Methyl Isobutyl Ketone → 5-Chloro-1,3-dihydro-2H-benzimidazol-2-one

HRID 1833677Notes

Reaction equation

HRID 1833677 reaction equation
[Cl:1][C:2]1[CH:17]=[CH:16][C:5]2[N:6](C3CCNCC3)[C:7](=[O:9])[NH:8][C:4]=2[CH:3]=1.C(=O)([O-])[O-].[Na+].[Na+].CC(C)CC(=O)C.BrCCCN1C2C=CC=CC=2N=N1>O>[Cl:1][C:2]1[CH:17]=[CH:16][C:5]2[NH:6][C:7](=[O:9])[NH:8][C:4]=2[CH:3]=1

Participants

6

Reactant 4

HCID 7909Methyl Isobutyl KetoneHCID 10340Sodium CarbonateHCID 1046075-Chloro-1,3-dihydro-1-(4-piperidinyl)-2H-benzimidazol-2-oneHCID 3732348HCID 3732348, compound

Product 1

HCID 2231315-Chloro-1,3-dihydro-2H-benzimidazol-2-one

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Procedure

A mixture of 5 parts of 5-chloro-1,3-dihydro-1-(4-piperidinyl)-2H-benzimidazol-2-one, 3.7 parts of sodium carbonate and 200 parts of 4-methyl-2-pentanone is stirred and refluxed with water-separator. Then there are added 4.8 parts of 1-(3-bromopropyl)-1H-benzotriazole and stirring is continued overnight at reflux temperature. The reaction mixture is cooled, water is added and the undissolved product is filtered off and set aside. The organic phase is separated from the filtrate, dried, filtered and evaporated. The residue is combined with the undissolved product (see above) and 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, yielding 2 parts (25%) of 1-{1-[3-H-benzotriazol-1-yl)propyl]-4-piperidinyl}-5-chloro-1,3-dihydro-2H-benzimidazol-2-one; mp. 203.4° C.

Workup

  1. stirringstirring
  2. temperatureat reflux temperature
  3. temperatureThe reaction mixture is cooled
  4. filtrationthe undissolved product is filtered off
  5. customThe organic phase is separated from the filtrate
  6. customdried
  7. filtrationfiltered
  8. customevaporated
  9. custompurified by column-chromatography over silica gel using
  10. additiona mixture of trichloromethane and methanol (95:5 by volume) as eluent
  11. customThe pure fractions are collected
  12. customthe eluent is evaporated
  13. customThe residue is crystallized from 4-methyl-2-pentanone

Sources & evidence

ORD record
ord-2321b7d8914b42be81f522b7af9d2cca
Source dataset
uspto-grants-1978_01
Patent number
US04066772

Reaction notes

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