3.2. Synthesis
General procedure for synthesis of compounds 2a–d. To a round-bottom flask 7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (1) (5 mmol) was added in the mixed solvent of DMF and THF (DMF:17 mL, THF:15 mL), stirred at room temperature until clear. NaH (7.5 mmol) was added in batches, stirred for 10 min at room temperature. Then, dibromoalkanes (15 mmol) were added to the mixture, followed by heating and refluxing. The reaction was monitored by TLC during the whole process. After the mixture fully reacted, the mixture was cooled with ice water, and extracted three times with ethyl acetate. The mixture was washed with ether and saturated NaCl solution, after being dried over anhydrous Na2SO4, the mixture was filtered and concentrated. The crude product was purified by silica gel column to obtain 2a–d (dichloromethane:methanol = 10:1, triethylamine 1‰).
9-(3-Bromopropyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2a). Compound 2a was prepared according to the general procedure from 7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (1) and 1,3-dibromopropane. White solid, 68.8% yield. 1H-NMR (400 MHz, CDCl3) δ: 8.67 (d, J = 5.4 Hz, 1H), 8.02 (d, J = 8.7 Hz, 1H), 7.87 (d, J = 5.4 Hz, 1H), 6.86–6.79 (m, 2H), 4.36 (t, J = 7.4 Hz, 2H), 3.91 (s, 3H), 3.51 (t, J = 6.4 Hz, 2H), 2.98 (s, 3H), 1.98–1.87 (m, 2H).
9-(4-Bromobutyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2b). Compound 2b was prepared according to the general procedure from 7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (1) and 1,4-dibromobutane. White solid, 70.1% yield.1H-NMR (400 MHz, CDCl3) δ: 8.21 (d, J = 5.2 Hz, 1H), 7.98 (d, J = 8.6 Hz, 1H), 7.77 (d, J = 5.2 Hz, 1H), 6.97–6.80 (m, 2H), 4.54 (t, J = 7.5 Hz, 2H), 3.95 (s, 3H), 3.49 (t, J = 6.4 Hz, 2H), 3.01 (s, 3H), 1.96–1.81 (m, 4H).
9-(5-Bromopentyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2c). Compound 2c was prepared according to the general procedure from 7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (1) and 1,5-dibromopentane. White solid, 68.3% yield. 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 4.8 Hz, 1H), 7.99 (d, J = 8.6 Hz, 1H), 7.74 (d, J = 5.4 Hz, 1H), 6.95–6.81 (m, 2H), 4.49 (t, J = 7.4 Hz, 2H), 3.96 (s, 3H), 3.41 (t, J = 6.4 Hz, 2H), 3.02 (s, 3H), 1.98–1.82 (m, 4H), 1.59–1.44 (m, 2H).
9-(6-Bromohexyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2d). Compound 2d was prepared according to the general procedure from 7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (1) and 1,6-dibromohexane. White solid, 66.1% yield. 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.4 Hz, 1H), 7.99 (d, J = 8.4 Hz, 1H), 7.74 (d, J = 4.0 Hz, 1H), 6.96–6.79 (m, 2H), 4.48 (t, J = 7.5 Hz, 2H), 3.96 (s, 3H), 3.40 (t, J = 6.4 Hz, 2H), 3.02 (s, 3H), 1.89–1.78 (m, 4H), 1.51–1.39 (m, 4H).
General procedure for synthesis of compounds 3a–d, 4a–d, 5a–d, 6a–d. To a round-bottom flask with a magnetic stirrer substituted cinnamic acid (1 mmol) in acetone (8 mL), triethylamine were added dropwise (5–10 drops), and stirred until completely dissolved. Compound 2a–d (3 mmol) was dissolved and dropped into the above reaction solution, stirred at room temperature for 3 h. The reaction was monitored by TLC during the whole process. After the mixture fully reacted, aqueous HCl was added to the solution to adjust pH to 3–5. The mixture was extracted three times with ethyl acetate. The organic phase was collected, washed twice with saturated NaHCO3 solution and saturated NaCl solution, respectively. The organic phase was then dried over anhydrous NaSO4, filtered and concentrated. Compounds 3a–d, 4a–d, 5a–d, 6a–d were obtained by further purification using silica gel column chromatography (dichloromethane:methanol = 10:1, triethylamine 1‰).
3-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl)propyl(E)-3-(4-methoxyphenyl) acrylate (3a). Compound 3a was prepared according to the general procedure from (E)-3-(4-methoxyphenyl)acrylic acid and 9-(3-bromopropyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2a). Yellow solid. 52.1% yield; mp 133.2–133.9 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.2 Hz, 1H), 7.96 (d, J = 8.4 Hz, 1H), 7.73 (d, J = 5.2 Hz, 1H), 7.65 (d, J = 16.0 Hz, 1H), 7.49 (d, J = 8.8 Hz, 2H), 6.94–6.87 (m, 4H), 6.29 (d, J = 16.0 Hz, 1H), 4.65 (t, J = 7.6 Hz, 2H), 4.28 (t, J = 5.8 Hz, 2H), 3.91 (s, 3H), 3.86 (s, 3H), 3.06 (s, 3H), 2.28–2.22 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 166.97, 161.53, 160.89, 144.97, 142.95, 140.47, 138.48, 135.12, 129.76, 129.48, 122.35, 115.21, 114.79, 114.33, 112.22, 108.82, 93.21, 61.42, 55.58, 55.34, 41.79, 29.86, 23.35; ESI-MS: calcd. for C26H26N2O4 [M + H]+ 431.1965; found 431.1955.
3-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) propyl (E)-3-(3,4,5-trimethoxyphenyl) acrylate (3b). Compound 3b was prepared according to the general procedure from (E)-3-(3,4,5-trimethoxyphenyl) acrylic acid and 9-(3-bromopropyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2a). White solid. 49.2% yield; m.p.: 102.6–104.2 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.2 Hz, 1H), 7.96 (d, J = 9.2 Hz, 1H), 7.73 (d, J = 5.2 Hz, 1H), 7.58 (d, J = 16.0 Hz, 1H), 6.90 (s, 2H), 6.76 (s, 2H), 6.31 (d, J = 16.0 Hz, 1H), 4.64 (t, J = 7.4 Hz, 2H), 4.29 (t, J = 5.8 Hz, 2H), 3.92 (s, 9H), 3.90 (s, 3H), 3.05 (s, 3H), 2.28–2.22 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 166.75, 161.05, 153.56, 145.42, 143.12, 140.54, 140.44, 138.59, 135.28, 129.73, 122.54, 116.68, 115.41, 112.40, 108.90, 105.41, 93.48, 61.80, 61.08, 56.28, 55.77, 41.97, 31.82, 29.95, 29.36, 23.45; ESI-MS: calcd. for C28H30N2O6 [M + H]+ 491.2177; found 491.2171.
4-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) propyl(E)-3-(2-nitrophenyl) acrylate (3c). Compound 3c was prepared according to the general procedure from (E)-3-(2-nitrophenyl) acrylic acid and 9-(3-bromopropyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2a). Yellow solid. 44.2% yield; m.p.: 128.6–129.3 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.2 Hz, 1H), 8.14 (d, J = 16.0 Hz, 1H), 8.08 (d, J = 7.2 Hz, 1H), 7.97 (d, J = 9.2 Hz, 1H), 7.73–7.64 (m, 3H), 7.60–7.56 (m, 1H), 6.90–6.87 (m, 2H), 6.33 (d, J = 16.0 Hz, 1H), 4.67 (t, J = 7.4 Hz, 2H), 4.33–4.29 (m, 2H), 3.92 (s, 3H), 3.05 (s, 3H), 2.30–2.24 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 165.67, 160.75, 148.18, 142.94, 140.40, 139.88, 138.10, 135.16, 130.41, 130.19, 129.26, 128.98, 124.79, 123.03, 122.25, 115.09, 112.14, 108.53, 93.31, 64.62, 55.60, 44.66, 28.47, 23.31; ESI-MS: calcd. for C25H23N3O5 [M + H]+ 446.1710; found 446.1716.
3-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) propyl (E)-2-(3,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl) acrylate (3d). Compound 3d was prepared according to the general procedure from (E)-2-(3,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl) acrylic acid and 9-(3-bromopropyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2a). White solid. 21.14% yield; m.p.: 173.6–175.2 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.28 (d, J = 5.2 Hz, 1H), 7.95 (d, J = 8.4 Hz, 1H), 7.71 (d, J = 5.2 Hz, 1H), 7.67 (s, 1H), 6.95 (d, J = 8.4 Hz, 1H), 6.89–6.83 (m, 2H), 6.80 (d, J = 9.2 Hz, 2H), 6.36 (s, 2H), 4.56 (t, J = 7.6 Hz, 2H), 4.33 (t, J = 5.8 Hz, 2H), 3.90 (s, 3H), 3.89 (s, 3H), 3.83 (s, 6H), 3.60 (s, 6H), 2.95 (s, 3H), 2.24–2.19 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 167.73, 161.00, 152.65, 149.46, 148.86, 143.00, 140.64, 140.37, 139.16, 138.38, 135.11, 130.86, 129.63, 128.40, 122.50, 122.23, 115.32, 112.92, 112.33, 111.68, 108.62, 108.17, 93.45, 62.51, 60.88, 55.75, 55.69, 41.99, 29.78, 23.24; ESI-MS: calcd. for C36H38N2O8 [M + H]+ 627.2701; found 627.2701.
4-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) butyl (E)-3-(4-methoxyphenyl) acrylate (4a). Compound 4a was prepared according to the general procedure from (E)-3-(4-methoxyphenyl) acrylic acid and 9-(4-bromobutyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2b). White solid. 43.6% yield; m.p.: 118.7–120.2 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.2 Hz, 1H), 7.98 (d, J = 9.6 Hz, 1H), 7.74 (d, J = 5.2 Hz, 1H), 7.63 (d, J = 16.0 Hz, 1H), 7.46 (d, J = 8.8 Hz, 2H), 6.91–6.88 (m, 4H), 6.29 (d, J = 16.0 Hz, 1H), 4.54 (t, J = 7.6 Hz, 2H), 4.25 (t, J = 6.4 Hz, 2H), 3.94 (s, 3H), 3.84 (s, 3H), 3.03 (s, 3H), 2.01–1.94 (m, 2H), 1.867–1.80 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 167.21, 161.44, 160.88, 144.76, 142.95, 140.44, 138.38, 135.21, 129.75, 129.42, 126.95, 122.39, 115.23, 115.12, 114.30, 112.26, 108.66, 93.37, 63.47, 55.68, 55.67, 44.38, 27.18, 26.13, 23.41; ESI-MS: calcd. for C27H28N2O4 [M + H]+ 445.2111; found 445.2116.
4-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) butyl (E)-3-(3,4,5-trimethoxyphenyl) acrylate (4b). Compound 4b was prepared according to the general procedure from (E)-3- (3,4,5-trimethoxyphenyl) acrylic acid and 9-(4-bromobutyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2b). Yellow solid. 49.0% yield; m.p.: 95.7–96.3 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.2 Hz, 1H), 7.99 (d, J = 9.2 Hz, 1H), 7.75 (d, J = 5.2 Hz, 1H), 7.59 (d, J = 16.0 Hz, 1H), 6.91–6.89 (m, 2H), 6.74 (s, 2H), 6.31 (d, J = 16.0 Hz, 1H), 4.55 (t, J = 7.8 Hz, 2H), 4.26 (t, J = 6.2 Hz, 2H), 3.94 (s, 3H), 3.89 (s, 9H), 3.03 (s, 3H), 2.02–1.95 (m, 2H), 1.87–1.80 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 166.83, 160.87, 153.40, 145.08, 142.95, 140.41, 140.19, 138.40, 135.21, 129.69, 129.44, 122.42, 116.87, 115.26, 112.28, 108.61, 105.23, 93.43, 63.67, 60.93, 56.13, 55.69, 44.37, 27.19, 26.12, 23.42; ESI-MS: calcd. for C29H32N2O6 [M + H]+ 505.2333; found 505.2339.
4-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) butyl (E)-3-(2-nitrophenyl) acrylate (4c). Compound 4c was prepared according to the general procedure from (E)-3-(2-nitrophenyl) acrylic acid and 9-(4-bromobutyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2b). White solid. 43.6% yield; m.p.: 130.9–132.2 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.28 (d, J = 5.2 Hz, 1H), 8.11 (d, J = 15.6 Hz, 1H), 8.04 (d, J = 8.0 Hz, 1H), 7.97 (d, J = 9.2 Hz, 1H), 7.73 (d, J = 5.2 Hz, 1H), 7.67–7.60 (m, 2H), 7.56–7.52(m, 1H), 6.90–6.87 (m, 2H), 6.34 (d, J = 16.0 Hz, 1H), 4.54 (t, J =7.8 Hz, 2H), 4.27 (t, J = 6.4 Hz, 2H), 3.94 (s, 3H), 3.03 (s, 3H), 2.01–1.93 (m, 2H), 1.87–1.80 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 165.62, 160.88, 148.22, 142.94, 140.41, 140.38, 138.36, 135.17, 133.49, 130.40, 130.33, 129.43, 129.08, 124.88, 122.73, 122.37, 115.20, 112.24, 108.69, 93.34, 64.07, 55.67, 44.32, 27.16, 26.03, 23.38; ESI-MS: calcd. for C26H25N3O5 [M + H]+ 460.1867; found 460.1865.
4-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) butyl (E)-2-(3,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl) acrylate (4d). Compound 4d was prepared according to the general procedure from (E)-2-(3,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl) acrylic acid and 9-(4-bromobutyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2b). White solid. 27.2% yield; m.p.: 95.7–97.4 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.6 Hz, 1H), 7.98 (d, J = 8.8 Hz, 1H), 7.73 (d, J = 5.2 Hz, 1H), 7.69 (s, 1H), 6.89 (dd, J = 2.0, 8.8 Hz, 1H), 6.83–6.81 (m, 2H), 6.76 (dd, J = 2.0, 8.4 Hz, 1H), 6.71 (d, J = 2.0 Hz, 1H), 6.34 (s, 2H), 4.47–4.43 (m, 2H), 4.29 (t, J = 6.2 Hz, 2H), 3.92 (s, 3H), 3.81 (s, 3H), 3.80 (s, 3H), 3.70 (s, 3H), 3.56 (s, 6H), 2.99 (s, 3H), 1.94–1.89 (m, 2H), 1.87–1.78 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 167.84, 161.86, 152.62, 149.30, 148.72, 144.00, 140.48, 139.07, 135.45, 134.70, 131.03, 129.65, 128.42, 122.97, 122.18, 119.25, 114.68, 112.86, 111.54, 109.93, 108.11, 105.32, 93.29, 64.26, 60.86, 55.78, 55.72, 44.52, 27.42, 26.18, 21.46; ESI-MS: calcd. for C37H40N2O8 [M + H]+ 641.2857; found 641.2844.
5-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) amyl (E)-3-(4-methoxyphenyl) acrylate (5a). Compound 5a was prepared according to the general procedure from (E)-3-(4-methoxyphenyl) acrylic acid and 9-(5-bromopentyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2c). White solid. 46.2% yield; m.p.: 91.1–92.3 °C; 1H-NMR (400 MHz, DMSO-d6) δ: 8.17 (d, J = 5.2 Hz, 1H), 8.08 (d, J = 8.4 Hz, 1H), 7.88 (d, J = 5.2 Hz, 1H), 7.66 (d, J = 8.8 Hz, 2H), 7.57 (d, J = 16.0 Hz, 1H), 7.20 (s, 1H), 6.98 (d, J = 8.4 Hz, 2H), 6.87 (d, J = 8.6 Hz, 1H), 6.44 (d, J = 16.0 Hz, 1H), 4.57 (t, J = 7.6 Hz, 2H), 4.13 (t, J = 6.6 Hz, 2H), 3.91 (s, 3H), 3.81 (s, 3H), 2.96 (s, 3H), 1.82–1.74 (m, 2H), 1.72–1.69 (m, 2H); 1.51–1.43 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 167.22, 161.33, 160.84, 144.44, 143.00, 140.31, 138.03, 135.15, 129.66, 129.40, 126.99, 122.33, 115.31, 115.10, 114.24, 112.21, 108.64, 93.32, 63.79, 55.63, 55.30, 44.66, 30.23, 28.50, 23.38, 23.20; ESI-MS: calcd. for C28H30N2O4 [M + H]+ 459.2278; found 459.2288.
5-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) amyl (E)-3-(3,4,5-trimethoxyphenyl) acrylate (5b). Compound 5b was prepared according to the procedure from (E)-3-(3,4,5-trimethoxyphenyl) acrylic acid and 9-(5-bromopentyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2c). White solid. 48.9% yield; m.p.: 103.7–104.7 °C; 1H-NMR (400 MHz, DMSO-d6) δ: 8.16 (d, J = 5.1 Hz, 1H), 8.08 (d, J = 8.4 Hz, 1H), 7.87 (d, J = 5.4 Hz, 1H), 7.57 (d, J = 15.9 Hz, 1H), 7.20 (s, 1H), 7.07 (s, 2H), 6.86 (d, J = 8.7 Hz, 1H), 6.64 (d, J = 15.9 Hz, 1H), 4.56 (t, J = 7.4 Hz, 2H), 4.14 (t, J = 6.5 Hz, 2H), 3.91 (s, 3H), 3.83 (s, 6H), 3.70 (s, 3H), 2.95 (s, 3H), 1.81–1.69 (m, 4H), 1.53–1.44 (m, 2H); 13C-NMR (100 MHz, DMSO-d6) δ: 166.88, 160.99, 153.55, 145.16, 143.21, 140.97, 139.93, 138.19, 135.02, 130.08, 128.90, 122.81, 117.76, 114.68, 112.67, 109.54, 106.40, 94.12, 64.19, 60.56, 56.50, 56.04, 44.41, 30.39, 28.47, 23.53, 23.20; ESI-MS: calcd. for C30H34N2O6 [M + H]+ 519.2490; found 519.2474.
5-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) amyl (E)-3-(2-nitrophenyl) acrylate (5c). Compound 5c was prepared according to the procedure from (E)-3-(2-nitrophenyl) acrylic acid and 9-(5-bromopentyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2c). Yellow solid. 44.2% yield; m.p.: 127.4–130.0 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.28 (d, J = 5.2 Hz, 1H), 8.11 (d, J = 16.0 Hz, 1H), 8.06 (d, J = 8.0 Hz, 1H), 7.97 (d, J = 9.2 Hz, 1H), 7.73 (d, J = 5.6 Hz, 1H), 7.69–7.62 (m, 2H), 7.54–7.58 (m, 1H), 6.89–6.86 (m, 2H), 6.34 (d, J = 16.0 Hz, 1H), 4.53–4.49 (m, 2H), 4.24 (t, J = 6.4 Hz, 2H), 3.95 (s, 3H), 3.03 (s, 3H), 1.95–1.87 (m, 2H), 1.82–1.75 (m, 2H), 1.59–1.50 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 165.82, 158.08, 148.23, 144.12, 140.01, 138.76, 136.94, 133.49, 130.58, 130.22, 129.14, 127.31, 124.87, 123.16, 118.24, 115.39, 113.62, 108.74, 104.15, 99.94, 64.73, 62.57, 59.60, 33.71, 32.46, 31.74, 24.40; ESI-MS: calcd. for C27H27N3O5 [M + H]+ 474.2023; found 474.2011.
5-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) pentyl (E)-2-(3,4-dimethoxyphenyl)-3- (3,4,5-trimethoxyphenyl) acrylate (5d). Compound 5d was prepared according to the procedure from (E)-2-(3,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl) acrylic acid and 9-(5-bromopentyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2c). White solid. 28.2% yield; m.p.: 117.4–119.9 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.28 (d, J = 5.2 Hz, 1H), 7.97 (d, J = 8.8 Hz, 1H), 7.73 (d, J = 5.2 Hz, 1H), 7.67 (s, 1H), 6.89 (d, J = 2.0 Hz, 1H), 6.87 (s, 1H), 6.85 (s, 1H), 6.77–6.75 (m, 2H), 6.35 (s, 2H), 4.39 (t, J = 7.8 Hz, 2H), 4.22 (t, J = 6.4 Hz, 2H), 3.94 (s, 3H), 3.86 (s, 3H), 3.82 (s, 3H), 3.79 (s, 3H), 3.58 (s, 6H), 2.96 (s, 3H), 1.88–1.84 (m, 2H), 1.76–1.73 (m, 2H), 1.51–1.43 (m, 2H); 13C-NMR (100 MHz, CDCl3) δ: 167.69, 162.39, 160.81, 152.47, 149.15, 148.54, 142.98, 140.20, 139.91, 138.86, 137.94, 135.10, 135.09, 131.21, 129.69, 129.37, 128.42, 122.14, 115.02, 112.95, 112.87, 112.15, 111.33, 108.54, 107.92, 93.33, 64.53, 60.72, 55.86, 55.58, 44.60, 30.08, 28.33, 23.26, 23.26, 23.08; ESI-MS: calcd. for C38H42N2O8 [M + H]+ 665.3014; found 655.3018.
6-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) hexyl (E)-3-(4-methoxyphenyl) acrylate (6a). Compound 6a was prepared according to the general procedure from (E)-3-(4-methoxyphenyl) acrylic acid and 9-(6-bromohexyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2d). Yellow solid. 37.6% yield; m.p.: 88.7–90.4 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.4 Hz, 1H), 7.97 (d, J = 8.4 Hz, 1H), 7.73 (d, J = 5.1 Hz, 1H), 7.63 (d, J = 16.2 Hz, 1H), 7.46 (d, J = 8.5 Hz, 2H), 6.84–6.90(m, 4H), 6.29 (d, J = 15.9 Hz, 1H), 4.45 (t, J = 7.8 Hz, 2H), 4.18 (t, J = 6.7 Hz, 2H), 3.94 (s, 3H), 3.82 (s, 3H), 3.02 (s, 3H), 1.90–1.81 (m, 2H), 1.74–1.66 (m, 2H), 1.50–1.45 (m, 4H); 13C-NMR (100 MHz, CDCl3) δ: 167.25, 161.27, 160.76, 144.30, 142.95, 140.37, 138.08, 135.16, 129.60, 129.28, 127.00, 122.28, 115.42, 115.11, 114.21, 112.15, 108.51, 93.31, 64.03, 55.60, 55.26, 44.68, 30.47, 28.60, 26.52, 25.76, 23.30; ESI-MS: calcd. for C29H32N2O4 [M + H]+ 473.2435; found 473.2433.
6-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) hexyl (E)-3-(3,4,5-trimethoxyphenyl) acrylate (6b). Compound 6b was prepared according to the general procedure from (E)-3-(3,4,5-trimethoxyphenyl) acrylic acid and 9-(6-bromohexyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2d). Yellow solid. 38.1% yield; m.p.: 73.7–73.9 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.29 (d, J = 5.2 Hz, 1H), 7.98 (d, J = 8.4 Hz, 1H), 7.74 (d, J = 5.2 Hz, 1H), 7.59 (d, J = 15.6 Hz, 1H), 6.91–6.86 (m, 2H), 6.75 (s, 2H), 6.33 (d, J = 16.0 Hz, 1H), 4.48 (t, J = 7.8 Hz, 2H), 4.20 (t, J = 6.6 Hz, 2H), 3.95 (s, 3H), 3.88 (s, 9H), 3.02 (s, 3H), 1.90–1.83 (m, 2H), 1.74–1.69 (m, 2H), 1.50–1.47 (m, 4H); 13C-NMR (100 MHz, CDCl3) δ: 166.95, 160.86, 153.36, 144.70, 143.08, 140.30, 140.05, 137.94, 135.19, 129.81, 129.46, 122.40, 117.21, 115.15, 112.26, 108.57, 105.15, 93.44, 64.24, 60.91, 56.10, 55.68, 44.76, 30.50, 28.61, 26.55, 25.77, 23.19; ESI-MS: calcd. for C31H36N2O6 [M + H]+ 533.2646; found 533.2648.
6-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) hexyl(E)-3-(2-nitrophenyl) acrylate (6c). Compound 6c was prepared according to the general procedure from (E)-3-(2-nitrophenyl) acrylic acid and 9-(6-bromohexyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2d). White solid. 33.9% yield; m.p.: 117.3–119.9 °C; 1H-NMR (400 MHz, DMSO-d6) δ: 8.16 (d, J = 5.1 Hz, 1H), 8.08 (d, J = 8.7 Hz, 2H), 7.95–7.90 (m, 2H), 7.87 (d, J = 5.1 Hz, 1H), 7.78 (t, J = 7.5 Hz, 1H), 7.68 (t, J = 7.7 Hz, 1H), 7.18 (s, 1H), 6.86 (d, J = 8.7 Hz, 1H), 6.62 (d, J = 15.9 Hz, 1H), 4.55 (t, J = 7.4 Hz, 2H), 4.16 (t, J = 6.5 Hz, 2H), 3.90 (s, 3H), 2.95 (s, 3H), 1.78–1.71 (m, 2H), 1.66–1.60 (m, 2H), 1.45–1.40 (m, 4H); 13C-NMR (100 MHz, CDCl3) δ: 165.67, 160.75, 148.18, 142.94, 140.40, 139.88, 138.10, 135.16, 133.40, 130.41, 130.19, 129.26, 128.98, 124.79, 123.03, 122.25, 115.09, 112.14, 108.53, 93.31, 64.62, 55.60, 44.66, 30.48, 28.47, 26.51, 25.76, 23.31; ESI-MS: calcd. for C28H29N3O5 [M + H]+ 488.2180; found 488.2201.
6-(7-Methoxy-1-methyl-9H-pyridine [3,4-b] indole-9-yl) hexyl (E)-2-(3,4-dimethoxyphenyl)-3– (3,4,5-trimethoxyphenyl) acrylate (6d). Compound 6d was prepared according to the general procedure from (E)-2-(3,4-dimethoxyphenyl)-3-(3,4,5-trimethoxyphenyl) acrylic acid and 9-(6-bromohexyl)-7-methoxy-1-methyl-9H-pyridine [3,4-b] indole (2d). White solid. 27.3% yield; m.p.: 113.1–115.0 °C; 1H-NMR (400 MHz, CDCl3) δ: 8.27 (d, J = 5.6 Hz, 1H), 7.99 (d, J = 8.8 Hz, 1H), 7.82 (d, J = 5.2 Hz, 1H), 7.68 (s, 1H), 6.93 (d, J = 8.8 Hz, 1H), 6.84 (s, 2H), 6.79–6.74 (m, 2H), 6.34 (s, 2H), 4.43 (t, J = 7.6 Hz, 2H), 4.18 (t, J = 6.6 Hz, 2H), 3.95 (s, 3H), 3.81 (s, 3H), 3.79 (s, 3H), 3.77 (s, 3H), 3.55 (s, 6H), 3.11 (s, 3H), 1.83–1.78 (m, 2H), 1.70–1.65 (m, 2H), 1.45–1.36 (m, 4H); 13C-NMR (100 MHz, CDCl3) δ: 167.90, 161.62, 153.13, 152.62, 149.25, 148.67, 143.88, 140.03, 138.95, 134.89, 131.39, 129.83, 128.61, 122.86, 122.28, 114.83, 113.03, 112.62, 111.47, 109.55, 108.04, 105.24, 93.42, 64.84, 60.86, 55.95, 55.72, 44.85, 30.50, 28.50, 26.46, 25.67; ESI-MS: calcd. for C39H44N2O8 [M + H]+ 669.3170; found 669.3196.