Synthesis
General procedure: 43 g of bis(thiobenzoyl)disulfide (142 mmol) and 51.68 g of 4,4'-azobis(4-cyanopentanoic acid) (WACO manufacture) were dissolved in 800 g of ethyl acetate and the reaction was carried out at reflux under nitrogen protection for 18 hours. Upon completion of the reaction, the organic phase was distilled under reduced pressure and purified by column chromatography to give 25 g of 4-cyano-4-(thiobenzoylthio)pentanoic acid in 63% yield. 23.14 g of bis(thiobenzoyl)disulfide (75.62 mmol) and 27.524 g of 4,4'-azobis(4-cyanopentanoic acid) (WACO manufacture) were dissolved in 400 g of ethyl acetate and the reaction was carried out at reflux under nitrogen protection for 18 hours. Upon completion of the reaction, the organic phase was distilled under reduced pressure and purified by column chromatography to give 16.9 g of 4-cyano-4-(thiobenzoylthio)pentanoic acid in 64% yield. 18.25 g of bis(thiobenzoyl)disulfide (59.65 mmol) and 21.7 g of 4,4'-azobis(4-cyanopentanoic acid) (WACO manufacture) were dissolved in 350 g of ethyl acetate and reacted at reflux under nitrogen protection for 18 hours. Upon completion of the reaction, the organic phase was distilled under reduced pressure and purified by column chromatography to give 12.7 g of 4-cyano-4-(thiobenzoylthio)pentanoic acid in 61% yield.
References
[1] Chemical Communications, 2011, vol. 47, # 38, p. 10656 - 10658
[2] Tetrahedron Letters, 1999, vol. 40, # 12, p. 2435 - 2438
[3] Patent: US2004/138492, 2004, A1. Location in patent: Page 3
[4] Patent: EP1149075, 2008, B1. Location in patent: Page/Page column 14
[5] Macromolecules, 2004, vol. 37, # 20, p. 7530 - 7537
