Christian V. Stevens

Bio: Christian V. Stevens is an academic researcher from Ghent University. The author has contributed to research in topics: Ionic liquid & Bicyclic molecule. The author has an hindex of 45, co-authored 467 publications receiving 11742 citations. Previous affiliations of Christian V. Stevens include Katholieke Universiteit Leuven & University of Minnesota.

Synthesis of 1-substituted epibatidine analogues and their in vitro and in vivo evaluation as α4β2nicotinic acetylcholine receptor ligands

Abstract: The highly potent natural alkaloid epibatidine remains a source of inspiration in the search for new analgesic drugs. In this paper, we describe an expansion of our previously reported synthesis of epibatidine analogues, and five synthetic alkaloids characterized by a symmetric, 1-substituted 7-azabicyclo[2.2.1]heptane skeleton, were evaluated for their biological activity. Two of these are binding selectively to the α4β2 subtype of the nicotinic acetylcholine receptor. Their Ki values were determined to be 40 and 290 nM. After a favourable evaluation of these compounds' cytotoxicity and metabolic stability, they were submitted to a rat tail flick test. The compounds did not show antinociceptive effects, which may be caused by a combination of insufficient potency and poor brain penetration.

Microreactor Technology as an Efficient Tool for Multicomponent Reactions

Abstract: Multicomponent reactions are an important tool in organic synthesis as they often allow the circumvention of multistep procedures by combining three or more molecules into one structure in a single step. An additional asset of the approach is the significant increase of the combinatorial possibilities, since a modification of the final product is easily accomplished by implementing minor changes in the reaction setup; this obviously allows considerable savings in time and resources. These advantages are of particular interest in pharmaceutical research for the construction of libraries. In order to increase the sustainability of chemical processes, the field is intensively explored, and novel reactions are frequently reported. Microreactor technology also offers a contemporary way of conducting chemical reactions in a more sustainable fashion due to the miniaturization and increased safety, and also in a technically improved manner due to intensified process efficiency. This relatively new technology is implemented in novel and improved applications and is getting more and more used in chemical research. The combination of the benefits from the two approaches clearly presents an attractive reaction design, and this chapter presents an overview of the reported examples in which the microreactor technology and the multicomponent approach are combined, usually with dramatically improved results compared to those previously reported.

Flow chemistry of main group and transition metal complexes

Abstract: The attractive heat and mass transfer properties of flow chemistry apparatus, combined with a small reactor volume allow for much safer operating conditions as well as a superior selectivity compared to standard batch reactions. The possibility to handle short-lived species led to the introduction of several new concepts such as ‘flash chemistry’, ‘space integration’, and ‘protecting group free flow synthesis’. Recently, the continuous flow synthesis of metal-NHC (NHC, N-heterocyclic carbene) complexes was reported, taking advantage of the fundamental mechanistic understanding along the reaction sequence leading to the metal-NHC bond formation using the weak base route. In addition to the synthesis of transition metal complexes, their use as efficient catalysts for various continuous flow organic transformations is well documented. Continuous flow reactors have earned their place as an important technology in organic synthesis, receiving increased interest in the past decade. The favorable heat and mass transfer capabilities, combined with the ease of scale-up, have not only made it a safer option in many cases, but often the only option when dealing with highly reactive, short-lived intermediates. In this review, an overview is given of the most recent advances made in the flow synthesis of organometallic compounds. This includes both main group and transition metal applications. Continuous flow reactors have earned their place as an important technology in organic synthesis, receiving increased interest in the past decade. The favorable heat and mass transfer capabilities, combined with the ease of scale-up, have not only made it a safer option in many cases, but often the only option when dealing with highly reactive, short-lived intermediates. In this review, an overview is given of the most recent advances made in the flow synthesis of organometallic compounds. This includes both main group and transition metal applications. the typical conditions used for organic reactions involving an alkyl halide and a carbonyl group in the presence of s- or p-block metals without isolating the organometallic intermediate. Therefore, the secondary/tertiary alcohols are produced in a one-pot reaction setup. a field of chemical synthesis where extremely fast reactions are conducted in a highly controlled manner to produce desired compounds with high selectivity. Fast heat and mass transfer derived from large surface-to-volume ratios of microreactors enable extremely fast and exothermic reactions to be conducted in a controlled way. reaction in which a halogen substituent moves to a new position on an aromatic ring system. when a sequence of reactions is conducted in a flow mode by adding components one at a time at different locations along the tubular reactor.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Production of first and second generation biofuels: A comprehensive review

Abstract: Sustainable economic and industrial growth requires safe, sustainable resources of energy. For the future re-arrangement of a sustainable economy to biological raw materials, completely new approaches in research and development, production, and economy are necessary. The ‘first-generation’ biofuels appear unsustainable because of the potential stress that their production places on food commodities. For organic chemicals and materials these needs to follow a biorefinery model under environmentally sustainable conditions. Where these operate at present, their product range is largely limited to simple materials (i.e. cellulose, ethanol, and biofuels). Second generation biorefineries need to build on the need for sustainable chemical products through modern and proven green chemical technologies such as bioprocessing including pyrolysis, Fisher Tropsch, and other catalytic processes in order to make more complex molecules and materials on which a future sustainable society will be based. This review focus on cost effective technologies and the processes to convert biomass into useful liquid biofuels and bioproducts, with particular focus on some biorefinery concepts based on different feedstocks aiming at the integral utilization of these feedstocks for the production of value added chemicals.

Chitosan chemistry and pharmaceutical perspectives.

Abstract: Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S. A. S. Nagar,Mohali, Punjab-160 062, India, Institute of Biochemistry, Faculty of Medicine, Polytechnic University, Via Ranieri 67, IT-60100 Ancona, Italy,Green Biotechnology Research Group, The Special Division for Human Life Technology, National Institute of Advanced Industrial Science andTechnology, 1-8-31 Midorigaoka, Ikeda, Osaka-563-8577, Japan, and Department of Medicinal Chemistry & Natural Products,The Hebrew University of Jerusalem, School of Pharmacy-Faculty of Medicine, Jerusalem 91120, IsraelReceived March 2, 2004