## 2 Materials and Methods
### Preparation and Characterization of Target Compounds
#### 2.2.3 General Procedure for the Synthesis of 6a-j
\({}^{1}\)H NMR (DMSO-d6, 600 MHz: \(\delta\) 4.97 (s, 2H, N-CH\({}_{2}\)-Ph), 7.01 (d, \(J\) = 8.4, 1H, ArH), 7.09 (t, 1H, ArH), 7.25 (m, 1H, ArH), 7.24-7.38 (m, 4H, ArH), 7.41 (t, 1H, ArH), 7.54 (t, 1H, ArH), 7.79 (d, \(J\) = 8.4, 1H, ArH), 7.86 (d, \(J\) = 7.8, 1H, ArH), 8.02 (d, \(J\) = 7.8, 1H, ArH), 8.12 (s, 1H, ArH), 8.60 (s, 1H, N=CH) ppm. \({}^{13}\)C NMR (DMSO-d6, 150 MHz: \(\delta\) 163.60, 158.67, 149.59, 145.61, 136.43, 136.10, 135.22, 134.12, 132.07, 131.88, 129.21, 129.10, 128.01, 127.73, 127.66, 123.65, 122.86, 116.20, 110.67 and 43.25 ppm. ESI mass m/z = 418 [M(\({}^{79}\)Br) + H]\({}^{+}\), 420 [M(\({}^{81}\)Br) + H]\({}^{+}\). 1-Benzyl-3-((4-bromobenzylidene)hydrazano)indolin-2-one (**6f**)  
Orange solid (68%) mp = 216-217 \({}^{\circ}\)C. IR (KBr): \(\
u_{\rm max}\) (cm\({}^{-1}\)): 2922 (C-H aliphatic), 1720 (C=O), 1602 (C=N). \({}^{1}\)H NMR (DMSO-d6, 600 MHz: \(\delta\) 4.95 (s, 2H, N-CH\({}_{2}\)-Ph), 6.85 (d, \(J\) = 7.2, 1H, ArH), 7.05 (t, 1H, ArH), 7.22-7.42 (m, 6H, ArH), 7.76 (d, \(J\) = 7.8, 2H, ArH), 7.9 (d, \(J\) = 7.8, 3H, ArH), 8.60 (s, 1H, N=CH) ppm. \({}^{13}\)C NMR (DMSO-d6, 150 MHz: \(\delta\) 163.67, 159.89, 149.91, 145.53, 136.42, 134.18, 132.94, 132.77, 131.15, 129.19, 128.01, 127.71-Benzyl-3-((2-methyl benzylidene)hydrazono)indolin-2-one (**6g**)  
Orange solid (60%) mp = 176-177 \({}^{\circ}\)C. IR (KBr): \(\
u_{\max}\) (cm\({}^{-1}\)): 2920 (C-H aliphatic), 1716 (C=O), 1624 (C=N). \({}^{1}\)H NMR (DMSO-d6, 600 MHz: \(\delta\) 2.53 (t, 3H, Ph-CH\({}_{3}\)), 4.96 (s, 2H, N-CH\({}_{2}\)-Ph), 7.0 (d, \(J\) = 7.8, 1H, ArH), 7.07 (t, 1H, ArH), 7.23-7.41 (m, 8H, ArH), 7.45 (t, 1H, ArH), 7.95 (d, \(J\) = 7.8, 1H, ArH), 8.08 (d, \(J\) = 7.2, 1H, ArH), 8.85 (s, 1H, N=CH) ppm. \({}^{13}\)C NMR (DMSO-d6, 150 MHz: \(\delta\) 163.80, 159.92, 149.81, 145.45, 139.86, 136.46, 134.04, 132.44, 131.80, 131.72, 129.19, 128.91, 128.07, 128.00, 127.71, 127.09, 123.54, 116.33, 110.59, 43.19 and 19.59 ppm. ESI mass m/z = 354 [M + H]\({}^{+}\). 1-Benzyl-3-((3-methylbenzylidene)hydrazono)indolin-2-one (**6h**)  
Pale orange solid (60%) mp = 138-139 \({}^{\circ}\)C. IR (KBr): \(\
u_{\max}\) (cm\({}^{-1}\)): 2920 (C-H aliphatic), 1718 (C=O), 1670 (C=N), 1606 (C=N). \({}^{1}\)H NMR (DMSO-d6, 600 MHz: \(\delta\) 2.38 (s, 3H, Ph-CH\({}_{3}\)), 4.95 (s, 2H, N-CH\({}_{2}\)-Ph), 7.0 (d, \(J\) = 8.4, 1H, ArH), 7.07 (t, 1H, ArH), 7.22-7.42 (m, 7H, ArH), 7.45 (t, 1H, ArH), 7.76 (s, 1H, ArH), 7.78 (d, \(J\) = 7.8, 1H, ArH), 7.95 (d, \(J\) = 7.2, 1H, ArH), 8.85 (s, 1H, N=CH) ppm. \({}^{13}\)C NMR (DMSO-d6, 150 MHz: \(\delta\) 163.74, 161.14, 149.83, 145.45, 139.06, 136.46, 134.03, 133.75, 133.43, 129.98, 129.62, 129.19, 129.13, 129.10, 127.99, 127.71, 126.45, 123.60, 117.81, 116.34, 110.57, 43.19 and 21.35 ppm. ESI mass m/z = 354 [M + H]\({}^{+}\). 1-Benzyl-3-((4-methylbenzylidene)hydrazono)indolin-2-one (**6i**)  
Pale red solid (82%) mp = 191-192 \({}^{\circ}\)C. IR (KBr): \(\
u_{\max}\) (cm\({}^{-1}\)): 2920 (C-H aliphatic), 1722 (C=O), 1683 (C=N), 1602 (C=N). \({}^{1}\)H NMR (DMSO-d6, 600 MHz: \(\delta\) 2.38 (s, 3H, Ph-CH\({}_{3}\)), 4.95 (s, 2H, N-CH\({}_{2}\)-Ph), 6.99 (d, \(J\) = 7.8, 1H, ArH), 7.07 (t, 1H, ArH), 7.22-7.41 (m, 8H, ArH), 7.27 (d, \(J\) = 8.4, 2H, ArH), 8.00 (d, \(J\) = 7.2, 1H, ArH), 8.65 (s, 1H, N=CH) ppm. \({}^{13}\)C NMR (DMSO-d6, 150 MHz: \(\delta\) 163.83, 161.88, 150.09, 145.40, 143.17, 136.48, 133.96, 131.14, 130.33, 129.53, 129.19, 127.98, 127.70, 123.55, 116.43, 110.54, 43.18 and 21.74 ppm. ESI mass m/z = 354 [M + H]\({}^{+}\). 1-Benzyl-3-((4-(methylthio)benzylidene)hydrazono)indolin-2-one (**6j**)  
Orange solid (65%) mp = 177-178 \({}^{\circ}\)C. IR (KBr): \(\
u_{\max}\) (cm\({}^{-1}\)): 2926 (C-H aliphatic), 1720 (C=O), 1606 (C=N). \({}^{1}\)H NMR (DMSO-d6, 600 MHz: \(\delta\) 2.49 (s, 3H, S-CH\({}_{3}\)), 4.97 (s, 2H, N-CH\({}_{2}\)-Ph), 7.01 (d, \(J\) = 7.8, 1H, ArH), 7.09 (t, 1H, ArH), 7.27 (m, 1H, ArH) 7.3-7.42 (m, 5H, ArH), 7.43 (d, \(J\) = 8.4, 2H, ArH), 7.92 (d, \(J\) = 7.8, 2H, ArH), 8.04 (d, \(J\) = 7.2, 1H, ArH), 8.70 (s, 1H, N=CH) ppm.