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

HRID 874594Notes

Reaction equation

HRID 874594 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 solution of 2.1 g (38 mmol) of KOH in 20 ml of water and then 6.7 g (30 mmol) of 1-aminopyridinium iodide are added to a solution of 2.5 g (15 mmol) of ethyl 4,4,4-trifluorobut-2-ynoate in 25 ml of dichloromethane. After stirring at ambient temperature for 5 h, water is added and the reaction medium is extracted with dichloromethane. The organic phase is washed with water, dried over magnesium sulfate, filtered and concentrated. The residue obtained is purified by chromatography on silica gel, elution being carried out with an 8/2 heptane/ethyl acetate mixture. 2.8 g (73%) of ethyl 2-trifluoromethylpyrazolo[1,5-α]pyridine-3-carboxylate are obtained in the form of a yellow solid.

Workup

  1. extractionthe reaction medium is extracted with dichloromethane
  2. washThe organic phase is washed with water
  3. dry with materialdried over magnesium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated
  6. customThe residue obtained
  7. customis purified by chromatography on silica gel, elution

Sources & evidence

ORD record
ord-e8f95a01418c4dc08cc0d1d2c6399112
Source dataset
uspto-grants-2015_03
Patent number
US08980897B2

Reaction notes

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