## 2 Materials and Methods  
### Experimental Procedures  
#### 2.1.1 Synthesis  
At 0 \({}^{\circ}\)C, a solution containing alkylamine (50 mmol) and triethylamine (7 mL, 50 mmol) in 200 mL of diethyl ether was prepared, to which carbon disulfide (CS\({}_{2}\), 3 mL, 50 mmol) was gradually added. The resulting reaction mixture was stirred at ambient temperatures for two hours. The formed white precipitate was collected by filtration, thoroughly washed with diethyl ether and subsequently dried under reduced pressure.  
The dithiocarbamate salt (28 mmol) was dissolved in 100 mL of acetonitrile, and chlorobutanone or chloroacetone was slowly introduced to the solution. The mixture, characterized by a yellow coloration, was allowed to stir overnight at room temperature. Following this, the solvent was removed through evaporation, yielding a viscous residue. This residue was then chilled to 0 \({}^{\circ}\)C, and 25 mL of concentrated sulfuric acid was cautiously added in a controlled dropwise manner. The reaction mixture was stirred continuously for three hours, followed by hydrolysis with ice water. The resulting solution was extracted using dichloromethane, and the organic layer was separated, washed with water and dried over anhydrous MgSO\({}_{4}\). After solvent evaporation, the crude product was purified by column chromatography, employing a dichloromethane/hexane (1:1) mixture as the eluent, to yield thiazoline-2-thiones [22]. Figure 2 illustrates the stepwise reaction mechanism for synthesizing thiazoline-2-thione derivatives. It highlights the key intermediates and chemical transformations. This visual representation facilitates a clearer understanding of the synthetic pathway.  
Figure 2: Illustration of the stepwise reaction mechanism for synthesizing thiazoline-2-thione derivatives.  
**1a:**: **R** = CH\({}_{3}\), R1 = CH\({}_{3}\), **R2** = CH\({}_{3}\), white powder. Yield: 84%. mp = 99 \({}^{\circ}\)C. \({}^{1}\)H NMR (CDCl\({}_{3}\)): $ 2.15 (q, 3H, CH\({}_{3}\)), 2.17 (q, 3H, CH\({}_{3}\)), 3.65 (s, 3H, CH\({}_{3}\)). \({}^{13}\)C NMR (CDCI\({}_{3}\)): $ 11.60 (CH\({}_{3}\)), 13.01 (CH\({}_{3}\)), 34.89 (N-CH\({}_{3}\)), 117.33 (C=C), 134.58 (C=C), 185.62 (C=S) [23].
**2b:**: **R** = CH\({}_{3}\), **R1** = CH\({}_{3}\), **R2** = H, white powder, yield 80%, mp = 111 \({}^{\circ}\)C. \({}^{1}\)H NMR (CDCI\({}_{3}\)): $ 2.18 (s, 3H, CH\({}_{3}\)), 3.55 (s, 3H, CH\({}_{3}\)), 6.23 (s, 1H, =CH). \({}^{13}\)C NMR (CDCI\({}_{3}\)): $ 16.15 (CH\({}_{3}\)), 34.63 (N-CH\({}_{3}\)), 106.40 (HC=C), 140.37 (HC=C), 188.29 (C=S) [23].
**3c:**: **R** = Et, **R1** = CH\({}_{3}\), **R2** = H, Pale brown powder, yield 90%, mp = 119\({}^{\circ}\)C. \({}^{1}\)H NMR (CDCI\({}_{3}\)): $ 1.29-1.32 (t, 3H, CH\({}_{3}\)CH\({}_{2}\)), 2.29 (d, 3H, CH\({}_{3}\)), 4.21-4.26 (q, 2H, CH\({}_{3}\)CH\({}_{2}\)), 6.24-6.25 (q, 1H, C=CH). \({}^{13}\)C NMR: $ 12.83 (CH\({}_{3}\)CH\({}_{2}\)), 15.31 (CH\({}_{3}\)), 42.30 (N-CH\({}_{2}\)), 106.31 (HC=C), 139.40 (HC=C), 187.58 (C=S).
**4d:**: **R** = Proply, **R1** = CH\({}_{3}\), **R2** = CH\({}_{3}\), brown crystal, yield 90%, mp = 85\({}^{\circ}\)C. \({}^{1}\)H NMR (DMSO-d6): $ 0.89-0.92 (t, 3H, CH\({}_{3}\)CH\({}_{2}\)), 1.61-1.71 (m, 2H, CH\({}_{3}\)CH\({}_{2}\)CH\({}_{2}\)), 2.13-2.14 (m, 3H, CH\({}_{3}\)), 2.21-2.22 (m, 3H, CH\({}_{3}\)), 4.06-4.10 (m, 2H, N-CH\({}_{2}\)). \({}^{13}\)C NMR (DMSO-d6): $ 11.44 (CH\({}_{3}\)CH\({}_{2}\)), 11.58 (CH\({}_{3}\)), 12.68 (CH\({}_{3}\)), 20.93 (CH\({}_{3}\)CH\({}_{2}\)CH\({}_{2}\)), 49.03 (N-CH\({}_{2}\)), 116.88 (C=C), 135.86 (C=C), 184.38 (C=S) (Figure S1).