Acetyl chloride → 2,4-Dibromo-5-hydroxyphenyl acetate

Participants

Reaction Conditions

Reaction Steps

Under nitrogen, 4,6-dibromo-1,3-benzenediol (10.58 gram, 39.5 millimoles, 1.0 equivalent) and triethylamine (11.0 milliliter, 7.99 grams, 79.0 millimoles, 2.0 equivalents) dissolved in dichloromethane (80 milliliters) were cooled to 0° C. Acetyl chloride (3.09 milliliters, 43.4 millimoles, 1.1 equivalents) were added over the course of 17 minutes. The reaction was allowed to warm to room temperature and was stirred overnight. The reaction was worked up by removal of the volatiles by rotary evaporation. The solid residue was taken up in 100 milliliters ethyl acetate. The mixture was allowed to stir for 5 minutes, and the precipitate was removed by filtration. The product was purified by gradient flash column chromatography (ethyl acetate in hexane, 0 to 40%). The product was obtained in the form of a colorless solid (6.73 grams, 21.7 millimoles, 55%). m.p.: 121.3° C.; 1H-NMR (400 MHz, CDCl3) δ 7.69 (s, 1H), 6.85 (s, 1H), 5.59 (s, 1H), 2.34 (s, 3H); 13C NMR (101 MHz, THF) δ 168.12, 155.60, 149.52, 136.49, 112.77, 108.40, 106.30, 20.59; FTIR 570, 647, 690, 707, 768, 842, 872, 920, 1025, 1060, 1168, 1206, 1240, 1367, 1394, 1489, 1580, 1599, 1718, 2936, 2993, 3082, 3296 cm−1; UV/Vis: 221, 229 (overlapping), 292 nm; ESI/MS/MS of m/z=309: 309 [M79Br/81Br-H]−, 267 [M79Br/81Br—(CH2C═O, H)]−, 81 [81Br]−, 79 [79Br]−; HRMS (ESI−): calc. for C8H5Br2O3− [M-H]− 306.8605, found 306.8622.

Provenance & Evidence