Jeremy Kister

synthetic route to quinoxyfen photometabolite 2‐chloro‐10‐fluorochromeno[2,3,4‐de]quinoline

BACKGROUND Quinoxyfen is a fungicide developed by Dow AgroSciences for the control of powdery mildew. Re-registration studies required gram quantities of 2-chloro-10-fluorochromeno[2,3,4-de]quinoline, a photometabolite of quinoxyfen. The only previous method of preparation of this photometabolite was by photolysis of quinoxyfen in less than 1% yield. Therefore, a new method allowing for the preparation of this photometabolite in gram quantities was required. RESULTS Several different metal catalyzed intramolecular cyclization approaches were investigated for the synthesis of 2-chloro-10-fluorochromeno[2,3,4-de]quinoline. While most methods failed to provide the desired product from a 2-bromophenyl derivative of quinoxyfen, a novel one-pot two-step synthesis led to the desired material in good yield from quinoxyfen. CONCLUSION A short and efficient synthetic route was developed to access 2-chloro-10-fluorochromeno[2,3,4-de]quinoline from readily available (4-fluoro-2-hydroxyphenyl)boronic acid and quinoxyfen and was found to be scalable, which enabled the preparation of the desired photometabolite in gram quantities thus meeting material requirements to complete regulatory studies for the re-registration of quinoxyfen.

Physicochemical property guidelines for modern agrochemicals: Physicochemical properties for agrochemicals

The relentless need for the discovery and development of new agrochemicals continues as a result of driving forces such as loss of existing products through the development of resistance, the necessity for products with more favorable environmental and toxicological profiles, shifting pest spectra, and the changing agricultural needs and practices of the farming community. These new challenges underscore the demand for novel, high-quality starting points to accelerate the discovery of new agrochemicals that address market challenges. This article discusses the efforts to identify the optimum ranges of physicochemical properties of agrochemicals through analysis of modern commercial products. Specifically, we reviewed literature studies examining physicochemical property effects and analyzed the properties typical of successful fungicides, herbicides, and insecticides (chewing and sap-feeding pests). From the analysis, a new set of physicochemical property guidelines for each discipline, as well as building block class, are proposed. These new guidelines should significantly aid in the discovery of next-generation agrochemicals.