[CH2:1](I)[CH2:2][CH3:3].[O-]CC.[Na+].[CH2:9]([C:11]1[NH:15][N:14]=[C:13]([C:16]([O:18][CH2:19][CH3:20])=[O:17])[CH:12]=1)[CH3:10]>C(O)C>[CH2:2]([C:1]1[N:15]([CH2:11][CH2:9][CH3:10])[N:14]=[C:13]([C:16]([O:18][CH2:19][CH3:20])=[O:17])[CH:12]=1)[CH3:3]Propyl iodide (0.43 mL, 4.46 mmol) and a solution of sodium ethoxide in ethanol (21%, 0.95 g, 3.27 mmol) were added to a solution of ethyl 5-ethyl-1H-pyrazole-3-carboxylate (0.5 g, 2.97 mmol) in ethanol (5 mL) at ambient temperature. The reaction was stirred overnight, and additional propyl iodide (0.05 mL) and sodium ethoxide in ethanol (21%, 0.1 g) were added. After 3 hours, the solvent was removed under reduced pressure and the residue was partitioned between an aqueous sodium chloride solution and methyl tert-butyl ether. The aqueous phase was extracted with methyl tert-butyl ether twice. The organic phases were combined, dried over sodium sulfate, filtered, and concentrated under reduced pressure to yield impure ethyl 5-ethyl-1-propyl-1H-pyrazole-3-carboxylate.
Wird geladen…
