Abstract:

In order to seek novel terpenoid repellent, 4 acetal derivatives of hydroxycitronellal, i.e., hydroxycitronellal dimethyl acetal, hydroxycitronellal 1, 2-ethandiol acetal, hydroxycitronellal 1, 3-propanediol acetal and hydroxycitronellal 1, 2-propanediol acetal, were synthesized in this study. Their structures were characterized using IR and MS, ¹H NMR, and ¹³C NMR (for hydroxycitronellal 1, 2-propanediol acetal only). Repellencies against Aedes albopictus, Anopheles sinensis and Culex pipiens were examined using the method described in GB/T 13917.9-2009. The results showed that the repellent activity of 10% (mass) solution of both hydroxycitronellal dimethyl acetal and hydroxycitronellal 1, 2-propanediol acetal against A. sinensis reached grade B as defined in GB/T 13917.9-2009, and that of a concentrated solution (20% in mass) of hydroxycitronellal 1, 2-propanediol acetal against A. sinensis even approached to grade A. Hydroxycitronellal 1, 2-propanediol acetal also showed the repellency to other mosquitoes as well: the repellent activity of 20% (mass) solutions against A. albopictus and that of 10% (mass) solutions against C. pipiens exceeded the grades B and A, respectively. These results indicate that the repellent activity difference against different mosquito species offers the theoretical basis for using the repellents in different situations.

Key words: Hydroxycitronellal, acetal derivatives, Aedes albopictus, Anopheles sinensis, Culex pipiens, repellency