Process for the preparation of a spiroheterocyclic pyrrolidine dione

1. A process for the preparation of a spiroheterocyclic pyrrolidine dione compound of formula (II)

wherein

X, Y and Z independently of each other are hydrogen, C 1-4 alkyl, C 3-6 cycloalkyl, C 1-4 haloalkyl, C 1-4 alkoxy, C 1-4 haloalkoxy, halogen, cyano, C 2-6 alkenyl, C 2-6 alkynyl, phenyl, or phenyl substituted by C 1-4 alkyl, C 1-4 haloalkyl, halogen or cyano;

m and n, independently of each other, are 0, 1, 2 or 3 and m+n is 0, 1, 2 or 3;

A is hydrogen, C 1-6 alkyl, C 1-6 haloalkyl, C 3-6 cycloalkyl, C 3-6 cycloalkyl(C 1-4 )alkyl, C 2-6 alkenyl, C 2-6 haloalkenyl, C 3-6 alkynyl, C 1-4 alkoxy(C 1-4 )alkyl, benzyl, phenyl or phenyl substituted by C 1-4 alkyl, C 1-4 haloalkyl, C 1-4 alkoxy, C 1-4 haloalkoxy, halogen or cyano; and

W is a group selected from W 1 to W 15 :

wherein R is hydrogen, C 1-6 alkyl, C 1-6 haloalkyl, C 1-6 cyanoalkyl, C 2-6 alkenyl, C 2-6 haloalkenyl, C 3-6 alkynyl, benzyl, C 1-4 alkoxy(C 1-4 )alkyl or C 1-4 alkoxy(C 1-4 )alkoxy(C 1-4 )alkyl;

R q is R or Q 2 ;

p is 0, 1 or 2; and

Q 2 is hydrogen, formyl, C 1-6 alkylcarbonyl or C 1-6 alkoxycarbonyl;

which process comprises

(a) treating a compound of the formula I or a salt thereof with a suitable base in an appropriate solvent (or diluent)

wherein X, Y, Z, m, n, A, and W have the meanings given in the formula (II) above and Q 1 is C 3-6 cycloalkyl, C 1-6 alkoxycarbonyl (C 1-6 )alkyl, p-tolylsulfonylmethyl, phenyl or phenyl substituted by one or more substituent selected from the group consisting of C 1-4 alkyl, C 1-4 haloalkyl, C 1-4 alkoxy, halogen, and nitro; and Q 2 is hydrogen, formyl, C 1-6 alkylcarbonyl or C 1-6 alkoxycarbonyl;

(b) optionally a compound of formula (III) is included in step (a),

wherein Q 3 is hydrogen, halogen, C 1-6 alkyl or C 1-6 alkoxy, L is O or N(C 1-6 alkyl) and Q 4 is C 1-6 alkyl, provided the solvent (or diluent), and if necessary the compound of formula (III), is selected to activate the —NQ 1 Q 2 group to become a leaving group.

2. The process according to claim 1 , wherein at least one of the solvent (or diluent), or if present, the compound of formula (III), is a dipolar aprotic solvent.

3. The process according to claim 1 , wherein the base is selected from alkali metal or alkaline earth metal hydroxides, alkali metal or alkaline earth metal hydrides, alkali metal or alkaline earth metal amides, alkali metal or alkaline earth metal alkoxides, alkali metal or alkaline earth metal acetates, alkali metal or alkaline earth metal carbonates, alkali metal or alkaline earth metal dialkylamides or alkali metal or alkaline earth metal alkylsilylamides, alkylamines, alkylenediamines, free or N-alkylated saturated or unsaturated cycloalkylamines, basic heterocycles, ammonium hydroxides and carbocyclic amines.

4. The process according to claim 1 , wherein Q 2 is hydrogen.

5. The process according to claim 1 , wherein Q 1 is phenyl or phenyl substituted by one or more substituent selected from methyl, ethyl, iso-propyl, trifluoromethyl, methoxy, ethoxy, fluoro, chloro and nitro.

6. The process according to claim 1 , wherein A is methyl.

7. The process according to claim 1 , wherein X, Y and Z independently of one another are selected from methyl, ethyl, iso-propyl, n-propyl, methoxy, fluoro, bromo or chloro, and wherein m+n is 1 or 2.