Trimethyl orthoacetate → 4-Bromo-6-chloro-2-methyl-1H-benzo[d]imidazole

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 to the mixture. The reaction mixture was stirred at 120° C. for 14 h, then cooled to RT and concentrated in vacuo. The residue was diluted with EtOAc (100 mL), treated with satd. aq. NaHCO3 (200 mL), filtered with Celite®, and washed with EtOAc (50 mL×3). The filtrate was washed with satd. aq. 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]+.

1. temperaturewas heated
2. temperatureat reflux for 4 h
3. temperaturecooled to RT
4. concentrationconcentrated in vacuo
5. additionThe residue was diluted with EtOAc (100 mL)
6. additiontreated with satd
7. filtrationaq. NaHCO3 (200 mL), filtered with Celite®
8. washwashed with EtOAc (50 mL×3)
9. washThe filtrate was washed with satd
10. dry with materialaq. NaHCO3, water, and brine, dried (MgSO4)
11. filtrationfiltered
12. concentrationconcentrated in vacuo

ORD record

ord-668d5d1a4aa049818f1af24e5de9bdbd

Source dataset

uspto-grants-2014_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08637537B2