描述了两步程序,用于区域选择性合成3-取代的2-氨基咪唑并[1,2- a ]嘧啶。关键步骤是2和3个取代的氨基咪唑并[1,2- a ]嘧啶混合物的Dimroth重排,可定量地产生一种区域异构体。报告了用于重排步骤的反应筛选。选择基于多组分异氰化物的反应作为合成前体的优选方式。已通过X射线测定某些代表性化合物来完成区域化学的阐明。
描述了两步程序,用于区域选择性合成3-取代的2-氨基咪唑并[1,2- a ]嘧啶。关键步骤是2和3个取代的氨基咪唑并[1,2- a ]嘧啶混合物的Dimroth重排,可定量地产生一种区域异构体。报告了用于重排步骤的反应筛选。选择基于多组分异氰化物的反应作为合成前体的优选方式。已通过X射线测定某些代表性化合物来完成区域化学的阐明。
Regioselective Synthesis of 3-Aminoimidazo[1,2-<i>a</i>]-pyrimidines under Continuous Flow Conditions
作者:Ashlie J. E. Butler、Mark J. Thompson、Patrick J. Maydom、James A. Newby、Kai Guo、Harry Adams、Beining Chen
DOI:10.1021/jo501861g
日期:2014.11.7
Multicomponent synthesis of 3-aminoimidazo[1,2-a]pyrimidines usually affords a product mixture containing varying amounts of the corresponding 2-amino regioisomer. Modified methods, particularly microwave heating, have been employed to suppress formation of this side-product, but none of the revised protocols are readily amenable to scale. A continuous flow adaptation was found to offer improved regioselectivity toward the targeted 3-amino regioisomer with significantly shorter reaction times and also widened the scope of the reaction to permit the use of aliphatic aldehyde building blocks.