Process for the preparation of phenylmalonic acid dinitriles

1. A process comprising:

reacting a compound of Formula (I)

wherein

X, Y and Z, independently of each other, represent fluoro, chloro or C 1-4 alkyl, and with the proviso that 1 or 2 of X and Y are, independently of each other, fluoro or chloro;

with an acid in the presence of water, and toluene or xylene to form a compound of Formula (III)

2. The process according to claim 1 , wherein the reacting of the compound of Formula (I) to the compound of Formula (III) is carried out at 120 to 155° C.

3. The process according to claim 1 , wherein the acid is sulphuric acid.

4. The process according to claim 1 , wherein X is methyl, Y is chloro, and Z is methyl.

5. The process according to claim 1 , further comprising reacting a compound of Formula (II)

wherein

X, Y and Z, independently of each other, represent fluoro, chloro or C 1-4 alkyl; and

L is a leaving group;

with the proviso that 1 or 2 of X and Y are, independently of each other, fluoro or chloro, with malononitrile in the presence of a base and a palladium catalyst to form the compound of Formula (I):

6. The process according to claim 5 , wherein the reacting the compound of Formula (II) to form the compound of Formula (I) comprises:

(i) reacting malononitrile with the base forms a malononitrile anion ([NCCHCN] − ); and

(ii) reacting the compound of Formula (II) with the malononitrile anion of step (i) in the presence of the palladium catalyst forms the compound of Formula (I).

7. The process according to claim 5 , wherein X is methyl, Y is chloro and Z is methyl.

8. The process according to claim 7 , wherein L is bromo.

9. The process according to claim 5 , wherein the base is an alkali metal hydroxide.

10. The process according to claim 5 , wherein the palladium catalyst is prepared in situ from palladium (lI) or palladium (0) compounds by complexing with phosphine ligands.

11. The process according to claim 5 , wherein the reacting the compound of Formula (II) to form the compound of Formula (I) is carried out in the presence of a dipolar solvent.

12. The process according to claim 5 , wherein the reacting the compound of Formula (II) to form the compound of Formula (I) is carried out at 110 to 150° C.

13. The process according to claim 9 , wherein the alkali metal hydroxide is sodium hydroxide.

14. The process according to claim 11 , wherein the dipolar aprotic solvent is N-methyl-2-pyrrolidone.

15. The process according to claim 6 , wherein the reacting of malononitrile with a base to form a malononitrile anion ([NCCHCN] − ) is done at between 10-15° C.

16. A process comprising:

charging a container having solid sodium hydroxide with an inert atmosphere;

dropping 1-methyl-2-pyrrolidone into the container and cooling to 10-15° C. while stirring;

dropping malononitrile into the container while maintaining a temperature of 10-15° C.;

distilling off the 1-methyl-2-pyrrolidone;

adding 2-bromo-5-chloro-1,3-dimethyl-benzene to the container;

adding palladium (II) chloride, triphenylphosphine, and 1-methyl-2-pyrrolidone to the container to react the 2-bromo-5-chloro-1,3-dimethyl-benzene to 2-(4-chloro-2,6-dimethyl-phenyl)propanedinitrile; and

recrystallizing the 2-(4-chloro-2,6-dimethyl-phenyl)propanedinitrile in iso-propanol.