Hydrogen Bromide → 4-bromophthalonitrile

Participants

Reaction Conditions

Reaction Steps

Compound 4 (24 g, 0.17 mol) was suspended in a stirring solution of 100 ml HBr (48%) and 100 ml of H2O cooled to −10° C. Sodium nitrite (14 g, 0.20 mol) was dissolved in ice water and added dropwise to the solution of 4-aminophthalonitrile. The exothermic reaction was carefully monitored and kept under 0° C. After 2 hours of stirring, the solution was added dropwise to a solution of Cu(I)Br (27 g, 0.18 mol) in 100 ml of HBr (48%) at −3° C. and stirred at 0° C. for 2 hours. To minimize foaming as well as increase the yield, methylene chloride was added to the solution and the reaction was allowed to proceed overnight for at least 24 hours. The organic layer was removed, and the aqueous layer was also extracted with toluene. The combined organic layers were washed with water, Na2S2O3 (saturated aqueous solution), water, brine, water, dried over MgSO4 and evaporated under reduced pressure. 25 g of an orange product were collected (73%). 1H NMR (CDCl3) δ: 7.99 (d, 1H), 7.94-7.91 (dd, 1H), 7.72-7.70 (d, 1H).6 13C{1H}NMR (CDCl3) 136.68, 136.42, 134.44, 128.19, 117.39, 114.76, 114.65, 114.04 ppm.

Provenance & Evidence