The carbonyl-carbonyl coupling route to penems : a stepwise analysis

Preparation and reactivity of novel azetidinyl(phosphoranylidene)acetates implicated in penem synthesis is discussed     

Multilevel parametrization for aerodynamical optimization of 3D shapes

We introduce and discuss a combination of methods and options that aim at the aerodynamical optimization of a flow around an arbitrary aircraft shape. The flow is governed by the Euler equations, discretized by a mixed element-volume method on a fixed unstructured tetrahedrization. The shape parametrization relies on the skin of the above mesh through a hierarchical representation. Descent-type and one-shot algorithms are devised and adapted to the solution of a few model problems.     

Inclusiveπ° production in 360 GeVpp interactions using the european hybrid spectrometer

The intermediate and forward gamma detectors of EHS are used to reconstructπ°'s produced by 360 GeV/cpp interactions in the Rapid Cycling Bubble Chamber (RCBC). Using thepp forwardbackward symmetry, the inclusiveπ° production cross section is obtainedσ _π°=(132±11) mb. The averageπ° multiplicity is determined as a function of the charged particle multiplicity. The (1?x) dependence is given for differentp _T regions.     

Mössbauer spectroscopic and SEM study of Campanian and Terra sigillata pottery from Spain

A combination of Mössbauer spectroscopy (CEMS and transmission) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX) was employed to study the differences between coat and body in Campanian and Terra Sigillata wares. Conclusions about type of clay, origin of colour, and fabric and firing technology are established.     

Über eine Modifikation der kolorimetrischen Bestimmung von Guanidingruppen mit dem Nitroprussiatreagens

Zusammenfassung Die Guanidingruppen in der Substanz P₇ und in Arginin lassen sich mit Nitroprussiat, Cyanoferrat(III) und Natronlauge bestimmen. Die Verwendung eines Lösungsmittelgemisches aus Isopropanol und Wasser verhindert die Bildung unlöslicher Niederschläge und erhöht in beträchtlichem Maß die Farbintensität und damit die Empfindlichkeit der Methode.

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A modification of the colorimetric determination of guanidine groups with the nitroprusside reagent

Summary The guanidine groups in the substance P₇ (dichlorohydrate of 2,4-diguanidino-phenyl-lauryl ester monohydrate) and in arginine may be determined by means of nitroprussiate, cyanoferrate(III) and caustic soda solution. The employment of a solvent mixture consisting of isopropanol and water prevents the formation of insoluble precipitates and enhances to a high degree the color intensity and hence the sensitivity of the method.

     

Synthesis and Mesomorphic Properties of 2,6-Disubstituted Tetralins

Synthesis and mesomorphic behavior of nine members of each of the two classes of 6-phenyl- and 2-phenyltetralins and five members of the 2-trans-cyclohexyltetralins are reported. The synthesis of one member of each class is described in detail. Besides the target compounds, more than twenty intermediates showed liquid crystalline properties; their transition temperatures are recorded (see Tables 1-6).