2-BROMO-1-(2,4-DIMETHOXY-6-HYDROXY)ETHANONE synthesis

Yield:18064-88-5 76.3%

Reaction Conditions:

Stage #1: 1,2,3-trimethoxybenzenewith carbon disulfide;aluminum (III) chloride at 0; for 0.5 h;Inert atmosphere;
Stage #2: 2-Bromoacetyl bromide at 45; for 48 h;Inert atmosphere;

Steps:

2-fluoro-1-(2-hydroxy-4,6-dimethoxyphenyl)ethanone

Underthe N₂ atmosphere, 1.68 g (10 mmol, 1eq) 1,3,5-trimethoxybenzene wasadded into dried 20 ml CS2. Cooled to 0 ^oC, 1.73 (13 mmol, 1.3 eq) anhydrous AlCl3 was added into the solution andstirred for about 30 min, followed by the addition of 2.22 g (11 mmol, 1.1 eq) 2-bromoacetylbromide. The mixture was stirred at 45 ^oC for about 48 hours until 1,3,5-trimethoxybenzenewas consumed completely. Then CS2 was removed and 30 ml aq. 3 N HCl was added,the mixture was left overnight. A large amount of water was added. The pH wasadjusted to about 3, extracted with ethyl acetate three times. The organiclayer was combined and dried by Mg₂SO₄, the crude productwas purified by si-gel column chromatography to afford 2.1 g 2-bromo-1-(2-hydroxy-4,6-dimethoxyphenyl)ethanone,white solid, yield 76.3%. The intermediate was dissolved into 20 ml dried acetonitrile,followed by the addition of tetrabutylammonium bromide and anhydrous potassiumfluoride (3.0 eq.). The mixture was refluxed for overnight. Afterthe starting material was consumed completely, the solvent was removed underreduced pressure. The crude product was purified by si-gel chromatography toafford desired compound 2-fluoro-1-(2-hydroxy-4,6-dimethoxyphenyl)ethanone 1.4g, pale white solid, yield 87.5%.

References:

Chen, Lijuan;Fan, Tiantian;Lei, Xiangui;Teichmann, Alexander Tobias;Wang, Amu;Wang, Chao;Wei, Zhe;Wieland, Frank Heinrich;Yang, Youzhe;Yin, Jinxiang;Zhou, Li;Zhu, Yue [European Journal of Medicinal Chemistry,2020,vol. 193] Location in patent:supporting information