Synthesis and biological evaluation of 2,3-diarylthiophenes as selective cox-2 inhibitors. part II: Replacing the heterocycle
摘要:
The thiophene ring of DuP 697 was replaced by a variety of heterocycles and the products were tested for their ability to inhibit human Cox-2 and Cox-1, the isozymes of cyclooxygenase.
transfer (PCET). Mechanistic experiments and DFT calculations support the possibility of a concerted protonelectron-transfer (CPET) pathway. This Birch-type reduction demonstrates that a small nucleophilic organic molecule can be used as a single electron-transfer (SET) reducing agent with a proper proton source.
metal-free reductionsystem, in which H2Se (or HSe–) produced in situ from Se/DMF/H2O acts as the active reducing species, has been developed. By using water as an inexpensive, safe, and environmentally friendly surrogate as the hydrogen donor, this newreductionsystem incorporating Se/DMF/H2O displayed high selectivity and good activity in the reduction of α,β-unsaturated ketones and alkynes. Therefore
一种新型的无金属还原系统,其中H 2 SE(或HSE组- )原位产生从硒/ DMF / H 2 ö充当活性还原物质,已经研制成功。通过使用水作为廉价,安全和环保的替代物作为氢供体,这种结合了SE / DMF / H 2 O的新还原系统在还原α,β-不饱和酮和炔烃方面显示出高选择性和良好的活性。因此,该还原系统具有很大的潜力,可以作为有机转化中通用而实用的还原方法。
Chemoselective Hydrogenation of Alkynes to (<i>Z</i>)<i>-</i>Alkenes Using an Air-Stable Base Metal Catalyst
A highly selective hydrogenation of alkynesusing an air-stable and readily available manganese catalyst has been achieved. The reaction proceeds under mild reaction conditions and tolerates various functional groups, resulting in (Z)-alkenes and allylic alcohols in high yields. Mechanistic experiments suggest that the reaction proceeds via a bifunctional activation involving metal–ligand cooperativity
CuI-catalyzed Suzuki coupling reaction of organoboronic acids with alkynyl bromides
作者:Shihua Wang、Min Wang、Lei Wang、Bo Wang、Pinhua Li、Jin Yang
DOI:10.1016/j.tet.2011.05.031
日期:2011.7
A CuI-catalyzed Suzuki cross-coupling reaction of organoboron derivatives with alkynyl bromides has been developed. In the presence of CuI (10 mol %) and 8-hydroxyquinoline (20 mol %), organoboron derivatives including aromatic and alkenyl boronic acids, potassium aryltrifluoroborates, and sodium tetraphenylborate reacted smoothly with 1-bromo-2-substituted acetylene to generate the corresponding cross-coupling
已经开发出CuI催化的有机硼衍生物与炔基溴化物的Suzuki交叉偶联反应。在CuI(10 mol%)和8-羟基喹啉(20 mol%)的存在下,有机硼衍生物(包括芳族和烯基硼酸,芳基三氟硼酸钾和四苯基硼酸钠)与1-溴-2-取代的乙炔平稳反应,生成相应的交叉偶联产物在C 2 H 5 OH中具有良好至极好的收率。重要的是要注意,芳族N,O-配体8-羟基喹啉是该反应最有效的配体。
Copper-catalysed, diboron-mediated <i>cis</i>-dideuterated semihydrogenation of alkynes with heavy water
作者:Xiaowei Han、Jiefeng Hu、Cheng Chen、Yu Yuan、Zhuangzhi Shi
DOI:10.1039/c9cc03213d
日期:——
efficiently mediate the transfer of two D atoms from heavy water directly onto alkynes through copper-catalysed cis-selective semihydrogenation. Avoiding the use of costly and flammable D2 gas, this safe and practical process can proceed with excellent chemoselectivity and stereoselectivity. Utilizing the present method as the key step, the formal asymmetrictotalsynthesis of d2-deuterium-labeled cis-combretastatin