Phosphorus oxychloride → 5-Chloropyrazolo(1,5-a)pyrimidine

HRID 1372493Notes

Reaction equation

HRID 1372493 reaction equation
O[C:2]1[CH:7]=[CH:6][N:5]2[N:8]=[CH:9][CH:10]=[C:4]2[N:3]=1.P(Cl)(Cl)([Cl:13])=O>>[Cl:13][C:2]1[CH:7]=[CH:6][N:5]2[N:8]=[CH:9][CH:10]=[C:4]2[N:3]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178516350HCID 178516350, compound

Product 1

HCID 210717595-Chloropyrazolo(1,5-a)pyrimidine

Procedure

A mixture of the product (1.35 g, 10.0 mmol) from Step A above and 7.5 mL of phosphorus oxychloride was warmed at reflux for 4 h. The mixture was cooled, and the volatiles were removed under reduced pressure. The dark residue was partitioned between ice water and dichloromethane, and the aqueous layer was extracted with additional dichloromethane. The combined organic extracts were dried over sodium sulfate and concentrated under reduced pressure to provide a light brown solid, which was purified by flash chromatography (silica gel; 0.5% methanol in dichloromethane eluant) to afford the title compound as a white solid. MS 153.8 and 155.8 (M+1).

Workup

  1. temperatureat reflux for 4 h
  2. temperatureThe mixture was cooled
  3. customthe volatiles were removed under reduced pressure
  4. customThe dark residue was partitioned between ice water and dichloromethane
  5. extractionthe aqueous layer was extracted with additional dichloromethane
  6. dry with materialThe combined organic extracts were dried over sodium sulfate
  7. concentrationconcentrated under reduced pressure
  8. customto provide a light brown solid, which
  9. customwas purified by flash chromatography (silica gel; 0.5% methanol in dichloromethane eluant)

Sources & evidence

ORD record
ord-25458e5f644d43eeb30af9138e3b25ac
Source dataset
uspto-grants-2007_01
Patent number
US07157490B2

Reaction notes

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