Bromine → 3-Bromo-7-methylimidazo[1,2-a]pyridine

HRID 985502Notes

Reaction equation

HRID 985502 reaction equation
[CH3:1][C:2]1[CH:7]=[CH:6][N:5]2[CH:8]=[CH:9][N:10]=[C:4]2[CH:3]=1.C([O-])(=O)C.[Na+].[Br:16]Br.C(=O)([O-])O.[Na+]>CO>[Br:16][C:8]1[N:5]2[CH:6]=[CH:7][C:2]([CH3:1])=[CH:3][C:4]2=[N:10][CH:9]=1

Participants

6

Reactant 4

HCID 24408BromineHCID 1366817-Methylimidazo(1,2-a)pyridineHCID 516892Sodium BicarbonateHCID 517045Sodium Acetate

Product 1

HCID 167404763-Bromo-7-methylimidazo[1,2-a]pyridineYield 100%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A cooled (−10° C.) suspension of 7-methylimidazo[1,2-α]pyridine (26 g, 0.2 mol) and sodium acetate (24.3 g, 0.3 mol) in methanol (150 ml) was treated with bromine (ca. 10 ml, 0.2 mol) added dropwise until the first permanent colour change occurred. Stirring was continued for a further 20 minutes before the reaction was poured into saturated aqueous sodium hydrogencarbonate (2 l). The resulting solid was filtered, washed with water and dried. Trituration with 5% ether in isohexane furnished 3-bromo-7-methylimidazo[1,2-α]pyridine as a red-brown powder (41.5 g, 100%). 1H NMR (360 MHz, CDCl3) δH 2.43 (3H, s), 6.76 (1H, d, J 7), 7.37 (1H, s), 7.53 (1H, s), 7.55 (1H, s), 8.00 (1H, d, J 7); m/z (ES+) 210/212 (M++H).

Workup

  1. temperatureA cooled
  2. additionadded dropwise until the first permanent colour change
  3. filtrationThe resulting solid was filtered
  4. washwashed with water
  5. customdried

Sources & evidence

ORD record
ord-539fb61bad284d26ab2b6780459376d6
Source dataset
uspto-grants-2005_03
Patent number
US06872731B2

Reaction notes

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