| 摘要 |
The present invention relates to a process for the synthesis of ortho-halogenated pyridinecarboxylic acids or pyridinecarboxamides. ortho-Halogenated pyridinecarboxylic acids are obtained by the reaction, in an organic solvent medium, of a halopyridine with an organolithium derivative, followed by reaction with CO2, then by hydrolysis and by acidification of the reaction medium. It is then possible to obtain the corresponding ortho-halogenated pyridinecarboxamides by the usual known methods. The invention also relates to (x+1)-fluoropyridine-x-carboxylic acid or (x+1)-fluoropyridine-x-carboxamide, x being equal to 2 or 3, and to 3-fluoropyridine-4-carboxylic acid or 3-fluoropyridine-4-carboxamide, which are novel compounds. ortho-Halogenated pyridinecarboxylic acids or pyridinecarboxamides are important intermediates in the synthesis of medicaments or of plant-protection derivatives.
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