Thiophene-3,4-diamine → 2-butyl-1H-thieno[3,4-d]imidazole

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Reaction Steps

A mixture of 3,4-diaminothiophene (116 mg, 1.01 mmol ) and ethyl valeroimidate hydrochloride (504 mg, 3.05 mmol) in absolute ethanol (20 mL) was heated to reflux for 1 hour, cooled to room temperature and stirred for 15 hours. The mixture was concentrated and purified by flash chromatography (SiO2, 25% EtOAc/hexanes) to give 140 mg (78%) of 2-n-butyl-1H-thieno[3,4-d]imidazole as a tan solid: 1H NMR (300 MHz, CDCl3)δ 6.70 (s, 2H), 2.81 (t, 2H, J=7.5 Hz), 1.88-1.74 (m, 2H), 1.48-1.35 (m, 2H), 0.90 (t, 3H, J=7.2 Hz); FAB-MS: 181 (M+ +1).

Provenance & Evidence