Suspension Concentrate crop protection formulation design and performance for low spray volume and UAS spray application.

BACKGROUND: Unmanned aerial systems (UAS) are providing interesting disruptive solutions for spray application of crop protection products with very-low spray volumes (VLV) down to 8 L/ha that offer improved sustainability through reduced water volumes and reduced soil compaction. However, the efficacy of products can be reduced by the significantly lower crop/plant spray coverage and formulation designs that can compensate for this are highly important here. RESULTS: Suspension Concentrate (SC) formulations designed for VLV use containing and delivering low dose rates (g/ha) of organosilicone alkoxylate high-spreading surfactants were found to result in leaf coverage of VLVs comparable to those observed at higher spray volumes. High spreading was observed on textured leaf surfaces containing sub-micron sized epicuticular wax crystals. Greenhouse fungal disease studies showed enhanced efficacy with these SC formulations compared to standard SC formulations without these additives and maintained the observed increase in efficacy when applied at VLV. Alternatively, SC formulations without high spreading formulants but containing uptake promoting nonionic surfactants showed enhanced cuticle penetration through isolated cuticles at VLV in comparison to higher spray volumes, with coffee-ring spray deposit microstructures present at VLVs. Similarly, greenhouse studies showed enhanced efficacy that was maintained at VLV relative to SCs without these additives. CONCLUSION: At VLVs, SC formulations applied at relatively low dose rates (g/ha) of formulants (adjuvants) enhancing spreading on the leaf surface and/or uptake of the active ingredient(s) maintained good spreading, uptake and biological efficacy in greenhouse studies overcoming the coverage limitations of SC formulations without these additives. This result is unexpected considering the low dose rate of adjuvants used. © 2023 Bayer AG. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Enantiocontrolled synthesis of a tetracyclic aminal corresponding to the core subunit of diazonamide A.

A chiral benzylic ether serves as an auxiliary for oxindole carboxylation (dr 5.2:1.0) that sets C10 configuration in a potential diazonamide precursor. The chiral substituent allows diastereomer separation and departs during a subsequent acid-catalyzed ring closure to form a tetracyclic aminal. With suitable N-protection, crystallization affords the aminal with 98-99% ee.

A nonenzymatic acid/peracid catalytic cycle for the Baeyer-Villiger oxidation.

The combined action of carbodiimide and hydrogen peroxide upon exposure to carboxylic acid catalysts serves to generate transient peracids that can be engaged in the Baeyer-Villiger rearrangement of ketones to lactones. Up to 35 turnovers of the catalytic cycle may be achieved. The conditions are especially useful in the context of reactive cyclohexanones, and allow the use of H2O2 as the terminal oxidant. A singular example of a chiral catalyst demonstrates, in principle, that enantioselective catalysis will be possible with this strategy for catalyst turnover.

Diastereoselective carboxyl migrations of 3-arylbenzofuranones.

Mixed benzofuranyl carbonates derived from chiral chloroformates rearranged in the presence of nucleophilic catalysts to give C-carboxylated benzofurans with variable dr. The use of chiral nucleophilic catalysts gave modest improvement in dr, but better results were obtained by optimizing auxiliary and catalyst. Thus, 8k was obtained with 9:1 dr.