Unexpected intramolecular nucleophilic cyclization of ureidoacetamide: A novel route towards the synthesis of 2,4,5-trisubsituted oxazoles
作者:Jianhui Liu、Yawen Dong、Guanglan Li、Xiangting Min、Mustafa Hussain
DOI:10.1016/j.tetlet.2019.05.028
日期:2019.6
5-diamine-4-aryloxazoles. The two-step synthesis provides seven target products in yields of 61–78% under mild conditions. This reaction involves an unusual pathway in which the electrophilic amide carbonyl carbon is activated by Hendrickson’s reagent and attacked by a nucleophilic ureido oxygen in a 5-exo-trig O-cycloisomerization.
由N-芳基-α-氨基酰胺与氰酸钾(KOCN)缩合制得的各种N,2-二芳基-2-脲基乙酰胺经过有效的Hendrickson试剂介导的亲核环化反应,得到2,5-二胺-4-芳基恶唑。在温和条件下,两步合成提供了7种目标产物,产率为61–78%。该反应包括一个不寻常的途径,其中的亲电子酰胺羰基碳是由Hendrickson的试剂在活化的和攻击通过亲核脲基氧的5-外型- TRIGÖ -cycloisomerization。