A condition variation study for radioiodination via triazene intermediates

Pyrrolidyl triazenes prepared by interception of the diazonium transient in the Sandmeyer reaction of amines can serve as useful intermediates in the iodination and radioiodination of aryl rings. Decomposition of such triazenes in the presence of iodide is acid-catalyzed and is sensitive to choice of solvent, acid, and triazene structure. A condition variation study by HPLC of four different solvent systems and two non-nucleophilic acids was carried out on the¹²³I iodination of the triazenes of p-nitroaniline, p-anisidine and p-toluidine. This method has proven useful in radiolabeling of two pharmaceutical analogs which were not amenable to labeling through the classic Sandmeyer method.     

Studies in qualitative inorganic analysis. Part XXIII

Summary Schemes for the analysis of the Iron group are reviewed. The advantages of the Midlands Association scheme are discussed.

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Zusammenfassung Die in der Literatur angeführten Arbeitsvorgänge für die qualitative Analyse der Eisengruppe werden besprochen. Die Vorteile des von The Midlands Association for Qualitative Analysis empfohlenen Analysenganges werden diskutiert.

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Résumé Ou présente une revue des méthodes d'analyse du groupe du fer. On discute les avantages du procédé de la «Midlands Association».

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Part XXII: Mikrochim. Acta [Wien]1965, 322.     

Luminescence characteristics of several classes of drugs affecting the central nervous system

The excitation, fluorescence and phosphorescence characteristics of 29 compounds of psychopharmacological interest have been studied in ethanol at 77 k. Phosphorescence lifetimes are reported and the low-temperature luminescence spectra discussed. Luminescence characteristics of several important 1,4-benzodiazepines in acidic, basic and neutral solution are reported.     

Spectrophotometric determination of phosphorus as phosphate in organic compounds and materials of biological origin using a flow-injection manifold with a mixing chamber

Summary A flow-injection manifold with mixing chamber has been developed for the determination of phosphate by reaction with molybdate and crystal violet. The insoluble blue dye salt is kept in colloidal solution with poly(vinyl alcohol) and measured at 560 nm. The injection rate is 100 h^–1. The detection limit is 0.01 g PO ₄ ^3– /ml based on 250 l injection volumes. The system has been applied to the determination of phosphate in serum samples and after appropriate mineralisation to organic compounds and to plant materials.     

A High‐Barrier Molecular Balance for Studying Face‐to‐Face Arene–Arene Interactions in the Solid State and in Solution

An atropisomeric molecular balance was developed to study face‐to‐face arene–arene interactions. The balance has a large central 1,4,5,8‐naphthalene diimide surface that forms intramolecular arene–arene interactions with two pendent arms. The balance adopts distinct syn and anti isomers with varying numbers of intramolecular interactions. Thus, the strength of the arene–arene interaction could be quantitatively measured by NMR spectroscopy from the anti/syn ratios. The size of the arene arms was easily varied, which allowed examination of the relationship between arene size and strength of the interaction. A nonlinear size dependence was observed in solution with larger arene arms having a disproportionately stronger arene–arene interaction. The intramolecular arene–arene interactions were also characterized in the solid state by X‐ray crystallography. These studies were facilitated by the kinetic stability of the syn and anti isomers at room temperature due to the high isomerization barrier (ΔG=27.0 kcal mol^?1). Thus, the anti isomer could be selectively isolated and crystallized in its folded conformation. The X‐ray structures confirmed that the anti isomers formed two strong intramolecular arene–arene interactions with face‐to‐face geometries. The solid‐state structure analysis also reveals that the rigid framework may contribute to the observed nonlinear size trend. The acetate linker is slightly too long, which selectively destabilizes the balances with smaller arene arms. The larger arene arms are able to compensate for the longer linker and form effective intramolecular arene–arene interactions.     

A study of the formation of silica-supported mixed magnesium-manganese spinel oxides from multicomponent gels

The effects of thermal treatment on composite materials prepared by the gelation of sols comprising large concentrations of metal oxide precursor salts have been investigated, in order to determine the compositional and thermal requirements for forming spinel magnesium manganates in such systems. The preparative technique has been found to give rise to derived gel materials in which the metal oxide phase, in the form of regular spherical particles, is dispersed throughout a continuous silica matrix. Silica-supported mixed magnesium and manganese spinel oxide phases were obtained for systems comprising at least 30 wt% metal nitrate after heating to temperatures between 700 and 850°C, but not without concomitant formation of Mn₂O₃ and modification of the silica network by magnesium.     

Synthesis of mesocyclic and macrocyclic polythioethers using the cesium dithiolate technique

The mesocyclic trithioethers, 1,4,7-trithiacyclodecane, 1,4,7-trithiacycloundecane, 1,4,8-trithiacycloundecane, and 1,5,9-trithiacyclododecane; the mesocyclic trithioether ketones, 1,4,7-trithiacyclodecan-9-one; 1,4,8-trithiacycloundecan-6-one, and 1,5,9-trithiacyclododecan-3-one; and the mesocyclic trithioether alcohols, 1,4,7-trithiacyclodecan-9-ol, 1,4,8-trithiacycloundecan-6-ol, and 1,5,9-trithiacyclododecan-3-ol, have been synthesized using the cesium dithiolate technique. In some cases, the corresponding macrocyclic hexathioether was isolated from the reaction mixture in addition to the mesocyclic trithioether; 1,4,7,11,14,17-hexathiacycloeicosane, 1,4,7,11,14,17-hexathiacycloeicosan-9,19-dione, 1,4,7,12,15,18-hexathiacyclodocosane, and 1,5,9,13,17,21-hexathiacyclotetracosane. Single-crystal X-ray structures have been determined for 1,5,9-trithiacyclododecan-3-ol and 1,4,7,12,15,18-hexathiacyclodocosane. For 1,5,9-trithiacyclododecane-3-ol, the compound crystallizes in the monoclinic space group, C2/c, with a = 10.5926( 9 ) Å, b = 15.582(2) Å, c = 13.6015(8) Å, β = 98.186(6)⁰, Z = 8, and R = 0.038. The macrocycle, 1,4,7,12,15,18-hexathiacyclodocosane, crystallizes in the orthorhombic space group, Pbca, with a = 21.406(5) Å, b = 9.810(2) Å, c = 10.225(2) Å, Z = 4, and R = 0.020.