tert-Butyl carbazate → tert-Butyl (3SR,5SR)-3-(2-chloro-4-fluorophenyl)-5-hydroxy-2-oxopiperidin-1-ylcarbamate

Participants

Reaction Steps

To a solution of methyl 2-(2-chloro-4-fluorophenyl)-3-(oxiran-2-yl)propanoate (4.56 g, 17.6 mmol) in 2-propanol (20 mL) was added tert-butyl carbazate (2.3 g, 17.6 mmol) and the reaction heated to reflux for 16 hours. The reaction was then concentrated to dryness, redissolved in toluene (20 mL) and 1,5,7-triazobicylo(4.4.0)dec-5-ene (0.6 g, 4.4 mmol) was added and the mixture heated to reflux for 3 hours. The reaction was then diluted with ethylacetate, washed with 1 N HCl, dried with sodium sulfate and the solvent was evaporated in vacuo. The residue was recystallised from hot ethyl acetate to afford the title compound was obtained as a colourless solid (1.7 g, 26%). The mother liquor contained the trans isomer.

Provenance & Evidence