Triphenylphosphine → (4S)-4-acetylthio-2-pyrrolidone

Participants

Reaction Steps

In 300 ml of tetrahydrofuran was suspended 4.5 g of (4R)-4-hydroxy-2-pyrrolidone, 23.4 g of triphenylphosphine was added thereto, and the mixture was stirred for 10 minutes. Subsequently, 14 ml of diethyl azodicarboxylate was added dropwise to the reaction mixture at -10° C., and the mixture was stirred at the same temperature for 10 minutes. After 6.3 ml of thioacetic acid was added drop-wise to the reaction mixture at -10° C. or lower, the mixture was stirred at the same temperature for 2 hours and the solvent was removed. The residue was crystallized from diisopropyl ether. After the crystals were removed by filtration, the filtrate was condensed under reduced pressure. The residue was purified by silica gel column chromatography (solvent; chloroform:ethanol=98:2)to obtain 3.8 g of (4S)-4-acetylthio-2-pyrrolidone as an oily product. NMR (CDCl3) δ: 2.29 (dd, 1H), 2.35 (s, 3H), 2.81 (dd, 1 H), 3.31 (dd, 1H), 3.88 (dd, 1H), 4.10 to 4.23 (m, 1H), 7.02 to 7.17 (b, 1H).

Provenance & Evidence