Diethyl Ether → 5-(2-Methoxy-5-nitrophenyl)-1-methyl-1H-pyrazole

Beteiligte Stoffe

Reaktionsschritte

A solution of N-methylpyrazole (5.12 g, 62.4 mmol) in THF (100 mL) was cooled to −78° C. and 2.5 M n-butyllithium in hexane (27.5 mL, 68.8 mmol) was added. After stirring for 30 minutes at the same temperature, 0.5 M zinc chloride in THF (107 mL, 53.5 mmol) and 1 M zinc chloride in diethyl ether (15.3 mL, 15.2 mmol) were added. The mixture was allowed to warm to room temperature and 2-iodo-4-nitroanisole (17.4 g, 62.4 mmol) followed by tetrakis(triphenylphosphine)palladium (3.6 g, 3.1 mmol) were added. After stirring at 60° C. for 20 hours, the black solution was concentrated on a rotary evaporator, and extracted with ethyl acetate and brine. Combined organic layers were dried over magnesium sulfate, filtered, and partly concentrated until a solid started to precipitate. Hexane was added, precipitate was filtered off, and washed with a cold 3:1 mixture of hexane/ethyl acetate to give 5-(2-methoxy-5-nitro-phenyl)-1-methyl-1H-pyrazole (8.6 g, 36.9 mmol, 59%) as a tan solid. LCMS m/z (%/o)=234 (M+H, 100). 1H NMR (400 MHz, CDCl3) δ: 8.34 (dd, J=2.8, 9.2 Hz, 1H), 8.19 (d, J=2.8 Hz, 1H), 7.56 (d, J=2.0 Hz, 1H), 7.08 (d, J=9.2 Hz, 1H), 6.31 (d, J=1.6 Hz, 1H), 3.96 (s, 3H), 3.74 (s, 3H).

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