Base-induced Cyclization of<i>N</i>-[Bis(ethoxycarbonyl)methyl]-2-bromo-3-hydroxybutyramide Derivatives
作者:Masao Shiozaki、Noboru Ishida、Tetsuo Hiraoka、Hiroshi Maruyama
DOI:10.1246/bcsj.57.2135
日期:1984.8
thoxycarbonyl)methyl]-2-bromo-3-hydroxybutyramide (5) with DBU yielded the bicyclic β-actam 13 by a direct cyclization, and its diastereoisomer 14 and the γ-lactam 15 via the trans-epoxide 6. The same treatment of (2S,3R)-isomer (11) gave the direct cyclization product 14 in 93% yield. On the other hand, reaction of 5 and 11 with sodium hydride afforded the 2-azetidinone derivatives (mainly 14 (23%)
(2R,3R)-N-(2,4-二甲氧基苄基)-N-[双(乙氧基羰基)甲基]-2-溴-3-羟基丁酰胺(5)用DBU处理得到双环β-内酰胺13环化,其非对映异构体14和γ-内酰胺15经由反式环氧化物6。(2S,3R)-异构体(11)的相同处理得到直接环化产物14,产率为93%。另一方面,5 和 11 与氢化钠的反应通过相应的环氧化物 6 和 12 得到 2-氮杂环丁酮衍生物(主要分别来自 5 的 14(23%)和来自 11 的 19(75%))。