New Allyldithiocarbimates: Synthesis, Structure and Antifungal Activity against Phakopsora pachyrhizi and Hemileia vastatrix

Twelve tetraphenylphosphonium allyldithiocarbimates were synthesized and fully characterized by high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), infrared and nuclear magnetic resonance (NMR) spectroscopies. The spectroscopic data indicated that the allyldithiocarbimate anions present Z configuration, as confirmed by X-ray crystallography. These new compounds inhibited the germination of Phakopsora pachyrhizi and Hemileia vastatrix at very low doses, with IC50 (concentration to achieve 50% of inhibition of spore germination) values ranging from 0.028 to 0.166 mmol L-1, and IC90 (concentration to achieve 90% of inhibition of spore germination) values varying from 0.156 to 0.528 mmol L-1. Allyldithiocarbimate salts are lead compounds for the development of new antifungals for coffee leaf rust and Asian soybean rust, devastating plant diseases with limited control options.