反应详情

The solution of 4-chloro-1,2-phenylenediamine (1.43 g) and chloroacetic acid (1.43 g) in 4M HCl (10 ml) was heated to reflux for 1 h. After cooling to rt overnight the mixture was filtered and the filtrate was cooled in an ice bath. With stirring the solution was adjusted to pH 8 with 25% ammonia solution. A gummy precipitate is formed which is cooled for 1 h. The aqueous layer is removed by decantation and the residue crystallised from acetone/water to yield 5-chloro-2-chloromethylbenzimidazole (1.4 g) as brownish solid.

1. temperatureto reflux for 1 h
2. filtrationwas filtered
3. temperaturethe filtrate was cooled in an ice bath
4. customA gummy precipitate is formed which
5. temperatureis cooled for 1 h
6. customThe aqueous layer is removed by decantation
7. customthe residue crystallised from acetone/water