Potassium Hydroxide → Ethyl 2-trifluoromethylpyrazolo[1,5-a]pyridine-3-carboxylate

HRID 517524Notes

Reaction equation

HRID 517524 reaction equation
[OH-].[K+].[I-].[NH2:4][N+:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1.[F:11][C:12]([F:21])([F:20])[C:13]#[C:14][C:15]([O:17][CH2:18][CH3:19])=[O:16]>O.ClCCl>[F:11][C:12]([F:20])([F:21])[C:13]1[C:14]([C:15]([O:17][CH2:18][CH3:19])=[O:16])=[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][N:5]2[N:4]=1

Participants

6

Reactant 3

HCID 14797Potassium HydroxideHCID 2733704Pyridinium, 1-amino-, iodide (1:1)HCID 3597254Ethyl 4,4,4-trifluoro-2-butynoate

Product 1

HCID 68088690Ethyl 2-trifluoromethylpyrazolo[1,5-a]pyridine-3-carboxylateYield 73%

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 6344DichloromethaneSolvent

Procedure

A mixture of 2.1 g (37.6 mmol) of potassium hydroxide and 6.7 g (30.1 mmol) of aminopyridinium iodide in 20 ml of water is added to a solution of 2.5 g (15.1 mmol) of ethyl 4,4,4-trifluorobut-2-ynoate in 25 ml of dichloromethane. After stirring for 5 h at ambient temperature, water is added and the mixture is extracted with dichloromethane. The organic phase is washed with water, dried over magnesium sulphate, filtered and concentrated to dryness. The crude product is purified by chromatography over silica gel eluted with an 80/20 heptane/ethyl acetate mixture. 2.8 g (73%) of ethyl 2-trifluoromethylpyrazolo[1,5-a]pyridine-3-carboxylate are obtained in the form of a yellow solid.

Workup

  1. extractionthe mixture is extracted with dichloromethane
  2. washThe organic phase is washed with water
  3. dry with materialdried over magnesium sulphate
  4. filtrationfiltered
  5. concentrationconcentrated to dryness
  6. customThe crude product is purified by chromatography over silica gel
  7. washeluted with an 80/20 heptane/ethyl acetate mixture

Sources & evidence

ORD record
ord-4055962cdfa54e37a3ec4013ba50657f
Source dataset
uspto-grants-2015_08
Patent number
US09115102B2

Reaction notes

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