Azobisisobutyronitrile → tert-Butyl 4-(bromomethyl)-1H-benzo[d]imidazole-1-carboxylate

HRID 1157904Notes

Reaction equation

HRID 1157904 reaction equation
[C:1]([O:5][C:6]([N:8]1[C:12]2[CH:13]=[CH:14][CH:15]=[C:16]([CH3:17])[C:11]=2[N:10]=[CH:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[Br:18]N1C(=O)CCC1=O.N(C(C)(C)C#N)=NC(C)(C)C#N>C(Cl)(Cl)(Cl)Cl>[C:1]([O:5][C:6]([N:8]1[C:12]2[CH:13]=[CH:14][CH:15]=[C:16]([CH2:17][Br:18])[C:11]=2[N:10]=[CH:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2]

Participants

5

Reactant 3

HCID 6547AzobisisobutyronitrileHCID 67184N-bromobutanimideHCID 15744963t-butyl 4-methyl-1H-benzimidazole-1-carboxylate

Product 1

HCID 15744964tert-Butyl 4-(bromomethyl)-1H-benzo[d]imidazole-1-carboxylateYield 60%

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent

Procedure

To a stirred solution of 4-methyl-benzimidazole-1-carboxylic acid tert-butyl ester (800 mg, 3.4 mmol) in CCl4 (7 mL) was added N-bromosuccinimide (730 mg, 4.1 mmol) and 2,2′-azobis(2-methylpropionitrile) (84 mg, 0.51 mmol). The resultant mixture was heated at reflux for 18 h after which it was filtered and concentrated to a yellow/orange syrup and crystals (1.4 g). Purification by column chromatography on silica gel (200:15—Hexanes:EtOAc) gave the desired title compound as a yellow syrup (635 mg, 60%). 1H NMR (300 MHz, CDCl3) δ 8.48 (s, 1H), 7.95 (dd, 1H, J=7.8, 1.5 Hz), 7.42-7.34 (m, 2H), 4.96 (s, 2H), 1.71 (s, 9H).

Workup

  1. temperatureat reflux for 18 h after which it
  2. filtrationwas filtered
  3. concentrationconcentrated to a yellow/orange syrup and crystals (1.4 g)
  4. customPurification by column chromatography on silica gel (200:15—Hexanes:EtOAc)

Sources & evidence

ORD record
ord-8b5e316171d141b7a64be1940f6dc5d6
Source dataset
uspto-grants-2010_10
Patent number
US07807694B2

Reaction notes

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