Rapid assessment of organophosphorous/carbamate exposure in the bivalve mollusc Mytilus edulis using combined esterase activities as biomarkers
摘要:
Carboxylesterases in bivalve molluscs exhibit greater sensitivity to organophosphorous and carbamate pesticides than acetylcholinesterase and are present at higher levels. The aim, of the present study was to combine measurement of both acetylcholinesterase and carboxylesterase activities in the marine bivalve Mytilus edulis in order to detect the effects of pesticide exposure. Spectrophotometric assays in microtitreplate format were optimised for use with M. edulis haemolymph and tissue homogenate samples. This permitted the nature and distribution of the enzymes to be determined. One predominant pharmacological form of activity consistent in its patterns of activation and inhibition with acetylcholinesterase was identified in the haemolymph with an apparent K-m for acetylthiocholineiodide of 1.33 mM. Carboxylesterase activity in the tissues was characterised by its preferential hydrolysis of the substrate analogue phenylthioacetate. Concentration-dependent inhibition of both activities was demonstrated following in vitro incubation with diisopropylfluorophosphate (DFP), paraoxon and eserine in the range 0.1-3.0 mM. When M. edulis (n = 10) were exposed for 24 h to concentrations of eserine or paraoxon of 0.05-1.0 mM, the percentage inhibition of acetylcholinesterase was in each case greater than for carboxylesterase and reached statistical significance at lower concentrations. In all exposures, a proportion of carboxylesterase activity was present which remained resistant to inhibition by either organophosphorous or carbamate compounds. The ecotoxicological significance of these findings for the environmental monitoring of pesticide exposure is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
Route Development and Bulk Synthesis of CP-865,569
摘要:
The synthesis of zwitterionic CP-865,569 by three different synthetic routes is described. The first two routes differ in the method of introducing the sulfonic acid at the penultimate step: by sulfite displacement of a benzylic chloride and by oxidation of a benzylic thioacetate. The third route is a convergent route to the drug candidate. The synthesis strategy was primarily driven by the need to introduce the sulfonic acid functionality at the final stage of the synthesis due to the high water solubility and low organic solubility of the desired product.
Synthesis and characterization of isotopically labelled drugs
作者:Frans M. Kaspersen、Jan F. Vader、Carel W. Funke、Eric M. G. Sperling
DOI:10.1002/recl.19931120218
日期:——
The article describes approaches for the synthesis and analysis of isotopically (2H, 3H, 13C, 14C, 35S) labelleddrugs necessary for the development of a pharmacologically active compound into a registered drug.
Stereospecific displacement of sulfur from chiral centers. activation via thiaphosphonium salts.
作者:Grant A. Krafft、Thomas L. Siddall
DOI:10.1016/s0040-4039(00)94972-4
日期:1985.1
The first general method for direct displacement of sulfur from chiral carbon centers has been developed. Chiral mercaptans are readily converted to the corresponding thiaphosphonium salts by treatment with t-butyl hypochlorite and hexamethylphosphorous triamide. Metathesis with ammonium hexafluorophosphate provides stable, isolable, crystalline salts which undergo clean nucleophilic diplacement with
Subsite‐Specific Reactions of a Cyclotriveratrylene [4Fe‐4S] Cluster Complex
作者:Gino P. F. Van Strijdonck、Petrus T. J. H. Ten Have、Martinus C. Peiters、Johannes G. M. Van Der Lindenm、Jan J. Steggerda、Roeland J. M. Nolte
DOI:10.1002/cber.19971300819
日期:1997.8
out exclusively at the unique iron site of a subsite-differentiatedcyclotriveratrylene [4Fe-4S] cluster complex. The effect of a variety of thiolate, phenolate, bidentate, and bridging ligands on the redox potential of the subsite-differentiated [4Fe-4S] cluster complex is studied and compared with the effects of such ligands on an [Fe4S4C14]2- cluster. The redox potential can be modulated within
配体交换反应仅在亚位点差异化的环三富四烯[4Fe-4S]簇复合物的独特铁位点上进行。研究了各种硫醇盐,酚盐,二齿酸盐和桥联配体对亚位点分化的[4Fe-4S]簇络合物的氧化还原电势的影响,并将这些配体对[Fe 4 S 4 C 14 ] 2-群集。氧化还原电势可以在-1.60至-1.80 V的范围内进行调节(vs. Fc 0 / +)通过改变配体。引入电子释放取代基将氧化还原电势移至更多的负值,而吸电子取代基具有相反的作用。取代位点的数量与簇的还原电位之间存在线性关系。
Ethane-1,2-diaminium bis[(2R)-2-bromo-3-phenylpropanoate], processes for its preparation and its use
申请人:——
公开号:US20040010039A1
公开(公告)日:2004-01-15
The present invention relates to ethane-1,2-diaminium bis[(2R)-2-bromo-3-phenyl-propanoate], the preparation of ethane-1,2-diaminium bis[(2R)-2-bromo-3-phenyl-propanoate] from (2R)-2-bromo-3-phenylpropionic acid and ethylenediamine in 2-propanol, and the use of ethane-1,2-diaminium bis[(2R)-2-bromo-3-phenyl-propanoate] for the preparation of ACE/NEP inhibitors.
Polythiolactone‐Decorated Silica Particles: A Versatile Approach for Surface Functionalization, Catalysis and Encapsulation
作者:Dustin Werner Kurka、Maximilian Niehues、Sergej Kudruk、Volker Gerke、Bart Jan Ravoo
DOI:10.1002/chem.202100547
日期:2021.5.17
novo synthesis followed by surface functionalization leading to tailormade properties for a specific purpose. Here, the design of robust “precursor” polymer‐decorated silica nano‐ and microparticles is demonstrated, which allows for easy post‐modification by polymer embedded thiolactone chemistry. To obtain this organic‐inorganic hybrid material, silica particles (SiO2P) were functionalizedvia surface‐initiated