Process for the preparation of pyrrolidinone compound herbicides and their intermediates

A process for the preparation of a compound of general formula II: wherein R1 is hydrogen or C1-C10 hydrocarbyl or heterocyclyl having 3 to 8 ring atoms, either of which may optionally be substituted with halogen (I.e. chlorine, bromine, fluorine or iodine), hydroxy, SO2NRR (where R and R are independently II or C1-C6 alkyl), SiR3 (where each R is independently C1-C4 alkyl or phenyl), cyano, nitro, amino, mono- and dialkylamino in which the alkyl groups have from 1 to 6 or more carbon atoms, acylamino, C1-C6 alkoxy, C1-C6 haloalkoxy, C1-C6 alkylthio, C1-C6 alkylsulphinyl, C1-C6 alkylsulphonyl, carboxy, carboxyamide, in which the groups attached to the N atom may be hydrogen or optionally substituted lower hydrocarbyl; alkoxy carbonyl wherein the alkoxy group may have from 1 to 6 or more carbon atoms, or aryl such as phenyl; each R2, R3, R4 and R5 is independently hydrogen or C1-C4 alkyl; A is an aromatic or heteroaromatic ring system optionally substituted with one or more substituents selected from: halogen or C1-C10 hydrocarbyl, -O(C1-C10 hydrocarbyl), -S(C1-C10 hydrocarbyl), -SO(C1-C10 hydrocarbyl) or -SO2 (C1-C10 hydrocarbyl), cyano, nitro, SCN, SiR3 (where each R is independently C1-C4 alkyl or phenyl), COR7, CR7NOR8, NHOH, ONR7R8, SF5, COOR7, SO2NR7R8, OR9 or NR10R11; and in which any ring nitrogen atom may be quaternised or oxidised; alternatively, and any two substituents of the group A may combine to form a fused 5- or 6- membered saturated or partially saturated carbocyclic or heterocyclic ring in which any carbon or quaternised nitrogen atom may be substituted with any of the groups mentioned above for A or in which a ring carbon atom may be oxidised; R7 and R8 are each independently hydrogen or C1-C10 hydrocarbyl; R9 is hydrogen, C1-C10 hydrocarbyl, SO2(C1-C10 hydrocarbyl), CIIO, CO(C1-C10 hydrocarbyl), COO(C1-C10 hydrocarbyl) or CONR7R8; R10 and R11 are each independently hydrogen, C1-C10 hydrocarbyl, O(C1-C10 hydrocarbyl), SO2(C1-C10 hydrocarbyl), CHO, CO(C1-C10 hydrocarbyl), COO(C1-C10 hydrocarbyl) or CONR7R8; any of the hydrocarbyl groups within the group A may optionally be substituted with halogen (i.e. chlorine, bromine, fluorine or iodine), hydroxy, SO2NRR (where R and R are independently H or C1-C6 alkyl), cyano, nitro, amino, mono- and dialkylamino in which the alkyl groups have from 1 to 6 or more carbon atoms, acylamino, C1-C6 alkoxy, C1-C6 haloalkoxy, C1-C6 alkylthio, C1-C6 alkylsulphinyl, C1-C6 alkylsulphonyl, carboxy, carboxyamid