8-Benzyloxy-6-ethoxycarbonyl-2,3-dimethylimidazo[1,2-a]pyridine → 6-Ethoxycarbonyl-8-hydroxy-2,3-dimethyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridine

HRID 895604Notes

Reaction equation

HRID 895604 reaction equation
C([O:8][C:9]1[C:10]2[N:11]([C:20]([CH3:24])=[C:21]([CH3:23])[N:22]=2)[CH:12]=[C:13]([C:15]([O:17][CH2:18][CH3:19])=[O:16])[CH:14]=1)C1C=CC=CC=1>C(O)C.[Pd]>[CH2:18]([O:17][C:15]([CH:13]1[CH2:12][N:11]2[C:20]([CH3:24])=[C:21]([CH3:23])[N:22]=[C:10]2[CH:9]([OH:8])[CH2:14]1)=[O:16])[CH3:19]

Participants

4

Reactant 1

HCID 121060828-Benzyloxy-6-ethoxycarbonyl-2,3-dimethylimidazo[1,2-a]pyridine

Product 1

HCID 121060846-Ethoxycarbonyl-8-hydroxy-2,3-dimethyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridineYield 14.5%

Reagents, catalysts & solvents 2

HCID 23938PalladiumCatalystHCID 702EthanolSolvent

Procedure

3 g of 8-benzyloxy-6-ethoxycarbonyl-2,3-dimethylimidazo[1,2-a]pyridine, suspended in 50 ml of ethanol, are treated with 0.5 g of 10% strength palladium/active carbon and hydrogenated under a hydrogen pressure of 50 bar for 20 hours at an oil bath temperature of 75° C. After cooling, the catalyst is filtered off, the filtrate is concentrated to ⅕ of the volume in vacuo and the colorless precipitate formed here is filtered off. The filtrate from the precipitate is concentrated to dryness and chromatographed on silica gel (eluent: methylene chloride/methanol 100/3). 0.32 g of 6-ethoxycarbonyl-8-hydroxy-2,3-dimethyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridine is obtained. For conversion into the title compound, it is dissolved in chloroform, treated with 1.6 g of manganese dioxide and stirred at room temperature for 20 h. It is then filtered off, the filtrate is concentrated to dryness in vacuo and the residue obtained is purified on silica gel (eluent: methylene chloride/methanol 13/1). 0.2 g of the title compound of melting point 138-40° C. (diethyl ether) is obtained.

Workup

  1. customfor 20 hours
  2. customtemperature of 75° C
  3. temperatureAfter cooling
  4. filtrationthe catalyst is filtered off
  5. concentrationthe filtrate is concentrated
  6. customthe colorless precipitate formed here
  7. filtrationis filtered off
  8. concentrationThe filtrate from the precipitate is concentrated to dryness
  9. customchromatographed on silica gel (eluent: methylene chloride/methanol 100/3)

Sources & evidence

ORD record
ord-a4c73ca0dc2c4719bce52451382c0051
Source dataset
uspto-grants-2005_07
Patent number
US06916825B2

Reaction notes

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