Synthesis and Biological Activities of Perillaldehyde-based Schiff Base-(thio) urea Compounds

Thirteen novel perillaldehyde-based Schiff base-(thio)urea compounds (5a-5m) were designed and synthesized by using perillaldehyde as starting material. Their structures were analyzed and characterized by FT-IR, 1H NMR, 13C NMR, and ESI-MS. The results of preliminary bioassay showed that, at the mass concentration of 50 mg/L, the inhibition rate of target compound 5f (R=p-FAr) against Physalospora piricola was 90.0% (close to that of the positive control azoxystrobin), and the inhibition rate of target compound 5d (R=Ar) against Alternaria solani was 91.8% (close to that of the positive control azoxystrobin). Besides, at the mass concentration of 100 mg/L, the target compounds 5c (R=cyclopentyl), 5i (R=p-CH3Ar) and 5a (R=CH3) exhibited 77.6%, 75.3% and 67.4% inhibition against the growth of rape (Brassica campestris) root, respectively (greater than positive control flumioxazin). Furthermore, substituted phenyl thioureas showed better antifungal and herbicidal activities than substituted phenyl ureas.