Ibudilast → 2-Isopropyl-3-(1-hydroxy-1-ethyl-2-methylpropyl)pyrazolo[1,5-a]pyridine

HRID 483087

Reaction equation

HRID 483087 reaction equation
[Mg].[CH2:2](I)[CH3:3].[CH:5]([C:8]1[C:16]([C:17](=[O:21])[CH:18]([CH3:20])[CH3:19])=[C:11]2[CH:12]=[CH:13][CH:14]=[CH:15][N:10]2[N:9]=1)([CH3:7])[CH3:6].[Cl-].[NH4+]>CCOCC.C1C=CC=CC=1>[CH:5]([C:8]1[C:16]([C:17]([OH:21])([CH2:2][CH3:3])[CH:18]([CH3:20])[CH3:19])=[C:11]2[CH:12]=[CH:13][CH:14]=[CH:15][N:10]2[N:9]=1)([CH3:7])[CH3:6]

Participants

7

Reactant 4

HCID 3671IbudilastHCID 6340IodoethaneHCID 25517Ammonium ChlorideHCID 5462224Magnesium

Product 1

HCID 133917112-Isopropyl-3-(1-hydroxy-1-ethyl-2-methylpropyl)pyrazolo[1,5-a]pyridine

Reagents, catalysts & solvents 2

HCID 241BenzeneSolventHCID 3283Diethyl EtherSolvent2×

Procedure

To a suspension of 1.32 g of magnesium in 10 ml of dry ether was gradually added a solution of 17 g of ethyl iodide in 15 ml of dry ether with stirring. After the addition was completed, the stirring was continued for an hour at room temperature. To the mixture was gradually added a solution of 2.5 g of 2-isopropyl-3-isobutyrylpyrazolo[1,5-a]pyridine in 10 ml of dry benzene under stirring. The mixture was stirred for an hour at room temperature, treated with 150 ml of aqueous 20% ammonium chloride solution under ice cooling, and extracted with ether. The ether layer was washed with saturated brine, dried over anhydrous sodium sulfate and cencentrated to dryness. The residue was recrystallized from hexane to give 1.5 g (54%) of the desired derivative as pale gray prisms, mp 96°-98° C.

Workup

  1. additionAfter the addition
  2. waitthe stirring was continued for an hour at room temperature
  3. stirringunder stirring
  4. stirringThe mixture was stirred for an hour at room temperature
  5. extractionextracted with ether
  6. washThe ether layer was washed with saturated brine
  7. dry with materialdried over anhydrous sodium sulfate
  8. customThe residue was recrystallized from hexane
  9. customto give 1.5 g (54%) of the desired derivative as pale gray prisms, mp 96°-98° C.

Sources & evidence

ORD record
ord-844f97a7dfe84ad1b08ff25636f733d4
Source dataset
uspto-grants-1986_03
Patent number
US04578392

Linked notes

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