Electronic Influence of the Thienyl Sulfur Atom on the Oligomerization of Ethylene by Cobalt(II) 6-(Thienyl)-2-(imino)pyridine Catalysis
摘要:
The position of the sulfur atom in the thienyl group of 6-(thienyl)-2-(imino)pyridine ligands strongly affects the catalytic activity of the corresponding tetrahedral high-spin dihalide Co-II complexes in the oligomerization of ethylene to alpha-olefins upon activation with methylaluminoxane (MAO). Complexes with the sulfur atom in the 3-position of the thienyl ring catalyze the selective conversion of ethylene to 1-butene, while catalysts containing thien-2-yl groups give C-4-C-14 alpha-olefins. In situ EPR experiments showed the occurrence of a spin state changeover with the formation of low-spin Co-II species upon activation of the catalyst precursors by MAO. DFT calculations suggest that only thien-2-yl rings allow for the coordination of the sulfur atom to the cobalt center in the MAO-activated systems.
An application of the PIFA-mediated [PIFA: phenyliodine(III) bis(trifluoroacetate)] biarylcoupling reaction is presented and extended to the formation of heterobiaryl connections. A preliminary study of the scope and limitations of this procedure was carried out in the synthesis of phenanthroids 11 from a series of phenethyl-substituted heterocycles 10. It was observed that in some cases a competitive
Mannich reactiohs of aryltrialkylstannunes in aprotic solvents
作者:Mark S. Cooper、Robin A. Fairhurst、Harry Heaney、George Papageorgiou、Robert F. Wilkins
DOI:10.1016/0040-4020(89)80024-9
日期:1989.1
Aryltributyl- and aryltrimethyl-stannanes react with a range of N,N-dialkylmethylene-imonium salts to afford N,N-dialkylaminomethyl derivatives in good yields. The method can be used to obtain regloisomers that are not available using classical procedures. “In situ” reactions can also be carried out using alkoxydialkylaminomethanes (aminol ethers) and bis(dialkylamino)methanes (aminals) together with
Azulene derivatives bearing heteroaryl groups in the 1,3-positions were synthesized, and the color and spectral changes occurring upon the addition of metal ions were examined. Of the compounds tested, title compound 4 appears to exhibit the most selective chromogenic behavior toward Hg 2+ ion.
Benzothiazole derivatives with activity as adenosine receptor ligands
申请人:——
公开号:US20030176695A1
公开(公告)日:2003-09-18
The present invention relates to substituted benzothiazole derivitives and to their pharmaceutically acceptable salts useful for the treatment of diseases related to the adenosine receptor.
本发明涉及替代苯并噻唑衍生物及其药学上可接受的盐,用于治疗与腺苷受体相关的疾病。
Benzothiazole derivatives with actitvity as adenosine receptor ligands
申请人:Alanine Alexander
公开号:US20050026906A1
公开(公告)日:2005-02-03
The present invention relates to substituted benzothiazole derivatives and to their pharmaceutically acceptable salts useful for the treatment of diseases related to the adenosine receptor.