Potassium Iodide → 1-{1-[3-(2,3-dihydro-2-oxo-1H-benzimidazol-1-yl)propyl]-4-piperidinyl}-1,3-dihydro-3-(1-methylethyl)-2H-benzimidazol-2-one

Participants

Reaction Steps

A mixture of 4.15 parts of 1-(3-chlorophenyl)-1,3-dihydro-3-(1-methylethenyl)-2H-benzimidazol-2-one, 3.9 parts of 1-(1-methylethyl)-3-(4-piperidinyl)-2H-benzimidazol-2-one, 3.2 parts of sodium carbonate, 0.1 parts of potassium iodide and 120 parts of 4-methyl-2-pentanone is stirred and refluxed overnight. The reaction mixture is cooled to room temperature, water is added and the layers are separated. The organic phase is dried, filtered and evaporated. The residue is stirred for 30 minutes with a solution of 12 parts of a concentrated hydrochloric acid solution in 40 parts of ethanol. The solvent is evaporated and the residue is suspended in water. The suspension is alkalized with a diluted ammonium hydroxide solution and the product is extracted with trichloromethane. The extract is dried, filtered and evaporated. The residue is purified by column-chromatography over silica gel using a mixture of trichloromethane and methanol (95:5 by volume) as eluent. The pure fractions are collected and the eluent is evaporated. The residue is crystallized from 4-methyl-2-pentanone. The product is filtered off and dried, yielding 4.2 parts (64%) of 1-{1-[3-(2,3-dihydro-2-oxo-1H-benzimidazol-1-yl)propyl]-4-piperidinyl}-1,3-dihydro-3-(1-methylethyl)-2H-benzimidazol-2-one; mp. 174.3° C.

Provenance & Evidence