CC(C)([O-])C.[Li+].[OH:7][C:8]1[C:13]([N+:14]([O-:16])=[O:15])=[C:12]([OH:17])[CH:11]=[CH:10][C:9]=1[C:18](=[O:20])[CH3:19].[CH2:21](Br)[C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1.C(O)C>CN(C=O)C>[CH2:21]([O:17][C:12]1[CH:11]=[CH:10][C:9]([C:18](=[O:20])[CH3:19])=[C:8]([OH:7])[C:13]=1[N+:14]([O-:16])=[O:15])[C:22]1[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=1Lithium tert-butoxide (4.06 g) was added to a stirred solution of 1-(2,4-dihydroxy-3-nitrophenyl)ethanone (example 11, step a) (10 g) in DMF (100 mL), under nitrogen, whilst maintaining the internal temperature below 30° C. After stirring for a further 10 minutes at ambient temperature, benzyl bromide (6.03 mL) was added and the mixture stirred for a further 20 h. Further benzyl bromide (3 mL) was added and the mixture stirred for 24 h. The reaction was quenched with water (300 mL), 1M aqueous sodium hydroxide (50 mL) was added and the mixture was washed with diethyl ether (2×300 mL), filtering through Celite to aid separation. The basic solution was cooled in ice/water, acidified with ice cold 2M hydrochloric acid (200 mL) and the resulting precipitate filtered off, washed with water and dried to afford a light brown solid. The solid was slurried with ethanol (100 mL) for 1 h and the solid filtered off, washed with cold ethanol (20 mL), and dried under vacuum at 40° C. to afford the subtitled compound as a light brown solid. Yield 6.8 g.
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