Isopropanol → 5-chloro-1,3-dihydro-1-(3-methyl-4-piperidinyl)-2H-benzimidazol-2-one

HRID 1729801Notes

Reaction equation

HRID 1729801 reaction equation
[Cl:1][C:2]1[CH:22]=[CH:21][C:5]2[N:6]([CH:10]3[CH2:15][CH2:14][N:13](C(OC)=O)[CH2:12][CH:11]3[CH3:20])[C:7](=[O:9])[NH:8][C:4]=2[CH:3]=1.[OH-].[K+].CC(O)C>O>[Cl:1][C:2]1[CH:22]=[CH:21][C:5]2[N:6]([CH:10]3[CH2:15][CH2:14][NH:13][CH2:12][CH:11]3[CH3:20])[C:7](=[O:9])[NH:8][C:4]=2[CH:3]=1

Participants

5

Reactant 3

HCID 3776IsopropanolHCID 14797Potassium HydroxideHCID 21500273methyl 4-(5-chloro-1,3-dihydro-2-oxo-2H-benzimidazol-1-yl)-3-methyl-1-piperidinecarboxylate

Product 1

HCID 215002835-chloro-1,3-dihydro-1-(3-methyl-4-piperidinyl)-2H-benzimidazol-2-one

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A mixture of 26 parts of methyl 4-(5-chloro-1,3-dihydro-2-oxo-2H-benzimidazol-1-yl)-3-methyl-1-piperidinecarboxylate, 36 parts of potassium hydroxide, 200 parts of 2-propanol and 6 parts of water is stirred and refluxed for 18 hours. The reaction mixture is evaporated and water is added to the residue. The whole is acidified with a concentrated hydrochloric acid solution, while cooling. The free base is liberated in the conventional manner and stirred with trichloromethane for 30 minutes. The layers are separated and the aqueous layer is extracted with trichloromethane. The combined organic phases are dried, filtered and evaporated. The oily residue solidifies on triturating in a mixture of 2,2'-oxybispropane and a small amount of 2-propanol. The product is filtered off and crystallized from 4-methyl-2-pentanone, yielding 5-chloro-1,3-dihydro-1-(3-methyl-4-piperidinyl)-2H-benzimidazol-2-one; mp. 198.9° C.

Workup

  1. temperaturerefluxed for 18 hours
  2. customThe reaction mixture is evaporated
  3. additionwater is added to the residue
  4. temperaturewhile cooling
  5. stirringstirred with trichloromethane for 30 minutes
  6. customThe layers are separated
  7. extractionthe aqueous layer is extracted with trichloromethane
  8. customThe combined organic phases are dried
  9. filtrationfiltered
  10. customevaporated
  11. customon triturating in a mixture of 2,2'-oxybispropane
  12. filtrationThe product is filtered off
  13. customcrystallized from 4-methyl-2-pentanone

Sources & evidence

ORD record
ord-1043390aac654e678e1e7bcf935e7c11
Source dataset
uspto-grants-1976_11
Patent number
US03989707

Reaction notes

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