氮气保护下,以4-羟基香豆素类化合物和2-丁炔酸酯类化合物为原料,1,8-二氮杂二环十一碳-7-烯(DBU)为催化剂,乙腈为溶剂,经Michael加成反应合成了11个新型4-羟基香豆素烯醚衍生物(3a~3k),其结构经1H NMR,13C NMR,IR和HR-MS(ESI)表征,其构型经H-H NOESY谱确定为Z构型。考察了投料比r[n(2-丁炔酸乙酯,2a)∶n(4-羟基香豆素,1a)]、溶剂、催化剂、反应温度和反应时间对3a收率的影响。结果表明:在最优条件[r=1.2,乙腈为溶剂,DBU作催化剂,于80℃回流反应18 h]下,3a收率最高(70%)。
Eleven novel 4-hydroxycoumarin vinyl ether derivatives (3a - 3k) were synthesized by Mi- chael addition of 4-hydroxycoumarins compounds and ethyl 2-butynoate compounds under nitrogen at- mosphere using DBU as the catalyst and acetonitrile as solvent. The structures were characterized by IH NMR, 13C NMR, IR and HR-MS(ESI). 3a were confirmed to be a Z configuration by H-H NOE- SY. Effects of molar ratio r[ n(2a): n(1a) ], solvents, catalysts, temperature and reaction time were investigated. The results showed that the highest yield of 3a was 70% under the optimum conditions [ r = 1.2, DBU as catalyst, reaction in CH3CN at 80 ℃ for 18 h].