Synthesis And Insecticidal Activity Of Novel Oxime Sulfonate Derivatives Of 2’(2’,6’)-(Di) Chloropicropodophyllotoxins

Podophyllotoxin, a naturally occurring aryltetralin cyclolignan, which is isolated from the roots and rhizomesof some Podophyllum species. People found that podophyllotoxin has a good poison activity on pests, and it is a potential source of plant pesticides. To discover novel natural-product-based pesticidal agents, a series of oxime sulfonate derivatives of 2′(2′,6′)-(di)chloropicropodophyllotoxins were prepared. Four results were obtained as follows:1. Twenty-five compounds were prepared, including seven intermediates and eighteen new oxime sulfonate derivatives of 2’(2’,6’)-(di)chloropicropodophyllotoxins. Their structures were all characterized by 1H NMR, HRMS, mp, and optical rotation. Among them, twenty-two derivatives were new compounds.2. Their insecticidal activity was evaluated at 1 mg/m L against the pre-third-instar larvae of Mythimna separata Walker(oriental armyworm). Among all derivatives, compounds 4c, 4d, 5c, 5d, 5f and 5g exhibited more promising insecticidal activity, with the final mortality rates greater than 50%, when compared to their precursor podophyllotoxin and the positive control, toosendanin.3. Some larvae with the slim and wrinkled bodies died at the larval stage, some larvae molted to malformed pupae or died during the pupation period, and more than half of the final mortality rates were generally occupied by the mortality rates at the emergence stage.4. It demonstrated that introduction of the chlorine atom at the C-2’ or C-2’, 6’ position on the E ring of picropodophyllotoxin or oxime sulfonate derivatives of picropodophyllotoxin was necessary for the insecticidal activity and introduction of a halogen(e.g., fluorine, chlorine, or bromine) atom-substituted phenylsulfonyl group on the oxime fragment of 2’(2’,6’)-(di)chloropicropodophyllones led to more promising compounds, such as 4c, 5c and 5d.