Benzo[4,5]imidazo[2,1-b]quinazolin-12-ones and benzo[4,5]imidazo[1,2-a]pyrido[2,3-d]pyrimidin-5-ones by a sequential N-acylation–SNAr reaction
作者:Krishna Kumar Gnanasekaran、Nagendra Prasad Muddala、Richard A. Bunce
DOI:10.1016/j.tetlet.2015.11.041
日期:2015.12
An efficient synthesis of benzo[4.5]imidazo[2,1-b]quinazolin-12-ones and benzo[4,5]imidazo[1,2-a]pyrido[2,3-d]pyrimidin-5-ones is reported from the reaction of 2-aminobenzimidazole with 2-haloaroyl chlorides. The reaction takes advantage of the 1,3-disposition of nucleophilic centers in 2-aminobenzimidazole and the similar arrangement of electrophilic sites in the acid chloride to assemble the central
有效合成苯并[4.5]咪唑并[2,1 - b ]喹唑啉-12-one和苯并[4,5]咪唑并[1,2- a ]吡啶[2,3 - d ]嘧啶-5-酮是报道了2-氨基苯并咪唑与2-卤代芳酰氯的反应。该反应利用2-氨基苯并咪唑中亲核中心的1,3-位和酰基氯中亲电位点的相似排列来组装中心六元环。在-10°C的DMF中,在NaHCO 3(2当量)存在下,用酰氯(1当量)对2-氨基苯并咪唑(1.2当量)进行初始处理,在饱和苯并咪唑氮原子上进行酰化反应。随后在同一反应容器中加热至75°C,然后通过S N完成合成Ar环由C2氨基封闭。该反应适用范围广,两步反应产率为76-98%。最终产物以互变异构平衡存在,其可以被N6处的酰化作用阻断。