[C:1]1([C:11](=[O:16])[CH2:12][C:13](=[O:15])[CH3:14])[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH:4]=[CH:3][CH:2]=1.[C:17](OCC)(=[O:23])[C:18]([O:20][CH2:21][CH3:22])=[O:19].[H-].[Na+].Cl>COCCOC.O>[C:1]1([C:11](=[O:16])[CH2:12][C:13](=[O:15])[CH2:14][C:17](=[O:23])[C:18]([O:20][CH2:21][CH3:22])=[O:19])[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH:4]=[CH:3][CH:2]=1
A solution of 1-(1-naphthalenyl)-1,3-butanedione (5.3 g) and diethyl oxalate (6.75 ml) in 1,2-dimethoxyethane (10 ml) was added dropwise to a stirred suspension of sodium hydride (3.6 g, 50% dispersion in mineral oil, washed with petrol 40-60° C.) in 1,2-dimethoxyethane (40 ml) under nitrogen. The stirred mixture was heated under reflux for 5 minutes, cooled, acidified with 2M hydrochloric acid (50 ml), diluted with water (50 ml) and filtered. The filtrate was extracted with ethyl acetate and the extract was dried and evaporated to yield ethyl 6-(1-naphthalenyl)-2,4,6-trioxohexanoate as a dark oil.
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