Potassium Carbonate → 6-(4-Fluorophenyl)-2,3-dimethyl-2,3-dihydropyrazolo[5,1-b][1,3]oxazole

HRID 570129

Reaction equation

[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH:12]=[C:11]([OH:13])[NH:10][N:9]=2)=[CH:4][CH:3]=1.C([O-])([O-])=O.[K+].[K+].CS(O[CH:25]([CH:27](OS(C)(=O)=O)[CH3:28])[CH3:26])(=O)=O>CN(C=O)C.O>[F:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]2[CH:12]=[C:11]3[O:13][CH:25]([CH3:26])[CH:27]([CH3:28])[N:10]3[N:9]=2)=[CH:6][CH:7]=1

Participants

Conditions

Temperature: 60 °C

Procedure

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.

Workup

customprepared
customat room temperature
extractionextracted with ethyl acetate
dry with materialThe organic layer was dried over anhydrous sodium sulphate
concentrationconcentrated
customto get the crude product
customPurification by column chromatography over silica gel (eluent 5-10% ethyl acetate in petrol ether)

Sources & evidence

ORD record: ord-5fdc646e557142ff9c0d88ee8192ca33
Source dataset: uspto-grants-2015_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09023844B2

Linked notes

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