Triphenylphosphine → 2,5-Dimethyl-7-(3-methylbutoxy)pyrazolo[1,5-a]pyridine-3-carboxylic Acid ethyl Ester

HRID 1486289Notes

Reaction equation

HRID 1486289 reaction equation
[OH:1][C:2]1[N:7]2[N:8]=[C:9]([CH3:16])[C:10]([C:11]([O:13][CH2:14][CH3:15])=[O:12])=[C:6]2[CH:5]=[C:4]([CH3:17])[CH:3]=1.[CH3:18][CH:19]([CH3:23])[CH2:20][CH2:21]O.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N(C(OCC)=O)=NC(OCC)=O>O1CCCC1.COC(C)(C)C>[CH2:14]([O:13][C:11]([C:10]1[C:9]([CH3:16])=[N:8][N:7]2[C:2]([O:1][CH2:21][CH2:20][CH:19]([CH3:23])[CH3:18])=[CH:3][C:4]([CH3:17])=[CH:5][C:6]=12)=[O:12])[CH3:15]

Participants

7

Reactant 4

HCID 11776TriphenylphosphineHCID 31260Isoamyl AlcoholHCID 220568ethyl N-ethoxycarbonyliminocarbamateHCID 178469270HCID 178469270, compound

Product 1

HCID 1178645772,5-Dimethyl-7-(3-methylbutoxy)pyrazolo[1,5-a]pyridine-3-carboxylic Acid ethyl Ester

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolventHCID 15413tert-Butyl methyl etherSolvent

Procedure

A solution of 180 mg (0.768 mmol) of 7-hydroxy-2,5-dimethylpyrazolo[1,5-a]pyridine-3-carboxylic acid ethyl ester from Example 8A in 7 ml of dry tetrahydrofuran was admixed with 0.167 ml (1.537 mmol) of 3-methylbutan-1-ol (CAS 123-51-3), 423.2 mg (1.614 mmol) of triphenylphosphine and 0.32 ml (1.614 mmol) of diethyl azodicarboxylate. The resulting mixture was stirred at room temperature for 1 h. Some of the solvent was drawn off under reduced pressure and the residue was admixed with 5 ml of tert-butyl methyl ether. The resulting precipitate was filtered off and the mother liquor was partitioned between dichloromethane (15 ml) and water (10 ml). The organic phase was removed and concentrated under reduced pressure. The residue was purified by flash chromatography using a prepacked silica gel cartridge (eluent:cyclohexane-ethyl acetate 10:1 to 1:1), which gave 225 mg (69% of theory, 72% pure) of the target compound.

Workup

  1. filtrationThe resulting precipitate was filtered off
  2. customthe mother liquor was partitioned between dichloromethane (15 ml) and water (10 ml)
  3. customThe organic phase was removed
  4. concentrationconcentrated under reduced pressure
  5. customThe residue was purified by flash chromatography
  6. customgave 225 mg (69% of theory, 72% pure) of the target compound

Sources & evidence

ORD record
ord-66538e5fc46d4126b51a0eef839a462f
Source dataset
uspto-grants-2016_08
Patent number
US09422285B2

Reaction notes

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