| 摘要 |
A method for preparing pyridine-2,3-dicarboxylic acid esters of the general formula: wherein R is C<SUB>1-6</SUB>-alkyl, C<SUB>3-6</SUB>-cycloalkyl, aryl or arylalkyl, and R<SUP>1 </SUP>to R<SUP>3</SUP>, independently of one another, represent hydrogen, C<SUB>1-6</SUB>-alkyl, fluorinated C<SUB>1-6</SUB>-alkyl, C<SUB>1-6</SUB>-alkoxy, (C<SUB>1-6</SUB>-alkoxy)-C<SUB>1-6</SUB>-alkyl or (C<SUB>1-6</SUB>-alkoxy)carbonyl. These esters are obtained from the corresponding 2,3-dichloropyridine, the corresponding alcohol ROH and carbon monoxide in the presence of a palladium-diphosphine complex and a weak base. Pyridine-2,3-dicarboxylic acid esters are herbicides or intermediates for the preparation of herbicides.
|
