Trimethyl orthoacetate → 4-Bromo-6-chloro-2-methyl-1H-benzo[d]imidazole
Reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([NH2:8])[C:3]=1[NH2:9].[Cl:10][Sn]Cl.CO[C:15](OC)(OC)[CH3:16]>CCO>[Br:1][C:2]1[C:3]2[N:9]=[C:15]([CH3:16])[NH:8][C:4]=2[CH:5]=[C:6]([Cl:10])[CH:7]=1Participants
5
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Procedure
A suspension of 3-bromobenzene-1,2-diamine (4.0 g, 15.90 mmol) and SnCl2 (17.9 g, 79.50 mmol) in EtOH (40 mL) was heated at reflux for 4 h. After cooling to RT, 1,1,1-trimethoxyethane (12.9 g, 79.50 mmol) was added. The reaction mixture was stirred at 120° C. for 14 h, cooled to RT and concentrated in vacuo. The residue was diluted with EtOAc (100 mL), treated with saturated NaHCO3 solution (200 mL), filtered through Celite®, and washed with EtOAc (50 mL×3). The filtrate was washed with saturated NaHCO3, water, and brine, dried (MgSO4), filtered, and concentrated in vacuo to afford 4-bromo-6-chloro-2-methyl-1H-benzo[d]imidazole as a yellow solid (3.5 g, 89.7%). MS (ESI): m/z=244.9 [M+1]+.