Patent ID: 6103906
Filing Date: 2000-08-15
Classification: C07D

Abstract:
A process for the preparation of a 2,6-pyridinedicarboxylic acid ester of the formula: ##STR5## wherein R.sup.1 is a C.sub.1-6 -alkyl group, a C.sub.3-8 -cycloalkyl group, an aryl group or an arylalkyl group, and R.sup.2 and R.sup.3 independently of one another are hydrogen or chlorine and R.sup.4 is hydrogen, a C.sub.3-8 -alkyl group, a C.sub.1-8 -alkyloxy group or fluorine, characterized in that a halopyridine of the formula: ##STR6## wherein R.sup.2, R.sup.3 and R.sup.4 have the above-mentioned meanings and X is a chlorine or bromine, is reacted with carbon monoxide and an alcohol of the formula:R.sup.1 --OH IIIwherein R.sup.1 has the above-mentioned meaning, in the presence of a base and of a complex of palladium, using a bisdiphenylphosphine of the formula: ##STR7## wherein Q is a C.sub.3 -C.sub.6 -alkanediyl group or a 1,1.sup.1 -ferrocenediyl group having cyclopentadienyl groups which are optionally substituted by C.sub.1 -C.sub.4 -alkyl or aryl groups and R.sup.5 to R.sup.8 independently of one another are hydrogen, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, monofluoromethyl, difluoromethyl, trifluoromethyl, fluorine, aryl, aryloxy, cyano or dialkylamino, the base is an alkali metal or alkaline earth metal acetate, carbonate, hydrogen carbonate, phosphate or hydrogen phosphate, the reaction temperature is 100.degree. to 250.degree. C. and the carbon monoxide pressure is 1 to 200 bar.