5,6-disubstituted-3-pyridylmethyl ammonium halide compounds useful for the preparation of 5- (substituted methyl)-2,3-pyridinedicarboxylic acids

A 5,6-disubstituted-3-pyridylmethyl ammonium halide compound having the structural formula ##STR30## wherein Z is hydrogen or halogen;

• Z.sub.1 is hydrogen, halogen, cyano or nitro;
• X is Cl, Br, I or R.sub.3 SO.sub.3 ;
• R.sub.3 is C.sub.1 -C.sub.4 alkyl or
• phenyl optionally substituted with one to three C.sub.1 -C.sub.4 alkoxy groups, C.sub.1 -C.sub.4 alkyl groups, nitro groups, cyano groups or halogen atoms;
• Y and Y.sub.1 are each independently OR.sub.4, NR.sub.4 R.sub.5 ;
• R.sub.4 and R.sub.5 are each independently hydrogen,
• C.sub.1 -C.sub.4 alkyl optionally substituted with C.sub.1 -C.sub.4 alkoxy or phenyl optionally substituted with one to three C.sub.1 -C.sub.4 alkyl groups, C.sub.1 -C.sub.4 alkoxy groups or halogen atoms, or
• phenyl optionally substituted with one to three C.sub.1 -C.sub.4 alkyl groups, C.sub.1 -C.sub.4 alkoxy groups or halogen atoms;
• R.sub.6 is hydrogen or C.sub.1 -C.sub.4 alkyl;
• Q is ##STR31## R, R.sub.1 and R.sub.2 are each independently C.sub.1 -C.sub.4 alkyl, and when taken together, R and R.sub.1 may form a 5- or 6-membered ring in which RR.sub.1 is represented by the structure:
• --(CH.sub.2).sub.n --, optionally interrupted by O, S or NR.sub.10, where n is an integer of 3,4 or 5, provided R.sub.2 is C.sub.1 -C.sub.4 alkyl;
• Z.sub.2 is O, S or NR.sub.10 ;
• R.sub.10 is C.sub.1 -C.sub.4 alkyl;
• and
• R.sub.11 and R.sub.12 are each independently hydrogen, halogen, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy, and when taken together, R.sub.11 and R.sub.12 may form a 5- or 6-membered saturated or unsaturated ring optionally interrupted by O, S, or NR.sub.10 and optionally substituted with one to three halogen atoms, C.sub.1 -C.sub.4 alkyl groups or C.sub.1 -C.sub.4 alkoxy groups.