[CH3:1][C:2]([C:4]1[CH:5]=[CH:6][C:7]([OH:10])=[CH:8][CH:9]=1)=[O:3].[H-].[Na+].[C:13](=O)([O:16]C)[O:14][CH3:15].Cl>CN(C=O)C>[OH:10][C:7]1[CH:8]=[CH:9][C:4]([C:2]([CH2:1][C:13]([O:14][CH3:15])=[O:16])=[O:3])=[CH:5][CH:6]=1A solution of 4-hydroxyacetophenone (500 g) in DMF (1.5 L) was slowly added to a suspension of sodium hydride (331 g) in DMF. The mixture was stirred for 15 min. till gas evolution had subsided. Dimethyl carbonate (1.55 L) was added and the reaction stirred overnight at room temperature. The reaction was worked up by pouring into ice (15 LB) followed by acidification to pH 2 with hydrochloric acid. The aqueous mixture was extracted with ethyl acetate (3×5 L) and this was washed with water (3×1 L) and brine, then dried (Na2SO4), filtered, and concentrated. The crude product was purified by chromatography on silica gel (10 Kg) with 15 to 40% ethyl acetate-hexane. The chromatographed product was recrystallized twice from ethyl acetate-hexane to yield 313 gm first crop material as a white powder with mp 90-92° C.
読み込み中…
