An efficient approach to the stereocontrolled synthesis of enamides

[reaction: see text] A fast, flexible, and efficient approach for the stereocontrolled synthesis of enamides has been developed starting from lactams and amides through the use of imides. This new approach provides access to enamide systems not easily or currently accessible through other approaches.     

Development of a UHPLC method for the assessment of the metabolic profile of cinitapride

An ultra high-performance liquid chromatographic method was developed to study the cinitapride metabolism. Metabolites were generated from the incubation of cinitapride with human liver microsomes. Cinitapride and its metabolites were separated by reversed-phase mode using a formate aqueous solution (pH 6.5) and acetonitrile as the components of the mobile phase. Chromatographic conditions, including the establishment of an elution gradient, were optimized for obtaining the maximum number of resolved components in the minimum analysis time. Experimental design and multicriteria decision-making strategies were utilized to facilitate the optimization of chromatographic conditions. Figures of merit were evaluated with cinitapride standards and incubated samples. Limits of detection are about 0.03 μmol/L, and repeatabilities are better than 0.06% for retention times and better than 3.5% for concentrations. The method was applied to characterize the in vitro cinitapride metabolism with human liver microsomes.     

DFT study of the gas‐phase thermal decomposition kinetics of 2‐ethoxypyridine into 2‐pyridone

The mechanism of the gas‐phase elimination kinetics of 2‐ethoxypyridine has been studied through the electronic structure calculations using density functional methods: B3LYP/6‐31G(d,p), B3LYP/6‐31++G(d,p), B3PW91/6‐31G(d,p), B3PW91/6‐31++G(d,p), MPW1PW91/6‐31G(d,p), MPW1PW91/6‐31++G(d,p), PBEPBE/6‐31G(d,p), PBEPBE/6‐31++G(d,p), PBE1PBE1/6‐31G(d,p), and PBE1PBE1/6‐31++G(d,p). The elimination reaction of 2‐ethoxypyridine occurs through a six‐centered transition state geometry involving the pyridine nitrogen, the substituted carbon of the aromatic ring, the ethoxy oxygen, two carbons of the ethoxy group, and a hydrogen atom, which migrates from the ethoxy group to the nitrogen to give 2‐pyridone and ethylene. The reaction mechanism appears to occur with the participation of π‐electrons, similar to alkyl vinyl ether elimination reaction, with simultaneous ethylene formation and hydrogen migration to the pyridine nitrogen producing 2‐pyridone. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Adsorption of endotoxins on Ca2+ iminodiacetic acid by metal ion affinity chromatography

Endotoxins (also known as lipopolysaccharides (LPS)) are undesirable by products of recombinant proteins, purified from Escherichia coli. LPS can be considered stable under a wide range of temperature and pH, making their removal one of the most difficult tasks in downstream processes during protein purification. The inherent toxicity of LPS makes their removal an important step for the application of these proteins in several biological assays and for a safe parenteral administration. Immobilized metal affinity chromatography (IMAC) enables the affinity interactions between the metal ions (immobilized on the support through the chelating compound) and the target molecules, thus enabling high efficiency separation of the target molecules from other components present in a mixture. Affinity chromatography is applied with Ca2+ iminodiacetic acid (IDA) to remove most of the LPS contaminants from the end product (more than 90%). In this study, the adsorption of LPS on an IDA-Ca2+was investigated. The adsorption Freundlich isotherm of LPS-IDA-Ca2+provides a theoretical basis for LPS removal. It was found that LPS is bound mainly by interactions between the phosphate group in LPS and Ca2+ligands on the beads. The factors such as pH (4.0 or 5.5) and ionic strength (1.0 mol/L) are essential to obtain effective removal of LPS for contaminant levels between endotoxin’ concentration values less than 100 EU/mL and 100000 EU/mL. This new protocol represents a substantial advantage in time, effort, and production costs.     

A comparative study of temperature dependence of induction time and oscillatory frequency in polymer‐immobilized and free catalyst Belousov‐Zhabotinsky reactions

Environment‐sensitive poly(N‐isopropylacrylamide) (PNIPAM) microgel particles with covalently bonded ruthenium(4‐vinyl‐4′‐methyl‐2,2′‐bipyridine) bis (2,2′‐bipyridine) [Ru(vmbipy)(bipy)₂] display periodic size changes when placed in Belousov‐Zhabotinsky (BZ) reaction substrates. The temperature dependency of the induction time and oscillatory frequency of the BZ reaction in this polymer‐immobilized catalyst system were compared to the bulk BZ reaction with the catalyst in the solution phase. Prolonged induction times are observed for the immobilized catalyst, compared with free catalyst, while little difference is observed on the oscillation frequency. The Arrhenius frequency factor calculated using the induction time for the immobilized catalyst BZ reaction is about seven times smaller than that for the free catalyst Ru(bipy) case. On the other hand, the Arrhenius frequency factors calculated using the oscillatory frequency are almost the same, showing similar reaction kinetics during the BZ oscillations. The tunability of the induction time using a polymer matrix, as we observed here, while maintaining similar oscillatory behavior, should provide a new dimension to control the self‐assembling of BZ active particles. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 847–854, 2009     

Rethinking Statistics Teaching for Operational Research

Statistics is a standard component of most Management Science or Operational Research courses. This paper argues that the teaching of Statistics in such courses should emphasise the philosophical aspects of the discipline, should concentrate on developing concepts rather than techniques, should stimulate ideas and should allow each student to reach his/her own level in the discipline. A postgraduate course structured in this way is described in detail.     

Diterpenes from teucrium capitatum L. X-ray crystal and molecular structure of lolin

Lolin, a new diterpene of the $\text{ent}$-clerodane type has been isolated from Teucrium capitatum. The X-ray structure and spectroscopic data of lolin is given.     

Aldermoor School: The Operational Researcher on the Side of the Community

There are well-established legal procedures that have to be followed when a school is proposed for closure in the UK. A reasoned case has to be made for the closure of the school and consultation with interested parties has to take place. This is an ideal opportunity for Community Operational Research to get involved. However, school closures are the result of a political programme, and a response which is based on analysis rather than on political pressure may simply be ignored, no matter how convincing the argument. This paper discusses the role of the Community Operational Researcher as a source of expert advice in a complicated issue. It is argued that, in this particular case, OR analysis served only to expose the impotence of individuals when faced with arbitrary administrative decisions.     

On the Joint Determination of Efficiencies in a Data Envelopment Analysis Context

Beasley studied the multiproduct Decision Making Unit, and offered a model for the joint determination of efficiencies within a Data Envelopment Analysis context. He applied his model to evaluating the efficiency of teaching and research activities at universities. This paper explores the theoretical justifications for Beasley's approach by concentrating on the dual of his model.