Nature 对氢化酶活性位点的设计指导了限制或逆转空气敏感、贱金属催化剂在与外来 O2 接触时析氢/氧化反应的降解的策略。[NiFeS]-H2ase 中的氧对硫的亲和力和 [NiFeSe]-H2ase 中的硒在有氧条件下产生含氧硫属元素,并通过维持活性位点的 NiFe 核心结构来延迟对金属的不可逆氧损伤。在试图确定 S 位氧吸收的控制特征时,相关的 Ni(µ-EPhX)(µ-S'N2)Fe (E = S 或 Se, Fe = (η5-C5H5)FeII(CO)) 配合物是通过苯环上的对位取代基(X = CF3、Cl、H、OMe、NMe2)进行电子调节,并在 Ni 和 Fe 之间的通讯、氧化还原电位和化学反应性方面进行了比较。O2 对 S-和 Se-氧化的研究发现硫属元素的单和双 O 原子吸收导致 4 元核 Ni(µ-EPhX)(µ-S'N2)Fe 转化为5 元 Ni-OE-Fe-S' 排列,其中
whereas the (C6H5)4SbO substituent differs in this respect from all other (C6H5)nMO groups. The low conjugating ability of the (C6H5)2SbS substituent and slight influence of steric hindrance upon its electronic effect have been explained by the operation of conformational factors. It has been established that the electronic interactions across the antimony—heteroatom bonds are mainly of inductive character
的19 F NMR技术已被用于研究的类型的化合物中的一价有机锑的基态电子效应和铋的取代基(C 6 H ^ 5)ñ MSC 6 ħ 4 F-3,(C 6 H ^ 5)n MSC 6 H 4 F-4,(C 6 H 5)4 SbOC 6 H 4 F-3,(C 6 H 5)4 SbOC 6 H 4 F-4和(4-FC 6 H 4)2 SbX,其中(C 6 H 5)n M =(C 6 H 5)2 Sb,(C 6 H 5)2 Bi和(C 6 H 5)4 Sb,X = C 6 H 5 S,CH 3首席运营官,Cl,Br。已经发现,含硫基团的给电子作用按以下顺序增加:(C 6 H 5)2 SbS <(C 6 H 5)2 BiS <(C 6 H 5)4 SbS中,取代基(C 6 H 5)4 SbS和(C 6 H 5)4 SbO在含重金属的(C 6 H 5)n MS和(C 6 H 5)n MO基团中电子释放最
Novel cholesterol lowering compounds
申请人:MERCK & CO. INC.
公开号:EP0512865A2
公开(公告)日:1992-11-11
Disclosed herein are compounds of structural formula (I)
which are useful as cholesterol lowering agents. These compounds are also useful as inhibitors of squalene synthetase, inhibitors of fungal growth, inhibitors of farnesyl-protein transferase and farnesylation of the oncogene protein Ras. These compounds are also useful in the treatment of cancer.