1-Bromo-3-chloropropane → 2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine

HRID 570126Notes

Reaction equation

HRID 570126 reaction equation
[C:1]1([C:7]2[CH:11]=[C:10]([OH:12])[NH:9][N:8]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.Br[CH2:14][CH2:15][CH2:16]Cl.C(=O)([O-])[O-].[K+].[K+]>C(#N)C>[C:1]1([C:7]2[CH:11]=[C:10]3[O:12][CH2:14][CH2:15][CH2:16][N:9]3[N:8]=2)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1

Participants

5

Reactant 3

HCID 80061-Bromo-3-chloropropaneHCID 11430Potassium CarbonateHCID 178515566HCID 178515566, compound

Product 1

HCID 894883542-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

A mixture of 3-phenyl-1H-pyrazol-5-ol (8.80 g, 0.055 mol), 1-bromo-3-chloropropane (9.5 g, 1.1 eq, 0.06 mol) and potassium carbonate (30.3 g, 4 eq, 0.22 mol) in acetonitrile (120 mL) is heated for 5.5 h under reflux. Thereafter the volatiles are evaporated and the residue is treated with 50 mL ethyl acetate. The residual solid is washed 2× with ethyl acetate and the combined organic phases are evaporated. The obtained crude product is triturated with methyl tert butylether and 6.4 g (53%) of 2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine are obtained as solid.

Workup

  1. temperatureis heated for 5.5 h
  2. temperatureunder reflux
  3. customThereafter the volatiles are evaporated
  4. additionthe residue is treated with 50 mL ethyl acetate
  5. washThe residual solid is washed 2× with ethyl acetate
  6. customthe combined organic phases are evaporated
  7. customThe obtained crude product
  8. customis triturated with methyl tert butylether and 6.4 g (53%) of 2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine
  9. customare obtained as solid

Sources & evidence

ORD record
ord-873d61d9d8ff453e991563b29e13958c
Source dataset
uspto-grants-2015_05
Patent number
US09023844B2

Reaction notes

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