alpha-hydroxy ketones undergo manganese dioxide-mediated oxidation followed by in situ trapping with aromatic or aliphatic 1,2-diamines to give quinoxalines or dihydropyrazines, respectively, in a one-pot procedure which avoids the need to isolate the highly reactive dicarbonyl intermediates. The scope and limitations of these procedures are outlined and modifications to this procedure are discussed
α-羟基酮经过
二氧化锰介导的氧化,然后通过一锅法分别与芳香族或脂肪族1,2-二胺原位捕获,分别得到
喹喔啉或二氢
吡嗪,避免了分离高反应性二羰基中间体的需要。概述了这些方法的范围和局限性,并讨论了对该方法的修改,其中在同一反应容器中进行还原,生成
哌嗪或氧化生成
吡嗪。