Iodine → 3-Iodo-1,4,5,6-tetrahydrocyclopenta[C]pyrazole
Reaction equation
[NH:1]1[C:5]2[CH2:6][CH2:7][CH2:8][C:4]=2[C:3](C(O)=O)=[N:2]1.C(=O)(O)[O-].[Na+].[I-:17].[Na+].II>ClC(Cl)C.O.ClCCl>[I:17][C:3]1[C:4]2[CH2:8][CH2:7][CH2:6][C:5]=2[NH:1][N:2]=1Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 3
Conditions
- Temperature
- 100 °C
Procedure
To a mixture of 1,4,5,6-tetrahydrocyclopenta[c]pyrazole-3-carboxylic acid (0.5 g, 3.29 mmol), and sodium bicarbonate (911 mg, 422 μL, 10.8 mmol) in dichloroethane (5 mL) and water (5 mL) were added in one portion sodium iodide (1.28 g, 8.54 mmol) and iodine (1.08 g, 4.27 mmol) and the mixture heated at to 100° C. (oil bath temperature) with vigorous stirring for 24 h. After cooling to 25° C. the mixture was diluted with dichloromethane then washed with 10% Na2S2O3 and saturated NaHCO3. The organic phases were combined, dried (MgSO4) and concentrated to a yellow solid which was dissolved in dichloromethane, cyclohexane added to promote solid formation and allowed to stand. The solid was separated by filtration and dried to give 3-iodo-1,4,5,6-tetrahydrocyclopenta[c]pyrazole (580 mg, 2.48 mmol, 75%) as needles. MS (M+H)+=234.9; 1H NMR (CDCl3) δ: 2.71-2.99 (m, 31H), 2.39-2.66 (m, 4H).
Workup
- temperatureAfter cooling to 25° C. the mixture
- washthen washed with 10% Na2S2O3 and saturated NaHCO3
- dry with materialdried (MgSO4)
- concentrationconcentrated to a yellow solid which
- dissolutionwas dissolved in dichloromethane
- additioncyclohexane added
- customThe solid was separated by filtration
- customdried
Sources & evidence
- ORD record
- ord-a88e31655db949cd8edc7aa4092bf350
- Source dataset
- uspto-grants-2014_02
- Patent number
- US08658646B2
Reaction notes
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