57757-57-0

6066-82-6

1119-62-6

57757-57-0

General procedure for the synthesis of bis(N-hydroxysuccinimide ester) 3,3'-dithiobispropionic acid from 3,3'-dithiobispropionic acid and N-hydroxysuccinimide: To a solution of dichloromethane (20 mL) containing 3,3'-dithiobispropionic acid (1 g, 4.75 mmol) was added sequentially 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride ( WSC) (2.16 g, 10.5 mmol) and N-hydroxysuccinimide (1.21 g, 10.5 mmol). The reaction mixture was stirred at room temperature for 2 hours. Upon completion of the reaction, the solution was concentrated by vacuum to remove the solvent and the obtained residue was purified by silica column chromatography (eluent ratio ethyl acetate/hexane = 1:5) to give the final target product 3,3'-dithiodipropionic acid bis(N-hydroxybutanediimide ester) (1.63 g, 85% yield). The structure of the product was confirmed by 1H NMR (DMSO-d6, 400 MHz) and FAB mass spectrometry: 1H NMR δ 3.16 (m, 8H), 2.82 (s, 8H); FAB mass spectrometry (DMSO-d6) [(M+H)+] calculated value of 405, measured value 405.