Hydrochloric Acid → 5-chloro-1,3-dihydro-1-(3-hydroxypropyl)-2H-benzimidazol-2-one

Participants

Reaction Steps

To a stirred solution of 40 parts of 3-[(2-amino-4-chlorophenyl)amino]-1-propanol in 140 parts of water and 24 parts of a hydrochloric acid solution 10 N is added dropwise a solution of 18 parts of potassium isocyanate in 40 parts of water (exothermic reaction: temperature rises to 35° C.). Upon completion, stirring is continued first for 30 minutes at room temperature and further for 20 hours at reflux temperature. The reaction mixture is allowed to stirr over week-end without heating. The precipitated product is filtered off and treated with a diluted hydrochloric acid solution in 4-methyl-2-pentanone. The whole is stirred and the layers are separated. The 4-methyl-2-pentanone-phase is washed with water, dried, filtered and evaporated, yielding 18 parts (32%) of 5-chloro-1,3-dihydro-1-(3-hydroxypropyl)-2H-benzimidazol-2-one; mp. 148.8° C.

Provenance & Evidence