反应详情

A stirred solution of 1,4-dimethoxy-2,3,5-trimethylbenzene (61.2 g) was dissolved into 350 mL acetic acid (1.0 M) and treated with a solution of Br2 (17.7 mL, 55.1 g,) in 115 mL acetic acid over 1 h. The reaction was stirred for an additional hour and poured over 1.5 l ice. The cloudy solution was filtered and the solids washed 2×200 mL H2O and dried under high vacuum. The product was azeotroped twice from toluene to remove residual acetic acid to give 73.6 g of 1-bromo-2,5-dimethoxy-3,4,6-trimethylbenzene as a red-brown solid.; Mp 57.2-62.8° C.; 1H NMR (400 MHz, CDCl3) δ=3.75 (s, 3 H), 3.66 (s, 3 H), 2.35 (s, 3 H), 2.22 (s, 3H), 2.17 (s, 3H) ppm.

1. filtrationThe cloudy solution was filtered
2. washthe solids washed 2×200 mL H2O
3. customdried under high vacuum
4. customThe product was azeotroped twice from toluene
5. customto remove residual acetic acid