Hydrazine → 2-Ethyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine

HRID 1245581Notes

Reaction equation

HRID 1245581 reaction equation
Cl[CH2:2][CH2:3][CH2:4][CH2:5][C:6](=O)[CH2:7][C:8](=O)[CH2:9][CH3:10].[NH2:13][NH2:14]>CC#N.O>[CH2:9]([C:8]1[CH:7]=[C:6]2[CH2:5][CH2:4][CH2:3][CH2:2][N:14]2[N:13]=1)[CH3:10]

Participants

5

Reactant 2

HCID 9321HydrazineHCID 21912828HCID 21912828, compound

Product 1

HCID 219127222-Ethyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 6342AcetonitrileSolvent

Procedure

To a solution of 1-chloro-5,7-nonanedione (14.74 g, from Step A) in a mixture of CH3CN (100 mL) and H2O (33 mL) was added 4.87 mL of hydrazine. After refluxing for 18 h, the reaction mixture was partitioned between EtOAc and aqueous NaHCO3 (saturated). Aqueous layer was extracted with EtOAc (3×). Combined organic phase was washed with brine and dried over anhydrous MgSO4. After concentration, the residue was purified by flash chromatography with 20% EtOAc in hexanes followed by 50% EtOAc in hexanes to give the title compound as a viscous oil. 1H NMR (500 MHz, CDCl3) δ 1.24 (t, 3H, J=7.5 Hz), 1.79–1.85 (m, 2H), 1.95–2.05 (m, 2H), 2.62 (q, 2H, J=7.8 Hz), 2.75 (t, 2H, J=6.4 Hz), 4.08 (t, 2H, J=6.1 Hz), 5.78 (s, 1H).

Workup

  1. temperatureAfter refluxing for 18 h
  2. customthe reaction mixture was partitioned between EtOAc and aqueous NaHCO3 (saturated)
  3. extractionAqueous layer was extracted with EtOAc (3×)
  4. washCombined organic phase was washed with brine
  5. dry with materialdried over anhydrous MgSO4
  6. concentrationAfter concentration
  7. customthe residue was purified by flash chromatography with 20% EtOAc in hexanes

Sources & evidence

ORD record
ord-00d1ced4f7324e288d5e44d7509ae18b
Source dataset
uspto-grants-2006_10
Patent number
US07125887B2

Reaction notes

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