1-Benzyl-3-(((4-chlorocyclohexa−1, 5-dien-1-yl) methylene)hydrazono)indolin-2-one (**6b**)

Dark red solid (30%) mp = 210–211 ◦C. IR (KBr): νmax (cm−1): 2918 (C-H aliphatic), 1718 (C=O), 1591 (C=N). 1H NMR (DMSO-d6, 600 MHz: δ 4.97 (s, 2H, N-CH2-Ph), 7.00 (d, *J* = 7.8, 1H, ArH), 7.08 (t, 1H, ArH), 7.24–7.44 (m, 6H, ArH), 7.64 (d, *J* = 7.8, 2H, ArH), 7.92 (d, *J* = 6.6, 1H, ArH), 8.05 (d, *J* = 7.8, 2H, ArH), 8.66 (s, 1H, N=CH) ppm. 13C NMR (DMSO-d6, 150 MHz: δ 163.69, 159.86, 150.00, 145.57, 137.31, 136.45, 134.18, 132.66, 131.03, 129.87, 129.20, 128.00, 127.72, 123.60, 116.30, 110.63 and 43.23 ppm. ESI mass m/z = 374 [M(35Cl) + H]<sup>+</sup>, 376 [M(37Cl) + H]<sup>+</sup>.
