Design, Synthesis and Biological Activity of Novel Substituted Phenyl Oxazol Based Compounds†

Abstract

Several famous bioactive heterocycles such as oxazole,imidazolidine and thiazolidine are widely used in both pharmaceutical and pesticide industry. To find new lead compounds with favorable biological activities,a series of novel substituted phenyl oxazol based compounds containing 2-nitroaminoimidazoline or thiazolidine was designed via the method of linking active sub-structures. The target compounds were synthesized from substituted benzoic acid in three steps. Their structures were confirmed by1H NMR and elemental analysis. The preliminary bioassay results indicated that some target compounds showed obvious inhibitory activities against Gibberella saubinetii,Rhizoctonia solani,Botrytis cinerea and Alternaria solan. Especially,compound 5q,with 62% and 86% inhibition rate against Gibberella saubinetii and Botrytis cinerea,respectively, exhibited equivalent activity to Polyoxin B with 57% and 85% inhibition rate at a concentration of 100 μg/mL. The structure-activity relationship indicated that the type and position of substituent on the benzene ring would influence the activity obviously. The halogen substituent was favorable to activity. Besides,compounds with ortho-substituent showed better activity than those with meta or para-substituent.