Synthesis and Antifeedant Activities of Rosin-Based Esters Against Armyworm.

A series of rosin based esters have been synthesized from dehydroabietic acid and maleopimaric acid, respectively. Their structures were confirmed by FT-IR, (1)H NMR, (13)C NMR and single crystal X-ray diffraction. Their antifeedant activities against armyworm were examined by leaf plate method. Methyl ester of dehydroabietic acid and maleopimaric acid were crystallized in orthorhombic system with cell dimensions of a = 26.352 [5] Å, b = 6.1020 [12] Å, c = 11.812 [2] Å and a = 7.9216 [11] Å, b = 11.9912 [16] Å, c = 23.425 [3] Å, respectively. They contained classic tricyclic hydrophenanthrene skeleton. The antifeedant results indicated that most rosin-based esters exhibited significant antifeedant activities at a concentration of 0.01 g mL(-1). Their feeding deterrence values were above 70% after 24h. The antifeedant activities for rosin-based esters increased with the growth of chain length of alcohol except (Ia). Some armyworm were found dead during the antifeedant activity test, by which we speculated that these synthetic rosinbased esters had stomach poison activities against armyworm.