Piperazine → 1-Benzothiophen-3-amine

Participants

Reaction Steps

A solution of methyl-3-aminobenzothiophene-2-carboxylate (1 g, 4.83 mmol, 1 eq) in 1-methyl-2-pyrrolidinone (8 mL) and piperazine (2.08 g, 24.13 mmol, 5 eq) was stirred at 130° C. overnight. Ice was added, and the mixture was extracted with EtOAc. The organic extracts were washed twice with water, dried, and concentrated in vacuo. The crude material was purified by flash chromatography on silica gel eluting with 33% ethyl acetate in hexanes to provide 600 mg (83%) of compound 39A as a yellow oil. HPLC: 98% at 1.043 min (retention time) (YMC S5 ODS 4.6×50 mm, 10-90% aqueous methanol over 4 minutes containing 0.2% phosphoric acid, monitoring at 220 nm).

Provenance & Evidence