Ethyl Acetate → 4H-3,1-Benzoxazin-4-one, 2,2'-(2-phenylethenylidene)bis-

Participants

Reaction Steps

The compound 11 (4.0 g, 9.3 mmol) was mmol) was dropwise added under ice cooling. To the mixture, 8 drops of dry DMF was further added, and the mixture was stirred at room temperature for 2 hours. After completion of the reaction, the solvent was removed, and the residue was extracted with chloroform. The extract was washed with 1N.HCl, saturated aqueous NaCl soluticn, 4% NaHCO3 aqueous solution, and saturated aqueous NaCl solution and dried over MgSO4. The solvent was evaporated to give a pale yellow solid. The resultant product was dissolved in a mixed solution of benzene:ethyl acetate=1:1 and applied on a silica gel column for chromatography (developing solvent, benzene:ethyl acetate - 1:1). After removing the solvent from the eluent containing 2,2'-phenylethenilidene-bis(3,1-benzoxazine-4-one) [Compound 52], the residue was crystallized from isopropyl ether to give the Compound 52 in white solid (3.0 g, yield, 82%), which was recrystallized from the mixed solvent of benzene and n-hexane to give white crystal (2.5 g, yield, 68%). m.p., 214°-215° C.

Provenance & Evidence