Dichloroacetic Acid → 5-Chloro-2-(dichloromethyl)-1H-benzimidazole-6-sulfonamide

Participants

Reaction Steps

To 11.8 g of 2-amino-4-chloro-5-sulfamyl aniline in 50 ml of 4 N hydrochloric acid was added 20.5 g of dichloroacetic acid and the suspension refluxed for 6 hours. Concentration in vacuo provided a dark viscous oil which was suspended in 150 ml of water and crystallized through vigorous scratching. The dark brown solid was then dissolved in methanol, the solution brought to a boil, and charcoal added. After boiling for five minutes, the suspension was filtered through filter paper, cooled and then filtered through Celite. Concentration in vacuo gave a viscous oil which upon setting at ambient temperature for 48 hours crystallized. Tritration with acetonitrile provided 4.5 g of beige crystals, m.p. 225°-227°.

Provenance & Evidence