Efficient Synthesis of Highly Functionalized Dihydropyrido[2,3-<i>d</i>]pyrimidines by a Double Annulation Strategy from α-Alkenoyl-α-carbamoyl Ketene-(<i>S</i>,<i>S</i>)-acetals
作者:Lei Zhao、Fushun Liang、Xihe Bi、Shaoguang Sun、Qun Liu
DOI:10.1021/jo0522106
日期:2006.2.1
strategy starting from easily available α-alkenoyl-α-carbamoyl ketene-(S,S)-acetals 1 and cheap reagents (NH4OAc, DMF, and POCl3) has been developed. In the first step of the double annulation route, 2-amino-3-carbamoyl-5,6-dihydro-4-pyridones 2 were created in high to excellent yields by a formal [5C + 1N] annulation reaction of ketene-(S,S)-acetals 1 with ammonia (from ammonium acetate). In the second step
通过易于获得的α-链烯酰基-α-氨基甲酰基烯酮-(S,S)-乙缩醛1和廉价的双[5 +1]环化策略,方便高效地合成高度官能化的二氢吡啶并[2,3- d ]嘧啶已经开发了试剂(NH 4 OAc,DMF和POCl 3)。在双重环化路线的第一步中,通过烯酮-(S的正式[5C + 1N]环化反应,以高至极高的产率生成了2-氨基-3-氨基甲酰基-5,6-二氢-4-吡啶酮2,S)-乙缩醛1与氨气(来自乙酸铵)。在双重环化策略的第二步中,高度官能化的二氢吡啶并[2,3- d] pyrimidine衍生物,7,8-二氢吡啶并[2,3- d ] pyrimidin-4(3 H)-ones 3(当R 1 =芳基时)和7,8-二氢吡啶并[2,3- d ] pyrimidines 4(当通过使2与过量的Vilsmeier试剂(DMF / POCl 3)反应,分别以中等至良好的产率构建R 1 = H )。提出了第二个[5