TY - JOUR A1 - Wu, Ke A1 - Ling, Yichen A1 - Ding, An A1 - Jin, Liqun A1 - Sun, Nan A1 - Hu, Baoxiang A1 - Shen, Zhenlu A1 - Hu, Xinquan T1 - A chromatography-free and aqueous waste-free process for thioamide preparation with Lawesson’s reagent JF - Beilstein Journal of Organic Chemistry PY - 2021/// VL - 17 SP - 805 EP - 812 SN - 1860-5397 DO - 10.3762/bjoc.17.69 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.17.69 KW - chromatography-free KW - Lawesson’s reagent KW - scale-up KW - thioamide KW - thionation N2 - After completing the thio-substitution with Lawesson’s reagent, ethanol was found to be effective in the decomposition of the inherent stoichiometric six-membered-ring byproduct from the Lawesson’s reagent to a highly polarized diethyl thiophosphonate. The treatment significantly simplified the following chromatography purification of the desired thioamide in a small scale preparation. As scaling up the preparation of two pincer-type thioamides, we have successfully developed a convenient process with ethylene glycol to replace ethanol during the workup, including a traditional phase separation, extraction, and recrystallization. The newly developed chromatography-free procedure did not generate P-containing aqueous waste, and only organic effluents were discharged. It is believed that the optimized procedure offers the great opportunity of applying the Lawesson’s reagent for various thio-substitution reactions on a large scale. ER -