2,3-Diaminopyridine → 2-[7-Methoxy-2-(1-methylethyl)benzofuran-4-yl]imidazo[4,5-b]pyridine

HRID 376254Notes

Reaction equation

HRID 376254 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[CH:5][C:6]([C:15](O)=O)=[C:7]2[C:11]=1[O:10][C:9]([CH:12]([CH3:14])[CH3:13])=[CH:8]2.[NH2:18][C:19]1[C:24]([NH2:25])=[CH:23][CH:22]=[CH:21][N:20]=1>P(Cl)(Cl)(Cl)=O>[CH3:1][O:2][C:3]1[C:11]2[O:10][C:9]([CH:12]([CH3:13])[CH3:14])=[CH:8][C:7]=2[C:6]([C:15]2[NH:25][C:24]3[C:19]([N:18]=2)=[N:20][CH:21]=[CH:22][CH:23]=3)=[CH:5][CH:4]=1

Participants

4

Reactant 2

HCID 99562,3-DiaminopyridineHCID 220095277-Methoxy-2-(1-methylethyl)benzofuran-4-carboxylic acid

Product 1

HCID 193616812-[7-Methoxy-2-(1-methylethyl)benzofuran-4-yl]imidazo[4,5-b]pyridine

Reagents, catalysts & solvents 1

HCID 24813Phosphorus oxychlorideSolvent

Procedure

4.6 g of 7-methoxy-2-(1-methylethyl)benzofuran-4-carboxylic acid and 2.2 g of 2,3-diaminopyridine are boiled under reflux for 4 h in 80 ml of phosphorus oxychloride. The mixture is largely evaporated in vacuo, the residue is partitioned between 100 ml of ice water and 500 ml of ethyl acetate and the aqueous phase is rendered alkaline with 50 percent sodium hydroxide solution. The organic phase is separated off, the aqueous phase is extracted a further two times by shaking with ethyl acetate, and the organic phases are combined, dried over ignited calcium carbonate and concentrated in vacuo. The residue is chromatographed on silica gel using a 1:1 mixture of toluene and ethyl acetate. After the evaporation of appropriate fractions, 1.7 g (28.3% of theory) of title compound having the m.p. 242° C. are obtained.

Workup

  1. customThe mixture is largely evaporated in vacuo
  2. customthe residue is partitioned between 100 ml of ice water and 500 ml of ethyl acetate
  3. customThe organic phase is separated off
  4. extractionthe aqueous phase is extracted a further two times
  5. customdried
  6. concentrationconcentrated in vacuo
  7. customThe residue is chromatographed on silica gel using
  8. additiona 1:1 mixture of toluene and ethyl acetate
  9. customAfter the evaporation of appropriate fractions, 1.7 g (28.3% of theory) of title compound
  10. customare obtained

Sources & evidence

ORD record
ord-4277348c6ee24ab58bbf2eb47fe8229c
Source dataset
uspto-grants-2000_02
Patent number
US06020340

Reaction notes

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