Methyl iodide → (6bR,10aS)-Ethyl 3-methyl-2-oxo-2,3,6b,7,10,10a-hexahydro-1H-pyrido[3',4':4,5]pyrrolo[1,2,3-de]quinoxaline-8(9H)-carboxylate

Participants

Reaction Steps

Sodium hydride (900 mg of 60% dispersion in oil; 22.5 mmol) was washed with hexane, and suspended in anhydrous dimethylformamide (5 mL). The suspension was added to a stirred solution of ethyl (6bR,10aS)-2-oxo-2,3,6b,9,10,10a-hexahydro-1H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxaline-8(7H)-carboxylate (6.02 g, 20 mmol) in anhydrous dimethylformamide (50 mL) under nitrogen. After gas evolution had subsided, the mixture was cooled in ice-water bath and treated with iodomethane (3.55 g., 25 mmol). The mixture was stirred at room temperature for 1 h and then concentrated. The residue was treated with water and extracted with dichloromethane (2×) and the extract was washed with brine, dried over magnesium sulfate and evaporated to dryness to yield 5.48 g (87%) of ethyl (6bR,10aS)-3-methyl-2-oxo-2,3,6b,9,10,10a-hexahydro-1H-pyrido[3′,4′:4,5]pyrrolo[1,2,3-de]quinoxaline-8(7H)-carboxylate as a tan solid, m.p. 149–151° C. (dec.). [M+H] calc. 316; found 316. 1H NMR (CDCl3, 300 MHz) δ 1.28 (t, J=7.3 Hz, 3H), 1.85 to 1.93 (m, 1H), 2.65 to 2.82 (m, 1H), 3.08 to 3.25 (m, 1H), 3.25 to 3.40 (m, 1H), 3.30–3.50 (m, 1H), 3.34 (s, 3H), 3.42 (d, J=14.3 Hz, 1H), 3.85 to 4.0 (m, 1H), 4.02 (d, J=14.3 Hz, 1H, 4.15 (q, J=7.2 Hz, 4H), 6.76 (d, J=8.1 Hz, 1H), 6.83 (t, J=7.3 Hz, 1H), 6.90 (d, J=7.3 Hz, 1H). MS (CI): 316 (M+H+).

Provenance & Evidence