Abstract:
As a continuous research on structure derivation and activity of natural monoterpenoid hinokitiol, 15 novel hinokitol carboxylic acid esters (
3) and 20 hinokitol sulfonate esters (isomers
5 and
6) were designed and synthesized from hinokitiol as a lead compound. The results of fungicidal activity showed that most of the target compounds at 50 μg/mL exhibited good fungicidal activity against
Valsa mali,
Rhizoctonia solani,
Botrytis cinerea, and
Colletotrichum orbiculare. The EC
50 values of
3a,
3f,
3g,
3o against
R. solani were 0.96, 1.05, 1.29 and 1.88 μg/mL, respectively, the EC
50 values of
3a,
3e and
3j were 3.60, 3.28 and 3.48 μg/mL against
V. mali, and the EC
50 values of
3d,
3f and
3g were 0.77, 0.51 and 0.67 μg/mL against
C. orbiculare, respectively, which were superior to hinokitol. In general, the fungicidal activity of carboxylate derivatives was significantly better than that of sulfonate derivatives. The position isomers of sulfonate derivatives possessed different fungicidal activities, among which the compound with configuration 1 has better activities.