Process for preparing 3 -(1 -hydroxyphenyl -1 -alkoximinomethyl) dioxazines

Preparation of 3-(1-hydroxyphenyl-1-alkoxyiminomethyl)dioxazine derivatives of formula (I), comprises: (a) rearranging O-hydroxyethyl-O'-alkyl-benzofuran-dionedioxime optionally in the presence of a diluent and optionally in the presence of a base or an acid; and (b) optionally separating the E-isomer from the optional mixture of stereoisomers, optionally in the presence of a diluent and optionally in the presence of an acid: A = alkyl; R1-R4 = H, halo, CN, NO2 or optionally halo substituted alkyl, alkoxy, alkylthio, alkylsulphinyl or alkylsulphonyl; Z1-Z4 = H, alkyl, haloalkyl or hydroxyalkyl; or CZ1Z2, CZ1Z3 or CZ3Z4 = cycloaliphatic ring.