A semisynthesis of 3 '-O-ethyl-5,6-dihydrospinosyn J based on the spinosyn A aglycone

作者：Zhang, Kai; Liu, Shenglan; Liu, Anjun; Chai, Hongxin; Li, Jiarong^*; Lamusi, A.^*

来源：Beilstein Journal of Organic Chemistry, 2017, 13: 2603-2609.

DOI：10.3762/bjoc.13.257

• 3-O-ethyl-2,4-di-O-methylrhamnose
• protecting groups
• semisynthesis
• spinetoram
• spinosyn A

Spinetoram, a mixture of 3 '-O-ethyl-5,6-dihydrospinosyn J (XDE-175-J, major component) and 3 '-O-ethylspinosyn L (XDE-175-L, minor component), is a novel kind of green and efficient insecticide with a broad range of action against various insects. Nowadays, spinetoram is widely used in agriculture and food storage. This work reports a 7-step semisynthesis of 3 '-O-ethyl-5,6-dihydrospinosyn J from spinosyn A aglycone. The C9-OH and C17-OH of the aglycone are successively connected to 3-O-ethyl-2,4-di-O-methylrhamnose and D-forosamine after selective protection and deprotection steps. Then, with 10% Pd/C as catalyst, the 5,6-double bond of the macrolide was selectively reduced to afford 3 '-O-ethyl-5,6-dihydrospinosyn J. In addition, the 3-O-ethyl-2,4-di-O-methylrhamnose is synthesized from rhamnose which is available commercially, while the D-forosamine and aglycone are obtained via the hydrolysis of spinosyn A. High yields were obtained in each step, and all intermediates in the synthesis were characterized by H-1 NMR, C-13 NMR and MS techniques. This study can be helpful for developing an efficient chemical synthesis of spinetoram, and it also offers opportunities to synthesize spinosyn analogues and rhamnose derivatives.

• 出版日期2017-12-6
• 单位北京理工大学; 中国农业科学院