Reaction #88092

Reaction equation

isobutyl bromide

7-iodo-3H-benzoimidazole-5-carboxylic acid methyl ester

Cs2CO3

→

7-iodo-3-isobutyl-3H-benzoimidazole-5-carboxylic acid methyl ester

Yield 87.0%

7-iodo-1-isobutyl-1H-benzoimidazole-5-carboxylic acid methyl ester

Yield 11.0%

Solvents

DMF

Conditions

Workup

1. 1
   Otherpartitioned between water and ethyl acetate
2. 2
   OtherThe organic layer was separated
3. 3
   Dryingdried over MgSO4
4. 4
   Filtrationfiltered
5. 5
   Concentrationconcentrated under reduced pressure
6. 6
   OtherPurification of the residue by column chromatography

Procedure

To a solution of 7-iodo-3H-benzoimidazole-5-carboxylic acid methyl ester (783 mg, 2.59 mmol) in DMF (50 mL) was added Cs2CO3 (1.69 g, 5.18 mmol), followed by isobutyl bromide ((0.338 mL, 3.11 mmol). The reaction mixture was stirred room temperature overnight, then partitioned between water and ethyl acetate. The organic layer was separated, dried over MgSO4, filtered and concentrated under reduced pressure. Purification of the residue by column chromatography gave 805 mg (87%) of 7-iodo-3-isobutyl-3H-benzoimidazole-5-carboxylic acid methyl ester (the regioisomer 7-iodo-1-isobutyl-1H-benzoimidazole-5-carboxylic acid methyl ester (100 mg, 11%) was recovered as separate fraction).

Source