Improved process for the preparation of substituted...

Details Improved process for the preparation of substituted... Improved process for the preparation of substituted...

C - Chemistry, Metallurgy

07

D

C07D 213/803 (2006.01) C07D 213/79 (2006.01) C07D 213/80 (2006.01) A01N 43/40 (2006.01)

Patent

CA 2335854

The invention relates to a method for producing substituted pyridine- carboxylic acids by ozonolysis of quinolines of the formula (I) which in position 2 and/or 3 and/or 4 are substituted by R3 and in position 6 and/or 7 by R4, whereby R1 and R2 are H or a C1-C3-alkyl group, R3 and R4 are a group which is inert under the reaction conditions and at least one of the rests R1 and R2 is not H. According to said method the quinolines are reacted in an aqueous acid solution at temperatures of between -5 and +40 °C with ozone, and the solution obtained in this way is maintained for between 0.5 and 15 hours at a temperature of between 0 and 100 °C with the addition of oxygen or air so as to break down the resulting peroxides. Thereafter the corresponding substituted pyridine-carboxylic acid of the formula (II), in which R3 has the meaning given above and R5 and R6 are OH or a C1-C3-alkyl, whereby at least one of the rests R5 and R6 are not OH, is isolated from the reaction mixture.

Procédé amélioré de préparation d'acides pyridine-carboxyliques substitués, par ozonolyse de quinolines de formule (I) qui sont substituées en position 2 et/ou 3 et/ou 4 par R>3< et en position 6 et/ou 7 par R>4<. Dans ladite formule, R>1< et R>2< représentent H ou un groupe alkyle C>1<-C>3< et R>3< et R>4< un groupe inerte dans des conditions de réaction, et au moins un des restes R>1< et R>2< n'est pas H. Selon ledit procédé, les quinolines sont mises en réaction dans une solution acide aqueuse à des température de -5 à +40 DEG C avec de l'ozone, la solution ainsi obtenue destinée à la décomposition des peroxydes formés est maintenue à une température de 0 à 100 DEG C pendant une durée allant jusqu'à 15 heures, avec introduction d'oxygène ou d'air, et l'acide pyridine-carboxylique substitué correspondant de formule (II) dans laquelle R>3< est tel que défini ci-dessus et R>5< et R>6< représentent OH ou alkyle C>1<-C>3<, au moins un des restes R>5< et R>6< n'étant pas OH, est alors isolé du mélange de réaction.

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