Process for preparing 1-alkyl-4- (2-chloro-3-alkoxy- 4-alkylsulfonylbenzoyl) -5-hydroxypyrazole and related compounds

摘要

Herbicidal 1-alkyl-4-(2-chloro-3-alkoxy-4-alkylsulfonylbenzoyl)-5-hydroxypyrazole compounds, as well as 1-halo-2-chloro-3-alkoxy-4-alkylsulfonylbenzene compounds and 2-chloro-3-alkoxy-4-alkylsulfonylbenzoic acid compounds, were prepared in good yield by the reaction of the corresponding 3-chloro compound with an alkali metal alkoxide compound. 1-Halo-2-chloro-3-alkoxy-4-alkylsulfonylbenzene and 1-halo-2,3-dichloro-4-alkylsulfonylbenzene compounds were converted to compounds having hydroxycarbonyl, alkoxycarbonyl, or 1-alkyl-5-hydroxypyrazole-4-carbonyl substituents in place of the 1-halo substituent by reaction with carbon monoxide and water, an alcohol, or a 1-alkyl-5-hydroxypyrazole compound, respectively, in the presence of a palladium II salt:trihydrocarbylphosphine complex type catalyst.