Synthesis And Insecticidal Activity Of -Dihydroagarofuran Ether Analogues

BACKGROUND1, 2, 4, 6, 8, 9, 12-hepthydroxyl--dihydroagarofuran is the main skeleton of -dihydroagarofuran sesquiterpenoids, which exhibit excellent insecticidal activity. To study further the structure-activity relationship of -dihydroagarofuran sesquiterpenoids towards finding novel botanical pesticides, two series of new structurally modified ether analogues were designed and synthesised, and their insecticidal activities were evaluated.RESULTSTwenty-two ether derivatives were synthesised using 1, 2, 4, 6, 8, 9, 12-hepthydroxyl--dihydroagarofuran as starting material. Bioassay results indicated that most of the derivatives, particularly compounds 5.1.2, 5.1.3, 5.1.7, 5.2.3, 5.2.6 and 5.2.7, exhibited significant insecticidal activity against the third-instar larvae of the oriental armyworm Mythimna separata. Most importantly, compound 5.2.7 showed the lowest LD50 value of 29.2 mu g g(-1) among these synthesised compounds, which provides some important hints for further design, synthesis and structural modification of -dihydroagarofuran sesquiterpenoids towards developing novel botanical insecticides.CONCLUSIONThe structure-activity relationship illustrated that the moiety at the 1-position affected the insecticidal activity significantly, and that specifically the derivatives with two or three carbon atoms at the 1-position showed promising insecticidal activity, with mortality over 60%, while those with o-F-Bn and p-F-Bn at the 6-position showed similar activity. (c) 2015 Society of Chemical Industry