The present invention provides a compound of formula I;
or a pharmaceutically acceptable salt thereof, wherein the variables R1, R2, R3, R4, R5, and A-B are defined herein, which are non-immunosuppresive, cyclophilin-binding, mPTP blockers and are therefore useful for the prevention or treatment of diseases or disorders such as HCV infection, stroke, multiple sclerosis, HBV infection, HPV infection, asthma, cancer, muscular dystrophy, sepsis, ischemia/reperfusion injury, and heart failure.
Cyclolithistide A is a peptide lactone isolated from marine lithistid sponges. Its entire structure, including absolute configurations, has been reported except the relative and absolute configurations of its characteristic residue, 4-chloroisoleucine (4-CIle). We synthesized four isomers of 4-CIle from furfural-derived N-Boc imine and propionaldehyde. Analysis of the acid hydrolysate of cyclolithistide
Cyclolithistide A 是从海洋 Lithistid 海绵中分离的肽内酯。其整个结构,包括绝对构型,除了其特征残基 4-氯异亮氨酸 (4-CIle) 的相对和绝对构型外,已有报道。我们从糠醛衍生的 N-Boc 亚胺和丙醛中合成了四种 4-CIle 异构体。对环石 A 的酸水解物和用 l- 和 d-FDA 衍生化后的 4-CIle 合成样品的分析使我们能够提出环石 A 中 4-氯异亮氨酸残基的绝对构型为 2S,3 R,4 R。
An Organocatalyzed Enantioselective Synthesis of (2<i>S</i>,3<i>R</i>,4<i>S</i>)-4-Hydroxyisoleucine and Its Stereoisomers
A concise enantioselective total synthesis of (2S,3/2,45)-4-hydroxyisoleucine and its stereoisomers is described. A key feature of this protocol is a catalytic enantioselective mannich reaction that is either anti- or syn-selective as genesis of chirality.