Iodine → Trifluoroacetic acid

HRID 1508530Notes

Reaction equation

HRID 1508530 reaction equation
[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([N:9]2[C:13]([C:14]([F:17])([F:16])[F:15])=[C:12]([C:18]([O:20][CH2:21][CH3:22])=[O:19])[CH:11]=[N:10]2)=[CH:5][CH:4]=1.[I:23]I.[O-:25]S([O-])(=S)=O.[Na+].[Na+].[CH3:32][OH:33]>S([O-])([O-])(=O)=O.[Ag+2].II.[O-]S([O-])(=O)=O.[Ag+].[Ag+]>[C:32]([OH:25])([C:14]([F:17])([F:16])[F:15])=[O:33].[I:23][C:8]1[CH:7]=[C:6]([N:9]2[C:13]([C:14]([F:17])([F:15])[F:16])=[C:12]([C:18]([O:20][CH2:21][CH3:22])=[O:19])[CH:11]=[N:10]2)[CH:5]=[CH:4][C:3]=1[O:2][CH3:1]

Participants

8

Reactant 4

HCID 807IodineHCID 887MethanolHCID 24477Sodium ThiosulfateHCID 13812946Ethyl 1-(4-methoxyphenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate

Product 2

HCID 6422Trifluoroacetic acidHCID 118600342HCID 118600342, compound

Reagents, catalysts & solvents 2

HCID 131734387HCID 131734387, compoundCatalystHCID 178418844HCID 178418844, compoundCatalyst

Procedure

Ethyl 1-(4-methoxyphenyl)-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate (1.1499 g, 3.66 mmol), iodine (0.929 g, 3.66 mmol), silver sulfate (1.141 g, 3.66 mmol) and MeOH (30 mL) were stirred at in a 75° C. oil bath. The reaction progress was followed by LCMS. Additional I2/Ag2SO4 (1.5 eq. each) were added. LCMS indicated some unreacted starting material while de-methylation of the methoxy group was observed. Na2S2O3 (sat., aq) was added to quench the reaction. Volatiles were removed under reduced pressure. The pot residue was taken up by EtOAc followed filtration. The separated aqueous phase was back extracted with EtOAc. The combined extracts were dried over Na2SO4, filtered and evaporated in vacuo. The resulting pot residue was purified by preparative HPLC (reverse phase, Kromasil® 100-5C18, 100×21.1 mm) eluting with acetonitrile/water+0.1% TFA (30% to 100% organic in 10 min, then to 100% for 2 min, 20 mL/min). Related fractions were pooled and evaporated under reduced pressure to afford a white solid as a TFA salt of the titled compound. LCMS calc.=439.98. found=441.05 (M+H)+. 1H NMR (CDCl3, 500 MHz) δ 8.09 (s, 1H), 7.85 (d, J=2.0 Hz, 1H), 7.37 (dd, J=8.8, 2.0 Hz, 1H), 6.88 (d, J=8.5 Hz, 1H), 4.37 (q, J=7.0 Hz, 2H), 3.95 (s, 3H), 1.38 (t, J=7.0 Hz, 3H).

Workup

  1. customto quench
  2. customthe reaction
  3. customVolatiles were removed under reduced pressure
  4. filtrationfiltration
  5. extractionThe separated aqueous phase was back extracted with EtOAc
  6. dry with materialThe combined extracts were dried over Na2SO4
  7. filtrationfiltered
  8. customevaporated in vacuo
  9. customThe resulting pot residue was purified by preparative HPLC (reverse phase, Kromasil® 100-5C18, 100×21.1 mm)
  10. washeluting with acetonitrile/water+0.1% TFA (30% to 100% organic in 10 min
  11. customevaporated under reduced pressure

Sources & evidence

ORD record
ord-0a804d403b174eab9cfa450e53ff0336
Source dataset
uspto-grants-2015_12
Patent number
US09221834B2

Reaction notes

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