A 1N aqueous saturated solution of sodium hydroxide (5 ml) was added to a solution of ethyl E-4-(2-furyl)-4-[4-(5-methyl-2-phenyl-4-oxazolylmethoxy)benzyloxyimino]butyrate (190 mg) in tetrahydrofuran (10 ml)-methanol (5 ml) and stirred at room temperature for 1 hour. 1N hydrochloric acid (5.5 ml) was added to the reaction mixture and extracted with ethyl acetate. The ethyl acetate layer was washed with an aqueous saturated solution of sodium chloride, dried (MgSO4) and concentrated. The residue was recrystallized from ethyl acetate-hexane to obtain E-4-(2-furyl)-4-[4-(5-methyl-2-phenyl-4-oxazolylmethoxy)benzyloxyimino]butyric acid (140 mg, yield 78%) as colorless crystals. m.p. 124-125° C.
