Pyridine → 1-Benzyl-2-ethyl-4-methoxy-6,7,8,9-tetrahydro-1h-benz[g]indole

Participants

Reaction Steps

A solution of 1-benzyl-2-(1-hydroxyethyl)-4-methoxy-6,7,8,9-tetrahydro-1H-benz[g]indole (1.0 g, 3.0 mmol) in tetrahydrofuran (5 mL) was treated with acetic anhydride (0.28 mL, 3.0 mmol), pyridine (0.53 mL, 6.6 mmol), 1,4-cyclohexadiene (3 mL), and 10% palladium-on-carbon (0.5 g) at 70° C. for 7 h. The mixture was cooled to room temperature, stirred for 18 h, heated at 80° C. for 9 h, cooled to room temperature, and stirred for 18 h. Additional portions of 10% palladium-on-carbon (0.5 g) and 1,4-cyclohexadiene (3 mL) were added and the resulting mixture stirred at 80° C. for 9 h. The mixture was cooled to room temperature, filtered, and concentrated in vacuo. The residue was dissolved in 9:1 hexanes/ether and treated with 10% aqueous citric acid (3 mL). The organic layer was filtered through silica gel, which was eluted with hexanes, methylene chloride, and ether. Concentration of the appropriate fractions provided 662 mg (70%) of the title compound as an amber foam. 1H NMR (CDCl3) δ 7.22 (m, 3H), 6.83 (d, J=7 Hz, 2H), 6.42 (s, 1H), 6.25 (s, 1H), 5.54 (s, 2H), 3.95 (s, 3H), 2.96 (m, 2H), 2.85 (m, 2H), 2.55 (q, J=6 Hz, 2H), 1.70 (m, 4H), 1.28 (t, J=6 Hz, 3H); MS ES+ m/e 320 (p+1).

Provenance & Evidence