Réaction #657311

Équation de réaction

3-(4-fluorophenyl)-1H-pyrazol-5-ol

K2CO3

butane-2,3-diyl dimethanesulfonate

→

6-(4-fluorophenyl)-2,3-dimethyl-2,3-dihydropyrazolo[5,1-b][1,3]oxazole

Rendement 71.8%

Solvants

DMF

water

Conditions de réaction

Traitement

1. 1
   Autreprepared
2. 2
   Autreat room temperature
3. 3
   Extractionextracted with ethyl acetate
4. 4
   SéchageThe organic layer was dried over anhydrous sodium sulphate
5. 5
   Concentrationconcentrated
6. 6
   Autreto get the crude product
7. 7
   AutrePurification by column chromatography over silica gel (eluent 5-10% ethyl acetate in petrol ether)

Mode opératoire

To a solution of 3-(4-fluorophenyl)-1H-pyrazol-5-ol (3 g, 16.8 mmol) in DMF (15 mL) was added K2CO3 (9.3 g, 67.4 mmol) and butane-2,3-diyl dimethanesulfonate (4.8 g, 18.5 mmol) (prepared as described in US2010/41748) at room temperature and then stirred for 16 h at 60° C. Thereafter, the reaction mixture was diluted with cold water and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulphate and concentrated to get the crude product. Purification by column chromatography over silica gel (eluent 5-10% ethyl acetate in petrol ether) yielded 6-(4-fluorophenyl)-2,3-dimethyl-2,3-dihydropyrazolo[5,1-b][1,3]oxazole (2.8 g, 71%) as yellow oil and a mixture of diastereoisomers.

Source