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

HRID 2202202Notes

Reaction equation

HRID 2202202 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-da66a1a6b1ec4e888b04d8e61a2e8ca1
Source dataset
uspto-grants-2016_06
Patent number
US09365529B2

Reaction notes

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