Investigation on the reactivity of isoxazol-5-ones towards 1,2-diaza-1,3-dienes: new entry to variously substituted (imidazol-2-yl)acetate and 1,3-oxazin-6-one derivatives
作者:Orazio A. Attanasi、Silvia Bartoccini、Gianfranco Favi、Gianluca Giorgi、Francesca R. Perrulli、Stefania Santeusanio
DOI:10.1016/j.tet.2011.10.118
日期:2012.1
derivative. The first aza-Michael addition is followed by an intramolecular second, affording a fused heterobicyclic system that, upon ring opening and decarboxylation processes, gives rise to novel substituted imidazoles with an acetate functionality in the 2-position. On the contrary, under the same reaction conditions, 3-phenylisoxazol-5-one provides a double Michael addition at two units of DD involving
1,2-二氮杂-1,3-二烯(DDs)在中性条件下会受到4-乙氧基羰基异恶唑-5-酮衍生物的N-亲核攻击。第一次氮杂-迈克尔加成之后是分子内第二种加成,提供稠合的杂环双环系统,其在开环和脱羧过程中产生具有2-位乙酸酯官能度的新型取代的咪唑。相反,在相同的反应条件下,3-苯基异恶唑-5-酮在DD的两个单元上首先涉及杂环的C-4和N-2提供双迈克尔加成。所得的二加合物自发地经历开环/闭环过程,该过程以提供1,3-恶嗪-6-衍生物的杂环的环扩大为结束。