Methanesulfonic Acid → 7-Methylcaprolactam

Participants

Reaction Conditions

Reaction Steps

Methanesulfonic acid (15 mL) was added to a solution of 2-methylcyclohexanone (2-1, 6.00 g, 53.5 mmol, 1 equiv) in DME (20 mL) at −40° C. Sodium azide (8.69 g, 134 mmol, 2.50 equiv) was added in four equal portions over 1 h as cooling was maintained. The cold bath was then removed and the reaction mixture was warmed to 23° C. and stirred for 20 h. The mixture was diluted with DME (20 mL) and basified to pH 9 with concentrated aqueous ammonium hydroxide solution. The resulting mixture was partitioned between brine (200 mL) and ethyl actetate (4×200 mL). The combined organic layers were dried over sodium sulfate and concentrated to give 7-methylazepan-2-one (2-2) as a pasty white solid. 1H NMR (300 MHz, CDCl3) δ 5.50 (br s, 1H), 3.50 (m, 1H), 2.43 (m, 2H), 2.05-1.30 (m, 6H), 1.21 (d, 3H,J=7.1 Hz).

Provenance & Evidence