29421-92-9Relevant articles and documents
Synthesis of Trisubstituted Thiophenes via a Halogen Dance Reaction at 2-Bromo-5-methylthiophene
Froehlich,Hametner,Kalt
, p. 325 - 330 (1996)
A new example of a selective halogen dance reaction was observed upon lithiation of 2-bromo-5-methylthiophene with LDA under appropriate reaction conditions. A series of 2-substituted 3-bromo-5-methylthiophenes was prepared by reacting the thus selectively generated intermediate 3-bromo-2-lithio-5-methylthiophene with various electrophiles to study scope and limitations of the reaction.
The catalytic behavior of heterocenes activated by TIBA and MMAO under a low Al/Zr ratios in 1-octene polymerization
Nifant'ev, Ilya E.,Vinogradov, Alexander A.,Vinogradov, Alexey A.,Churakov, Andrei V.,Bagrov, Vladimir V.,Kashulin, Igor A.,Roznyatovsky, Vitaly A.,Grishin, Yury K.,Ivchenko, Pavel V.
, p. 12 - 24 (2019/01/03)
A series of SiMe2-bridged ansa-zirconocenes LZrCl2 derived from heterocyclic ligands such as cyclopenta[1,2-b:4,3-b’]dithiophene, 5,6-dihydroindeno[2,1-b]indole and 5,10-dihydroindeno[1,2-b]indole, called “heterocenes” were synthesized and characterized by NMR spectroscopy and by X-ray diffraction analysis. These complexes were activated by triisobutylaluminium (TIBA) at AlTIBA/Zr ratio ～75 and then by MMАO-12 at AlMAO/Zr ratio ～10, and were studied in the polymerization of 1-octene in the absence or presence of molecular hydrogen. In the absence of molecular hydrogen, derivatives of cyclopenta[1,2-b:4,3-b’]dithiophene and dihydroindeno[2,1-b]indole demonstrated high catalytic activity, while dihydroindeno[1,2-b]indole complexes catalyzed slow polymerization with the formation of ultrahigh molecular weight poly(1-octene)s. In the presence of molecular hydrogen, derivatives of dihydroindeno[1,2-b]indole showed an order of magnitude increase in the catalytic activity. β-Hydride elimination, β-hexyl elimination and Zr-Al transfer were detected as the main chain release mechanisms depending on the nature of the ligand used. A novel chain termination with selective formation of –C(Me)=CHCH2– unsaturations was detected. It was found that heterocenes maintained a high catalytic activity up to 120 °C. Due to their high thermal stability and good hydrogen response, heterocenes are promising catalysts for the oligomerization and hydrooligomerization of α-olefins in the production of high-quality motor oil base stocks.
SYNTHESIS OF CYCLOPENTADIENEDITHIOPHENE DERIVATIVES
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Page/Page column 11, (2008/06/13)
A process for preparing cyclopentadiene derivatives having formula (I) wherein T1 is selected from the group consisting of oxygen (O), or sulphur (S); R1, R2, R3 an d R4, are hydrogen atoms, or hydrocarbon radicals; comprising the following steps: a) reacting a compound of formula (II) with a compound of formula (III) in the presence of a palladium or nickel based catalyst and a base; b) contacting the obtained compound with a carbonylating system; and c) treating the product obtained in step b) with a reducing agent.
