m-Chloroperbenzoic acid → HCID 178437532, compound

HRID 1729433Notes

Reaction equation

HRID 1729433 reaction equation
[CH2:1]([C:3]1[NH:4][C:5]2[C:6]([N:12]=1)=[N:7][CH:8]=[CH:9][C:10]=2[CH3:11])[CH3:2].ClC1C=CC=C(C(OO)=[O:21])C=1>C(Cl)(Cl)Cl>[CH2:1]([C:3]1[NH:4][C:5]2[C:6]([N:12]=1)=[N+:7]([O-:21])[CH:8]=[CH:9][C:10]=2[CH3:11])[CH3:2]

Participants

4

Reactant 2

HCID 70297m-Chloroperbenzoic acidHCID 186930362-ethyl-7-methyl-3H-Imidazo[4,5-b]pyridine

Product 1

HCID 178437532HCID 178437532, compoundYield 96.6%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

A solution of 2-ethyl-7-methylimidazo[4,5-b]pyridine (28 g, 174 mmol) and m-chloroperbenzoic acid (80-90%, 44.6 g) in CHCl3 (300 mL) was heated at reflux for 0.5 hours. The mixture was concentrated and purified (SiO2, 100% CH2Cl2 gradient to 30% CH2Cl2 /MeOH) to give 29.8 g of 2-ethyl-7-methylimidazo[4,5-b]pyridine-4-oxide as a solid. 1H NMR (300 MHz, CD3OD) δ 8.13 (d, 1H, J=6 Hz), 7.13 (d, 1H, J=6 Hz), 3.01 (q, 2H, J =7.5 Hz), 2.60 (s, 3H), 1.46 (t, 3H, J=7.5 Hz). A mixture of the N-oxide (29.75 g, 0.168 mol), CHCl3 (25 mL) and POCl3 (160 mL) was heated to 80° C. for 1 hours. After pouring over ice, the mixture was neutralized by careful addition of NH4OH and extracted with EtOAc. Concentration gave 23.8 g of 5-chloro-2-ethyl-7-methylimidazo[4,5-b]pyridine as a solid. 1H NMR (250 MHz, CDCl3) δ 7.07 (s,1 H) 3.10 (q, 2H, J=7.5 Hz), 2.67 (s, 3H), 1.48 (t, 3H, J=7.5 Hz).

Workup

  1. temperatureat reflux for 0.5 hours
  2. concentrationThe mixture was concentrated
  3. custompurified (SiO2, 100% CH2Cl2 gradient to 30% CH2Cl2 /MeOH)

Sources & evidence

ORD record
ord-45f57be81f7f47a6a90c77053c4a409a
Source dataset
uspto-grants-1994_07
Patent number
US05332744

Reaction notes

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