Chloroacetic Acid → 5-chloro-2-(chloromethyl)-1H-1,3-benzodiazole

Beteiligte Stoffe

Reaktionsschritte

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.

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