Substituted coumarin amidines: useful building blocks for the preparation of [1]benzopyrano[4,3-b]pyridin-5-one and [1]benzopyrano[4,3-d]pyrimidin-5-one derivatives
作者:Egle M. Beccalli、Alessandro Contini、Pasqualina Trimarco
DOI:10.1016/j.tet.2005.03.050
日期:2005.5
synthesis of [1]benzopyrano[4,3-b]pyridin-5-ones 4a–f and 4g–j starting from 3-formylcoumarin and 3-cyanocoumarin N-functionalized amidines 3a–f and 3g–j, respectively, was reported. The ring-closure reaction mechanism, under basic or acidic media, was proposed. Furthermore, the reaction of 3-formylamidines 3a,c–f with ammonium acetate gave good yields of 2-substituted [1]benzopyrano[4,3-d]pyrimidin-5-ones
的[1]苯并吡喃并[4,3-合成b ]吡啶-5-酮4A - ˚F和4克- Ĵ从3- formylcoumarin和3-氰基香豆素起始ñ -官能化脒3A - ˚F和3克- Ĵ,分别是报告。提出了在碱性或酸性介质下的闭环反应机理。此外,3-甲酰idine3a,c - f与乙酸铵的反应产生了2-取代的[1]苯并吡喃并[4,3 - d ]嘧啶-5-酮7的良好收率。