yttrium‐pillared silicotungstate dimer (see picture) catalyzes the cyanosilylation of structurally diverse ketones and aldehydes with trimethylsilyl cyanide (TMSCN). The reactions proceed selectively and afford the corresponding cyanohydrin trimethylsilyl ethers. The catalytic performance is significant, in particular for aldehydes, with a turnover number of 18 000 and a turnover frequency of 540 000 h−1
available MgO and anion exchange resins. This catalyst also acts as a heterogeneous catalyst for the epoxidation of electron-deficient olefins with hydrogen peroxide. Further, the catalyst/product(s) separation can be easily carried out by the simple filtration (or centrifugation) and the reaction is immediately stopped by the removal of the solid catalyst, suggesting that the nature of the observed
Trimethysilyl triflate in organic synthesis11Part 11 of this series. Part 10: S. Murata and R. Noyori, Tetrahedron Letters 2107 (1981).
作者:R. Noyori、S. Murata、M. Suzuki
DOI:10.1016/s0040-4020(01)93263-6
日期:——
Trimethylsilyl triflate is a powerful silylating agent for organic compounds and acts as a catalyst which accelerates a variety of nucleophilic reactions in aprotic media. The reactions proceed via one-center, electrophilic coordination of the silyl group to hetero functional groups and exhibit unique selectivities.
BENZAMIDE DERIVATIVES AS P2X7 RECEPTOR ANTAGONISTS
申请人:Hilpert Kurt
公开号:US20140073651A1
公开(公告)日:2014-03-13
The invention relates to benzamide derivatives of formula (I),
wherein R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, n and Y are as defined in the description, their preparation and their use as pharmaceutically active compounds.
calcination of the Sn–W hydroxide at 800 °C acts as an effective and reusable solid catalyst for CCbond‐formingreactions, such as the cyclization of citronellal, the Diels–Alder reaction, and the cyanosilylation of carbonyl compounds with trimethylsilyl cyanide (see scheme). The observed catalysis was truly heterogeneous, and the recovered catalyst could be reused without loss of its high catalytic performance