Phosphorus oxychloride → 7-Chloro-2,5-dimethylpyrazolo(1,5-a)pyrimidine

HRID 1016460Notes

Reaction equation

HRID 1016460 reaction equation
[CH3:1][C:2]1[CH:12]=[C:5]2[NH:6][C:7]([CH3:11])=[CH:8][C:9](=O)[N:4]2[N:3]=1.P(Cl)(Cl)([Cl:15])=O>>[Cl:15][C:9]1[N:4]2[N:3]=[C:2]([CH3:1])[CH:12]=[C:5]2[N:6]=[C:7]([CH3:11])[CH:8]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178422355HCID 178422355, compound

Product 1

HCID 184069877-Chloro-2,5-dimethylpyrazolo(1,5-a)pyrimidineYield 77%

Procedure

2,5-Dimethyl-4H-pyrazolo[1,5-a]pyrimidin-7-one (3.5 g, 21 mmol) in phosphorus oxychloride (20 mL) was stirred at reflux. After 3 hours the dark purple reaction was cooled and then extracted from ice water with ethyl acetate. The combined organic layers were washed with water and saturated aqueous sodium bicarbonate, dried (Na2SO4) and then concentrated under reduced pressure to give the title compound (3.0 g, 77%) as a brown solid: +APcI MS (M+1)+ 182; H NMR (CDCl3) δ: 6.74 (s, 1H), 6.42 (s, 1H), 2.55 (s, 3H), 2.53 (s, 3H).

Workup

  1. temperatureat reflux
  2. customAfter 3 hours the dark purple reaction
  3. temperaturewas cooled
  4. extractionextracted from ice water with ethyl acetate
  5. washThe combined organic layers were washed with water and saturated aqueous sodium bicarbonate
  6. dry with materialdried (Na2SO4)
  7. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-7060ad0f63c4482bbfd5f824482bd4d1
Source dataset
uspto-grants-2002_11
Patent number
US06476038B1

Reaction notes

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