3.6.4. (E)-3-((E)-1-(4-Methoxyphenyl)-3-(4-nitrophenyl)allylidene)-1-methylindolin-2-one (**3dc**)

Reflux for 20 h; 45% yield; red solid; mp = 143.1–144.6 ◦C; *R*<sup>f</sup> = 0.54 (silica gel, hexane:EtOAc:CH2Cl2 = 4:1:2); 1H NMR (500 MHz, CDCl3): *δ* 9.48 (d, *J* = 16.0 Hz, 1H), 8.19–8.15 (m, 2H), 7.65 (d, *J* = 8.7 Hz, 2H), 7.22–7.18 (m, 2H), 7.16 (td, *J* = 7.7, 1.1 Hz, 1H), 7.12–7.06 (m, 2H), 6.77 (d, *J* = 7.7 Hz, 1H), 6.67 (td, *J* = 7.7, 1.0 Hz, 1H), 6.51 (d, *J* = 16.0 Hz, 1H), 5.95 (d, *J* = 7.4 Hz, 1H), 3.95 (s, 3H), 3.30 (s, 3H) ppm; 13C NMR (125 MHz, CDCl3): *δ* 168.0, 160.1, 149.6, 147.5, 143.5, 143.3, 137.8, 132.3, 130.1, 129.2, 129.1 128.3, 125.1, 124.2, 123.2, 121.9, 114.9, 107.9, 55.6, 26.0 ppm; HRMS (EI): calcd for C25H20N2O4 [M+] : 412.1423, found 412.1422.
