Design, synthesis and fungicidal activity of N-substituted benzoyl-1,2,3,4-tetrahydroquinolyl-1-carboxamide

To find a new lead compound with high biological activity, a series of N-substituted benzoyl-1,2,3,4-tetrahydroquinolyl-1-carboxamide were designed using linking active substructures method. The target compounds were synthesized from substituted benzoic acid by four steps and their structures were confirmed by (1)H NMR, IR spectrum and elemental analysis. The in vitro bioassay results indicated that some target compounds exhibited excellent fungicidal activities, and the position of the substituents played an important role in fungicidal activities. Especially, compound 5n, exhibited better fungicidal activities than the commercial fungicide flutolanil against two tested fungi Valsa mali and Sclerotinia sclerotiorum, with EC50 values of 3.44 and 2.63mg/L, respectively. And it also displayed good in vivo fungicidal activity against S. sclerotiorum with the EC50 value of 29.52mg/L.