1,2-Dibromoethane → Ethyl 2,3-dihydropyrazolo[5,1-b]oxazole-6-carboxylate

HRID 2216617Notes

Reaction equation

HRID 2216617 reaction equation
[OH:1][C:2]1[NH:6][N:5]=[C:4]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH:3]=1.C(=O)([O-])[O-].[K+].[K+].Br[CH2:19][CH2:20]Br>C(#N)C>[O:1]1[CH2:20][CH2:19][N:6]2[N:5]=[C:4]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH:3]=[C:2]12

Participants

5

Reactant 3

HCID 78391,2-DibromoethaneHCID 11430Potassium CarbonateHCID 178469373HCID 178469373, compound

Product 1

HCID 69588863Ethyl 2,3-dihydropyrazolo[5,1-b]oxazole-6-carboxylateYield 43.7%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

To the stirred suspension of ethyl 5-hydroxy-1H-pyrazole-3-carboxylate (10.34 g, 0.66 mol) and 36.62 g of potassium carbonate in 500 ml of acetonitrile was added 13.68 g of 1,2-dibromoethane, and refluxed for 16 hours. The reaction mixture was allowed to cool to room temperature, then filtered, the solid was washed with acetonitrile. The filtrate was concentrated to an oil. The residue was dissolved in ethyl acetate and extracted with water. The organic phase was dried over MgSO4 and evaporated to dryness. 5.80 g of the desired product was obtained (48%).

Workup

  1. temperaturerefluxed for 16 hours
  2. filtrationfiltered
  3. washthe solid was washed with acetonitrile
  4. concentrationThe filtrate was concentrated to an oil
  5. dissolutionThe residue was dissolved in ethyl acetate
  6. extractionextracted with water
  7. dry with materialThe organic phase was dried over MgSO4
  8. customevaporated to dryness

Sources & evidence

ORD record
ord-41f40700d771491b841b390806a90b77
Source dataset
uspto-grants-2006_09
Patent number
US07112582B2

Reaction notes

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