## 3 Materials and Methods
### Preparation of 2-substituted-N-(5-((4-sulfamoylphenyl)azo)thiazol-2-yl)acetamide Derivatives **7**  
A suspension of compound **6** (1 mmol, 0.54 g), 2-mercaptoethanoldiazole or 2-mercaptoethanolbenzoxazole (1 mmol) and CH\({}_{3}\)COONa (0.16 g) was heated under reflux in 15 mL ethyl alcohol for 2 h; after which, the formed precipitate upon cooling was filtered, washed by cold ethanol, and dried to give the anticipated compounds **7a** and **7b**, respectively. _2-(Benzothiazol-2-ylthio)-N-(5-((4-sulfamoylphenyl)azo)-4-antiyyrinylthiazol-2-yl)acetamide (7a)_. Brown solid, yield = 72%, m.p. = 285-287 \({}^{\circ}\)C. IR (\(\overline{v}\)/cm\({}^{-1}\)): 3341, 3257 (NH\({}_{2}\) and N-H), 1705 cm\({}^{-1}\) (C=O). \({}^{1}\)H-NMR (DMSO-\(d_{6}\)): \(\delta\) 2.75 (s, 3H, CH\({}_{3}\)), 3.36 (s, 3H, CH\({}_{3}\)), 4.42 (s, 2H, CH\({}_{2}\)), 7.32-7.94 (m, 15H, Ar-H and NH\({}_{2}\)), 12.76 ppm (s, 1H, NH). MS (EI): \(m/z\) (\(\%\)) = 676 (molecular ion, 13.8%). Analysis for C\({}_{29}\)H\({}_{24}\)N\({}_{8}\)O\({}_{4}\)S\({}_{4}\) (676): Calcd. : C, 51.47; H, 3.57; N, 16.56%. Found: C, 51.68; H, 3.66; N, 16.68%. _2-(Benzoxazol-2-ylthio)_-N-(_5-((4-sulfonylphenyl)azo)_-_4-antipyrinylthiazol-2-yl)_acetamide_ (**7b**). Brown solid, yield = 64%, m.p. = 274-275 \({}^{\circ}\)C. IR (\(\overline{v}\)/cm\({}^{-1}\)): 3336, 3248 (NH\({}_{2}\) and N-H), 1699 cm\({}^{-1}\) (C=O). 1H-NMR (DMSO-\(d_{6}\)): 8 2.68 (s, 3H, CH\({}_{3}\)), 3.33 (s, 3H, CH\({}_{3}\)), 4.41 (s, 2H, CH\({}_{2}\)), 7.40-7.92 (m, 15H, Ar-H and NH\({}_{2}\)), 12.86 (s, 1H, NH). MS (EI): \(m/z\) (%) = 660 (molecular ion, 21.2%). Analysis for C\({}_{29}\)H\({}_{24}\)N\({}_{8}\)O\({}_{5}\)S\({}_{3}\) (660): Calcd. : C, 52.72; H, 3.66; N, 16.96%. Found: C, 52.90; H, 3.58; N, 17.07%. _3.7. Preparation of 2-((4-antipyrinylthiazol-2-yl)imino)thiazol-4-one_ (**9**)  
A solution of chloroacetamido derivative **1** (10 mmol, 3.62 g) and ammonium thiocyanate (15 mmol, 1.14 g) in 20 mL ethanol was heated under reflux for 5 h. The precipitate that formed upon cooling was isolated by filtration and recrystallized from EtOH to furnish thiazol-4-one derivative **9**. Yellow solid, yield = 80%, m.p. = 201-202 \({}^{\circ}\)C. IR (\(\overline{v}\)/cm\({}^{-1}\)): 3128 (N-H), 1714 (C=O). 1H-NMR (DMSO-\(d_{6}\)): 8 2.65 (s, 3H, CH\({}_{3}\)), 3.31 (s, 3H, CH\({}_{3}\)), 4.05 (s, 2H, CH\({}_{2}\)), 7.31-7.60 (m, 6H, Ar-H and thiazole-H5), 12.06 (s, 1H, NH). 1\({}^{\rm 3C}\)-NMR (DMSO-\(d_{6}\)): 8 11.80, 33.76, 35.48, 104.51, 108.71, 122.66 (2C), 124.71, 128.31 (2C), 133.64, 141.46, 151.48, 159.24, 162.66, 165.29, 174.39. Analysis for C\({}_{17}\)H\({}_{15}\)N\({}_{5}\)O\({}_{2}\)S\({}_{2}\) (385): Calcd. : C, 52.97; H, 3.92; N, 18.17%. Found: C, 52.86; H, 3.95; N, 18.21%. _3.8. Synthesis of 2-((4-antipyrinylthiazol-2-yl)imino)-5-arylidenethiazolidin-4-one Derivatives_ **10a-c**  
A suspension of thiazol-4-one derivative **9** (2 mmol, 0.77 g) and the appropriate para-substituted benzaldehyde derivative (2 mmol) in 15 mL glacial CH\({}_{3}\)COOH containing 0.5 g fused CH\({}_{3}\)COONa was heated under reflux for 4 h. The reaction mixture was cooled and then poured into ice-water and the precipitate was filtered and recrystallized from ethanol. _2-((4-Antipyrinylthiazol-2-yl)imino)-5-(4-methoxybenzylidene)thiazolidin-4-one_ (**10a**). Yellow powder, yield = 74%, m.p. = 241-243 \({}^{\circ}\)C. IR (\(\overline{v}\)/cm\({}^{-1}\)): 3176 (N-H), 1698 (C=O). 1H-NMR (DMSO-\(d_{6}\)): 8 2.61 (s, 3H, CH\({}_{3}\)), 3.28 (s, 3H, CH\({}_{3}\)), 3.84 (s, 3H, OCH\({}_{3}\)), 7.14 (d, \(J\) = 8.80 Hz, 2H, Ar-H), 7.28-7.62 (m, 8H, Ar-H and thiazole-H5), 7.73 (s, 1H, olefinic CH=C), 12.62 (s, 1H, NH). 1\({}^{\rm 3C}\)-NMR (DMSO-\(d_{6}\)): 8 12.45, 34.36, 55.18, 106.26, 113.87 (2C), 117.37, 122.41, 123.32 (2C), 127.35, 129.49 (2C), 130.31 (2C), 133.89, 142.26, 145.60, 151.05, 155.83, 159.07, 161.71, 162.66, 164.09, 167.63. Analysis for C\({}_{25}\)H\({}_{21}\)N\({}_{5}\)O\({}_{3}\)S\({}_{2}\) (503): Calcd. : C, 59.63; H, 4.20; N, 13.91%. Found: C, 59.46; H, 4.26; N, 13.98%.