Reaction Steps
To the mixture of 2-Carbethoxy-8-bromo-5-n-octyl-1,2,3,4-tetrahydropyrido[4,3-b]indole (4b, 1 equiv.), m-tolylboronic acid (1.1 equiv.) and Pd(PPh3)4 (0.05 equiv.) in 12 mL 1,4-dioxane was added 4 mL aqueous solution of K2CO3 (3 equiv.). The mixture was refluxed under N2 atmosphere for about 10 h. On cooling, the solvent was evaporated and the resulting residue was extracted with DCM (20 mL×3), the DCM layer was washed with brine, dried (Na2SO4) and filtered. The residue obtained on removal of the solvent was purified by column chromatography on silica gel with EtOAc/hexane as eluting solvents to give the target compound 2-carbethoxy-8-m-tolyl-5-octyl-1,2,3,4-tetrahydropyrido[4,3-b]indole (7). Yield: 60.4%. 1H NMR (300 Hz, CDCl3) δ 7.67 (br, 1H), 7.48-7.43 (m, 3H), 7.35-7.31 (m, 2H), 7.15-7.12 (m, 1H), 4.76 (s, 2H), 4.22 (q, 2H, J=7.2 Hz), 4.03 (t, 2H, J=7.2 Hz), 3.91 (br, 2H), 2.84 (br, 2H), 2.45 (s, 3H), 1.77-1.73 (m, 2H), 1.35-1.27 (m, 13H), 0.89 (t, 3H, J=6.5 Hz). 13C NMR (75 Hz, CDCl3) δ 156.09, 142.48, 138.10, 135.83, 132.72, 128.50, 128.09, 126.98, 125.57, 124.39, 120.83, 118.99, 116.15, 109.29, 106.70, 61.49, 60.36, 43.21, 41.31, 31.75, 30.38, 29.28, 29.13, 27.04, 22.57, 21.56, 14.73, 14.16, 14.03.
