Ammonium Chloride → Tert-butyl 5-aminothiophene-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a suspension of tert-butyl 5-nitrothiophene-2-carboxylate (Int. 54) (2.230 g, 9.73 mmol) in a mixture of EtOH (60 ml) and water (30 ml), iron powder (3.26 g, 58.4 mmol) and ammonium chloride (0.364 g, 6.81 mmol) were added. The reaction was stirred at 80° C. for 3 hours and then at RT overnight. The mixture was filtered through a celite pad and the filtrate was evaporated to dryness. The crude was then dissolved in EtOAc and washed with brine; the organic phase was dried over sodium sulfate and the solvent evaporated under vacuum. The residue was purified by filtration through a silica gel cartridge (petroleum ether/EtOAc=9/1 to 6/4) to yield tert-butyl 5-aminothiophene-2-carboxylate (Int. 55) (1.481 g, 7.43 mmol, MS/ESI+200.0 [MH]+).

Provenance & Evidence