24544-04-5

57190-17-7

General procedure for the synthesis of 2-bromo-1,3-diisopropylbenzene from 2,6-diisopropylaniline: 181 ml of 47% hydrobromic acid solution (1.57 mol) was slowly added dropwise to 35.5 g (0.20 mol) of 2,6-diisopropylaniline over a 15-minute period at room temperature. The white suspension formed was cooled to -56°C and 23.6 g (0.34 mol) of sodium nitrite was added in batches over 10 min and stirring was continued at the same temperature for 1 hr. Subsequently, 250 ml of pre-cooled ether was slowly added over 10 minutes and the temperature of the reaction mixture was slowly raised to -15°C over 2 hours until no more gas escaped. The reaction mixture was again cooled to -56°C and 24 mL of water was added followed by 118.5 g (0.41 mol) of sodium carbonate decahydrate to give a brown suspension. The reaction mixture was warmed to room temperature within 3 hours and the gas was released from -32°C. The resulting orange suspension was continued to be stirred at room temperature for 16 hours. After completion of the reaction, the aqueous phase was separated and the organic phase was washed three times with water, dried and concentrated in vacuum. Further purification by silica gel column chromatography (eluent: heptane) afforded the target product 2-bromo-1,3-diisopropylbenzene as a colorless oil (yield: 38.7 g, 80%).1H NMR (400 MHz, CDCl3) data: δ = 1.33 (d, 12H), 3.54-3.66 (m, 2H), 7.19-7.23 (m, 2H) , 7.30-7.35 (m, 1H).