Thionyl Chloride → 5-chloro-1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one

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Reaction Steps

A mixture of 20 parts of 5-chloro-1,3-dihydro-1-(3-hydroxypropyl)-2H-benzimidazol-2-one, 34 parts of sulfinyl chloride and 300 parts of trichloromethane is stirred and refluxed for 4 hours. The trichloromethane is evaporated and the residue is crystallized from 4-methyl-2-pentanone (activated charcoal). The product is filtered off (the filtrate is set aside), yielding a first fraction of 8.2 parts of 5-chloro-1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one. The filtrate, which was set aside, is concentrated and the concentrate is stirred with 2,2'-oxybispropane. The precipitated product is filtered off and dried, yielding a second fraction of 8 parts of 5-chloro-1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one.

Provenance & Evidence