Syntheses and photophysical properties of some 5(2)-aryl-2(5)-(4-pyridyl)oxazoles and related oxadiazoles and furans

A number of 5-aryl-2-(4-pyridyl)oxazoles, a 2-aryl-5-(4-pyridyl)oxazole, the related oxadiazole and furan, several 2-(4-pyridyl)cycloalkano[d]oxazoles, and many of their quaternary salts were prepared. No single standard synthesis was effective for preparation of more than a few of the 25 free bases described; methods often unique to a base were employed. Minor variations in structure sometimes produced large differences in absorption and emission wavelengths, as well as in the magnitude of the extinction coefficient. The salts are of interest as laser dyes, scintillation fluors, biological stains, and shifters for luminescent solar concentrators.     

Ein Trennungsgang in einem Tropfen

Zusammenfassung Mit Hilfe der bereits früher beschriebenen Ringofenmethodik wurde ein Trennungsgang ausgearbeitet, der folgende Ionen berücksichtigt: Pb, Bi, Cu, Cd, Sn, Sb, Fe, Co, Ni, Mn, Cr, Zn, Al, Ti. Zur Analyse reicht ein Tropfen von etwa 1,5l aus, soferne die darin enthaltenen Mengen die Durchführung einer Identitätsreaktion noch gestatten. Die Ionen werden in vier Gruppen getrennt, die als Ring I, II und III und Tüpfelfleck bezeichnet werden. Die Nachweisreaktionen werden auf dem Papier mit Hilfe bereits bekannter, für diesen speziellen Zweck aber abgewandelter Reaktionen durchgeführt. Vier Beispiele werden angeführt, bei denen mit 35g und weniger gearbeitet wurde. Die Analyse nimmt nur etwa eine Stunde in Anspruch.

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Summary With the aid of the ring furnace method previously described, it has been possible to work out a method of separation taking account of following ions: Pb, Bi, Cu, Cd, Sn, Sb, Fe, Co, Ni, Mn, Cr, Zn, Al, Ti. A drop of about 1.5l is sufficient for the analysis, provided the amounts of the cations present still permit the identification reactions. The ions are separated into 4 groups, designated as Ring I, II, III, and fleck. The detection reactions are conducted on the paper with the aid of familiar reactions, which however have been modified for this particular purpose. Four examples are cited, employing 35g or less. The analysis requires only about one hour.

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Résumé Au moyen de la méthode du four annulaire déjà décrite, on a élaboré une méthode de séparation qui concerne les ions suivants: Pb, Bi, Cu, Cd, Sn, Sb, Fe, Co, Ni, Mn, Cr, Zn, Al, Ti. Pour l'analyse une goutte de 1,5 l suffit en tant que les quantités contenues permettent encore l'exécution d'une réaction d'identification. Les ions sont séparés en quatre groupes qui sont désignés par anneau 1, 2, 3 et tache de goutte. Les réactions d'identification sont exécutées sur papier au moyen d'essais déjà connus mais modifiés pour ce but spécial. On donne le mode opératoire pour quatre exemples exécutés avec 35g et mÊme moins. L'analyse ne demande qu'une heure.

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Für das gro\e Interesse und die stete Förderung meiner Arbeit erlaube ich mir an dieser Stelle dem Vorstand des Institutes, Herrn o. ö. Prof. Dr.Robert Strebinger, meinen ergebensten Dank auszusprechen.     

Preparation of fluorine compounds of groups 13 and 14: a study case for the diagonal relationship of aluminum and germanium

The synthesis of carbaalanes of composition [(AlF)₆(AlNMe₃)₂(CR)₆] containing terminal fluorine atoms is described. The clusters have in common that the central core consists of eight aluminum and six carbon atoms. Six of the eight aluminum atoms are bearing six terminal fluorine atoms. The fluorination of (t-BuNCH₂AlH)₄ results in the formation of the aggregate (t-BuNCH₂AlF)₄. In group 14, the fluorine containing unsaturated compounds LGeF, LGeS(F), LGeSe(F), and LGeNSiMe₃(F) were prepared (LHC(CMeNAr)₂), Ar = 2,6-iPr₂C₆H₃ and Ar = 2,6-Me₂(C₆H₃)).     

Facile Synthesis of 2′-Deoxyribofuranosides of Allopurinol and 4-Amino-1H-pyrazolo[3,4-d]pyrimidine via Phase-Transfer Glycosylation

Phase-transfer glycosylation of 4-methoxy-1H-pyrazolo[3,4-d]pyrimidine with the 2-deoxyribofuranosyl chloride 9 formed the N(1)-β-nucleoside 10a as main product (39%). As by-products the α-D -anomer 11a (7%) and the N(2)-isomer 12a (18%) were isolated. Assignment of these isomers was made on the basis of their ¹H- and ¹³C-NMR spectra. Removal of the sugar-protecting groups yielded the 4-methoxy-nucleosides 10b, 11b , and 12b , respectively. Nucleophilic displacement of the 4-MeO-group gave the 2-deoxyribofuranosides 1–4 of allopurinol and 4-amino-1H-pyrazolo[3,4-d]pyrimidine.     

Solid-phase synthesis of lipidated peptides

Characteristic partial structures of lipidated proteins embodying different lipid groups as well as additional fluorescent tags or a maleimide for coupling to proteins can be synthesized readily by means of a new solid-phase technique employing the oxidative cleavage of the hydrazide linker as well as on-resin farnesylation and palmitoylation after appropriate deprotection of cysteine thiol groups as the key steps.     

Template-assisted self assembly of two lipophilic polyion aggregates derived from sodium tetraphenyl imidodiphosphinate-complexes containing sodium ions in four different coordination environments

The molecular structures of two lipophilic polyion aggregates derived from tetraphenyl imidodiphosphinate are described: [Na(crown ether)][MNa(2)[Ph(2)P(O)NP(O)Ph(2)](4)] with crown ether = 15-crown-5 for 1and benzo-15-crown-5 for (M = Na(+) for 1 and Na(H(2)O)(+) for 2).     

Die kristall- und molekülstruktur von Fe3Te2(CO)9

The crystal and molecular structure of Fe₃Te₂(CO)₉ has been determined by X-ray diffraction analysis. The compound crystallizes in the triclinic space group P$\text{1}$ with a 952.5(4), b 1314.3(8), c 694.7(2) pm, α 95.27(4), β 112.78(3), γ 81.44(4)° and Z = 2 (R = 0.036, using 2079 reflections).     

Separation of sodiated isobaric disaccharides and trisaccharides using electrospray ionization-atmospheric pressure ion mobility-time of flight mass spectrometry

A series of isobaric disaccharide-alditols, four derived from O-linked glycoproteins, and select trisaccharides were rapidly resolved using tandem high resolution atmospheric pressure ion-mobility time-of-flight mass spectrometry. Electrospray ionization was used to create the gas-phase sodium adducts of each carbohydrate. Using this technique it was possible to separate up to three isobaric disaccharide alditols and three trisaccharides in the gas phase. Reduced mobility values and experimentally determined ion-neutral cross sections are reported for each sodium-carbohydrate complex. These studies demonstrated that ion mobility separations at atmospheric pressure can provide a high-resolution dimension for analysis of carbohydrate ions that is complementary to traditional mass spectral (m/z) ion analysis. Combining these independent principles for separation of ions provides a powerful new bioanalytical tool for the identification of isomeric carbohydrates.