Phosphorus oxychloride → 2-Chloropyrazolo[1,5-a]pyridine

HRID 530030Notes

Reaction equation

HRID 530030 reaction equation
[N:1]1[N:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]2=[CH:3][C:2]=1O.O=P(Cl)(Cl)[Cl:13]>>[Cl:13][C:2]1[CH:3]=[C:4]2[CH:9]=[CH:8][CH:7]=[CH:6][N:5]2[N:1]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178515341HCID 178515341, compound

Product 1

HCID 122844332-Chloropyrazolo[1,5-a]pyridine

Procedure

A stirred solution of pyrazolo[1,5-a]pyridin-2-ol (27-1; 0.9 g, 0.0067 mol) in POCl3 (10 mL) was heated in a sealed tube at 145° C. for 6 h. The reaction mixture was cooled to room temperature, poured into ice cold water (20 mL) and extracted with dichloromethane (3×20 mL). The combined organic layers were washed with saturated sodium chloride, dried over sodium sulphate and concentrated under vacuum to afford the crude compound, which was purified by column chromatography to obtain the title compound. 1H NMR (400 MHz, DMSO-d6) δ 8.36-8.34 (d, J=7.2 Hz, 1 H), 7.44-7.42 (d, J=9.2 Hz, 1 H), 7.17-7.13 (m, 1 H), 6.78-6.74 (m, 1 H), 6.43 (s, 1 H). MS (M+1): 152.8.

Workup

  1. extractionextracted with dichloromethane (3×20 mL)
  2. washThe combined organic layers were washed with saturated sodium chloride
  3. dry with materialdried over sodium sulphate
  4. concentrationconcentrated under vacuum
  5. customto afford the crude compound, which
  6. customwas purified by column chromatography

Sources & evidence

ORD record
ord-c5075422d4994c00b5a740a524b8be16
Source dataset
uspto-grants-2016_05
Patent number
US09351973B2

Reaction notes

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