In a 100 mL single-necked flask, add m-bromobenzyl azide (5 mmol, 1.06 g) and chloroform (25 mL) as solvent. Under argon protection, add 25 mL of dichloromethane solution containing boron tribromide (18 mmol, 4.50 g) dropwise at 2 °C. After the addition is complete, react at 45 °C for 14 h. After the reaction is complete, quench with ethanol (25 mL) for 0.5 h. The reaction solution becomes clear. The reaction solution is concentrated by rotary evaporation and then recrystallized from methanol/ether to obtain the white target product with a yield of 84% (0.781 g).
Melting point: 252-254℃; 1HNMR (500MHz, CDCl3)δ7.45(s,1H),7.38(d,J＝8.0,1H),7.23(d,J＝7.5 ,1H),7.16(t,J=7.5,1H),3.80(s,2H),2.85(bs,2H);13CNMR(125MHz,CDCl3)δ144.0, 130.2,126.1,122.7,45.3; HRMS(ESI)calcdforC7H8BrN[M+H]+:184.98401; found: 184.98389.
