Sodium hydride → HCID 67260271, compound

Participants

Reaction Conditions

Reaction Steps

3-(2-thienyl)-1H-pyrazole (33.3 mmol) was dissolved in 100 mL dry N,N-dimethylformamide and cooled to 0° C. under argon atmosphere. Sodium hydride (39.9 mmol, 60% dispersion in mineral oil) was added in portions at 0° C. The reaction mixture was allowed to warm to room temperature and was stirred at room temperature for 15 min. After cooling to 0° C. again, propyl iodide (49.9 mmol) was added dropwise at 0° C. The reaction mixture was stirred at room temperature for 14 h. Water and MTBE were added to the reaction mixture. The phases were separated and the aqueous phase was extracted with MTBE. The combined organic extracts were successively washed with water and brine, dried over MgSO4, filtered and concentrated. 6.50 g of a mixture of 1-propyl-3-(2-thienyl)-1H-pyrazole and 1-propyl-5-(2-thienyl)-1H-pyrazole (81:19; 99% yield) were obtained. 1.0 g of this mixture was used as such in the next step. 5.50 g of the mixture were purified again by chromatography on silica gel (toluene:ethyl acetate 100:0 to 0:100) to afford 4.35 g of 1-propyl-3-(2-thienyl)-1H-pyrazole and 1-propyl-5-(2-thienyl)-1H-pyrazole (67% yield) and 0.40 g of 1-propyl-5-(2-thienyl)-1H-pyrazole (6% yield).

Provenance & Evidence