bluuebunny/crossref_metadata_2025 huggingface dataset:
Nucleoside von Fluorzuckern, XV. Synthese von Thymin‐Nucleosiden der 6‐Fluor‐D‐glucopyranose und 6‐Fluor‐D‐galaktopyranose
Authors: Etzold G. , Von Janta‐Lipinski M. , Langen P.
Published: January 2005

1‐β‐D‐Glucopyranosyl‐thymin 1 und 1‐β‐D‐Galaktopyranosyl‐thymin 13 ergeben mit äquimolaren Tosyl‐oder Mesylchlorid bevorzugt die entsprechenden 6′‐O‐Sulfonyl‐Nucleoside 6 und 7 bzw. 14 und 15. In geringer Menge entstehen die 2′,6′‐Di‐O‐sulfonyl‐Derivate 4 und 5. Während in der Glucose‐Reihe besonders die Tosylverbindung leicht mit Alkalifluorid zum 6′‐Desoxy‐6′‐fluor‐Nucleosid 10 reagiert, gelingt die analoge Substitution in der Galaktose‐Reihe nur schwer.

Die Kondensation 2,3,4‐Tri‐O‐acetyl‐6‐O‐tosyl‐D‐glucopyranosylbromid 2 bzw. von 1,2,3,4‐Tetra‐O‐acetyl‐6‐desoxy‐6‐fluor‐D‐galaktose 18 mit 2,4‐Bis‐O‐trimethylsilyl‐thymin 3 führt zu Nucleosiden, die nach der Entacetylierung mit 6 bzw. 1‐(6′‐Desoxy‐6′‐fluor‐β‐D‐galaktopyranosyl)‐thymin 20 identisch sind.
Struktur und Reaktivität heterosubstituierter Nitrile. XVI[1]. Kinetik und Mechanismus der Arylcyanatbildung aus Bromcyan und Phenolen
Authors: Bacaloglu Ilse , Glatt Horst , Bacaloglu Radu , Martin Dieter , Nadolski Karin
Published: January 2005

Die Geschwindigkeitskonstanten zweiter und dritter Ordnung der Reaktion von Bromcyan mit Phenolen in Gegenwart tertiärer aliphatischer Amine wurden in wasserfreiem Aceton bestimmt. Der erste Schritt der Reaktion besteht im nucleophilen Angriff des tertiären Amins an das Bromcyan. Es bildet sich durch eine schnelle Gleichgewichtsreaktion ein N‐Cyano‐N,N,N‐trialkylammoniumbromid, das im langsamsten Schritt der Reaktion einen nucleophilen Angriff des Phenols oder eine Dissoziation erleidet. Die Bevorzugung einer dieser Reaktionen wird von der Nucleophilie und der sterischen Hinderung des tertiären Amins sowie von der Nucleophilie des Phenols bestimmt.
Reaktionen von 2,6‐Diallyloxy‐4‐alkyl(aryl)‐1,3,5‐triazinen mit 1, 3‐Dipolen
Authors: Rembarz G. , Fischer E. , Heckl Y. , Zager M.
Published: January 2005

Die Darstellung der 2,6‐Diallyloxy‐4‐alkyl(aryl)‐1,3,5‐triazine 2a—d wird beschrieben. Mit Nitriloxiden und Nitriliminen ergeben sie Cycloaddukte des Typs 3a—h und 4a—g.
DIELS‐ALDER Reaktionen. VI. Weitere Untersuchungen der bei der Homodimerisierung von acyclischen C5‐Dienen‐(1,3) entstehenden Reaktionsprodukte
Authors: Kahlert K. , Pritzkow W. , Zimmermann G.
Published: January 2005

Es wurde die Produktverteilung der Homodimeren von Isopren, trans‐Piperylen und cis‐Piperylen in Abhängigkeit von der Reaktionstemperatur in Toluol als Lösungsmittel bestimmt, und durch Extrapolation auf den Umsatz null wurden die durch Konkurrenzreaktionen entstehenden Produkte ermittelt. Aus den erhaltenen Meßdaten wurden die Geschwindigkeitskonstanten und die Aktivierungsparameter für die Bildung der bei der thermischen Homodimerisierung des trans‐Piperylens ausschließlich entstehenden Sechsringdimeren sowie für die aus Isopren gebildeten Vier‐, Sechs‐ und Achtringprodukte berechnet.

Wie bei analogen Untersuchungen des Butadiens bereits festgestellt wurde [3], liegen die Aktivierungsparameter der symmetrieerlaubten Sechsringbildung und der symmetrieverbotenen Bildung von Vier‐ u. Achtringdimeren auch bei der Homodimerisierung des Isoprens sehr nahe beieinander.
Über die Konfigurationen und Konformationen einiger unsymmetrisch S‐substituierter 2,3‐Dimercaptobernsteinsäuren
Authors: Larsson Erik
Published: January 2005

Einige Säuren HOOCCH(SR)CH(SR′)COOH (R/R′  HOOCCH2, C6H5, C6H5CH2 und p‐ClC6H4CH2, R ≠ R′) wurden aus HOOCC(SR)  CHCOOH und R′SH dargestellt. Ihre Konfigurationen und Konformationen werden diskutiert.
Pyrazolonderivate. I. Synthese, Stereochemie und photochemisches Verhalten von Azomethinen des 1,5‐Dimethyl‐2‐phenyl‐4‐formyl‐Δ4‐pyrazolinon‐(3) (Antipyrinaldehyd)
Authors: Freyer Wolfgang , Tomaschewski Georg
Published: January 2005

Durch Kondensation von Antipyrinaldehyd mit primären Aminen wurde eine Reihe Schiffscher Basen erhalten. Mit Hilfe der 1H‐NMR‐Spektroskopie und der 15N‐Isotopentechnik wird nachgewiesen, daß die Azomethine als E‐Isomere vorliegen. Das photochemische Verhalten der Anile ist durch eine E‐/Z‐Isomerisierung an der CN‐Doppelbindung geprägt. Die photochemisch erzeugten Spezies lassen sich bei tiefen Temperaturen nachweisen.
Untersuchungen zur intramolekularen CC‐Verknüpfung von Dienen durch Basenkatalyse. III. [1] Cyclisierung von Diallylaminen
Authors: Schmidt H. , Spitzmüller I.
Published: January 2005

Diallylalkylamine 1 lassen sich mit Kalium auf Aluminiumoxid zu den jeweiligen Dipropenylaminen isomerisieren. Das thermodynamische Gleichgewicht liegt dabei völlig auf der Seite der trans, trans‐Isomeren. Wird der Alkylrest in den Diallylalkylaminen durch eine elektronenanziehende Gruppe ersetzt, so erfolgt Ringschluß zu Tetrahydropyridinen. Während Diallyläther 3 unter den Bedingungen der Basenkatalyse kein Ringschlußprodukt bildet, läßt sich Diallylsulfid 4 zu 5‐Methylthiacyclohexen‐(2) 4a isomerisieren.
Peptide. XXVII. [1] Synthese von Bradykinin‐Analoga und Partialsequenzen mit Tryptophan in Position 5
Authors: Reissmann S. , Arold H. , Filatova M. P. , Feist H.
Published: January 2005

Es wird die Synthese von [5‐Trp, 8‐Tyr]‐, [5‐Trp, 6‐Gly]‐Bradykinin und den C‐terminalen Partialsequenzen beschrieben. Die Analoga und Partialsequenzen werden für Fluoreszenzuntersuchungen eingesetzt.
Solvomercurierung und Demercurierung. III. Neue Heterocyclen aus substituierten 2,8‐Dithia‐4, 10‐diaza‐1, 7‐dimercuracyclododecanen
Authors: Ried Walter , Park Sang‐Woo
Published: January 2005

Die Dithiadiazadimercuracyclododecane 1a, 1b werden durch NaBH4 zu den trisubstituierten Thioharnstoffen 2a, 2b reduziert bzw. durch Thioacetamid zu 1‐Methyl‐3‐phenyl‐4‐vinyl‐imidazolidinthion‐(2) 4a bzw. 1‐Methyl‐3‐o‐tolyl‐4‐vinyl‐imidazolidinthion‐(2) 4b fragmentiert.
Chemische Synthese des Nonanucleosidoctaphosphats dA‐T‐G‐A‐T‐G‐A‐A‐A
Authors: Weiss R. , Birch‐Hirschfeld E.
Published: January 2005

Chemical Synthesis of the Nonanucleosideoctaphosphate dA‐T‐G‐A‐T‐G‐A‐A‐A

For studies on the specifity of enzymes, the nonanucleoside octaphosphate dATGATGAAA was required. Its chemical synthesis is reported starting with the monomers dA, dpT, dpG and dpA.
Über die Addition von Nitrosylhydrogensulfat an Olefine
Authors: Kisan Werner , Pritzkow Wilhelm
Published: January 2005

Durch Addition von Nitrosylhydrogensulfat an trisubstituierte Olefine in flüssigem Schwefeldioxid als Lösungsmittel sind die entsprechenden α‐Sulfatooxime zugänglich. Die Sulfatooxime sind zersetzlich. Sie reagieren mit Nucleophilen unter Austausch der Sulfatgruppe; die Reaktion verläuft wahrscheinlich nach einem Eliminierungs‐Additions‐Mechanismus über Nitrosoolefine als kurzlebige Zwischenprodukte. Setzt man Nitrosylhydrogensulfat in Gegenwart von Schwefelsäure und von niederen gesättigten Kohlenwasserstoffen mit trisubstituierten oder asymmetrisch disubstituierten Olefinen un und hydrolysiert das Gemisch dann vorsichtig mit Wasser bzw. mit wässerigen Lösungen von Ammoniak oder Natronlauge, so erhält man in guten Ausbeuten die entsprechenden α‐Hydroxyoxime. Setzt man Nitrosylhydrogensulfat mit Eisessig‐Lösungen von unsubstituierten Cycloolefinen um, so erhält man in mäßigen Ausbeuten die entsprechenden α‐Acetoxyoxime.
Nucleoside von Fluorzuckern. XVI. Halogensubstitutionen und Konfigurationsumkehr am Lactolring vom 6′‐Fluor‐D‐glucopyranosyl‐thymin
Authors: von Janta‐Lipinski M. , Etzold G. , Langen P.
Published: January 2005

Nucleosides of Fluorine Carbohydrates. XVI. Halogene Substitutions and Inversion of Configuration at the Lactol Ring of 6′‐Fluoro‐D‐glucopyranosyl Thymine

1‐(6′‐Deoxy‐6′‐fluoro‐β‐D‐glucopyranosyl)‐thymine 1 reacts with equimolar amounts' of tosyl chloride to give the 2′‐O‐tosyl derivative 2. Treatment of 1 with mesyl chloride gives predominantly a derivative with three sulfonyl groups in the molecule.

2 reacts both with bromides and iodides but not with fluorides to give the corresponding 2′‐deoxy‐2′‐halogeno derivatives. 2 can be transformed into an 2,2′‐anhydronucleoside 10 that reacts with HCl, HBr and HF/AlF3 to give the 2′‐chloro‐, 2′‐bromo‐, and 2′‐fluoro derivatives of 1‐(2′,6′‐dideoxy‐6′‐fluoro‐β‐D‐glucopyranosyl)‐thymine 7, 12, and 13 respectively.

Hydrogenation of 7 affords the 6′‐fluoro analog of the nucleoside phosphorylase inhibitor “deoxyglucosyl thymine” possessing a defined β‐configuration.

The alkaline hydrolysis of the anhydronucleoside 10 yields the 1‐(6′‐deoxy‐6′‐fluoro‐β‐D‐mannopyranosyl)‐thymine 15, the epimer of 1.
Halogenlipide. I. Massenspektrometrische Strukturuntersuchung stellungsisomerer Fettsäureester der Halogenpropandiole (Desoxyhalogen‐glyceride)
Authors: Kraft R. , Brachwitz H. , Etzold G. , Langen P. , Zöpfl H.‐J.
Published: January 2005

Halogenolipids. I. Mass Spectrometric Structure Investigation of the Isomeric Halogeno‐propanediols Esterified with Fatty Acids (Deoxyhalogeno‐glycerides)

The mass spectrometric behaviour of the isomers of cytostatic effective halogeno‐propanediols esterfied with fatty acids (deoxyhalogeno‐monoglycerides and deoxyhalogeno‐diglycerides) are investigated. The unambiguous structure of individual isomers is deduced from the characteristic fragmentation patterns of mass spectra. The synthesis of the mentioned compounds is described.
Umsetzung von 2,3‐Dichlormaleinimiden mit Ethoxycarbonylmethylentriphenylphosphoran und Folgereaktionen
Authors: Augustin M. , Schneider B. , Köhler M.
Published: January 2005

Reaction of 2,3‐Dichloromaleimides with Ethoxycarbonylmethylenetriphenylphosphorane and Secondary Reactions

2, 3‐Dichloromaleimide 1a reacts with ethoxycarbonylmethylenetriphenylphosphorane under alkenylation to give 3, 4‐dichlor‐5‐ethoxycarbonylmethylidene‐3‐pyrrolin‐2‐one 2. With N‐substituted 2, 3‐Dichloromaleimides 1b–1f one chloroatom is substituted to give 2‐(ethoxycarbonyltriphenylphosphoranyl)‐methylene‐3‐chloro‐maleinimides 3. The reactions of 2 and 3a with various nucleophiles are investigated.
Synthese von 2‐Heterocyclidenamino‐1,3‐diazatrimethincyaninen
Authors: Fanghänel E. , Richter A. M.
Published: January 2005

Synthesis of 2‐Heterocyclidenamino‐1, 3‐diaza‐trimethincyanines

The synthesis of 2‐[3‐methyl‐benzthiazol‐(1, 3)‐inylidene‐(2)‐amino]‐ and of substituted 2‐[1, 3‐dithiolyliden‐(2)‐amino]‐1, 3‐diaza‐trimethincyanines is described. The heterocyclic imines 1 react with phosgene or thiophosgene to the corresponding ureas 2 and thiureas 3, respectively. Alkylation of 3 to the 2‐alkylmercapto‐1, 3‐diaza‐trimethincyanines 4 and subsequent condensation with imine 1 yields the dyes 5. The chemical and spectroscopical data of cyanines 5 are described.
Gibberelline. CIII. Synthese von 8‐Amino‐gibbanen
Authors: Hung Ph. D. , Adam G.
Published: January 2005

Gibberellins. CIII. Synthesis of 8‐Amino‐gibbanes

For investigations of the structure‐activity relationships of gibberellin phytohormones the synthesis of 8‐amino‐gibbanes is described. The reaction pathway involves condensation of gibberellin C (1a) and its methylester 1b with primary amines to the corresponding azomethins 1c–11 followed by stereoselective NaBH4‐reduction to 8α‐amino gibbanes 2a–2r.
Der „Nornialisierungsfaktor”︁ für die Toinatenmutante chloronerva. XV. Peptidanaloga des Phytosiderophors Nicotianamin
Authors: Ripperger H. , Schreiber K. , Faust J.
Published: January 2005

The “Normalizing Factor” for the Tomato Mutant chloronerva. XV. Peptide Analogues of the Phytosiderophore Nicotianamine

Some peptide analogues of the phytosiderophore nicotianamine, (2S, 3′S, 3″S)‐N‐[3‐(3‐amino‐3‐carboxypropylamino)‐3‐carboxypropyl]‐azetidine‐2‐carboxylic acid, have been synthesized from protected amino acids by the EEDQ or the DCC method. They exhibited no biological effect with regard to the phenotypical normalization of the tomato mutant chloronerva.
About nitrile‐formamide‐chloride‐adducts. IX. Synthesis of 1,3‐ or 1,5‐disubstituted 1,2,4‐triazoles by the reaction of nitrile‐formamide chloride‐adducts and their products of hydrolysis with hydrazines
Authors: Liebscher Jürgen , Rumler Andrea
Published: January 2005

2‐Aza‐3‐chloro‐2‐propeniminium salts 5, which are easily available by the addition of formamide chlorides 1 to nitriles 2 react smoothly with hydrazines 9 giving rise to 1,3‐disubstituted 1,2,4,‐triazoles 11. When the 2‐aza‐3‐chloro‐2‐propeniminium salts 5 are hydrolysed first the resulting N‐acyl‐formamidinium salts 6 react with hydrazines 9 to 1,5 disubstituted 1,2,4‐triazoles 13 via isolable N‐acyl‐formamidrazones 12.
β‐Fur‐2‐yl‐α‐halogenacrylonitrile. I. Darstellung von β‐Fur‐2‐yl‐ß‐aminoacrylonitrilen und β‐Fur‐2‐yl‐α‐aminoacrylonitrilen
Authors: Jähnisch K. , Seeboth H. , Krause E. , Callejas D. R.
Published: January 2005

β‐Fur‐2‐yl‐α‐halogenacrylonitriles. I. Preparation of β‐Fur‐2‐yl‐ß‐aminoacrylonitriles and β‐Fur‐2‐yl‐α‐aminoacrylonitriles

β‐Fur‐2‐yl‐α‐halogenacrylonitriles 1 react with secondary amines to yield β‐fur‐2‐yl‐ß‐aminonitriles 2 and β‐fur‐2‐yl‐α‐aminoacrylonitriles 3. The 1 H‐n.m.r. spectra of the E/Z isomers are discussed.
Synthese und Reaktionsverhalten von N‐(3‐Chlorbenzo[b]‐thiophen‐2‐carbonyl)imino‐Dithiokohlensäure‐Derivaten
Authors: Richter M. , Augustin M. , Strauss K.
Published: January 2005

Synthesis and Reaction Behaviour of N‐(3‐Chlorobenzo[b]thiophene‐2‐carbonyl)‐imino‐dithiocarbonic Derivatives

3‐Chlorobenzo[b]thiophene‐2‐carbonyl‐chloride 1 was treated with potassium rhodanide to afford the appropriate acyl isothiocyanate 3, which adds nucleophilic agents as amines and thioles in good yields.

Addition of methanethiole and subsequent alkylation of the dithiocarbamate 7 gives S, S‐dimethylimino‐dithiocarbonate 8. 3‐Chlorobenzo[b]thiophene‐2‐carboxamide 2 reacts with carbon disulphide and phenyl isothiocyanate by chlorine substitution and cyclisation to benzo[b]thieno[2, 3‐e]thiazines 9, 10 or 11. The structure of the final products were determined by analytical and spectroscopical dates.
Prostaglandine und Prostaglandinvorstufen. Untersuchungen zur Synthese von 8‐Methylprostansäurederivaten
Authors: Schwarz S. , Weber Gisela , Meyer M. , Schick H. , Welzel H.‐P.
Published: January 2005

Prostaglandins and Prostaglandin Intermediates. Synthetic Approach to 8‐Methyl Prostanoic Acid Derivatives

Starting from the chiral key‐product 1 the 8‐methyl prostanoic acid derivative 13 was prepared within 10 steps. Construction of the α‐side chain involves DIBAH‐reduction of the lacton moiety of 1 followed by Wittig‐olefination with a C5‐ylide. C1‐Homologation of the oxo group of 1 via cyanhydrin synthesis and Wittig‐olefination with a C7‐ylide are important steps to form the ß‐side chain of compound 13.
Studies on the Autoxidation of Phenylacetylene
Authors: Pritzkow Wilhelm , Rao Tarigopula Siva Sankara
Published: January 2005

Phenylacetylene is oxidized slowly by molecular oxygen at 110°C. The main oxidation products are benzoic acid, benzoic anhydride, and benzaldehyde. Besides the oxidation, thermal dimerization, oligomerization, and polymerization processes also take place. As individual products 1,4‐diphenylbut‐1‐yn‐3‐ene and 1,3,5‐triphenylbenzene were identified. About 80% of the phenylacetylene consumed are converted into products of low volatility which could not be detected by gas chromatography.

The autoxidation of acetylenic hydrocarbones [1] preferably yields products of the attack at CH bonds in α‐position to the CC triple bond. An attack at the CC riple bond was a first proved in the case of phenylacetylene, which besides polymeric products yielded benzaldehyde, acetophenone, and organic acids [2]. Later, in the causes of the isomeric octynes [3] and of various 1‐Phenylalk‐1‐ynes [4] an attack at the CC triple bond was also proved. As the primary products of the oxidative attack at the CC triple bond short‐lived oxirenes or their valence isomers, the corresponding ketocarbenes are to be expected. Indeed, their rearrangement products were found in the oxidation mixtures of both the isomeric ocytnes [3] and the 1‐phenylalk‐1‐ynes [4]. Other products of the oxidative attack at the CC triple bond are lower carboxylic acids, formally produced by oxidative cleavage of the CC triple bond [3, 4].
NMR‐Spektroskopische Untersuchungen an 2‐Acetyl‐3‐amino‐acrylsäureestern
Authors: Michalik M.
Published: January 2005

N.M.R. Spectroscopical Investigations on 2‐Acetyl‐3‐aminoacrylates

The 2‐Acetyl‐3‐aminoacrylates 3 exist as Z/E‐isomers, in which intramolecular H‐bonds are formed between NH and acetyl or ester groups. The E‐isomers are favoured due to the greater acceptor ability of the acetyl compared with ester group. In arylamino substituted compounds 3 a linear correlation with σp constants have been found for 1H chemicals shifts of CH and NH protons and for 13C chemical shifts of C‐2 and C‐3, respectively, representing an optimal transmission of substituent effects through the enamino system.

The barriers of rotation around the CC‐bond of 3 have been determined by d n.m.r.spectroscopy. From coalescence phenomena the free activation enthalpies ΔG≠ of rotational process are determined and discussed with respect to substituent effects, a thermal rotational mechanism is postulated.
Determination of relative Autoxidation Rates of Simple Alkylaromatic Hydrocarbons by competitive reactions
Authors: Pritzkow Wilhelm , Thomas Gerda , Willecke Lothar
Published: January 2005

Relative rates of oxidative attack at the CH bonds in α‐position to the aromatic nucleus were determined for 10 simple alkylaromatic hydrocarbons. The results obtained by competitive oxidations of binary mixtures were shown to be consistent. From these results and the regioselectivity data already published, relative reactivities referring to the tertiary CH bond of cumene were calculated for all CH bonds of the hydrocarbons studied.

As expected, p‐alkyl groups increase the reactivity of CH bonds in α‐position to the aromatic nucleus. On the other hand, large alkyl groups, bound to the α‐C atoms, decrease the reactivity of the α‐CH bonds.
ortho‐Spezifische Bromierung von Phenolen
Authors: Schmitz Ernst , Pagenkopf Ingeborg
Published: January 2005

Ortho‐Specific Bromination of Phenols

Phenol as well as 3‐substituted phenols are brominated exclusively in the orthopositions by N.N‐dibromomethylamine, yielding 2.6‐dibrominated phenols in excellent yields. Phenols bearing an ortho‐substituent need N‐bromomethylamine as the brominating agent to take up one bromine atom into the free ortho‐position. para‐Bromination is not observed in either case. 1‐Naphthol gives 2‐bromo‐1‐naphthol, 8‐hydroxyquinoline gives 7‐bromo‐8‐hydroxyquinoline with 80% and 98% yield respectively. ortho‐Specific chlorination of phenols was carried out in some cases using N‐chloro‐alkylamines.
Cyclisierungsreaktionen β,γ‐ungesättigter Kohlensäurederivate. IX. Regiochemie der elektrophilen Cyclofunktionalisierung β,γ‐ungesättigter Carbamidsäureester mit Brom – Synthese von Oxazolidin‐2‐onen und Tetrahydro‐2H‐1,3‐oxazin‐2‐onen
Authors: Mühlstädt M. , Olk B. , Widera R.
Published: January 2005

Cyclization Reactions of β,γ‐Unsaturated Derivatives of Carbonic Acid. IX. Regiochemistry of Electrophilic Cyclofunctionalization of β,γ‐Unsaturated Carbamic Acid Esters with Bromine – Synthesis of Oxazolidine‐2‐ones and Tetrahydro‐2H‐1,3‐oxazine‐2‐ones

N,N‐Disubstituted β,γ‐unsaturated urethanes (1) and bromine react in methylene chloride at room temperature. The crotyl urethanes (1a–1c and 1e) and bromine give mixtures of corresponding saturated urethanes (dibromine adducts) (2a–2c and 2e), the oxazolidine‐2‐ones (3a–3c and 3e), and the tetrahydro‐2H‐1,3‐oxazine‐2‐ones (4a–4c and 4e). The reaction of γ,γ‐dimethylallyl urethanes (1f–1h) with bromine gives similar results. A useful synthetic route to N‐substituted tetrahydro‐2H‐1,3‐oxazine‐2‐ones (4l–4q) is demonstrated by the reaction of cinnamyl urethanes (1l–1q) with bromine.
Untersuchungen zur Sensibilisierung von Azofarbstoff‐Perhalogenid‐Systemen
Authors: Haessner Carmen , Epperlein J.
Published: January 2005

Investigations Concerning Sensitization of Silver Free Information Recording Materials with Azo Dyes and Polyhalogen Compounds

Recording materials mentioned in the title are sensitive to the visible region of light. The reason therefore is an energy transfer from the azo dye to the polyhalogen compounds, preferentially CBr4. It's possible to separate the absorption spectra of azo compounds used in this work into two gaussian functions, which relates to n,π*‐ and π,π*‐transitions. Only the excitation of the n,π*‐transition causes sensitization. A mechanisms of sensitization is proposed.
Reaktionen geminaler Dithiolate mit (Z)‐1,4‐Dichlor‐but‐2‐en
Authors: Rudorf W.‐D. , Schwarz R. , Augustin M.
Published: January 2005

Reactions of Geminal Dithiolates with (Z)‐1,4‐Dichloro‐but‐2‐ene

Geminal dithiolates 2 and 7 react with (Z)‐1,4‐dichloro‐but‐2‐ene either to give 4‐vinyl‐1,3‐dithiolanes 3 or 4, 7‐dihydro‐1,3‐dithiepines 4 and 8, respectively. Another method for the synthesis of 4 and 8 is the reaction of ketene dichlorides 5 or isocyanide dichloride 9 with the disodium salt of (Z)‐but‐2‐ene‐1,4‐dithiol. The formation of the corresponding 1,3‐dithiolanes can be excluded in these cases. 1H‐ and 13C‐n.m.r. spectra are in accordance with the structures and are discussed.
Synthese von 8H‐1,2,4‐Triazolo[4,3‐a]perimidinen
Authors: Burkhardt U. , Johne S.
Published: January 2005

Synthesis of 8H‐1,2,4‐Triazolo[4,3‐a]perimidines

Reaction of 2‐hydrazinoperimidine (3) with carboxylic acids or its orthoesters leads to 8H‐1,2,4‐triazolo[4,3‐a]perimidines (5a–h). 3 and aldehydes yield the aldehydehydrazones (6b,c,d) which are converted in 5 by air oxidation. The structures of the new compounds were determined by means of i.r., u.v., 1H‐n.m.r. and mass spectroscopy.
Zur Umkupplung von 4‐Arylazo‐2‐pyrazolin‐5‐onen mit p‐Chinondiiminkationen
Authors: Fanghänel E. , Akhlaq M. S. , Grossmann N. , Willscher U.
Published: January 2005

Recoupling of 4‐Arylazo‐2‐pyrazoline‐5‐ones with p‐Quinonediimine Cations

4‐Arylazo‐2‐pyrazoline‐5‐ones (1a–j) readily undergo coupling reaction with p‐quinonediimine cations (2a, b) to form azomethin dyes (3a, b). The dependence of the rate constants kK of the dye formation on the substituents of 1a–j as well as on the ionic strength show that the rate‐determining step of the coupling reaction is the formation of the intermediate 4 in a bimolecular reaction between the carbanions of 1a–j and p‐quinonediimine (2a, b).

It became evident that the benzenediazoniumion (5a–j) is eliminated in the reaction of 4 to 3a, b. Under the coupling conditions used, substituted benzene is formed in the reduction reaction of 5a, b by the p‐phenylendiamine (7a, b) or by the leuco dye (6a, b).
A study on Claisen Condensation with Diethyl Anilinodiacetate
Authors: Metwally Mohamed Abbas , Afsah El‐Sayed M.
Published: January 2005

Sodium hydride prompted reactions of diethyl anilinodiacetate 1 with acetophenone, p‐nitroacetophenone, p‐fluoroacetophenone and acetylthiophene result in the formation of tetraketones 3a–d. Evidence is presented to support the formation of 3a–d, via a sequence of reactions involving condensation with hydrazine, their acetyl derivatives, and cyclization with polyphosphoric acid. The structures of the hitherto unknown ring systems have been confirmed by i.r., p.m.r. and mass spectral data.
Bipyridines. XIX. Synthesis of some novel 2,7,9,10‐Tetraazaphenanthrene derivatives
Authors: Kaczmarek Łukasz
Published: January 2005

[4,4′‐Bipyridine]‐3,3′‐diamine (1) reacts with HNO2 in H2SO4 to form 2,7,9,10‐tetraazaphenanthrene (2) and 9H‐pyrrolo[2,3‐c:5,4‐c′]dipyridine (3) instead of expected bipyridinediol 4 or furodipyridine 5. On the other hand, diazotization of 1 in hydrohalogenic acids leads to novel 3‐halogeno‐2,7,9,10‐tetraazaphenanthrenes 10 or 11 and this reaction represents a new type of regioselective nucleophilic substitution of hydrogen atom in heteroaromatic species. The proposed pathway of reactions was supported by an experiment with the hypothetic intermediate, i.e. 2,7,9,10‐tetraazaphenanthrene‐9‐imine (8), which was obtained on independent route.
Synthesis of biologically active 4‐benzyl‐1(2H)‐phthalazinones and 2‐aryl‐3(2H)‐1‐benzal‐isoindolinones
Authors: Bedair A. H. , Lamphon R. Q. , Ghazal S. A. El
Published: January 2005

4‐Benzyl‐2‐1(2H) phthalazonyl derivatives of type 2, 3, 5a, b were synthesized by Mannich reaction of 4‐benzylphthalazinone 1 which by the reaction with diazomethane yielded O‐methylated derivative 4. Various 1‐benzal‐2‐substituted aryl‐3(2H) isoindolinones 7a–f, 8a–e were also prepared. Its i.r., 1H‐n.m.r. and mass spectra were discussed. Some of them exhibit pronounced antimicrobial activities.

A number of phthalazinones have found application in clinical medicine [1–3] due to the their pronounced antipyretic, analgesic and tuberculostatic activity and the importance of some benzylidenephthalimidines as stabilisers for halogen containing high polymers [4] and the local anesthetic activity superior to that of procaine [5], tempted us to procure some new phthalazinones and isoindolinones with biological interest.
Aromatenstrukturtypenanalyse von raffinierten Erdölprodukten durch UV‐Spektroskopie
Authors: Deutsch K. , Kühn H.‐J. , Polzin M. , Deutsch I. , Grunow S. , Stöcker J.
Published: January 2005

Aromatic Structure Type Analysis of Hydrotreated Petroleum Fractions by U.V.‐Spectroscopy

20 K boiling cuts were produced from hydrotreated petroleum products by means of distillation. From such close fractions, defined pure aromatic types can be separated by preparative elution adsorption chromatography (EAC) on dual‐packed (Silicagel‐Alumina gel) columns. The extinction coefficients of the various separated types are measured at suitable wave lengths and used for calculating the average extinction coefficients of aromatic types for wide boiling fractions. Utilizing these values on quantitative u.v.‐analysis of technical hydrotreated products, the results correspond well with those of EAC and 1H‐n.m.r. spectroscopy.
Investigation of the dimethyl acetal formation during the Ozonization of Alkenes in methanol
Authors: Theil Fritz , Schick Hans
Published: January 2005

Dimethyl acetal formation during the ozonization of olefins in methanol followed by reduction with dimethyl sulfide has been occasionally reported in the literature. This acetalization can be completely suppressed, when the ozonization is carefully monitored by g.l.c. or t.l.c. analysis and stopped immediately after the consumption of the olefin. It was proved that the acetal formation observed earlier is the result of an acid catalysed reaction accelerated by dimethyl sulfide and dimethyl sulfoxide present in the reaction mixture. The acidic catalyst is formic acid formed from methanol by oxidation with excessive ozone.
Verbesserte Synthese von 8‐Amino‐2‐methyl‐4‐phenyl‐1,2,3,4‐Tetrahydroisochinolin
Authors: Ivanov T. B. , Mondeshka Diana M. , Angelova Ivanka G.
Published: January 2005

An Improved Synthesis of 8‐Amino‐2‐methyl‐4‐phenyl‐1,2,3,4‐Tetrahydroisoquinoline

The regioselectivity of the reaction of 2‐nitrobenzylmethylamine (1) and styrenoxide (2) leading to a mixture of the isomeric aminoalcohols 3a and 3b has been studied. The course of the reaction strongly depends on the type of the solvent used as reaction medium. The highest selectivity (3a:3b = 9:1) was achieved with a combination of polar aprotic and protic solvents (DMFA and ethanol). 1H n.m.r. spectroscopy was used for identification of the isomers as well as for the determination of their ratio in the crude reaction mixtures. The isomer ratio remains unaffected during catalytic reduction (Ra‐Ni) of 3a/3b to a mixture of the corresponding aminoalcohols 4a and 4b. Pure 3a, 4a and 4b were independently synthesized for comparison. Cyclodehydration of crude 4a/4b mixtures gives 5 in a very good yield.
Chromium(III) compounds as catalysts for Hydrocarbon Oxidation and hydroperoxide decomposition
Authors: Blau Karla , Kovacs O. , Lauterbach Gerlinde , Makhoul M. , Pritzkow W. , Tien Tieu Dung
Published: January 2005

Chromium stearate and chromium acetylacetonate are very active catalysts both for the oxidation of hydrocarbons by molecular oxygen and for the decomposition of organic hydroperoxides. During these reactions they also catalyze the oxidation of secondary alcohols to the corresponding ketones by organic hydroperoxides. From organic hydroperoxides and chromium(III)compounds chromium (VI) compounds are formed which are probably the effective agents oxidizing secondary alcohols to ketones.
Spintrapping‐Untersuchungen zum Verhalten des Pentacarbonylrhenium‐Radikals
Authors: Rehorek D. , Martino Silvana Di , Kemp T. J.
Published: January 2005

Spin Trapping Investigations on the Behaviour of the Pentacarbonyl Rhenium Radical

Both ·Re(CO)5 and ·Re2(CO)9⊕ radicals have been spin‐trapped by nitroso compounds during the photolysis of [Re2(CO)10] at room temperature in CH2Cl2 solution. Interaction with nucleophiles Nu, such as pyridine, PPh3, AsPh3, and SbPh3, led to ·Re(CO)4Nu radicals. Although only ·Re(CO)4PPh3 gave a persistent spin adduct with nitrosodurene, the formation of the other substitution products was evidenced by their increased reactivity towards carbon halides. In the presence of dioxygen, superoxide is formed and trapped.
Exciplexes of zinc meso‐tetraphenylporphyrin with arenediazonium salts, oxygen and p‐benzoquinone
Authors: Becker H. G. O. , Lehmann T. , Zieba J.
Published: January 2005

Zinc meso‐tetraphenylporphyrin (ZnTPP) forms triplet exciplexes with different arenediazonium salts (p‐Et2N, p‐MeO, p‐Me, p‐t‐Bu, p‐H, p‐Cl, p‐Br) and p‐benzoquinone, and a singlet exciplex with oxygen (probably formed after energy transfer from excited ZnTPP to 3O2 to yield 1O2).

The absorption spectra of these exciplexes are nearly identical and – except of pronounced fine structures – similar to the spectrum of 3(ZnTPP)*.

By means of WARE treatment of flash‐photolytically determined rate constants or of quantum yields equilibrium constants, lifetimes and further data of diazonium salt exciplexes are determined. The equilibrium constants and lifetimes are very similar and amount to about 104 M−1 and 20 μs, respectively.

The equilibrium constants of the oxygen and p‐benzoquinone exciplexes are determined by competition experiments; they amount also to about 104 M−1.

The diazonium salt exciplexes belong to the charge‐shift type. Their equilibrium constants are, therefore, independent of the solvent polarity, as is interestingly also observed for the oxygen exciplex which formally belongs to the charge‐separation type.

The p‐benzoquinone exciplex dissociates in acetonitrile as has been found also by other authors.
Tieffarbige Systeme mit Oxalsäurestruktur — eine Strukturkorrektur
Authors: Beckert R. , Bauer W.
Published: January 2005

Deep Coloured Systems with Oxalic Acid Substructure‐a Structural Correction

Basing on a recent spectroscopic investigation the structure of earlier described deeply coloured systems derived from oxalic acid imidochlorides and thioacetamide has to be revised. Due to the poor solubility of these systems their spectroscopic characterization led to the misinterpretation as tetramethin‐bridged thiazolines 1. By means of 1H‐NOE‐Difference‐Spectroscopy of newly synthesized derivatives with lipophilic substituents a imidazolin‐thion substructure 4 has been found. Such an arrangement of the heteroatoms clearly reflects a 1,3‐rearrangement with participation of the oxalic acid system.
Synthesis of Mammalian Gonadoliberin Analogs with the N‐terminal glutamine or glutamine or glutamic acid
Authors: Masiukiewicz Elżbieta , Rzeszotarska Barbara , Fortuna Gabriela , Kochman Kazimierz
Published: January 2005

Synthesis of two mammalian gonadoliberin analogs, [Gln1]GnRH and [Glu1]GnRH, in solution by the peptide segment coupling of the [(2 + 4) + 4] type has been described.
Cycloadditions‐Eliminierungsreaktionen mit 4‐Aryl‐5‐arylimino‐1,2,4‐dithiazolidin‐3‐onen (Senföloxiden)
Authors: Tittelbach Franz
Published: January 2005

Cycloaddition Elimination Reactions of 4‐Aryl‐5‐arylimino‐1,2,4‐dithiazolidin‐3‐ones (Mustard Oil Oxides)

4‐Aryl‐5‐arylimino‐1,2,4‐dithiazolidin‐3‐ones (1) react with isocyanates, isothiocyanates, and cyanic acid esters by exchange of the COS‐part from 1 affording thiadiazole and dithiazole derivatives 4, 5, 6 or 12. The reaction products are able to give further exchange reactions. Ring opening of 2‐substituted 4‐aryl‐5‐arylimino‐1,2,4‐thiadiazolin‐3‐ones (4) and ‐3‐thiones (6) yields thio‐ and dithiobiurets (7, 8) with aryl substituent in 3‐position. Oxidation of dithiobiurets, generated from 6, affords dithiazolidines 9, which are Dimroth‐isomers of 6.
Reactions of 2‐arylhydrazones of 1,2,3‐triketones with 1,2‐diaminoethane. II. Synthesis of 2,9‐Diarylazo‐3,8‐dimethyl‐1,10‐diphenyl‐4,7‐diaza‐2,8‐decadiene‐1,10‐diones and 6‐Amino‐2‐arylazo‐3‐methyl‐1‐phenyl‐4‐aza‐2‐hexen‐1‐ones
Authors: Opozda Ewa , Śledziewska Ewa
Published: January 2005

The reaction of 2‐arylhydrazones of 1‐phenyl‐1,2,3‐butanetrione with 1,2‐diaminoethane yields 2,9‐diarylazo‐3,8‐dimethyl‐1,10‐diphenyl‐4,7‐diaza‐2,8‐decadiene‐1,10‐dione (2a‐d) (Schiff base type A) and monocondensation products ‐ 6‐amino‐2‐arylazo‐3‐methyl‐1‐phenyl‐4‐aza‐2‐hexen‐1‐ones (3a‐e) (“half” units ‐ Schiff bases type B). The structure of both types of compounds characterized on the basis of spectroscopic data (m.s., i.r., 1H‐n.m.r.).
Strukturanalytische Untersuchungen an Folgeprodukten aus Sulfonamiden. VIII. Zur Struktur der Reaktionsprodukte aus 1,1,3‐trisubst. Thioharnstoffen und N‐Tosyl‐iminothiokohlensäuremethylester‐chlorid
Authors: Hans M. , Schöffmann T. , Dehne H. , Matos E. N.
Published: January 2005

Structure‐Analytical Investigations of Consecutive Products of Sulphonamides. VIII. About the Structure of Reaction Products from 1,1,3‐Trisubst. Thioureas and N‐Tosyl‐iminothiocarbonic Acid Methylester Chlorides

The structure of a variety of reaction products from 1,1,3‐trisubstituted thioureas (1 a–e) and N‐tosyl‐iminothiocarbonic acid methylester chlorides (2) is investigatigated with respect to whether a sequence SO2NCSC (structure I) or SO2NCNC (structure I) is form ed. The problem is solved by means of m.s. and i.r. spectra as well as the Feigl test. The results of these investigations show that structure I is formed.
Synthese von 6‐(pyrid‐4‐yl)‐substituierten Pyrido[: 3‐d]pyrimidinen und 1,8‐Naphthyridinen
Authors: Haber H. , Hagen V. , Schlender M.
Published: January 2005

Synthesis of 6‐(4‐pyridinyI)‐substituted Pyrido[2,3‐d]pyrimidines and 1,8‐Naphthyridinms

A series of new 6‐(4‐pyridinyl)‐substituted pyrido‐[2,3‐d]pyrimidines 2–4and 1,8‐naphthyridines 6, respectively, is described. Cyclisation of 2‐amino‐5‐(4‐pyridinyl)‐pyridinm‐3‐carboxamide 1a with diethyl oxalate gives the pyrido‐[2,3‐d]pyrimidinm 2a. Alkylation of(2a) yields the 3‐ethylaminoxyrido[2,3‐d]pyrimidine derivative 2b. Saponification of 2a,b gives the corresponding carboxylic acids 3a,b, which are decarboxylated by heating above the melting point to give 4a, b. The 2‐amino‐5‐(4‐pyridinyl)‐pyridinm carboxylic acid derivatives 1 b–e react with ethylmalonylchloridm and diethyl malonate to afford the 1,8‐naphthyridines 6b–e. The 1‐oxide 7 in a similar reaction gives 8 and the oxdiazole(9) which is converted by ring transformation to the 1,8‐naphthyridine 10.
Neue Möglichkeiten zur Verwendung von 2‐Furaldehyd: Synthese von Oxaundecan‐1,2,10,11‐tetraol
Authors: Marzec K.
Published: January 2005

New Possibilities of Application of 2‐Furancarboxaldehyde: Synthesis of 6‐Oxaundecane‐1,2,10,11‐tetraol

Starting from 2‐furancarboxaldehyde (1), a method for the synthesis of 6‐oxaundecane‐1,2,10,11‐tetraol (8) is presented and the possibilities of applying this compound for the preparation of polyurethane resins are discussed. In addition, a method for the preparation of new di(pent‐4‐enyl)ether (7) is described.
Zur Molekülverknüpfung mit Schwefelchloriden. X. Bis(arylamino‐chloralkyl)‐sulfane aus N‐β‐Methallyl‐N‐tosyl‐anilinen und Schwefeldichlorid
Authors: Hollmann K. , Ecke M. , Mühlstädt M.
Published: January 2005

Molecule Linkage by Sulfur Chlorides. X. Bis(arylamino‐chloroalkyl)‐sulfanes from N‐β‐Methallyl‐N‐tosyl‐anilines and Sulfur Dichloride

Reactions of differently substituted N‐β‐methallyl‐N‐tosyl‐anilines 1 with sulfur dichloride yield bis(arylamino‐chloroalkyl)‐sulfanes 2 and 3 and dihydrobenzo‐1,4‐thiazines 4. The structural assignment of the products 2 and 3 was carried out by mass spectroscopy and 1H‐n.m.r.‐spectroscopy.
2,2‐Disubstituted Cyclopentane‐1,3‐diones. Part 5. Simple Procedures for the Preparation of Racemic (1RS,5RS)‐5‐Methyl‐2‐oxabicyclo[3.3.0]octane‐3,6‐dione Starting from 2,2‐Disubstituted Cyclopentane‐l,3‐diones
Authors: Schick H. , Ballschuh S. , Welzel H.‐P. , Schwarz S.
Published: January 2005

2‐Methyl‐2‐(prop‐2‐enyl)cyclopentane‐1,3‐dione (15) can be transformed on two different routes into the racemate (1RS,5RS)‐5‐methyl‐2‐oxabicyclo[3.3.0]octane‐3,6‐dione (rac‐13), a key intermediate for the synthesis of 8‐methylprostaglandins. Both routes are characterized by a non‐selective reduction of a 2,2‐disubstituted cyclopentane‐l,3‐dione to the corresponding cyclopentane‐l,3‐diol, followed by lactonization and oxidation of the remaining hydroxy group.
Eine neue Gruppe vom Nereistoxin abgeleiteter Verbindungen ‐ Synthese von Bis‐dimethylamino‐tris‐disulfanen
Authors: Mühlstädt M. , Heinicke J. , Schubert H.
Published: January 2005

A New Group of Compounds Derived from Nereistoxin ‐ Synthesis of Bis‐dimethylamino‐tris‐disulfanes

The reaction of organo‐thiosulfates, BUNTE‐salts, with mercaptans is a convenient synthesis of disulfanes. Similarly bis‐BUNTE‐salt 7 and tert. butyl mercaptan give bis‐disulfane 5c [9]. By treating 7 with several aliphatic mercaptans we found the formation of the tris‐disulfanes 8a–d in preparative amounts in addition to the bis‐disulfanes 5a–d expected. This reaction was investigated. The preparation of the compounds 8 is described and a proposal is given for a mechanism of the formation of 8 as a thiol‐disulfide‐interchange.
Synthese und Eigenschaften von 2‐Methoxycarbonylmethylen‐ und 2‐ (Formyl‐methoxycarbonylmethylen)‐2H‐Thiopyran‐3‐carbonsäureme‐thylester
Authors: Greif D. , Pulst M. , Weissenfels M. , Scheinmann Feodor
Published: January 2005

Synthesis and Properties of Methyl‐2‐methoxycarbonylmethylene‐ and ‐2‐(formyl‐ methoxycarbonylmethylene)‐2H‐thiopyran‐3‐carboxylates

Dimethyl‐2‐chloro‐propene‐l,3‐dicarboxylate is a easily available reactive C2‐building block for the synthesis of 2H‐thiopyran derivatives la — n in good yields via [C3S + C2]‐cyclisation reactions using β‐thioxoaldehydes and their derivatives as C3S‐synthons. The structure of the stable red products with Z‐configuration (side chain in position 2 of the ring) is elucidated by means of several analytical and spectroscopic methods including X‐ray analysis of compounds 1h and lk.

Treating of 1 with Vilsmeier reagent yields title compounds 2 with a remarkable less reactive formyl group at the exo‐methylene group. There is obviously a shielding effect of the carboxylate groups.
Novel Meisenheimer Complexes by the Reaction of 4,6‐Dinitrobenzofuroxan with Pyridinium Ylides
Authors: Niclas H.‐J. , Kind J. , Ramm M.
Published: January 2005

The reaction of 4,6‐dinitrobenzofuroxan 1 with pyridinium ylides 2 affords σ‐CC bonded Meisenheimer complexes 3. The structure of these adducts is studied by n. m. r. spectroscopy and X‐ray structure analysis.
Untersuchung zur Regio‐ und Stereoselektivität der Reaktion von 7,8‐Dimethoxy‐1‐phenyl‐2,3,4,5‐tetrahydro‐1H‐3‐benzazepin mit Phenyloxiranen
Authors: Mondeshka Diana M. , Angelova Ivanka G. , Ivanov Tschavdar B. , Tomov Emil
Published: January 2005

Reaction of Benzazepines with Phenyloxiranes

The reaction between the 7,8‐dimethoxy‐1‐phenyl‐2,3,4,5‐tetrahydro‐1H‐3‐benzazepines ( ± )‐1, (1S)‐(−)− 1 und (1R)−( + )− 1 and racemic or optically active phenyloxiranes 2a–d leads to a mixture of the regioisomcric carbinoles 3a–d and 4a–d, respectively. In all cases the reaction is not stereospecific, but regiospecific with regard to the p‐phenyl substituted phenyloxiranes 2b–d. The ratio of the isomers was determined by HPLC and the structures of the regioisomers 3a and 4a were deduced from the 1H‐n.m.r. spectra. The newly synthesized carbinols proved to be strong re‐uptake in hibitors of the monoamines dopamine (DA), norepinephrine (NE) and serotonine (5‐HT).
Analytical force constant calculation as a minimization problem
Authors: Sellers Harrell
Published: January 2005

In this letter we show that the calculation of analytic second derivatives of variational potential energy surfaces with respect to nuclear coordinates is a minimization problem.
A HAM/3 study of substituted benzenes
Authors: Takahata Y.
Published: January 2005

The semiempirical HAM/3 method is used to study ionization potentials, electron affinities, heats of formation, stabilization energies, dipole moments, and charge of mono‐ and disubstituted benzenes. Ionization potentials and electron affinities are calculated with good accuracy. The ground state properties are generally not well calculated by HAM/3. Errors in heats of formation and dipole moments are up to 50 kcal/mol and 2.4 D.
Vibronic interaction in one‐dimensional polymer
Authors: Tachibana Akitomo , Inoue Takayuki , Yamabe Tokio , Hori Kenzi
Published: January 2005

Asymptotic properties of the “attractive” vibronic coupling in a one‐dimensional polymer are analyzed. The strength of the vibronic coupling grows linearly with the size of polymer, which may relate to the softening mechanism of Coulombic repulsive interaction between a Cooper pair of superconducting electrons.
The variational alternant molecular orbital method for 3‐D and 2‐D hydrogen molecule
Authors: de Andrada E Silva E. A. , da Cunha Lima I. C. , da Silva A. Ferreira
Published: January 2005

The Variational alternant molecular orbital method (VAMO) is described and applied to the case of three‐dimensional and two‐dimensional hydrogen molecules. The energies of the electron system are obtained, together with the equilibrium distances of the molecules. The intergrals equivelent to the Slater's integrals of the nonvariational method are described. Applications of this method to realizable systems are described.
Degeneracy lifting in graphite and boron nitride: A perturbational approach
Authors: Lafemina John P. , Lowe John P.
Published: January 2005

The degeneracy lifting in the pi bands, near the Fermi energy, for two‐ and three‐dimensional graphites and boron nitride are qualitatively determined, without calculation, using first‐order perturbation theory and the concept of transferability. The relationships between the band diagrams for several three‐dimensional modifications of graphite and boron nitride are presented in a simple orbital context.
Dynamical analysis of correlated wavefunctions
Authors: Moscardó Federico , San‐Fabián Emilio
Published: January 2005

A comparative dynamical analysis of several quasi‐exact wavefunctions for helium has been carried out by computing their corresponding correlation coefficients. The aim is to use the resulting information to study the correlation included in approximate wavefunctions within the factor correlation model. Information about the possibility of making simplifications in the approximate wavefunctions and about the flexibility of the quasi‐exact wavefunctions is also obtained.
On the quenching of Li(2p) by HCl: Nonadiabatic effects
Authors: Yarkony David R.
Published: January 2005

The electronic structure aspects of the quenching reaction Li(2P) + HCl → LiCl + H were studied using ab initio state averaged multiconfiguration self consistent field/configuration interaction methods. This reaction proceeds through an avoided crossing of the 1, 2 2A' potential energy surfaces. A region of strong electronic nonadiabaticity was located and (first derivative) nonadiabatic coupling strengths computed. This region of strong electronic nonadiabaticity occurs near a (local) minimum on the 2 2A' potential energy surface which is exoergic relative to its reactant asymptote, Li(2P) + HCl.
Excitation energies, oscillator strengths, and frequency dependent polarizabilities of Be: Comparison of TDHF, EOM (second order), and MCTDHF
Authors: Graham Richard L. , Yeager Danny L.
Published: January 2005

Low‐lying excitation energies from the ground state of Be were calculated using a basis set of 61 Cartesian Gaussian functions. Three approximations were employed: the time‐dependent Hartree–Fock (TDHF), second‐order equations‐of‐motion (EOM), and multiconfigurational time‐dependent Hartree–Fock (MCTDHF). The TDHF excitation energies are 0.5–1.1 eV lower than experiment, and the EOM values are 0.3–1.2 eV lower than experiment, whereas the MCTDHF excitation energies deviate on the absolute average from experiment by only 0.03 eV. We found that in an MCTDHF calculation, any proper MCSCF stationary point is a good reference (i.e., initial) state, not just the ground state. Experimental values for oscillator strength are accurately known only for the 2s2X1S → 2s2p1P0 transition. The TDHF value and the MCTDHF value agree with experiment, but the EOM value does not. The agreement of the TDHF value with experiment seems to be coincidental, because for higher lying transitions the TDHF values differ by approximately a factor of two or more from the more accurate MCTDHF. Frequency independent polarizabilities, α(0), were also calculated with the TDHF, HRPA, and MCTDHF and frequency dependent polarizabilities, β(ω), were calculated with the MCTDHF. No experimental data for Be polarizabilities exist, but we expect the MCTDHF values to be among the most accurate calculations available.
Free energy and dispersion forces via response functions
Authors: Obcemea Ceferino H.
Published: January 2005

In a recent paper [5], Ford, Lewis, and O'Connell proposed a remarkable formula for the change in the free energy in terms of the susceptibility alone. This formula came out of their treatment of a quantum oscillator interacting (via dipole coupling) with a blackbody radiation field at finite temperature T. As a result, they found a modification to the Planck formula due to finite line width and a positive energy shift which is of quantum electrodynamical origin.

I shall show in this paper that the above result is a general one, not specific to the problem considered, and whose essence can already be traced to the early works of van Kampen and Liftshitz on the theory of van der Waals forces, Maradudin et al. on point defects in lattices, and Mahanty and others on dispersion forces. The above formula can be deduced directly using the argument theorem in theory of contour integration.
Rotational decoupling of vibrational modes due to rotational excitation: Application to a model of the HDO stretching motions
Authors: Shirts Randall B.
Published: January 2005

Rotational motion can have a significant effect on intramolecular vibrational dynamics. In this paper, we explore the recently discovered phenomenon of rotational decoupling through both quantum mechanical and classical methods. It is found in a model system for the stretching motions of HDO, that rotational motion about the c axis can decouple the stretches. This fact can be understood as a cancellation between kinetic and centrifugal coupling as illuminated using classical resonance analysis and quantum matrix element calculations. The significance of this phenomenon is discussed in infrared multiple photon absorption experiments with specific application to isotope separation in HDO.