Pyrazole → 1-(3-nitrothiophen-2-yl)-1H-pyrazole

Participants

Reaction Steps

Potassium tert-butoxide (2.28 g, 20.3 mmol) and 1H-pyrazole (2.02 g, 29.7 mmol) in DMF (50 ml) was stirred for 30 min. 2-chloro-3-nitrothiophene (2.56 g, 15.6 mmol) was added and the solution was placed into a preheated oil bath at 100° C. After stirring for 1 h, the solution was diluted with brine and extracted with diethyl ether. The combined organic extracts were dried over magnesium sulfate, filtered and concentrated under reduced pressure. The residue was flash chromatographed with 9:1, 4:1, 7:3, 3:2, and 1:1 hexane:ethyl acetate as the eluant to yield impure 1-(3-nitrothiophen-2-yl)-1H-pyrazole. Method [1] Retention time 1.52 min by HPLC (MH+ 196).

Provenance & Evidence