Benzocaine → 4-{2-[2-(4-Chloro-phenyl)-5,6-difluoro-benzoimidazol-1-yl]-2-cyclohexyl-acetylamino}-benzoic acid ethyl ester

HRID 1161316Notes

Reaction equation

HRID 1161316 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[N:12]([CH:13]([CH:17]3[CH2:22][CH2:21][CH2:20][CH2:19][CH2:18]3)[C:14](O)=[O:15])[C:11]3[CH:23]=[C:24]([F:28])[C:25]([F:27])=[CH:26][C:10]=3[N:9]=2)=[CH:4][CH:3]=1.[NH2:29][C:30]1[CH:40]=[CH:39][C:33]([C:34]([O:36][CH2:37][CH3:38])=[O:35])=[CH:32][CH:31]=1>S(Cl)(Cl)=O.CN(C)C1C=CN=CC=1.ClCCl>[CH2:37]([O:36][C:34](=[O:35])[C:33]1[CH:39]=[CH:40][C:30]([NH:29][C:14](=[O:15])[CH:13]([N:12]2[C:11]3[CH:23]=[C:24]([F:28])[C:25]([F:27])=[CH:26][C:10]=3[N:9]=[C:8]2[C:5]2[CH:4]=[CH:3][C:2]([Cl:1])=[CH:7][CH:6]=2)[CH:17]2[CH2:22][CH2:21][CH2:20][CH2:19][CH2:18]2)=[CH:31][CH:32]=1)[CH3:38]

Participants

6

Reactant 2

HCID 2337BenzocaineHCID 66619321[2-(4-Chloro-phenyl)-5,6-difluoro-benzoimidazol-1-yl]-cyclohexyl-acetic acid

Product 1

HCID 686454934-{2-[2-(4-Chloro-phenyl)-5,6-difluoro-benzoimidazol-1-yl]-2-cyclohexyl-acetylamino}-benzoic acid ethyl esterYield 63.6%

Reagents, catalysts & solvents 3

HCID 142844-(Dimethylamino)pyridineCatalystHCID 6344DichloromethaneSolventHCID 24386Thionyl ChlorideSolvent

Conditions

Temperature
0 °C

Procedure

The solution of 3.0 g (7.4 mmol) [2-(4-chloro-phenyl)-5,6-difluoro-benzoimidazol-1-yl]-cyclohexyl-acetic acid in 5.4 ml thionylchloride was stirred under reflux. After 1 h the volatile components were removed at a rotary evaporator, the residue taken up in toluene and evaporated (three times). The remaining oil was dissolved in 30 ml dichloromethane, cooled to 0° C. and added dropwise on a solution of ethyl 4-aminobenzoate (1.35 g, 8.1 mmol) and 2.72 g (22.2 mmol) 4-dimethylaminopyridine dissolved in 30 ml dichloromethane. The cooling bath was removed and stirring was continued for another 4 h. The reaction was poured on 25% aqueous hydrochloric acid solution, the phases separated and the aqueous phase extracted with dichloromethane. The combined organic phases were washed with brine, dried over magnesium sulfate, filtered and evaporated. The residue was purified by column chromatography on silica gel using heptane:ethyl acetate (1:0 to 1:1 v/v) as eluant to afford the title compound as a colorless solid (2.6 g, 62%). MS (ES+): 552 (M+H).

Workup

  1. temperatureunder reflux
  2. customAfter 1 h the volatile components were removed at a rotary evaporator
  3. customevaporated (three times)
  4. dissolutionThe remaining oil was dissolved in 30 ml dichloromethane
  5. customThe cooling bath was removed
  6. additionThe reaction was poured on 25% aqueous hydrochloric acid solution
  7. customthe phases separated
  8. extractionthe aqueous phase extracted with dichloromethane
  9. washThe combined organic phases were washed with brine
  10. dry with materialdried over magnesium sulfate
  11. filtrationfiltered
  12. customevaporated
  13. customThe residue was purified by column chromatography on silica gel

Sources & evidence

ORD record
ord-45dc0950b6ca4f23a8cfa5aa9e06f4fd
Source dataset
uspto-grants-2010_10
Patent number
US07816540B2

Reaction notes

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