Reversal of Selectivity in Gold-Catalyzed Cyclizations of 3,3-Disubstituted 1,4-Diynes
摘要:
A general synthetic access to 3,3-disubstituted 1,4-diynes bearing a quaternary carbon center from acetylacetone was developed. The compounds were cyclized to the corresponding enol ethers by cationic gold complexes. The reactions occur in complete exo-selectivity in contrast to compounds incorporating an alkoxy substituent in the 3-position. A mechanistic rationale for this reversal of selectivity is provided.
Pyrazole compounds as anti-inflammatory and analgesic agents
申请人:——
公开号:US20040019045A1
公开(公告)日:2004-01-29
This invention provides a compound of the formula (I):
1
wherein:
R
1
represents a hydrogen atom, an alkyl group, etc.; R
2
represents a hydrogen atom, a halogen atom, etc.; R
3
represents an alkyl group, etc.; R
4
represents an aryl group, etc.;
A represents an aryl
1
, etc; B represents an alkylene etc.; X represents NH, etc.;
or a pharmaceutically acceptable ester of such compound, and pharmaceutically acceptable salts thereof.
These compounds are useful for the treatment of medical conditions mediated by prostaglandin such as pain, fever or inflammation, etc. This invention also provides a pharmaceutical composition comprising the above compound.
[EN] PROCESSES FOR PREPARING COMPLEXES COMPRISING RHODIUM(II) AND CARBOXYLATE LIGANDS<br/>[FR] PROCÉDÉS DE PRÉPARATION DE COMPLEXES COMPRENANT DU RHODIUM(II) ET DES LIGANDS CARBOXYLATE
申请人:STOCKHOLM UNIV HOLDING AB
公开号:WO2019025575A1
公开(公告)日:2019-02-07
There is provided herein a process for the preparation of a complex of formula (I): Rh(II)2 Xn, wherein X and n have meanings provided in the description, comprising the step of reacting: (a) a source of Rh(III); and (b) a source of X, wherein the reaction is performed in the presence of: (c) a suitable reducing agent, and wherein the reaction is performed under basic conditions.
Anion-Induced Enantioselective Cyclization of Diynamides to Pyrrolidines Catalyzed by Cationic Gold Complexes
作者:Asmaa Kamal Mourad、Juliane Leutzow、Constantin Czekelius
DOI:10.1002/anie.201205416
日期:2012.10.29
Only chiral anions do the job! Optically active goldcomplexes derived from substituted binol hydrogen phosphate catalyze the desymmetrizing cyclization of 1,4‐diynamides. This reaction provides access to synthetically useful, chiral methylene pyrrolidines with an all‐carbon‐substituted quaternary stereocenter.
OLEFIN POLYMERIZATION CATALYST, PROCESS FOR PRODUCING OLEFIN POLYMER, POLYPROPYLENE RESIN COMPOSITION AND ARTICLE COMPRISING THE SAME
申请人:SUMITOMO CHEMICAL COMPANY, LIMITED
公开号:US20130109789A1
公开(公告)日:2013-05-02
An olefin polymerization catalyst is obtained by bringing the following components (A), (B) and (C) into contact with one another:
(A) a solid catalyst component for olefin polymerization containing a titanium atom, a magnesium atom and a halogen atom;
(B) an organoaluminum compound; and
(C) a triether represented by formula (I).
An olefin polymerization solid catalyst can be provided having a sufficiently high polymerization activity and an ability to produce an olefin polymer with a low content of low-molecular weight components and amorphous components.
[EN] PROCESSES FOR PREPARING STERICALLY CONGESTED DICARBOXYLIC ACID LIGANDS AND PRODUCTS THEREOF<br/>[FR] PROCÉDÉS DE PRÉPARATION DE LIGANDS D'ACIDE DICARBOXYLIQUE ENCOMBRÉS STÉRIQUEMENT ET LEURS PRODUITS