The reactions of dioxanyl and cyclohexylradicals with 2- and 3-X-pyridines (X = CN, COMe, CO2Me) give a single substitution product deriving by addition at the 5- and 6-positions respectively; with 4-X-pyridines substitution occurs preferentially at the 3-position. If the reactions are carried out with protonated pyridines other positional isomers are obtained. From the synthetic point of view the
A straightforward acylaltion of pyridine derivatives has been developed using K2S2O8 as the oxidant and water as a green solvent. The corresponding 2-acylpyridines were synthesized with high chemo- and regioselectivity in good to high yields. This efficient and practical method could serve as a new tool for the convenient synthesis of 2-benzoylpyridines of interest for future pharmaceutical and chemical
使用K 2 S 2 O 8作为氧化剂和水作为绿色溶剂,开发了吡啶衍生物的直接酰基化方法。以高至高产率合成具有高化学和区域选择性的相应的2-酰基吡啶。这种有效和实用的方法可以用作方便地合成感兴趣的2-苯甲酰基吡啶的新工具,以用于未来的药物和化学应用。
Ligands and catalyst systems thereof for ethylene oligomerisation to linear alpha olefins
申请人:——
公开号:US20030119921A1
公开(公告)日:2003-06-26
Mixed bis-imine pyridine ligands of formula (I), wherein Z
1
, which is different from Z
2
, is an optionally substituted aryl group; and Z
2
comprises an optionally substituted heterohydrocarbyl moiety, or an optionally substituted aryl group in combination with a metal, said optionally substituted aryl group being &pgr;-co-ordinated to the metal;
1
mixed bis-imine pyridine complexes comprising a ligand of formula (I); mixed ionic bis-imine pyridine complexes comprising a ligand of formula (I); and processes for the production of alpha olefins from ethylene, using said complexes.