| 摘要 |
The invention relates to a process for the preparation of pyridylcarboxylic amides and esters I, Formula (I) wherein Hal, X and Rhave the meanings given in claim 1, which comprises the following steps: (a) heating a mixture consisting essentially of trichloromethylpyridine II, Formula (II), wherein Hal has the meaning given, and 1.0 to 1.5 equivalents of concentrated sulfuric acid, characterized in that the trichloromethylpyridine II in a liquid form is added to the concentrated sulfuric acid at a temperature from 110 °C to 160 °C; and (b) reacting the intermediate product obtained in step (a) with an amine or alcohol III, HXR, wherein X and Rhave the meaning given, optionally in the presence of a solvent and/or a base., (I), (II) |
