Patent ID: 6916934

Claim:
A process for preparing 1-(pyridinyl)-1,1-dialkoxy-1-aminoethane derivatives of the formula (I) wherein R 1 and R 2 are each independently straight-chain or branched (C 1 -C 6 )-alkyl, or R 1 and R 2 together with the oxygen atoms form a cyclic ketal wherein R 1 and R 2 together are a (C 2 -C 4 )-alkylidene group, and wherein the pyridine radical is substituted in the 2-, 3- or 4-position, comprising: (a), converting acetylpyridine of the formula (V) using an aqueous solution of a hydroxylammonium compound or an aqueous solution of hydroxylamine, in the presence of an inorganic base, to the acetylpyridine oxime metal salt of the formula (IX) wherein n is 1 or 2 and M n+ is an alkali metal or alkaline earth metal ion (b), reacting the acetylpyridine metal salt of the formula (IX) with a solution of a p-toluenesulfonic acid derivative (X) containing a leaving group Y wherein Y is F, Cl or Br, in a suitable solvent which is water-immiscible or sparingly water-soluble or water-insoluble to give the acetylpyridine tosyl oxime of the formula (XI) the reaction proceeding in a biphasic mixture of water and suitable solvent, optionally with the use of one or more phase transfer catalysts, (c), reacting acetylpyridine tosyl oxime of the formula (XI) with a mixture of an alkali metal alkoxide, an alkali metal hydroxide, an alkaline earth metal alkoxide or an alkaline earth metal hydroxide with an alcohol to produce a compound of the formula (I), wherein alkoxide is R 1 O − or R 2 O − , and wherein alcohol is R 1 OH or R 2 OH, and R 1 and R 2 are each as defined for the compound of the formula (I); and conducting the process continuously or batchwise independently for each process step (a) to (c).