摘要
室温条件下,研究了铜催化可见光诱导8-氨基喹啉衍生物C5位二氟烷基化反应。以蓝色LED为光源,面式-三(2-苯基吡啶)合铱配合物〔fac-Ir(ppy)3〕为光敏剂,8-氨基喹啉衍生物与二氟溴乙酸乙酯产生的二氟乙酸乙酯自由基发生C—C偶联反应。在Cu I催化下合成15个C5位二氟烷基化的8-氨基喹啉衍生物(Ⅲa~Ⅲo)。通过1HNMR、13CNMR、FTIR和HR-MS对产物的结构进行确证。8-氨基喹啉衍生物的转化率为50%~90%,反应收率范围为21%~58%。该反应条件温和,含有卤素、硫醚和氰基官能团的底物都能发生反应。自由基捕获剂2,2,6,6-四甲基哌啶-1-氧(TEMPO)能捕获到二氟乙酸乙酯自由基,验证该反应过程可能经过自由基单电子转移。
Acopper-catalyzed visible light induced difluoroalkylation reaction of 8-aminoquinoline derivatives at the C5-position was developed at room temperature.The C—C coupling reaction between 8-aminoquinoline derivatives and free radicals of ethyl difluoroacetate produced by ethyl difluorobromoacetate was carried out with blue LED as light source,fac-tris[2-(2-pyridinyl)phenyl]iridium complexes[fac-Ir(ppy)3]as photosensitizer.Fifteen difluoroalkylated 8-aminoquinoline derivatives(Ⅲa~Ⅲo)at the C5 position were synthesized in the presence of a catalytic amount of cuprous iodide.These products were characterized by 1 HNMR,13 CNMR,FTIR,and HR-MS.The conversion rates of starting materials were 50%~90%,and yields of products was in the range from 21%to 58%.The reaction conditions are mild,and the substrates containing halogen,thioether,and cyan functional groups can react.Free radical scavenger 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)could capture free radicals of ethyl difluoroacetate,indicating that the reaction process may undergo free radical single electron transfer.
作者
赵鹏达
倪珊梅
宋小文
周琢强
ZHAO Pengda;NI Shanmei;SONG Xiaowen;ZHOU Zhuoqiang(College of Materials and Energy,South China Agricultural University,Guangzhou 510642,Guangdong,China;Jieyang Institute of Technology,Jieyang 522000,Guangdong,China)
出处
《精细化工》
EI
CAS
CSCD
北大核心
2020年第8期1678-1683,共6页
Fine Chemicals
关键词
8-氨基喹啉
二氟溴乙酸乙酯
碘化亚铜
光诱导反应
医药原料
8-aminoquinoline
ethylbromodifluoroacetate
cuprous iodide
light induced reaction
drug materials
