Acetyl chloride → 2-Methyl-1-phenyl-1H-benzimidazole-5-carboxylic acid

HRID 74147Notes

Reaction equation

HRID 74147 reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]([CH:8]=[CH:9][C:10]=1[NH:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)[C:5]([OH:7])=[O:6].[C:18](Cl)(=O)[CH3:19]>C1(C)C=CC=CC=1>[CH3:18][C:19]1[N:11]([C:12]2[CH:13]=[CH:14][CH:15]=[CH:16][CH:17]=2)[C:10]2[CH:9]=[CH:8][C:4]([C:5]([OH:7])=[O:6])=[CH:3][C:2]=2[N:1]=1

Participants

4

Reactant 2

HCID 6367Acetyl chlorideHCID 7738213-Amino-4-phenylamino-benzoic acid

Product 1

HCID 6199262-Methyl-1-phenyl-1H-benzimidazole-5-carboxylic acidYield 83.7%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Procedure

A 2-neck flask was charged with 3-amino-4-phenylaminobenzoic acid (see Synthesis Example 1-2) (1.40 g, 6.35 mmol) and anhydrous toluene (15 mL) and this was refluxed. To this was added dropwise over approx. 15 minutes acetyl chloride (1.00 g, 12.70 mmol) in toluene solution (approx. 2.5 mL), and this was stirred under these conditions for 2.5 hours. This was allowed to cool to room temperature, and was extracted with dilute aqueous sodium hydroxide solution (10%, 200 mL). After separating the dark orange aqueous layer, it was cooled in ice (5 to 10° C.), and concentrated hydrochloric acid (12 M) was added to the liquid to give approx. pH 4. The precipitated crystals were filtered off, washed with distilled water, and dried under reduced pressure with heating to yield the title compound (1.34 g, 83.5% yield) as a light purple solid.

Workup

  1. temperaturethis was refluxed
  2. extractionwas extracted with dilute aqueous sodium hydroxide solution (10%, 200 mL)
  3. customAfter separating the dark orange aqueous layer, it
  4. temperaturewas cooled in ice (5 to 10° C.)
  5. additionconcentrated hydrochloric acid (12 M) was added to the liquid
  6. customto give approx. pH 4
  7. filtrationThe precipitated crystals were filtered off
  8. washwashed with distilled water
  9. customdried under reduced pressure
  10. temperaturewith heating

Sources & evidence

ORD record
ord-9c48cc25c75048139b1380aaaa01133d
Source dataset
uspto-grants-2014_09
Patent number
US08829035B2

Reaction notes

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