Process for the preparation of 2,3-pyridinedicarboximides

A process for the preparation of a 2,3-pyridinedicarboximide having the structural formula I ##STR23## wherein R is hydrogen, C.sub.1 -C.sub.6 alkyl or C.sub.1 -C.sub.6 alkoxymethyl;

• R.sub.1 is hydrogen, C.sub.1 -C.sub.6 alkyl, C(O)R.sub.2,
• phenyl optionally substituted with any combination of from one to four halogen, or one to two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro or cyano groups,
• benzyl optionally substituted on the phenyl ring with any combination of from one to four halogen, or one to two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro or cyano groups, or ##STR24## R.sub.2 is C.sub.1 -C.sub.6 alkyl, benzyl or phenyl optionally substituted with any combination of from one to four halogen, or one to two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro or cyano groups;
• R.sub.3 and R.sub.4 are each independently C.sub.1 -C.sub.4 alkyl;
• and
• R.sub.5 is cyano or CONH.sub.2, which process comprises reacting an oxime or hydrazone having the structural formula II ##STR25## wherein R is as described above;
• R.sub.6 is C.sub.1 -C.sub.6 alkyl;
• R.sub.7 is OR.sub.8 or NR.sub.9 R.sub.10 ;
• R.sub.8 is hydrogen, C.sub.1 -C.sub.6 alkyl, C(O)R.sub.11,
• phenyl optionally substituted with any combination of from one to four halogen, or one to two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro or cyano groups, or
• benzyl optionally substituted on the phenyl ring with any combination of from one to four halogen, or one to two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro or cyano groups;
• R.sub.11 is C.sub.1 -C.sub.6 alkyl, OR.sub.12, NR.sub.12 R.sub.13, benzyl or
• phenyl optionally substituted with any combination of from one to four halogen, or one to two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro or cyano groups;
• R.sub.12 and R.sub.13 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl,
• benzyl or
• phenyl optionally substituted with any combination of from one to four halogen, or one to two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro or cyano groups;
• and
• R.sub.9 and R.sub.10 are each independently hydrogen, C.sub.1 -C.sub.6 alkyl,
• benzyl or
• phenyl optionally substituted with any combination of from one to four halogen, or one to two C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, nitro or cyano groups,
• with a maleimide having the structural formula III ##STR26## wherein R.sub.1 is as described above.