Triethylamine → 4-chloro-1,3-dihydro-3-(3-hydroxypropyl)-2H-benzimidazol-2-one methanesulfonate

Participants

Reaction Steps

To a stirred mixture of 9 parts of 4-chloro-1,3-dihydro-3-(3-hydroxypropyl)-2H-benzimidazol-2-one, 7 parts of N,N-diethylethanamine and 130 parts of dichloromethane are added dropwise 12 parts of methanesulfonyl chloride (exothermic reaction: temperature rises to reflux). Upon completion, stirring is continued for 1 hour at reflux temperature. The reaction mixture is cooled and poured onto water. The organic phase is separated, washed with acidified water, dried, filtered and evaporated. The residue is crystallized from 4-methyl-2-pentanone, yielding 9 parts (75%) of 4-chloro-1,3-dihydro-3-(3-hydroxypropyl)-2H-benzimidazol-2-one methanesulfonate.

Provenance & Evidence