Water → 3,3-dichloro-2-piperidinone

Part A. δ-Valerolactam (22.22 g, 222.89 mmol) was stirred in CHCl3 (500 mL) at 0° C. PCl5 (140.0 g, 68.29 mmol) was added portionwise. The resulting slurry was stirred at reflux for 3 h until the solution became clear. The mixture was cooled in an ice bath and H2O was added carefully until the PCl5 was quenched completely. The two layers were separated. The organic layer was washed with H2O (3×) and brine (2×), dried over MgSO4, filtered, and concentrated to dryness to give 3,3-dichloro-2-piperidinone (31.63 g, yield: 85%). This solid (16.50 g, 98.80 mmol) was dissolved in DMF (20 mL), and Li2CO3 (21.93 g, 296.40 mmol, 3.0 eq) was added. The mixture was stirred at 120° C. for 1 day. The solvent was further concentrated, and 1N HCl was added to acidify the mixture. It was then extracted with CHCl3 (6×). The organic layers were washed with H2O, brine, dried over MgSO4, and concentrated to dryness to give almost pure 3-chloro-5,6-dihydro-2(1H)-pyridinone (11.13 g, 87%).

1. temperatureat reflux for 3 h until the solution
2. temperatureThe mixture was cooled in an ice bath
3. customwas quenched completely
4. customThe two layers were separated
5. washThe organic layer was washed with H2O (3×) and brine (2×)
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated to dryness

ORD record

ord-36c17d3eff3142a2accdacbfd2de3e35

Source dataset

uspto-grants-2007_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07312214B2