Novel and insecticidal isobutylamides from Dinosperma erythrococca

Through insecticidal bioassay-guided fractionation and isolation, five isobutylamides 1-5 were isolated from n-hexane and EtOAc extracts of the aerial parts of Dinosperma, erythrococca (Rutaceae). The structures of compounds 1-5 were established through 1D and 2D NMR. Compounds 1-3 were identified as erythrococcamides A-C and represent two novel classes of isobutylamide. Compounds 4-5 were identified as N-(2-hydroxy-2-methylpropyl)-6-phenyl-2(E),4(E)-hexadienamide (4)(1,2) and N-(2-methylpropyl)-6-pbenyl-2(E),4(E)-hexadienamide (5),(1,3) respectively. Compound 1 showed lethal activity against the housefly (Musca domestica) (kill EC50 = 20.2 ppm) and the tobacco budworm (Heliothis virescens) (kill EC50 = 74.2 ppm). Compound 4 showed lethal activity against H. virescens at 500 ppm, while compound 5 showed lethal activity against M. domestica at 500 ppm.