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Synthetic methodology for the synthesis of heterocycles is of continuous and high interest with applications in materials, catalysis, and medicines. Multicomponent reactions are suitable tools to efficiently generate chemically diverse sets of heterocycles with sufficient structural complexity. Especially isocyanides have proven to be particularly versatile building blocks in these one‐pot processes. Due to their electronic structure, isocyanides are able to act sequentially or simultaneously as a nucleophile and an electrophile. Traditionally, isocyanides are therefore frequently used in multicomponent chemistry. In the recent literature, numerous reactions have been reported that involve formal cycloadditions of isocyanides with conjugated heterodienes. This Focus Review aims at mapping this reactivity and at providing insight into the relationship between the various reported reaction partners and the observed reactivity modes. 相似文献
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Kruithof A Ploeger ML Janssen E Helliwell M de Kanter FJ Ruijter E Orru RV 《Molecules (Basel, Switzerland)》2012,17(2):1675-1685
Non-fused 3,6-dihydro-2H-1,3-thiazine-2-thiones constitute a so far rather unexplored class of compounds, with the latest report dating back more than two decades. Thiazine-2-thiones contain an endocyclic dithiocarbamate group, which is often found in pesticides, in substrates for radical chemistry and in synthetic intermediates towards thioureas and amidines. We now report the multicomponent reaction (MCR) of in situ-generated 1-azadienes with carbon disulfide. With this reaction, a one-step protocol towards the potentially interesting 3,6-dihydro-2H-1,3-thiazine-2-thiones was established and a small library was synthesized. 相似文献
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J.S. Vrouwenvelder J.A.M. van Paassen J.M.C. van Agtmaal M.C.M. van Loosdrecht J.C. Kruithof 《Journal of membrane science》2009
The relation between biofouling and membrane flux in spiral wound nanofiltration and reverse osmosis membranes in drinking water stations with extensive pretreatment such as ultrafiltration has been studied. The flux – water volume flowing through the membrane per unit area and time – is not influencing the development of membrane biofouling. Irrespective whether a flux was applied or not, the feed spacer channel pressure drop and biofilm concentration increased in reverse osmosis and nanofiltration membranes in a monitor, test rigs, a pilot scale and a full-scale installation. Identical behavior with respect to biofouling and feed channel pressure drop development was observed in membrane elements in the same position in a nanofiltration installation operated with and without flux. Calculation of the ratio of diffusive and convective flux showed that the diffusive flux is considerably larger than the convective flux, supporting the observations that the convective flux due to permeate production is playing an insignificant role in biofouling. Since fouling occurred irrespective of the actual flux, the critical flux concept stating that “below a critical flux no fouling occurs” is not a suitable approach to control biofouling of spiral wound reverse osmosis and nanofiltration membranes. 相似文献
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Methyl-methine linkages of Novolac, a commercially available t-butylphenol acetylene condensed (TBPA) resin, have been identified by recognition of pyrolysis pathways using pyrolysis-gas chromatography/mass spectrometry (Py-GC/mS) in vulcanized rubber. The diagnostic mass spectrum of t-butylphenol with methyl-methine linkages between phenolic rings was observed at m/z 192, corresponding to 4-t-butyl-2-ethyl-6-methylphenol. Other molecular ions were observed at m/z 178, 164, and 150 in the characteristic pyrolyzates. The ion at m/z 192 in the TBPA resin was observed to be characteristic for methyl-methine linkages between the phenolic groups, and the analytical pyrolysis-GC/mS method was thus able to identify the resin at low levels in vulcanized rubber. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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Lucy Rutten Dr. Birgit Wieczorek Jean‐Paul B. A. Mannie Cornelis A. Kruithof Dr. Harm P. Dijkstra Dr. Maarten R. Egmond Prof. Martin Lutz Dr. Robertus J. M. Klein Gebbink Prof. Piet Gros Prof. Gerard van Koten Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(17):4270-4280
Crystal‐clear structures : The first crystal structures of organometallic pincer–cutinase hybrids (see figure) provide insight into the 3D structural arrangement of both the protein and the organometallic pincer moiety, and reveal different binding modes for different pincers.
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Kruithof CA Casado MA Guillena G Egmond MR van der Kerk-van Hoof A Heck AJ Klein Gebbink RJ van Koten G 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(23):6869-6877
The work described herein presents a strategy for the regioselective introduction of organometallic complexes into the active site of the lipase cutinase. Nitrophenol phosphonate esters, well known for their lipase inhibitory activity, are used as anchor functionalities and were found to be ideal tools to develop a single-site-directed immobilization method. A small series of phosphonate esters, covalently attached to ECE "pincer"-type d8-metal complexes through a propyl tether (ECE=[C6H3(CH2E)(2)-2,6]-; E=NR2 or SR), were designed and synthesized. Cutinase was treated with these organometallic phosphonate esters and the new metal-complex/protein hybrids were identified as containing exactly one organometallic unit per protein. The organometallic proteins were purified by membrane dialysis and analyzed by ESI-mass spectrometry. The major advantages of this strategy are: 1) one transition metal can be introduced regioselectively and, hence, the metal environment can potentially be fine-tuned; 2) purification procedures are facile due to the use of pre-synthesized metal complexes; and, most importantly, 3) the covalent attachment of robust organometallic pincer complexes to an enzyme is achieved, which will prevent metal leaching from these hybrids. The approach presented herein can be regarded as a tool in the development of regio- and enantioselective catalyst as well as analytical probes for studying enzyme properties (e.g., structure) and, hence, is a "proof-of-principle design" study in enzyme chemistry. 相似文献
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H. W. Wilschut U. Dammalapati D. J. van der Hoek K. Jungmann W. Kruithof C. J. G. Onderwater B. Santra P. D. Shidling L. Willmann 《Pramana》2010,75(1):163-170
One of the greatest successes of the Standard Model of particle physics is the explanation of time-reversal violation (TRV)
in heavy mesons. It also implies that TRV is immeasurably small in normal nuclear matter. However, unifying models beyond
the Standard Model predict TRV to be within reach of measurement in nuclei and atoms, thus opening an important window to
search for new physics. We will discuss two complementary experiments sensitive to TRV: Correlations in the β-decay of 21Na and the search for an electric dipole moment (EDM) in radium. 相似文献
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