| 摘要 |
A process for preparing mesotrione enolate comprising the step of providing a solution of mesotrione in organic solvent and contacting the solution with a moderate base in the presence of water at pH 6-8 to form an aqueous mesotrione enolate solution. Preferably the solvent is selected from an ether, a haloalkane, a cycloalkane, and organic nitrile such as acetonitrile, and mixtures thereof. Preferably, the moderate base is selected from a trialkylamine, an alkali metal carbonate, an alkali metal phosphate, an alkaline earth metal carbonate, and alkaline earth metal phosphate, or mixtures thereof. Also claimed is a process for preparing mesotrione comprising conducting an enol ester rearrangement of 3-oxocyclohex-1-enyl-4-(methylsulfonyl)-2-nitrobenzoate by treatment with a cyanide ion source and a moderate base in an organic solvent where the enol ester rearrangement is carried out in the absence of a phase transfer catalyst, a transition metal salt, and an azole. Preferably the source of cyanide ion is acetone cyanohydrin. Also claimed is a process for preparing mesotrione comprising crystallising mesotrione from organic solvent in a batch-wise fashion. |
