| 摘要 |
The present invention relates to a process for the preparation of 2-halogenopyridine derivatives of the general formula (I) <IMAGE> in which X represents halogen and Y represents halogeno, nitro, formyl, cyano, carboxyl, carbamoyl, alkyl, halogenoalkyl, alkoxyalkyl, dialkoxyalkyl, alkoxycarbonyl, alkylaminocarbonyl or dialkylaminocarbonyl, with the exception of compounds in which X represents chlorine and Y simultaneously methyl, which is characterised in that, in a first step, pyridine 1-oxides of the general formula (II) <IMAGE> in which Y has the abovementioned meaning are reacted with an organic nitrogen base A and an electrophilic compound, if appropriate in the presence of a diluent, to give compounds of the general formula (III) <IMAGE> in which A represents the radical of an organic nitrogen base, Y has the abovementioned meaning and Z<-> represents an anion formed from an electrophilic compound, if appropriate the compounds of the formula (III) are isolated as crude products or if appropriate further purified, and, in a second step, these compounds are reacted with a halogenating agent at temperatures between 10@C and 150@C, if appropriate in the presence of an alkyl halide and if appropriate in the presence of a diluent. The invention furthermore relates to the new compounds of the formula (III). |
