Sodium pyrazolo[1,5-a]pyrimidin-5-olate → pyrazolo[1,5-c]pyrimidin-5(4H)-one

HRID 474318Notes

Reaction equation

HRID 474318 reaction equation
[N:1]1[N:5]2[CH:6]=[CH:7][C:8]([O-:10])=[N:9][C:4]2=[CH:3][CH:2]=1.[Na+]>C(O)(=O)C.O>[N:1]1[N:5]2[CH:4]=[N:9][C:8](=[O:10])[CH2:7][C:6]2=[CH:3][CH:2]=1

Participants

4

Reactant 1

HCID 58063145Sodium pyrazolo[1,5-a]pyrimidin-5-olate

Product 1

HCID 66676395pyrazolo[1,5-c]pyrimidin-5(4H)-oneYield 85.5%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Procedure

Sodium pyrazolo[1,5-a]pyrimidin-5-olate (13.47 g) was dissolved in 500 mL of acetic acid and 100 mL of water, stirred 15 minutes then evaporated to dryness under vacuum. The residue was suspended in 300 mL of 9:1 dichloromethane:methanol and vacuum filtered through silica gel to remove sodium acetate. The silica gel pad was washed with 700 mL of additional dichloromethane:methanol solution. The combined dichloromethane:methanol solution was concentrated to dryness. The solid product was suspended in 1:1 hexane:dichloromethane and filtered to yield 9.9 g (85%) pyrazolo[1,5-c]pyrimidin-5(4H)-one. LCMS (ESI) m+H=136.0; 1H NMR (400 MHz, DMSO-d6) δ: 12.1 (s broad exchangeable, 1H), 8.47 (d, 1H, J=7.9), 7.75 (d, 1H, J=1.9), 5.94 (d, 1H, J=7.5), 5.81 (d, 1H, J=1.7).

Workup

  1. customthen evaporated to dryness under vacuum
  2. filtrationmethanol and vacuum filtered through silica gel
  3. customto remove sodium acetate
  4. washThe silica gel pad was washed with 700 mL of additional dichloromethane
  5. concentrationThe combined dichloromethane:methanol solution was concentrated to dryness
  6. filtrationdichloromethane and filtered

Sources & evidence

ORD record
ord-9768608903ba41dabaca4aacff514c38
Source dataset
uspto-grants-2014_01
Patent number
US08637526B2

Reaction notes

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