Substituted pyrido[1,2-a]pyrimidin-4-ones, quinazolin-4-ones and thieno[2,3-d]pyrimidin-4-ones represent a potent class of plant protection agents possessing high protectant activity against powdery mildew strains of fungi. These compounds prevent pathogen penetration via inhibition of appressorial formation following spore germination on the leaf surface.  The lead compound was prepared as a herbicide intermediate and was found to exhibit modest powdery mildew control in a non-targeted high-throughput screening effort.  Synthetic follow-up gave rise to much more active analogs that prompted field evaluation.  However, poor greenhouse to field translation required a crucial scaffold-hop to a new heterocyclic ring system that maintained excellent levels of activity under field conditions.  A multiple year optimization effort gave rise to the commercial product proquinazid, that provided excellent preventative powdery mildew control on cereals, grapes and other crops at very low rates of application.  Proquinazid is a member of FRAC (Fungicide Resistance Action Committee) 13 (signal transduction inhibitors).  This talk will focus on chemistry, biology and SAR for this agrochemical class along with some of the challenges overcome in bringing a compound to the marketplace.

Lessons learned in the discovery and optimization of a potent class of powdery mildew control agents

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.