Alkylation of ethyl 4-hydroxybenzoate (I) with 2-iodobenzyl bromide (II) affords the 4-benzyloxybenzoate (III). Subsequent reaction of ester (III) with hydrazine hydrate produces the hydrazide (IV), which is subjected to a Michael reaction with acrylonitrile (V), yielding (VI). Finally, cyclization of the hydrazide (VI) with triphosgene gives rise to the target ozadiazole derivative.