摘要
7-O-取代-8-甲基香豆素和4-H-色烯-4-酮化合物是合成Seco-DCK和Seco-DCP类似物的重要中间体.报道了在NBS/CCl4条件下,这两类化合物8-位甲基溴代反应的情况.通过实验发现,这两类化合物8-位甲基溴代反应较一般芳环苄位的溴代更为复杂,存在多个反应位点.影响8-位甲基溴代选择性和收率的主要因素有三:邻位基团空间位阻大小、自由基引发催化剂的使用与否以及邻位基团的电性因素.通过控制反应条件,可以中等收率得到8-位甲基溴代化合物.
The bromination of 7-O-substituted-8-methyl-coumarins and 4H-chromen-4-ones,two key in-termediates in the synthesis of Seco-DCK and Seco-DCP analogues,with N-bromosuccinimide in CCl4 is reported.The experimentation showed that the selectivity of bromination of 8-methyl is more complicated than that of common benzyls,due to the presence of multiple reactive sites in these two title substrates.Diversity of the products was discussed and the reasonable explanation for which was provided.The bulky group of 7-O-substitutes,its electric property as well as addition of free radical initiator could affect the selectivity and the yield of bromination of 8-methyl.The desired 8-bromomethyl products could be obtained in mild yields under optimized condition.
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2010年第11期1737-1741,共5页
Chinese Journal of Organic Chemistry
基金
国家自然科学基金(No.30873164)
科技部的综合性新药研究开发技术大平台(No.2009ZX09301-011)资助项目