The Dutch resolution variant of the classical resolution of racemates by formation of diastereomeric salts:Family behaviour in nucleation inhibition

The resolution of racemates through their diastereomeric salts can be positively affected by the addition of small amounts of suitable nucleation inhibitors. This discovery is a logical extension of “Dutch Resolution”, in which equimolar amounts of resolving agents that are members of the same family (i.e., structurally related) are used. We conducted a systematic search for nucleation inhibitors of the resolving agent 1-phenylethylamine. A wide range of amines that bear possible family resemblances to 1-phenylethylamine was investigated. It was found that (R)-1-phenylbutylamine is a good inhibitor of (R)-1-phenylethylamine. Results of turbidity measurements showed that, for the model case of mandelic acid resolution, the chief effect of this inhibitor was to widen the metastable zone for the more soluble diastereomer. This observation is in accordance with previous experience. Further scouting for possible family members revealed a wide variation in the effectiveness of inhibitors, dependent on their structure. By far the most effective inhibitors are bifunctional 1-phenylethylamine and/or 1-phenylbutylamine analogues. The effect of racemic inhibitors was found to approach that of enantiomerically pure inhibitors of the same absolute configuration of the 1-phenylethylamine used for resolution. The most effective inhibitors were tested for the resolution of a structural variety of racemates, and were shown to be broadly applicable.

Coordination as a service to enable agile business networks

This paper surveys the current organizational requirements of agile business networks and then studies how emerging ICT are addressing the needs. The paper concludes that while several requirements are covered by novel cloud and Saas offerings, several requirements related to service coordination, collaboration, risk management and relation management are not properly addressed by ICT offerings yet. The paper proposes coordination as a service (CAAS) to fill this gap and outlines the key characteristics of CAAS

Dynamic mechanical properties of polystyrene/low density polyethylene blends

The loss and shear moduli of polystyrene [9003-53-6]-low-d. polyethylene [9002-88-4] blends, some addnl. contg. ethylene-styrene block copolymer (I) [25068-12-6] were examd. at -160 to +100 Deg. Anomalies in the low-temp. shear moduli are due to nonadhesion between the components. Only very small amts. of I are required to ensure the adhesion between the polyethylene and polystyrene phases. The polyethylene and I can be treated as one phase. In some cases the presence of I causes formation of a continuous network throughout the polystyrene matrix, as shown by the low shear moduli of these blends. Phase reversal of polyethylene-polystyrene blends causes an increase in the loss modulus at 40 Deg, which is attributed to an increased friction caused by phase entanglements. This increase is more pronounced if an excess of polyethylene is presen

Accurate quantitation of pentaerythritol tetranitrate and its degradation products using liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry

After an explosion of pentaerythritol tetranitrate (PETN), its degradation products pentaerythritol trinitrate (PETriN), dinitrate (PEDiN) and mononitrate (PEMN) were detected using liquid chromatography-atmospheric-pressure chemical-ionization-mass spectrometry (LC-APCI-MS). Discrimination between post-explosion and naturally degraded PETN could be achieved based on the relative amounts of the degradation products. This information can be used as evidence when investigating a possible relationship between a suspect and a post-explosion crime scene. The present work focuses on accurate quantitation of PETN and its degradation products, using PETriN, PEDiN and PEMN standards specifically synthesized for this purpose. With the use of these standards, the ionization behavior of these compounds was studied, and a quantitative method was developed. Quantitation of PETN and trace levels of its degradation products was shown to be possible with accuracy between 85.7% and 103.7% and a precision ranging from 1.3% to 11.5%. The custom-made standards resulted in a more robust and reliable method to discriminate between post-explosion and naturally-degraded PETN. © 2014 Elsevier B.V

Diastereoselective Addition of Allylzinc Bromide to Imines Derived from (R)-Phenylglycine Amide

The highly diastereoselective addition of allylzinc bromide to imines derived from (R)-phenylglycine amide is reported. Homoallylamines with high enantiomeric purity are obtained from the adducts in three steps on removal of the chiral auxiliary by means of a nonreductive protocol. Removal of the auxiliary by hydrogenation leads to the saturated amines, also in high enantiomeric purity.