Synthesis of Highly Substituted γ‐Butyrolactones by a Gold‐Catalyzed Cascade Reaction of Benzyl Esters

Easily accessible benzylic esters of 3‐butynoic acids in a gold‐catalyzed cyclization/rearrangement cascade reaction provided 3‐propargyl γ‐butyrolactones with the alkene and the carbonyl group not being conjugated. Crossover experiments showed that the formation of the new C?C bond is an intermolecular process. Initially propargylic–benzylic esters were used, but alkyl‐substituted benzylic esters worked equally well. In the case of the propargylic–benzylic products, a simple treatment of the products with aluminum oxide initiated a twofold tautomerization to the allenyl‐substituted γ‐butyrolactones with conjugation of the carbonyl group, the olefin, and the allene. The synthetic sequence can be conducted stepwise or as a one‐pot cascade reaction with similar yields. Even in the presence of the gold catalyst the new allene remains intact.     

Condensation of pyridoxal with the methyl ester of glycine

Condensation of pyridoxal with the methyl ester of glycine gave the aminocoumarin analog 3-amino-8-rnethyl-2-oxo-2H-pyrano[2,3-c]pyridine-5-methanol (III), and not the expected aldimine. The structure of the compound was deduced by independent synthesis and by comparing its NMR spectrum with that of 3-aminocoumarin. The new reaction provides routes for the synthesis of α⁴-pyridoxylideneglycine and α⁴-pyridoxyloxoacetic acid derivatives. It may also provide a model for irreversible inactivation of vitamin B₆ in biochemical systems.     

Heuristische Verfahren zur Tourenplanung bei der Hausmüllentsorgung in ländlichen Regionen

Zusammenfassung Tourenprobleme bei der Hausmüllsammlung lassen sich in die Reihe der Lieferplanprobleme einordnen. Zur Lösung praktischer Größenordnungen werden hier einfache heuristische Verfahren (Prioritätsregeln) vorgestellt, weniger um der Vielzahl heuristischer Verfahren weitere hinzuzufügen als vielmehr dem Praktiker einen vielversprechenden Weg beim Lösen seiner Probleme aufzuzeigen.

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Summary The discussed solid waste collection problem shows the properties of the so called truck dispatching problem. To solve problems for typical problem structure heuristic rules are pointed out in order to show the planner an efficient way of problem solving.

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Zusammenfassung dreier Vorträge im 4. planungstechnischen Seminar Tourenplanung bei der Abfallbeseitigung am Institut für Siedlungswasserwirtschaft der Universität Karlsruhe am 1.10.1976.     

Detection of norbolethone,an anabolic steroid never marketed,in athletes' urine

Norbolethone (13-ethyl-17-hydroxy-18,19-dinor-17alpha-pregn-4-en-3-one) is a 19-nor anabolic steroid first synthesized in 1966. During the 1960s it was administered to humans in efficacy studies concerned with short stature and underweight conditions. It has never been reported by doping control laboratories. Norbolethone was identified in two urine samples from one athlete by matching the mass spectra and chromatographic retention times with those of a reference standard. The samples also contained at least one likely metabolite. The samples were also unusual because the concentrations of endogenous steroids were exceptionally low. Since norbolethone is not known to be marketed by any pharmaceutical company, a clandestine source of norbolethone may exist.     

Synthesis and characterization of a magnetic semiconductor Na(2)RuO(4) containing one-dimensional chains of Ru(6+)

A new ternary ruthenium oxide Na(2)RuO(4) was prepared and shown to crystallize with a new structure type. Single crystal X-ray diffraction measurements reveal that Na(2)RuO(4) consists of RuO(4) chains made up of RuO(5) trigonal bipyramids by sharing axial corners. Na(2)RuO(4) is a magnetic semiconductor with a variable range hopping behavior, and its molar magnetic susceptibility chi(mol) has a broad maximum at approximately 74 K. The derivative d(chi(mol).T)/dT exhibits a peak at 37.7 K which has been confirmed by heat capacity measurement to be due to long-range antiferromagnetic ordering.     

Convergence of m-bonacci ‘golden ratios’

This paper proves that the ratios of consecutive terms of the m-bonacci sequence converge to a limit φ_m < 2 and, as m → ∞, these φ_m converge to 2. Further, it is shown that the generating functions for the m-bonacci sequences converge pointwise to the geometric series.     

Multi-functionality of fluorescent nanocrystals in glass ceramics

Thermal processing of as-made fluorozirconate glasses, which were additionally doped with rare-earth and chlorine ions, results in the formation of fluorescent nanocrystals therein. For medical applications, the glasses were doped with divalent europium ions as the fluorescent rare-earth ion, while trivalent neodymium was used to develop up-conversion systems. The samples were annealed up to 290 °C to initiate the growth of hexagonal or orthorhombic phase BaCl₂ nanocrystals therein. Upon annealing some of the rare-earth ions were incorporated into the BaCl₂ nanocrystals leading to enhanced fluorescence properties. The particle diameters were in the range of a few nanometers to several tens of nanometers.