Reaction #657313

Reaction equation

1-{[3-(4-fluorophenyl)-1H-pyrazol-5-yl]oxy}acetone

acetic acid

p-TsOH

→

6-(4-fluorophenyl)-3-methylpyrazolo[5,1-b][1,3]oxazole

Yield 46.3%

Solvents

toluene

EtOAc

Conditions

Workup

1. 1
   workup.ADDITIONwas charged at RT
2. 2
   Washwashed with brine
3. 3
   DryingThe organic layer dried over sodium sulphate
4. 4
   Concentrationconcentrated under reduced pressure
5. 5
   Otherto get the crude which
6. 6
   Otherwas then purified by column chromatography 100-200 mesh)
7. 7
   Washeluted with 5-10% ethyl acetate in hexane as eluent

Procedure

To a stirred solution of 1-{[3-(4-fluorophenyl)-1H-pyrazol-5-yl]oxy}acetone (0.25 g, 1.0 mmol) in toluene, equipped with dean stark apparatus, acetic acid (2 ml) and p-TsOH (25 mg, cat.) was charged at RT and the reaction mass was refluxed at 130° C. for 16 h. After completion, the reaction was diluted with EtOAc (50 ml) and washed with brine. The organic layer dried over sodium sulphate and concentrated under reduced pressure to get the crude which was then purified by column chromatography 100-200 mesh) eluted with 5-10% ethyl acetate in hexane as eluent to get compound 6-(4-fluorophenyl)-3-methylpyrazolo[5,1-b][1,3]oxazole (0.1 g, yield 43%).

Source