The present invention relates to a process for preparing crystalline methyl N-[2-[[[1-(4-chlorophenyl)-1H-pyrazol-3-yl]oxy]methyl]phenyl]-N-methoxycarbamate (I), comprisinga) reacting a compound of formula II; with an alkylating agent in the presence of a base in the presence of a polar solvent selected from alcohols and ketons;b) the addition of water.展开▼