Isopropyl iodide → 4-iodo-1-isopropyl-5-(2-thienyl)-1H-pyrazole

To a solution of 4-iodo-3-(2-thienyl)-1H-pyrazole (1.1 mmol) in 3 mL dry N,N-dimethylformamide under argon atmosphere was added sodium hydride (1.3 mmol, 60% dispersion in mineral oil) in portions. The reaction mixture was stirred at room temperature, then isopropyl iodide (1.7 mmol) was added dropwise. After 2 h at room temperature, 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 to afford 350 mg of a mixture of 4-iodo-1-isopropyl-3-(2-thienyl)-1H-pyrazole and 4-iodo-1-isopropyl-5-(2-thienyl)-1H-pyrazole (75:25; 99% yield). The mixture was purified by chromatography on silica gel (cyclohexane:ethyl acetate 100:0 to 0:100) to afford 151 mg 4-iodo-1-isopropyl-3-(2-thienyl)-1H-pyrazole (42% yield) and 42 mg of 4-iodo-1-isopropyl-5-(2-thienyl)-1H-pyrazole (11% yield).

1. customThe phases were separated
2. extractionthe aqueous phase was extracted with MTBE
3. washThe combined organic extracts were successively washed with water and brine
4. dry with materialdried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated

ORD-Eintrag

ord-dba3f5a6c9404197b76e9d28317e759f

Quelldatensatz

uspto-grants-2014_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08685974B2