Verbessertes Verfahren zur Herstellung von N,N-Bis(alkoxyalkyl)-pyridin -2,4-dicarbonsäurediamiden.

摘要

The invention relates to a process for the preparation of N,N'-bis(alkoxyalkyl)diamides of pyridine-2,4-dicarboxylic acid, and to the use of these compounds for preparing drugs for oral administration. The process according to the invention yields the compounds of the formula I in which R<1> is C1-C4-alkyl which is monosubstituted with C1-C4-alkoxy, by initially A) reacting pyridine-2,4-dicarboxylic acid in toluene with a 2-3-fold excess of SOCl2 at temperatures of 90-110 DEG C, dissolving the resulting intermediate in dioxane and B) mixing 4 times the molar amount of alkoxyalkylamine of the formula II H2N-(R<2>)-OR<3> (II) in which R<2> is C1-C4-alkylene and R<3> is C1-C4-alkyl with dioxane, and subsequently, at a temperature of -5 to +5 DEG C, either adding the solution prepared as in A) dropwise to the solution prepared as in B), or adding the solution prepared as in B) dropwise to the solution prepared as in A), and then allowing reaction to continue at room temperature.