Sodium Iodide → 5-Iodopyrazolo[1,5-a]pyrimidine

HRID 751280Notes

Reaction equation

HRID 751280 reaction equation
Cl[C:2]1[CH:7]=[CH:6][N:5]2[N:8]=[CH:9][CH:10]=[C:4]2[N:3]=1.[I-:11].[Na+].C(Cl)(=O)C.C(=O)([O-])[O-].[K+].[K+].S([O-])([O-])=O.[Na+].[Na+]>C(#N)C.C(OCC)C>[I:11][C:2]1[CH:7]=[CH:6][N:5]2[N:8]=[CH:9][CH:10]=[C:4]2[N:3]=1

Participants

8

Reactant 5

HCID 5238Sodium IodideHCID 6367Acetyl chlorideHCID 11430Potassium CarbonateHCID 24437Sodium SulfiteHCID 210717595-Chloropyrazolo(1,5-a)pyrimidine

Product 1

HCID 497615315-Iodopyrazolo[1,5-a]pyrimidineYield 51.7%

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 6342AcetonitrileSolvent

Procedure

Dissolve 5-chloro-pyrazolo[1,5-a]pyrimidine (Hans Reimlinger et al., Chem. Ber. 1970, 103, 3252-3265; 1.15 g, 7.5 mmol) and sodium iodide (5.6-g, 37.4 mmol) in anhydrous acetonitrile (50 mL). Add acetyl chloride (2.7 ml, 37.9 mmol). Stir and reflux under nitrogen for 20 h. Pour the reaction mixture into a stirring mixture of 0.5M aqueous potassium carbonate (200 mL), 1.0M aqueous sodium sulfite (50 mL), and diethyl ether (350 mL). Separate the organic layer, dry over anhydrous magnesium sulfate, filter and concentrate under reduced pressure. Chromatograph the crude product on flash silica using neat dichloromethane to obtain 950 mg (51%) of the title compound as a yellow solid. TOF MS ES+ exact mass calculated for C6H4N310): m/z=245.9528; Found: 245.9517. 1H NMR (400 MHz, DMSO-d6) δ 8.82 (d, J=7 Hz, 1H), 8.18 (d, J=2 Hz, 1H), 7.32 (d, J=7 Hz, 1H), 6.69 (d, J=2 Hz, 1H).

Workup

  1. temperaturereflux under nitrogen for 20 h
  2. additionPour the reaction mixture
  3. customSeparate the organic layer
  4. dry with materialdry over anhydrous magnesium sulfate
  5. filtrationfilter
  6. concentrationconcentrate under reduced pressure

Sources & evidence

ORD record
ord-7d5e51ceb5694f19a478045568068a57
Source dataset
uspto-grants-2008_07
Patent number
US07405299B2

Reaction notes

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