Process for the preparation of dialkyl pyridine-2,3-dicarboxylate and derivatives thereof from dialkyl dichlorosuccinate

Claim 1

A process for the preparation of a compound of formula I ##STR5## wherein R is C 1 -C 6 alkyl; X and Z are independently hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 alkoxy or C 2 -C 5 alkenyl and Y is hydrogen, halogen, C 1 -C 6 alkyl optionally substituted with one to three halogens, hydroxy groups, C 1 14 C 4 alkoxy groups or C 1 -C 4 alkylthio groups, C 1 -C 4 alkoxycarbonyl, aminocarbonyl, phenylthio, substituted phenylthio, phenoxy, substituted phenoxy, phenyl or substituted phenyl which comprises reacting a dialkyl dichlorosuccinate of formula II ##STR6## wherein R is C 1 -C 6 alkyl with a dehydrohalogenating agent in the presence of a solvent to form a first intermediate, reacting said first intermediate with an ammonia source to form a second intermediate, reacting said second intermediate with an α, β-unsaturated aldehyde or ketone of formula III ##STR7## wherein X, Y and Z are described above and an acid in the presence of the solvent, to form the formula I pyridinedicarboxylate compound.