Regioselective synthesis of 1- and 4-substituted 7-oxopyrazolo[1,5-a]pyrimidine-3-carboxamides
作者:Miha Drev、Uroš Grošelj、Špela Mevec、Eva Pušavec、Janja Štrekelj、Amalija Golobič、Georg Dahmann、Branko Stanovnik、Jurij Svete
DOI:10.1016/j.tet.2014.09.020
日期:2014.11
The synthesis of 7-substituted pyrazolo[1,5-a]pyrimidine-3-carboxamides was studied. First, methyl 7-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylate (5) was prepared in three steps from methyl 5-amino-1H-pyrazole-4-carboxylate (3). Treatment of 5 with POCl3 gave the highly reactive 7-chloro derivative 10, which was reacted with amines, benzyl alcohol, and phenylboronic acid in the presence of Pd-catalyst
研究了7-取代的吡唑并[1,5 - a ]嘧啶-3-羧酰胺的合成。首先,分三步从5-氨基-1 H-吡唑-4-羧酸甲酯(3)制备7-羟基吡唑并[1,5- a ]嘧啶-3-羧酸甲酯(5)。用POCl 3处理5得到高反应性的7-氯衍生物10,其在Pd-催化剂的存在下与胺,苯甲醇和苯基硼酸反应,得到相应的7-取代的衍生物11。酯5和11的水解,然后酰胺化,得到相应的羧酰胺16a – h和15。7-羟基吡唑并[1,5- a ]嘧啶-3-羧酸衍生物5和16的N-烷基化的区域选择性可通过羧基官能团调节。仲酰胺16a - f的烷基化提供了1-烷基衍生物17a - f,而酯5和叔酰胺16g,h则选择性地提供了4-烷基衍生物14a - d和16m,n。