Reaction #75166

Reaction equation

6-chloro-1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one

4-(4-chlorophenyl)-4-piperidinol

sodium carbonate

potassium iodide

→

6-chloro-1-{3-[4-(4-chlorophenyl)-4-hydroxy-1-piperidinyl]propyl}-1,3-dihydro-2H-benzimidazol-2-one

Solvents

4-methyl-2-pentanone

water

water

Conditions

Workup

1. 1
   TemperatureAfter cooling
2. 2
   Otherthe layers are separated
3. 3
   DryingThe 4-methyl-2-pentanone-phase is dried
4. 4
   Filtrationfiltered
5. 5
   Otherevaporated
6. 6
   OtherThe oily residue is purified by column-chromatography over silica gel using
7. 7
   workup.ADDITIONa mixture of trichloromethane and 10% of methanol as eluent
8. 8
   OtherThe pure fractions are collected
9. 9
   Otherthe eluent is evaporated
10. 10
    OtherThe solid residue is crystallized from 4-methyl-2-pentanone

Procedure

A mixture of 5.6 parts of 6-chloro-1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one, 4.2 parts of 4-(4-chlorophenyl)-4-piperidinol, 6.4 parts of sodium carbonate, 0.2 parts of potassium iodide and 200 parts of 4-methyl-2-pentanone is stirred and refluxed overnight with water-separator. After cooling, water is added and the layers are separated. The 4-methyl-2-pentanone-phase is dried, filtered and evaporated. The oily 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 solid residue is crystallized from 4-methyl-2-pentanone, yielding 3.5 parts of 6-chloro-1-{3-[4-(4-chlorophenyl)-4-hydroxy-1-piperidinyl]propyl}-1,3-dihydro-2H-benzimidazol-2-one; mp. 180.6° C.

Source