Iodine → 3-Iodo-5-methyl-pyrazole-1-carboxylic acid tert-butyl ester

HRID 2068631Notes

Reaction equation

HRID 2068631 reaction equation
[I:1]I.N(OCCC(C)C)=O.[C:11]([O:15][C:16]([N:18]1[C:22]([CH3:23])=[CH:21][C:20](N)=[N:19]1)=[O:17])([CH3:14])([CH3:13])[CH3:12].S([O-])([O-])(=O)=S.[Na+].[Na+]>C(Cl)Cl>[C:11]([O:15][C:16]([N:18]1[C:22]([CH3:23])=[CH:21][C:20]([I:1])=[N:19]1)=[O:17])([CH3:14])([CH3:13])[CH3:12]

Participants

6

Reactant 4

HCID 807IodineHCID 8053Isoamyl NitriteHCID 24477Sodium ThiosulfateHCID 113215371H-Pyrazole-1-carboxylicacid,3-amino-5-methyl-,1,1-dimethylethylester

Product 1

HCID 581103133-Iodo-5-methyl-pyrazole-1-carboxylic acid tert-butyl esterYield 16.6%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

Iodine (0.774 g, 3.0 mmol) was dissolved in DCM (5 mL) then isoamyl nitrite (0.682 mL, 5.1 mmol) was added followed by the slow addition of 3-amino-5-methyl-pyrazole-1-carboxylic acid tert-butyl ester (0.50 g, 2.54 mmol) as a solution in DCM (4 mL). The reaction mixture was stirred at room temperature for 1.5 hours and then poured onto saturated sodium thiosulfate solution. The phases were separated and the aqueous layer was extracted with DCM (×3). The organics were washed with brine then dried over sodium sulfate, filtered and evaporated. The crude material was purified by chromatography on a silica II cartridge, eluting with 2-6% ethyl acetate in pentane to give 3-iodo-5-methyl-pyrazole-1-carboxylic acid tert-butyl ester as a solid (0.13 g).

Workup

  1. customThe phases were separated
  2. extractionthe aqueous layer was extracted with DCM (×3)
  3. washThe organics were washed with brine
  4. dry with materialthen dried over sodium sulfate
  5. filtrationfiltered
  6. customevaporated
  7. customThe crude material was purified by chromatography on a silica II cartridge
  8. washeluting with 2-6% ethyl acetate in pentane

Sources & evidence

ORD record
ord-24b0fac314a541a8a8cdd997e113b670
Source dataset
uspto-grants-2012_10
Patent number
US08299063B2

Reaction notes

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