The yields of the following procedures are higher than those reported in the literature (Erik Galvez, P. R., Felix Urp. (2009). Organic Synthesis, 86, 70). To a sealed tube was added aqueous KOH (2.7 g, 48.4 mmol, 5 eq., dissolved in 8 mL of water), 2 mL of ethanol, CS2 (2.9 mL, 48.4 mmol, 5 eq.) and (S)-(+)-2-amino-3-methyl-1-butanol (1.0 g, 9.69 mmol, 1 eq.). The reaction mixture was heated at 80 °C for 15 h, followed by purging with N2 to remove excess CS2. The reaction solution was neutralized with 1 M aqueous HCl and extracted with EtOAc (3 x 60 mL). The organic layers were combined, washed with brine (5 mL), dried over MgSO4 and concentrated in vacuum. The crude product was purified by silica gel column chromatography to afford (S)-4-isopropylthiazolidine-2-thione as a yellow solid (1.19 g, 76% yield). The characterization data of the product were in agreement with literature reports.
