Hydrochloric Acid → 2-((Butylsulfanyl)carbonothioyl)sulfanyl)propanoic acid

Beteiligte Stoffe

Reaktionsschritte

Acetone (700 mL) and tetrapropylammonium bromide (5.58 g, 21.0 mmol) were added with stirring to a solution of sodium hydroxide (10.5 g, 0.263 mol) in water (36 mL), followed by 1-butanethiol (23.7 g, 0.263 mol). After 20 min, carbon disulfide (17 mL, 21.7 g, 0.285 mol) was added and stirring was continued for 15 min, after which 2-bromopropanoic acid (40.14 g, 0.263 mol) was added. The reaction was stirred overnight, then acidified to pH<1 with 2 M hydrochloric acid (100 mL). The acetone was removed under reduced pressure and the remaining mixture was extracted with ether (400 mL). The extract was washed with water (2×100 mL), saturated sodium chloride solution (200 mL), dried (sodium sulfate), and evaporated. The oily residue was crystallized by the addition of ice (500 g), the crystals were collected by filtration and washed with water (5×100 mL) and then dried in a vacuum oven at room temperature. The resulting impure product was redissolved in ether (400 mL) and extracted with saturated sodium bicarbonate (5×150 mL). The combined aqueous extracts were acidified to pH<1 with concentrated hydrochloric acid and extracted with ether (400 mL). The organic extract was washed with saturated sodium chloride (200 mL), dried (sodium sulfate), and evaporated under reduced pressure. The residue was crystallized by the addition of ice (500 g) and the solid was collected and washed with water (5×1 50 mL), then dried in a vacuum oven to give the title compound (15, R3=C4H9) as a yellow solid (39.0 g, 62%).

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