Tert-Butyl nitrite → Ethyl 5-ethylthiophene-3-carboxylate

Participants

Reaction Steps

2-Amino-5-ethyl-thiophene-3-carboxylic acid ethyl ester (2.5 g, 12.5 mmol) was added to a suspension of t-butyl nitrite (18.8 mmol) and copper (II) bromide (15.1 mmol) in ethanol (120 mL). The reaction mixture was stirred for 15 minutes then saturated aqueous ammonium chloride (7 mL) was added and the mixture stirred for a further 15 minutes. The solvent was removed under vacuum and product partitioned between diethyl ether and water. The organic layer was dried over magnesium sulphate, filtered and the solvent removed. The product was purified by column chromatography on silica, eluting with 0%-10% ethyl acetate in cyclohexane. The fractions containing the desired product were concentrated under vacuum to give the title compound (1.2 g). 1H NMR (400 MHz, CHCl3-d): δ 7.9 (s, 1H), 7.2 (s, 1H), 3.4 (q, 2H), 2.8 (q, 2H), 1.4 (m, 6H).

Provenance & Evidence