Hydrochloric Acid → 2-Methylbenzimidazole

Participants

Reaction Steps

Methanol (2 ml) and a 10% aqueous solution of sodium hydroxide (0.2 ml) were added to optically active 6-(2-benzoyloxy-1-pentane)sulfonylcarbamoyl-1-(2,4-dichlorobenzyl)-2-methyl-benzimidazole isomer with shorter retention time as obtained in Production Example 34 (277 mg) and the mixture was stirred for 90 minutes at room temperature. A 10% aqueous solution of sodium hydroxide (0.36 ml) was further added thereto and stirring was continued for 50 minutes under heating at 50° C. The solution was allowed to cool for 70 minutes to room temperature and 1N hydrochloric acid (1.4 ml) was added thereto and the resulting solution was cooled with ice. Deposited crystals were collected by filtration, washed three times with water (2 ml) and twice with chloroform (1ml), and dried by heating under reduced pressure to obtain optically active 1-(2,4-dichlorobenzyl)-6(2-hydroxy-1-pentane)sulfonyl-carbamoyl)-2-methylbenzimidazole with longer retention time on CHIRALPAK AD (79) (143 mg).

Provenance & Evidence