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Short Paper | Regular issue | Vol 87, No. 1, 2013, pp.163-176
Published online, 22nd November, 2012
DOI: 10.3987/COM-12-12611
The New Convenient Synthesis of Novel γ-Alkylidenebutenolides from 6-Aminopenicillanic Acid

Bin Yu, En Zhang, Yuan Fang, Xiao-nan Sun, Jing-li Ren, De-quan Yu,* and Hong-min Liu*

*New Drug Research & Development Center, School of Pharmaceutical Science, Zhengzhou University, Zhengzhou 450001, China

Abstract

Butenolides have good biological activity and serve as the important unit of pharmaceutical intermediates, of which γ-alkylidenebutenolides have gained wide attention over the last past decades particularly. A simple and practical method for the synthesis of butenolide 6 and its 5-substituted analogues 7a-t via vinylogous aldol reaction from 6-aminopenicillanic acid (6-APA) with the ratio of Z/E isomers between 1.1/1.0 and 1.0/0 under mild conditions in 6 steps was first reported. Besides, we also reported the methanolysis behaviors of azetidinone fused oxazoline derivatives. All the synthesized γ-alkylidenebutenolides are new and are currently being evaluated for their biological activities.