1-Fluoro-2-nitrobenzene → Ethyl 5-ethyl-2-(2-nitroanilino)-thiophene-3-carboxylate

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Reaction Conditions

Reaction Steps

Ethyl 2-amino-5-ethyl-thiophene-3-carboxylate (Ber. 99, 94-100) (40 g, 0.2 mol) in dry tetrahydrofuran (150 ml) was stirred under nitrogen and cooled to -40° C. n-Butyl lithium (125 ml of 10.2% w/v solution in hexane, 0.2 mol) was added keeping the temperature below -30° C. The mixture was then stirred at -30° C. for a further 15 minutes. This solution was blown by nitrogen through an inverted "U" tube into a solution of o-fluoro-nitrobenzene (28 g, 0.2 mol) in dry tetrahydrofuran (100 ml) maintained at 15°-30° C. The mixture was stirred overnight. The resulting ink-blue solution was poured into three volumes of ice water, extracted with ether (3×500 ml), washed with water (2×500 ml), dried and then evaporated to dryness. The deep red oil was dissolved in ethanol (200 ml) and chilled overnight. Crystals of the title compound was filtered off and dried in vacuo at 50° C.

Provenance & Evidence