Synthesis, fungicidal activity and phloem mobility of phenazine-1-carboxylic acid diacylhydrazine derivatives

Phenazine-1-carboxylic acid (PCA, Shenqinbactin) and its derivative phenazine-1-carboxylic hydrazine are natural products that have been characterized to have unique chemical structures and interesting bioactivities. However, neither of them has phloem mobility. In this paper, phenazine-1-carboxylic acid and maleic hydazide were used as the corporate lead compounds which were introduced into the diacylhydrazine scaffold, and17 new compounds were designed and synthesized. Their structures were confirmed by 1H NMR, HRMS and X-Ray. The preliminary bioassay results showed that most of the compounds exhibited significant fungicidal activities against Thanatephorus cucumeris at the concentration of 50 mg/L. In particular, compound 6m showed the best fungicidal activity against T. cucumeris with the rate of 92% at 50 mg/L. However, all target compounds do not have phloem mobility.