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

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).

1. additionwas added
2. stirringthe mixture was stirred at the same temperature for 10 minutes
3. stirringlower, the mixture was stirred at the same temperature for 2 hours
4. customthe solvent was removed
5. customThe residue was crystallized from diisopropyl ether
6. customAfter the crystals were removed by filtration
7. customcondensed under reduced pressure
8. customThe residue was purified by silica gel column chromatography (solvent

ORD record

ord-7668dc4c70384c55901d6234289ad889

Source dataset

uspto-grants-1995_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05414081