L-Proline as an efficient and reusable promoter for the synthesis of coumarins in ionic liquid.
The effect of L-proline as a promoter on the condensation reaction of salicylaldehyde or its derivatives with ethyl acetoacetate in neutral ionic liquid [emim]BF4 was studied. All reactions were carried out under mild reaction conditions and achieved high yields. Moreover, the ionic liquid containing L-proline could be recycled and reused for several times without noticeably decreasing in productivity. The results show that the L-proline-[emim]BF4 system has a potential in contribution to the development of environmentally friendly and inexpensive processes in organic syntheses.
Liu
Xiu-hong
XH
Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Fan
Ji-cai
JC
Liu
Yang
Y
Shang
Zhi-cai
ZC
D003374:Coumarins / Q000138:chemical synthesis*; D052578:Ionic Liquids / Q000737:chemistry*; D011392:Proline / Q000737:chemistry*
D003374:Coumarins; D052578:Ionic Liquids; D011392:Proline