Chlorosuccinimide → Methyl 5-chloro-4-(4-chloro-1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate

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Reaction Steps

Methyl 5-chloro-4-[(1Z)-1-(1-ethyl-2-methylidenehydrazino)-1-propen-1-yl]-2-thiophenecarboxylate (260 mg, 0.96 mmol) and 1-chloro-2,5-pyrrolidinedione (154 mg, 1.15 mmol) in THF (4 mL) were heated at 70° C. under N2 for 2 h, concentrated and purified on silica (EtOAc/Hex, 10-30%) to afford the title compound (0.281 g, 83%) as a syrup: LC-MS (ES) m/z=305 (M+H)+.

Provenance & Evidence