efficient and versatile palladium-catalyzed reductive azo cleavage is disclosed for the synthesis of diverse heteroaromatic 1,2-diamines, a valuable synthetic building block to develop new fused heteroaromatic systems. As synthetic example, several substituted pyrazolo[5,1-b]purines were synthesized in yields up to 96% by using microwave irradiation in the cyclocondensation of these 1,2-diamines with orthoesters
一种微波辅助方法,通过3-氧代-2-(2-芳基
肼基亚甲基)
丁腈与5-
氨基-环戊基的环化反应,选择性合成功能化的6-(芳基
二氮烯基)
吡唑并[1,5 - a ]
嘧啶-7-胺。已开发出无溶剂条件下的1 H-
吡唑。该方法的特点是具有广泛的底物范围,操作简便,经济性高和无需色谱纯化即可获得高收率的特点。另外,公开了有效且通用的
钯催化的还原性偶氮裂解,用于合成各种杂芳族1,2-二胺,这是开发新的稠合杂芳族体系的有价值的合成构件。作为合成实例,几种取代的
吡唑并[5,1- b通过使用微波辐射在这些1,2-二胺与原酸酯的环缩合反应中合成]
嘌呤,收率可达96%。