Intramolecular Alkylation of Aromatic Compounds XXXVI [1]. Stereoselective Synthesis of C/D- cis -Configured Ergolines

 The stereoselective synthesis of cis-ergoline is presented. Starting from rac-N-benzoyl tryptophan methyl ester, the key compound indolinylmethylpyridin-3-one was prepared via a seven-step reaction in good yield. Since its cyclization to the desired ergolinone failed, the key compound was reduced to yield the two diastereomeric pyridin-3-ols; only one of them cyclized in trifluoromethanesulfonic acid, affording cis-ergoline. Catalytic hydrogenation of the latter gave N,N′-dimethyldihydroergoline, the X-ray crystallography of which revealed both the correct structure and identical relative configurations at C-5a and C-6a (SS or RR). Hydroboration and subsequent perruthenate oxidation of the Δ⁹-ergoline provided access to the regioisomeric ergolinols and ergolinones.     

Aufbau und Schmelzverhalten von Nickel-Kupfer-Bor und Nickel-Kupfer-Silicium Legierungen

Within the group of boride and suicide containing hard alloys, those based on copper have recently found increasing interest as wear-resisting stratification and high-temperature structural materials. For the development of the best alloy, the phase conditions in the systems nickel-copper-boron and nickel-copper-silicon were elucidated from the isothermal profiles at 700°. Melting behaviours (important from a practical point of view) in the area of low metalloid contents are presented in the cases of (Ni-Cu-B) mixed crystals, Ni₃B alloy, as well as Ni-Cu-10 atomic % B and Ni-Cu-10 atomic % Si.     

K3[MO4][MO3N] (M=Tc,Re) – Nitridotrioxidorhenate and -technetate from Highly Alkaline Media

The reactions of ammonium perrhenate and pertechnetate in highly alkaline medium led to the isotypic mixed anionic nitridotrioxidorhenate and -technetate K ₃[MO₄][MO₃N] (M= Tc, Re). Both compounds occur as colorless crystals, which were investigated by single crystal X-ray diffraction. Furthermore, K₃[ReO₄][ReO₃N] has been studied by means of X-ray photoelectron spectroscopy to determine the oxidation state of rhenium. The obtained results have been complemented by magnetic measurements. IR and Raman spectroscopy indicated the presence of Re−O as well as Re−N bonds.     

The Supramolecular Structural Chemistry of Pentafluorosulfanyl and Tetrafluorosulfanylene Compounds

The analysis of crystal structures of SF₅- or SF₄-containing molecules revealed that these groups are often surrounded by hydrogen or other fluorine atoms. Even though fluorine prefers F⋅⋅⋅H over F⋅⋅⋅F contacts, the latter appeared to be important in many compounds. In a significant number of datasets, the closest F⋅⋅⋅F contacts are below 95 % of the van der Waals distance of two F atoms. Moreover, a number of repeating structural motifs formed by contacts between SF₅ groups was identified, including different supramolecular dimers and infinite chains. Among SF₄-containing molecules, the study focused on SF₄Cl compounds, including the first solid-state structure analyses of these reactive species. Additionally, electrostatic potential surfaces of a series of Ph-SF₅ derivatives were calculated, pointing out the substituent influence on the ability of F⋅⋅⋅X contact formation (X=F or other electronegative atom). Interaction energies were calculated for different dimeric arrangements of Ph-SF₅, which were extracted from experimental crystal structure determinations.     

Acceleration of absolute negative mobility

Recently, the counter intuitive migration phenomenon of absolute negative mobility (ANM) has been demonstrated to occur for colloidal particles in a suitably arranged post array within a microfluidic device [1]. This effect is based on the interplay of Brownian motion, nonlinear dynamics induced through microstructuring, and nonequilibrium driving, and results in a particle movement opposite to an applied static force. Simultaneously, the migration of a different particle species along the direction of the static force is possible [19], thus providing a new tool for particle sorting in microfluidic device format. The so far demonstrated maximum velocities for micrometer-sized spheres are slow, i. e., in the order of 10 nm per second. Here, we investigate numerically, how maximum ANM velocities can be significantly accelerated by a careful adjustment of the post size and shape. Based on this numerical analysis, a post design is developed and tested in a microfluidic device made of PDMS. The experiment reveals an order of magnitude increase in velocity.     

Accurate response by postponement

Accurate response and postponement are two strategies for a firm to deal with demand uncertainty and better match supply with demand. Under accurate response, reactive capacity could be used for customized make-to-order (MTO) production according to customer demands. On the other hand, using postponement a firm could perform the non-postponed activities speculatively and use reactive capacity only to customize the final product thereby enhancing the profitability of accurate response. Surprisingly existing research in the areas of accurate response and postponement does not address this potential. In this paper we aim to fill this gap by proposing a stylized model for accurate response by postponement.     

Studying the interdependence of contractual and operational flexibilities in the market of specialty chemicals

This paper focuses on the market of specialty chemicals and deals with the joint investigation and valuation of contractual and operational flexibilities from a manufacturers’ point of view. In this market, customized services related to research, development and manufacturing of chemicals, intermediates and active pharmaceutical ingredients are offered to a small number of customers. Traditionally, customers are granted a large degree of freedom with respect to demand quantity and time exposing the manufacturer to high uncertainty and financial risk. Using a model-based approach we quantify the effect of this contractual flexibility and relate it to the manufacturing flexibility concerning capacity allocation. Through the valuation of these flexibilities we provide first insights for the manufacturer on which customer requests to accept, how to set up the associated contracts with the customers and how to allocate capacity for a given portfolio of products.