## 2 Experimental
### General Procedure for the Preparation of 2-Aryldiendehydrazineyl-4-phenylthiazole **2a-d**
Yield 94% (1.38 g), m.p. 299-301 \({}^{\circ}\)C (EtOH). NMR \({}^{1}\)H (DMSO-d\({}_{6}\), \(\delta\), ppm, \({}^{3}\)\({}_{\rm HH}\), Hz): 11.52 s (1H, NH), 9.05 s (1H, CH-S), 8.55 s (1H, CH=N), 7.87 d (\(J\) = 9, 1H, Har), 7.82 s (1H, Har coumarin), 7.65 t (\(J\) = 9, 1H, Har), 7.45-7.36 m (3H, Har), 6.80 s (1H, Har phenol), 1.40 s (9H, t-Bu), 1.35 s (9H, t-Bu). \({}^{13}\)C NMR (DMSO-d\({}_{6}\), \(\delta\), ppm): 166.4, 159.2, 152.8, 147.2, 146.2, 144.6, 142.5, 139.0, 138.5, 136.1, 132.3, 129.4, 125.2, 120.8, 119.6, 116.4, 110.6, 35.5, 35.3, 32.9, 29.6. FT-IR, v, cm\({}^{-1}\): 3416 (O-H), 1710 (C=O), 1608 (C=C), 1375 (C=H Ar). Calc., %: C, 65.97; H, 5.95; N, 8.55; S, 6.52. Found, %: C, 65.82; H, 6.02; N, 8.57; S, 6.46. General Procedure for the Preparation of 2-(2-_Arylidenelydrazinyl_)-5,5-_dimethyl-5,6-_dilydrobenzo[d]thiazol-7(4H)-ones **3a**-**d**  
A solution of thiosemicarbazone **1a**-**d** (3 mmol), bromodimedone (3 mmol, 0.42 g) and sodium acetate (9 mmol, 0.74 g) was stirred and refluxed for 4 h in 15 mL of EtOH with 1 ml of acetic acid. Reaction mixture was cooled to room temperature and poured into ice water, and the precipitate formed was filtered off. The resulting crystals were recrystallized from the appropriate solvent. (2-(2,4-dihydroxybenzylidene)hydrazinyl)-5,5-dimethyl-5,6-dihydrobenzo[d]thiazol-7(4H)-one (**3a**) prepared from bromodimedone and **1a** (0.63 g). Yellow solid. Yield 68% (0.68 g), m.p. 155-156 \({}^{\circ}\)C (EtOH) NMR \({}^{1}\)H (DMSO-d\({}_{6}\), \(\delta\), ppm, \({}^{3}\)\({}_{\rm HH}\), Hz): 12.39 s (1H, NH), 10.33 s (1H, OH), 9.94 s (1H, OH), 8.31 s (1H, CH), 7.40 d (1H, \(J\) = 9.0 Hz, Har), 6.31 s (2H, Har), 2.62 s (2H, CH\({}_{2}\)), 2.29 s (2H, CH\({}_{2}\)), 1.03 s (6H, 2 CH\({}_{3}\)). \({}^{13}\)C NMR (DMSO-d\({}_{6}\), \(\delta\), ppm) 8 199.3, 189.0, 162.0, 161.3, 159.1, 129.7, 112.5, 111.6, 108.6, 107.7, 104.0, 102.9, 51.1, 34.9, 28.4. FT-IR, v, cm\({}^{-1}\): 3674 (O-H), 1621 (C=O), 1587 (C=N Ar), 1520, 1110 (C-O). Calc., %: C, 65.97; H, 5.95; N, 8.55; S, 6.52. Found, %: C, 65.82; H, 6.04; N, 8.49; S, 6.56. 2-(2-(4-hydroxy-3-methoxybenzylidene)hydrazineyl)-5,5-dimethyl-5,6-dihydrobenzo[d]thiazol-7(4H)-one (**3b**) prepared from bromodimedone and **1b** (0.68 g). Yellow solid. Yield 84% (0.87 g), m.p. 188-191 \({}^{\circ}\)C (EtOH). NMR \({}^{1}\)H (DMSO-d\({}_{6}\), \(\delta\), ppm, \({}^{3}\)\({}_{\rm HH}\), Hz): 8 9.62 s (1H, OH), 8.00 s (1H, CH), 7.23 s (1H, Har), 7.09 d (1H, \(J\) = 9.0 Hz, Har), 6.82 d (1H, \(J\) = 9.0 Hz, Har), 3.79 s (3H, CH\({}_{3}\)-O), 2.64 s (2H, CH\({}_{2}\)), 2.30 (2H, CH\({}_{2}\)), 1.02 s (6H, 2 CH\({}_{3}\)). 13C NMR (DMSO-d\({}_{6}\), \(\delta\), ppm) 190.5, 189.7, 172.7, 165.6, 149.5, 148.5, 146.5, 125.7, 121.9, 117.9, 116.1, 109.9, 56.0, 51.2, 34.9, 28.4. FT-IR, \(\
u\), cm\({}^{-1}\): 3674 (O-H), 1620 (C=O), 1599 (C=C Ar), 1567 (C=N). Calc., %: C, 59.11; H, 5.54; N, 12.17; S, 9.28. Found, %: C, 59.18; H, 5.62; N, 12.14; S, 9.21. 2-(2-(3,5-di-_tert_-butyl-4-hydroxybenzylidene)hydrazinyl)-5,5-dimethyl-5,6-dihydrobenzo[d] thiazol-7(4H)-one (3c) prepared from bromodimedone and **1c** (0.92 g). White solid. Yield 71% (0.91 g). m.p. 166-167 \({}^{\circ}\)C (AcOH). NMR \({}^{1}\)H (DMSO-d\({}_{6}\), \(\delta\), ppm, \({}^{3}\)\({}_{\rm HH}\), Hz): 8.05 s (1H, CH); 7.43 s (2H, Ar); 2.60 s (2H, CH\({}_{2}\)); 2.25 s (2H, CH\({}_{2}\)); 1.37 s (18H, 2(CH\({}_{3}\))); 1.01 s (6H, 2(CH\({}_{3}\))); NMR\({}^{13}\)C (DMSO-d\({}_{6}\), \(\delta\), ppm): 189.0, 173.7, 172.8, 166.0, 156.5, 147.0, 139.7, 126.0, 124.0, 117.1, 51.2, 34.9, 34.9, 30.6, 28.5, 21.9. FT-IR, \(\
u\), cm\({}^{-1}\): 3380 (O-H), 1620 (C=O), 1580 (C=N), 1577 (C=C Ar), 1045 (C=O). Calc, %: C, 67.41; H, 7.78; N, 9.83; S, 7.50. Found, %: C, 67.35; H, 7.82; N, 9.69; S, 7.52. 2-(2-(4,6-di-_tert_-butyl-2,3-dihydroxybenzylidene)hydrazineinyl)-5,5-dimethyl-5,6-dihydrobenzo[d] thiazol-7(4H)-one (3d) prepared from bromodimpedance and **1d** (0.97 g). Yellow solid. Yield 91% (1.21 g), m.p. 130-132 \({}^{\circ}\)C (EtOH: H\({}_{2}\)O 3:1).