Potassium Iodide → 1-{3-[4-(4-fluorobenzoyl)-1-piperidinyl]propyl}-1,3-dihydro-5-(trifluoromethyl)-2H-benzimidazol-2-one

Participants

Reaction Steps

A mixture of 4.2 parts of 1-(3-chloropropyl)-1,3-dihydro-5-(trifluoromethyl)-2H-benzimidazol-2-one, 3.6 parts of (4-fluorophenyl) (4-piperidinyl) methanone hydrochloride, 10 parts of sodium carbonate, 0.1 parts of potassium iodide and 80 parts of 4-methyl-2-pentanone is stirred and heated till reflux. Refluxing is continued overnight. After cooling to room temperature, the reaction mixture is poured onto water. The organic phase is separated, dried, filtered and evaporated. The residue is purified by column-chromatography over silica gel using a mixture of trichloromethane and 10% of methanol as eluent. The pure fractions are collected and the eluent is evaporated. The residue is crystallized from a mixture of 4-methyl-2-pentanone and 2,2-oxybispropane, yielding 1.4 -parts (20%) of 1-{3-[4-(4-fluorobenzoyl)-1-piperidinyl]propyl}-1,3-dihydro-5-(trifluoromethyl)-2H-benzimidazol-2-one; mp. 160.2° C.

Provenance & Evidence