Water → ethyl 1-ethyl-1H-indazole-5-carboxylate

HRID 73076Notes

Reaction equation

HRID 73076 reaction equation
[NH:1]1[C:9]2[C:4](=[CH:5][C:6]([C:10]([OH:12])=[O:11])=[CH:7][CH:8]=2)C=N1.[C:13]([O-])([O-])=O.[Cs+].[Cs+].I[CH2:20][CH3:21].O.C[N:24]([CH:26]=O)[CH3:25]>>[CH2:26]([N:24]1[CH:25]=[C:4]2[C:9]([CH:8]=[CH:7][C:6]([C:10]([O:12][CH2:20][CH3:21])=[O:11])=[CH:5]2)=[N:1]1)[CH3:13].[CH2:26]([N:24]1[C:25]2[C:8](=[CH:7][C:6]([C:10]([O:12][CH2:20][CH3:21])=[O:11])=[CH:5][CH:4]=2)[CH:9]=[N:1]1)[CH3:13]

Participants

7

Reactant 5

HCID 962WaterHCID 6228DimethylformamideHCID 6340IodoethaneHCID 10796Cesium carbonateHCID 42484541H-Indazole-5-carboxylic acid

Product 2

HCID 66837854ethyl 1-ethyl-1H-indazole-5-carboxylateYield 65%HCID 66837900ethyl 2-ethyl-2H-indazole-5-carboxylateYield 31%

Procedure

To a suspension of 1H-indazole-5-carboxylic acid (500 mg, 3.08 mmol) and Cs2CO3 (2.01 g, 6.17 mmol) in DMF (10 mL) was added iodoethane (1.92 g, 12.33 mmol) at room temperature. The mixture was stirred at room temperature for 1 day. The mixture was poured into H2O, extracted with EtOAc, dried over Na2SO4, filtered and concentrated. The residual oil was purified by silica gel column chromatography (0-60% EtOAc in hexane) to give ethyl 2-ethyl-2H-indazole-5-carboxylate (208 mg, 31%) as a white solid and ethyl 1-ethyl-1H-indazole-5-carboxylate (435 mg, 65%) as a white solid.

Workup

  1. extractionextracted with EtOAc
  2. dry with materialdried over Na2SO4
  3. filtrationfiltered
  4. concentrationconcentrated
  5. customThe residual oil was purified by silica gel column chromatography (0-60% EtOAc in hexane)

Sources & evidence

ORD record
ord-df34564870fa44b9bea4bfa8153490d0
Source dataset
uspto-grants-2014_09
Patent number
US08829026B2

Reaction notes

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