Ruthenium Carbene Complexes with N,N‘-Bis(mesityl)imidazol-2-ylidene Ligands: RCM Catalysts of Extended Scope
摘要:
The ruthenium carbene complexes 3a,b bearing imidazol-2-ylidene ligands constitute excellent precatalysts for ring-closing metathesis (RCM) reactions allowing the formation of tri- and tetrasubstituted cycloalkenes. They also apply to annulations that are beyond the scope of the standard Grubbs carbene 1 as well as to ring-closing reactions of acrylic acid derivatives even if the resulting alpha,beta-unsaturated lactones (or lactams) are tri- or tetrasubstituted. The reactivity of 3a was found to be highly dependent on the reaction medium: particularly high reaction rates are observed in toluene, although this solvent also leads to an increased tendency of the catalyst to isomerize the double bonds of the substrates.
Ruthenium Carbene Complexes with N,N‘-Bis(mesityl)imidazol-2-ylidene Ligands: RCM Catalysts of Extended Scope
摘要:
The ruthenium carbene complexes 3a,b bearing imidazol-2-ylidene ligands constitute excellent precatalysts for ring-closing metathesis (RCM) reactions allowing the formation of tri- and tetrasubstituted cycloalkenes. They also apply to annulations that are beyond the scope of the standard Grubbs carbene 1 as well as to ring-closing reactions of acrylic acid derivatives even if the resulting alpha,beta-unsaturated lactones (or lactams) are tri- or tetrasubstituted. The reactivity of 3a was found to be highly dependent on the reaction medium: particularly high reaction rates are observed in toluene, although this solvent also leads to an increased tendency of the catalyst to isomerize the double bonds of the substrates.
HYDROLYTICALLY STABLE RESINS FOR USE IN ANION-EXCHANGE CHROMATOGRAPHY
申请人:DIONEX CORPORATION
公开号:EP0964878B1
公开(公告)日:2007-09-12
EP0964878A4
申请人:——
公开号:EP0964878A4
公开(公告)日:2004-12-22
US5925253A
申请人:——
公开号:US5925253A
公开(公告)日:1999-07-20
US5936003A
申请人:——
公开号:US5936003A
公开(公告)日:1999-08-10
[EN] HYDROLYTICALLY STABLE RESINS FOR USE IN ANION-EXCHANGE CHROMATOGRAPHY<br/>[FR] RESINES HYDROLYTIQUEMENT STABLES POUR CHROMATOGRAPHIE PAR ECHANGE D'ANIONS
申请人:DIONEX CORPORATION
公开号:WO1998039367A1
公开(公告)日:1998-09-11
(EN) In accordance with the present invention, an improved anion-exchange chromatographic composition has been formed which comprises synthetic resin support particles and anion exchange compounds attached thereto, wherein the anion-exchange compounds comprise an internal reactive group, which may be an ester, ketone or amide group, and a terminal quaternary ammonium salt which functions as an anion-exchange site. The compositions of the present invention exhibit improved hydrolytic stability as compared to other known anion-exchange chromatographic compositions due to the presence of linkers which increase the number of atoms separating the internal reactive group form the nitrogen atom of the terminal ammonium anion-exchange site. Formed articles and methods employing the anion-exchange chromatographic composition are also provided.(FR) L'invention porte sur une composition chromatographique échangeuse d'ions améliorée comportant des particules-support de résine synthétique et des composés échangeurs d'anions leur étant liés. Lesdits composés échangeurs d'anions comprennent un groupe réactif interne pouvant être un groupe ester, cétone ou amide, et un sel terminal d'ammonium quaternaire à fonction de site échangeur d'anions. Ladite composition présente une stabilité hydrolytique améliorée par rapport aux autres compositions chromatographiques échangeuses d'ions connues en raison de la présence de liants qui augmentent le nombre des atomes séparant le groupe réactif interne des atomes d'azote du site terminal d'ammonium échangeur d'anions. L'invention porte également sur des articles et procédés utilisant la susdite composition.