Synthesis of a regioisomeric analogue of the 3C-protease inhibitor thysanone via a Hauser annulation strategy
作者:Margaret A. Brimble、Scott I. Houghton、Paul D. Woodgate
DOI:10.1016/j.tet.2006.11.046
日期:2007.1
access activated naphthoquinone 3, a key intermediate for the synthesis of thysanone 1, proved unreliable. In contrast to this, Hauser annulation of regioisomeric 3-cyano-4,6-dimethoxy-(3H)-isobenzofuran-1-one 13 with ethyl acrylate proceeded readily affording ethyl 5,7-dimethoxy-1,4-naphthoquinone 12, after oxidation of the initial dihydroxynaphthalene 16. Allylation of naphthoquinone 12 followed by
豪瑟(Hauser)将3-氰基-5,7-二甲氧基-(3 H)-异苯并呋喃-1-酮4与丙烯酸乙酯的环合反应作为获得活化的萘醌3的方法,活化的萘醌3是合成胸腺酮1的关键中间体,被证明是不可靠的。与此形成对比的是,区域异构体3-氰基-4,6-二甲氧基-(3 H)-异苯并呋喃-1-酮13与丙烯酸乙酯的豪瑟环化反应轻松进行,得到乙基5,7-二甲氧基-1,4-萘醌12,初始二羟基萘氧化后16。萘醌12的烯丙基化,然后还原甲基化和Wacker氧化,得到酮11经历了CBS还原为(2 'S)-酒精19,然后环化为内酯20。还原内酯,然后氧化脱甲基,得到(1 S,3 S)-6,8-二甲氧基-1-羟基-3-甲基吡喃并[2,3 - c ] -1,4-萘醌22,其为区域异构体3C蛋白酶抑制剂胸腺嘧啶1。