Semi-synthesis and insecticidal activity of spinetoram J and its D-forosamine replacement analogues

• Kai Zhang,
• Jiarong Li,
• Honglin Liu,
• Haiyou Wang and
• Lamusi A

Beilstein J. Org. Chem. 2018, 14, 2321–2330, doi:10.3762/bjoc.14.207

• , a mixture of ≈85% spinosyn A and ≈15% spinosyn D [7], is considered a highly effective bioinsecticide, and it has been widely used for the management of various insect pests. Compared with spinosad, spinetoram is more active and has a longer duration of control against many insect pests, such as

• for the application of spinetoram, as well as for the further research on spinetoram. In the previous study [13], we had reported a semi-synthesis of spinetoram J with spinosyn A aglycon as initiator (Scheme 1). However, in the previous route, C9–OH and C17–OH of the aglycone needed to be protected

• reported in the previous study [27], spinosyn A could be hydrolyzed to 17-pseudoaglycone under weak sulfuric acid conditions, indicating that the C9 glycosidic bond was more stable than the C17 glycosidic bond under weak sulfuric acid conditions (Scheme 2). Similar to spinosyn A, both D-forosamine and 2’,3

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

• Kai Zhang,
• Shenglan Liu,
• Anjun Liu,
• Hongxin Chai,
• Jiarong Li and
• Lamusi A

Beilstein J. Org. Chem. 2017, 13, 2603–2609, doi:10.3762/bjoc.13.257

• , 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

• 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 1H NMR, 13C 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. Keywords: 3-O-ethyl-2,4-di-O-methylrhamnose; protecting groups; semisynthesis; spinetoram; spinosyn A; Introduction Spinosyns, a large family of secondary metabolites produced by aerobic fermentation of Saccharopolyspora spinosa, are a