| 摘要 |
The invention relates to a novel process and novel intermediates for the preparation of 2-amino-5-methylpyridine (I) <IMAGE> The process is characterised in that, in a first step, 3-methylpyridine-1-oxide, of the formula (II), <IMAGE> is reacted with a trialkylamine of the general formula (III> R3N (III> in which R represents alkyl, and with an electrophilic compound, if appropriate in the presence of a diluent, to give the ammonium salt of the general formula (IV) <IMAGE> in which R has the abovementioned meaning and Z(-) represents an anion formed by an electrophilic compound, and, if appropriate, the compound (IV) is isolated as a crude intermediate and, if appropriate, subjected to further purification, and then, in a second step, a) either the ammonium salt of the formula (IV) is reacted with hydrogen bromide, if appropriate in the presence of a diluent, at temperatures of between 150 DEG C and 300 DEG C, b) or, alternatively, an alkyl compound RZ is eliminated from the compound (IV) by customary methods and the resulting 2-dialkylamino-5-methylpyridine of the general formula (V) <IMAGE> in which R has the abovementioned meaning, is reacted with hydrogen bromide, if appropriate in the presence of a diluent, at temperatures between 150 DEG C and 300 DEG C. Compound (I) is an intermediate for the preparation of agrochemicals, for example herbicides. |
