reaction of 2-chloromethyl-4,5-dichloropyridazin-3(2H)-one () with some phenols in the presence of a base in organic solvents. Seven diphenoxy derivatives were synthesized selectively from and phenols under two optimized conditions. The product distributions of these reactions are dependent on the base, the solvent, and/or the substitutes of phenols. J. Heterocyclic Chem., (2009).