Novel tri- and tetra-substituted pyrimido[4,5-d]pyridazines-2(1H,3H,7H)-ones have been synthesized via the regiospecific condensation reaction of hydrazine derivatives with 5-acetyl-4-aryloyl-6-methyl-3,4-dihydropyrimidinones in the presence of $SiO_2-Y(NO_3)_3$ as a green and recyclable catalyst under solvent-free conditions. All products were obtained in high yields and short reaction time. Employing this method is in accord with green chemistry principles.
新型三取代和四取代的
嘧啶并[4,5-d]
吡嗪-2(1H,3H,7H)-酮已通过在无溶剂条件下,利用氢化
肼衍
生物与5-乙酰基-4-芳基酰基-6-甲基-3,4-二氢
嘧啶酮的区域特异性缩合反应合成,反应过程中使用了
$SiO_2-Y(NO_3)_3$作为绿色可回收催化剂。所有产品均在高产率和短反应时间内获得。采用这种方法符合绿色
化学原则。