reaction of 1 a, b with cyclohexanone afforded hexahydronaphthalene derivatives (3 a, b). In contrast to the behaviour of 1 a, b, cyclohexanone reacts with 4a–c to yield the propenylidenecyclohexanone derivatives (5a–c). The reaction of 1a with acetylacetone gives 4H‐pyran 6 and a 1:2‐adduct 8 a. On treatment of 8 a with sodium metal in the presence of dioxane, the pyrano [2, 3‐b]pyridine (9a) was obtained. When 1 b, c reacted with acetylacetone, the only isolable products were 8 b,c. Reaction of 4a with acetylacetone gives acyclic compound 10. This on treatment with basic reagents, gives the pyran derivative (13).
Thioharnstoffverbindungen und Metallkomplexe aus N‐Thiocarbamoylbenzimidoylchloriden
Authors: Beyer Lothar , Hartung Jürgen , Köhler Ronald
Published: January 2005

Derivatives of Thioureas and Metal Complexes from N‐Thiocarbamoyl‐benzimidoyl Chlorides.

The reactions of nickel(II)‐coordinated N‐benzoyl‐thioureas with acid chlorides are described. With different nucleophiles the title compounds N‐thiocarbamoyl‐benzimidoyl‐chlorides yield N‐thiobenzoyl‐thioureas, N‐thiocarbamoyl‐benzimido(thio)esters and N‐thiocarbamoyl‐benzamidines as chelating agents, respectively. By cyclisation 1,3,5‐thiadiazin‐2‐thiones and 1,2,4‐triazoles were obtained. The formation, structure and bonding situation of the ligands and the transition metal complexes are discussed. 1,2,4‐Dithiazolium‐halometalates, 1,3,5‐oxadiazinium salts and selenium analogous are included in this review.
Tetranuclear Thioureacopper(II) Complexes
Authors: Makáňová Darina , Kováčik Ivan , Ondrejovič Gregor
Published: January 2005

By replacement of methanol in the Cu4OX6(MeOH)4 (X  Cl, Br) complexes with thiourea (tu), N,N′‐diphenylthiourea (diftu), N,N′‐dimethlthiourea (dimtu), tetramethylthiourea (tmtu) and acetylthiourea (actu), the complexes Cu4OCl6L4 where L  tu, tu(0.3 Et2O), diftu, dimtu, tmtu, actu (0.5Et2O) and the complexes Cu4OBr6L4, where L  tu, diftu, dimtu, tmtu have been prepared. Their infrared and electronic spectra indicate the presence of Cu4O grouping and the trigonal bipyramidal coordination of copper(II). These complexes exhibit e.p.r. signals in the temperature range 100–260 K, in contrast to other known complexes of this structural type, which showed the e.p.r. signals at significantly lower temperatures. Thiourea and its derivatives are not able to reduce copper(II) in reaction with the tetranuclear Cu4OX6(MeOH)4 complexes in methanol‐ether solution due to the redox stabilizing effect of the tetranuclear structure.
Synthese und Eigenschaften neuartiger Alkalimetall‐Alkoxo‐ und ‐Aroxocobaltate(II)
Authors: Ibrahim Aisha Ismail , Gaube W. , Kalies W. , Witt B.
Published: January 2005

Synthesis and Properties of Novel Alkali Metal Alkoxo‐ and Aroxocobaltates(II).

By reaction of CoBr2 or CoBr2 · 2THF with 4–5 moles of MOR in THF, M  Li, Na, K, R = iso‐propyl (iPr), phenyl (Ph), 2‐naphthyl (2‐Naph), the following novel alkali metal alkoxo‐ and aroxocobaltates(II) have been prepared.

Li2Co(OiPr)4 · LiBr · 3THF (1), Na2Co(OiPr)4 · THF (2), KCo(OiPr)3 · THF (3), Li2Co(OPh)4 · 4THF (4), Na2Co(OPh)4 · 5THF (5), K2Co(OPh)4·0,75THF (6), Li2Co(O‐2‐Naph)4 · 4THF (7), Na2Co(O‐2‐Naph)4 · 5THF (8), K2Co(O‐2‐Naph)4 · 2THF (9), and K3Co(O‐2‐Naph)5 · 2THF (10).

The blue and violet, crystalline and very air‐sensitive (i.e. protolytically sensitive) compounds, some with good solubilities in organic solvents, eliminate THF in vacuo at temperatures between 50 and 100°C to yield the corresponding THF‐free compounds (1a) to (10a).

Electronic spectra (VIS/NIR) and the results of magnetic measurements at 293 K point to preferred (but not exclusive) tetrahedral coordination of cobalt(II).
Studies on the oxidation of enamines with molecular oxygen. III. Oxidation of some amino styrenes
Authors: Blau K. , Burgemeister I. , Grasnick J. , Voerckel V.
Published: January 2005

In the oxidation of the amino styrenes 1a–1j only products of the oxidative attack at the C  C double bond and hydrolysis products are obtained. Aprotic dipolar solvents and the addition of molecular sieve 5A promote the oxygen uptake. The addition of hydrochinone to the oxidation system does not influence the rate of oxygen absorption or the yields of the oxidation products.
Sulfochlorierung von 1,2‐Naphthochinondiazid‐(2) mit Chlorsulfonsäure
Authors: Sauer E. , Polz K. , Schopf G. , Bendig J.
Published: January 2005

Sulfochlorination of 1,2‐Naphthoquinone‐(2)‐diazide by Chlorosulfonic acid.

The sulfochlorination of 1,2‐naphthoquinone diazide‐(2) (1) by chlorosulfonic acid was investigated. The yields of the formed products (1,2‐naphthoquinone diazide‐(2)‐4‐sulfonic acid (4), 1,2‐naphthoquinone diazide‐(2)‐5‐sulfonic acid (5), 1,2‐naphthoquinone diazide‐(2)‐4‐sulfochloride (2) and 1,2‐naphthoquinone diazide‐(2)‐5‐sulfochloride (3)) depend on the temperature and on the time of reaction. The highest yields of the favoured 1,2‐naphthoquinone diazide‐(2)‐4‐sulfochloride (2) are obtained at 63°C and after a reaction time of 80 minutes (50%).
119Sn‐NMR spektroskopische Untersuchungen an Tributylzinnderivaten aromatischer Sulfonsäuren
Authors: Thunecke Frank , Borsdorf Rolf
Published: January 2005

119Sn‐NMR Spectroscopic Investigations of Tributyltin Derivatives of Aromatic Sulfonic Acids.

Tributyltin derivatives of nine aromatic sulfonic acids were synthesized and investigated by means of 119Sn‐n.m.r. spectroscopy. 119Sn‐chemical shifts and 1J (Sn, C) coupling constants in dependence on temperature and concentration were applied to study the association processes of the substances in solution. In CDCl3 as a solvent a monomeric/polymeric equilibrium of the substances was demonstrated, while CD3OD as a donor solvent forms five‐coordinated complexes with the tin compounds.
The Influence of DDT‐Preventing Agents upon the Impact Sensitivity of the polyurethane‐bonded RDX
Authors: Wen Li , Quancai Song , Wenbin Wang , Yongke Chen
Published: December 2004

The effect of some DDT‐preventing agents (DPAs) and their mixtures on the impact sensitivity of RDX/PU has been studied. All specimen for drop‐hammer test were prepared by solvent‐slurry method. Two ways were used in adding DPA. The behavior of moulding powders obtained to the mechanical impact were assessed using KAST Impact Hammer. The results have shown that some DPA decreased the impact sensitivity of RDX/PU with different degree, and the loading way of DPA also had obvious effect on it. Finally, the characteristic heights H50 and the remained quantities of samples after impacting were analyzed and discussed.
Pulsed Laser Induced Decomposition of Energetic Polymers: Comparison of ultraviolet (355 nm) and infrared (9.3 μm) initiation
Authors: Haas Yehuda , Ben‐Eliahu Yeshayahu , Welner Shmuel
Published: December 2004

Irradiation of the energetic polymer GAP (glycidyl azido polymer) by a high power pulsed UV laser leads to its rapid decomposition. A large amount of solid and gaseous material is released, and in the presence of an inert gas, a shock wave develops. Comparison with an inert polymer indicates that the energy released by the exothermicity of the decomposition reaction contributes significantly to the shock formative energy. The energy released in the micro‐explosion can be estimated from the analysis of the shock front propagation velocity. It is found that irradiation of polymers in which GAP is diluted by an inert polymer, may lead to a higher shock intensity than irradiation of neat GAP. Possible causes for this apparent inconsistency (which is not observed upon initiation by a pulsed infrared laser) are discussed.
The influence of post‐exposure temperature on the toxicity of insecticides to Ostrinia nubilalis (Lepidoptera: Crambidae)
Authors: Musser Fred R , Shelton Anthony M
Published: January 2005

The influence of post‐treatment temperature on the toxicities of two pyrethroids (lambda‐cyhalothrin and bifenthrin), a carbamate (methomyl) and a spinosyn (spinosad) to Ostrinia nubilalis (Hübner) larvae was evaluated in laboratory assays. From 24 to 35 °C, the toxicities of the pyrethroids decreased 9.5‐ and 13.6‐fold while spinosad toxicity decreased 3.8‐fold. The toxicity of methomyl did not change significantly. The results demonstrate that the most effective insecticide against a pest may vary with environmental conditions. In situations where comparable products from multiple insecticide classes are available, temperature should be included as a factor in the decision‐making process. Copyright © 2005 Society of Chemical Industry
The group theoretical approach to nuclear quadrupole resonance
Authors: Boyle L. L.
Published: December 2004

The phenomenon of nuclear quadrupole resonance is presented from the grouptheoretical point of view. This approach allows one to discuss the splitting of the nuclear spin states without prior wave‐mechanical calculation. Nuclear quadrupole moments are also compared with moecular quadrupole moments and the differences discussed. Finally the selection rules are deduced.
Frequency‐dependent polarizability of open‐shell atomic systems
Authors: Roy H. P. , Gupta A. , Mukherjee P. K.
Published: December 2004

The time‐dependent variational principle is used to calculate the frequency‐dependent dipole polarizabilities of 2p open‐shell atomic systems. A general theory is built up to include frequency‐dependent perturbations using the Roothaan–Hartree–Fock (HFR) formalism. The excitation energies corresponding to the low‐lying excited states of the system are obtained from the poles of the dynamic polarizability values. A fairly accurate knowledge of transition oscillator strengths is also obtained from a knowledge of the polarizability values near the poles. The excitation energies and oscillator strengths are compared with available data.
The spin‐orbit interaction in the configuration nlNn'l using nonorthogonal radial orbitals
Authors: Jucys A. P. , Sabas K. V. , Kupliauskis Z. J.
Published: December 2004

Formulas for the calculation of matrix elements of the simplified operator of the spin‐orbit interaction for the configuration n1lNn2l are deduced for the case when radial orbitals are nonorthogonal. The coefficients of the radial integrals are tabulated for the configuration pNp. The fine structure of the excited configuration of the carbon atom is calculated.
Orbital optimisation in single open‐shell configurations: A sequential unconstrained minimisation technique
Authors: Mukherjee Debashis
Published: December 2004

A simple algorithm for optimising the orbitals for single open‐shell configurations which utilises a sequential unconstrained minimisation technique (SUMT) suggested by Morrison is presented in this paper. As numerical illustrations, the orbitals of the lowest π – π* singlet and triplet (Ms = 0) states of three conjugated hydrocarbons are optimised by the algorithm. The advantages of using the SUMT method are also emphasised.
Operator formalism for forming ket vectors under some constraints
Authors: Morikawa Tetsuo
Published: December 2004

Reformulation, generalization, and application of Löwdin's symmetric orthonormalization, of orthogonalization of two sets of vectors, and of McWeeny's variational method of a density matrix, etc., by means of an operator for forming ket vectors on which are imposed some conditions, are presented.
Orbit‐orbit molecular integrals over Gaussian orbitals
Authors: Lo B. W. N.
Published: December 2004

Analytical formulas are derived for integrals of the orbit‐orbit operator in the Breit‐Pauli Hamiltonian. The present method differs from an earlier one in the introduction of a new auxiliary function Gn(a) which is an integral of Shavitt's Fm(t) function. A method for its evaluation is discussed and some numerical examples are given.
Upper and lower bounds to critical values of the Hartree operator
Authors: Behling R. , Bongers A. , Küpper T.
Published: December 2004

Upper and lower bounds for the minimal critical energy E of the Hartree operator for helium are calculated. We show that a Ritz analogous procedure for the calculation of the upper bounds converges to the exact value. The lower bound to E yields that the ground state EH of the helium atom is strictly lower than 2E.
A model for the helix–coil transition of DNA
Authors: Porta Jordi
Published: December 2004

The helix–coil phase transition of DNA is studied through a model equivalent to the one used in the theory of superconductivity. A distribution function for the excitations analogous to the usual Fermi function is obtained which depends on the parameter T0, the maximum temperature at which all pairs of bases are bonded. The expression for the number of unbonded pairs of bases depends only on the two parameters, T0 and Tc (critical temperature).