Aryldiones incorporating a [1,4,5]oxadiazepane ring. Part 2: chemistry and biology of the cereal herbicide pinoxaden.

Background: Pinoxaden is a new cereal herbicide that provides outstanding levels of post-emergence activity against a broad spectrum of grass weed species for worldwide selective use in both wheat and barley.

Results: Factors influencing activity and tolerance to pinoxaden were in part linked to distinct structural parts of the active ingredient. Three complementary contributions that decisively impact upon the herbicidal potency against grasses were identified: a preferred 2,6-diethyl-4-methyl aromatic substitution pattern, a dione area suitable for proherbicide formation and beneficial adjuvant effects.

Synthesis of unsymmetrical aroyl acyl imides by aminocarbonylation of aryl bromides.

Aroyl imides were prepared by a palladium-catalyzed aminocarbonylation reaction of aryl bromides with carbon monoxide and primary amides in good yields (58-72%). The reactions were carried out under mild conditions (5 bar, 120 degrees C) using 1 mol % of a palladium phosphine complex. Several aryl bromides were reacted with formamide, acetamide, benzamide, and benzenesulfonamide, respectively.

A More Efficient Catalyst for the Carbonylation of Chloroarenes.

The right ligand enables the efficient carbonylation of unactivated chloroarenes. A general synthesis of benzoic acid derivatives is possible with the palladium-ferrocenylphosphane catalysts.