The general procedure for the synthesis of S-4-benzylthiazolidine-2-thione from the compound (CAS: 131744-19-9) is as follows: the crude oxazolidinethione was dissolved in carbon disulfide (CS2, 364.0 mL, 5.95 mol), followed by the addition of 1N aqueous potassium hydroxide (KOH) solution (5.95 L). The reaction mixture was heated to 100 °C and stirred at this temperature for 16 hours. After completion of the reaction, the mixture was cooled to room temperature and extracted with dichloromethane (CH2Cl2, 3 x 3 L). The organic layers were combined, dried with anhydrous sodium sulfate (Na2SO4), filtered and rinsed through a silica gel plug (800 g) with a 1:1 solvent mixture of hexane/ethyl acetate (EtOAc, 2 L). Subsequently, the crude product was concentrated by rotary evaporation. The crude product was further purified by fast chromatography using a gradient elution from hexane to 1:1 hexane/ethyl acetate to give S-4-benzylthiazoline-2-thione (S2, 201.5 g, 81% yield). Supporting information S2: Thin-layer chromatography (TLC, 1:1 hexane/EtOAc): Rf = 0.31; 1H NMR (CDCl3, 500 MHz) δ 8.36 (broad single peak, 1H), 7.32 (multiple peaks, 2H), 7.26 (multiple peaks, 1H), 7.18 (multiple peaks, 2H), 4.46 (double double peaks, J = 7.5, 15.0 Hz, 1H), 3.50 (double triple peak, J = 7.9, 11.5 Hz, 1H), 3.25 (double triple peak, J = 7.2, 11.5 Hz, 1H), 3.04 (multiple peaks, 1H), 2.93 (multiple peaks, 1H); 13C NMR (CDCl3, 125 MHz) δ 200.5, 135.7, 129.0, 128.9, 127.2, 65.1, 39.7, 37.8; Fourier Transform Infrared Spectroscopy (FTIR, thin film) vmax 3154, 1602, 1495, 1437, 1327, 1297, 1279, 1233, 1204, 1040, 1008, 957, 743 cm-1; High Resolution Electrospray Ionization Mass Spectrometry (HR- ESI-MS) m/z calculated value for C10H11NS2 [M]+: 209.0333, measured value 209.0342.
