Triethylamine → 5-chloro-1,3-dihydro-1-(3-hydroxypropyl)-2H-benzimidazol-2-one methanesulfonate

Participants

Reaction Steps

To a stirred and cooled (ice-water bath) mixture of 14.1 parts of 5-chloro-1,3-dihydro-1-(3-hydroxypropyl)-2H-benzimidazol-2-one, 8 parts of N,N-diethylethanamine and 195 parts of dichloromethane are added dropwise 7.8 parts of methanesulfonyl chloride. Upon completion, stirring is continued first for 15 minutes while still cooling an further for 1 hour at reflux temperature. The dichloromethane is evaporated and the residue is dissolved in 4-methyl-2-pentanone and water while heating. The layers are separated and the organic phase is stirred with 100 parts of water, while cooling in an ice-bath. The precipitated product is filtered off and dried, yielding 10 parts (53%) of 5-chloro-1,3-dihydro-1-(3-hydroxypropyl)-2H-benzimidazol-2-one methanesulfonate; mp. 140° C.

Provenance & Evidence