2-methyl-2,3,4,5-tetrahydro-1H-pyrido(4,3-b)indole → 6-(2-Methyl-1,2,3,4-tetrahydro-pyrido[4,3-b]indol-5-yl)hexanoic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

2-Methyl-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole (17) (0.50 g, 2.7 mmol) was placed under argon and dissolved in 5 mL of anhydrous DMF. Potassium tert-butoxide (0.32 g, 2.8 mmol) was dissolved in 3 mL of anhydrous DMF and added slowly to the reaction at room temperature. The reaction turned from orange to dark brown. After 15 min, 6-bromohexanoic acid methyl ester (0.56 g, 2.7 mmol) and 5 mg of potassium iodide were added to the reaction at room temperature. The reaction was heated to 80° C. for 2 h upon which a precipitate formed and the reaction turned from dark brown to dark orange. The reaction was then diluted with 30 mL of ethyl acetate and 30 mL of water. The organic layer was isolated and the aqueous layer extracted with ethyl acetate (2×10 mL). The combined organic layers were washed with water (2×20 mL), brine (15 mL), dried (Na2SO4) and concentrated in vacuo. Purification by MPCC (0-80% gradient of ethyl acetate in hexane) afforded the title compound (0.35 g, 40%) as a yellow oil. 1H NMR (400 MHz, DMSO): δ 7.46 (m, 2H), 7.17 (m, 1H), 7.06 (m, 1H), 4.46 (m, 2H), 4.10 (t, 2H, J=7.0 Hz), 3.66 (m, 2H), 3.56 (s, 3H), 3.16 (m, 2H), 3.00 (s, 3H), 2.28 (t, 2H, J=7.4 Hz), 1.66 (m, 2H), 1.55 (m, 2H), 1.29 (m, 2H). 13C NMR (100 MHz, DMSO): δ 173.7, 136.7, 131.3, 124.7, 121.9, 119.7, 118.0, 110.3, 101.8, 51.6, 51.0, 50.5, 42.9, 42.2, 33.6, 29.8, 26.1, 24.6, 19.8. ESI-HRMS (m/z): [M+H]+ calcd. for C19H26N2O2, 315.1959. found, 315.1945.

Provenance & Evidence