Process for the preparation of a spiroheterocyclic pyrrolidine dione

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, C1-4alkyl, C3-6cycloalkyl, C1-4haloalkyl, C1-4alkoxy, C1-4haloalkoxy, halogen, cyano, C2-6alkenyl, C2-6alkynyl, phenyl, or phenyl substituted by C1-4alkyl, C1-4haloalkyl, 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, C1-6alkyl, C1-6haloalkyl, C3-6cycloalkyl, C3-6cycloalkyl(C1-4)alkyl, C2-6alkenyl, C2-6haloalkenyl, C3-6alkynyl, C1-4alkoxy(C1-4)alkyl, benzyl, phenyl or phenyl substituted by C1-4alkyl, C1-4haloalkyl, C1-4alkoxy, C1-4haloalkoxy, halogen or cyano;
• and
• W is a group selected from W1 to W15:
• wherein R is hydrogen, C1-6alkyl, C1-6haloalkyl, C1-6cyanoalkyl, C2-6alkenyl, C2-6haloalkenyl, C3-6alkynyl, benzyl, C1-4alkoxy(C1-4)alkyl or C1-4alkoxy(C1-4)alkoxy(C1-4)alkyl;
• Rq is R or Q2;
• p is 0, 1 or 2;
• and
• Q2 is hydrogen, formyl, C1-6alkylcarbonyl or C1-6alkoxycarbonyl;
• 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 Q1 is C3-6cycloalkyl, C1-6alkoxycarbonyl (C1-6)alkyl, p-tolylsulfonylmethyl, phenyl or phenyl substituted by one or more substituent selected from the group consisting of C1-4alkyl, C1-4haloalkyl, C1-4alkoxy, halogen, and nitro;
• and Q2 is hydrogen, formyl, C1-6alkylcarbonyl or C1-6alkoxycarbonyl;
• (b) optionally a compound of formula (III) is included in step (a),
• wherein Q3 is hydrogen, halogen, C1-6alkyl or C1-6alkoxy, L is O or N(C1-6alkyl) and Q4 is C1-6alkyl, provided the solvent (or diluent), and if necessary the compound of formula (III), is selected to activate the —NQ1Q2 group to become a leaving group.