Seven 2-tert-butyl-4-chloro-5-（3′-aryl-2′-oxo-5′-oxazolidinylmethoxy）-3（2H）pyridazinones were synthesized via the reaction of aryl isocyanates and 2-tert-butyl-4-chloro-5-（2,3-epoxypropyloxy）-3（2H）（pyridazinones） prepared by the reaction of 2-tert-butyl-4-chloro-5-hydroxy-3（2H）pyridazinones with epichlorohydrin. The structures of the title compounds were confirmed by 1H NMR, HR MS and IR. The （bioassay） tests showed the inhibition of compound 2b and that of compound 2c against Colletotrichum （lagenarium） under （500 mg/L） were 33% and 50%, respectively.
