Sulfuric Acid → Ethyl [(6S)-6-(3,5-difluorophenyl)-3,3-dimethyl-2,4-dioxopiperidin-1-yl]acetate

HRID 1367180Notes

Reaction equation

[F:1][C:2]1[CH:3]=[C:4]([C@H:9]2[N:14]([CH2:15][C:16]([O:18][CH2:19][CH3:20])=[O:17])[C:13](=[O:21])[C:12]([CH3:23])([CH3:22])[C@@H:11]([OH:24])[CH2:10]2)[CH:5]=[C:6]([F:8])[CH:7]=1.OS(O)(=O)=O>CC(C)=O.O.[O-2].[O-2].[O-2].[Cr+6]>[F:1][C:2]1[CH:3]=[C:4]([C@H:9]2[N:14]([CH2:15][C:16]([O:18][CH2:19][CH3:20])=[O:17])[C:13](=[O:21])[C:12]([CH3:23])([CH3:22])[C:11](=[O:24])[CH2:10]2)[CH:5]=[C:6]([F:8])[CH:7]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of ethyl [(4S,6S)-6-(3,5-difluorophenyl)-4-hydroxy-3,3-dimethyl-2-oxopiperidin-1-yl]acetate (470 mg, 1.377 mmol, described in Intermediate 21) in acetone (24 mL) at 0° C. was added a solution of chromium (VI) trioxide (174 mg, 1.740 mmol) in H2O (0.5 mL) and H2SO4 (0.147 mL, 2.75 mmol), in three portions over 5 min and the mixture was stirred at 0° C. for 30 min. Most of the acetone was removed by concentration in vacuo, and the residue was basified with saturated aqueous NaHCO3 (75 mL) and extracted with EtOAc (2×100 mL). The combined organic layers were washed with brine (40 mL) and dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by silica gel chromatography, eluting with a gradient of CH2Cl2:CH3OH—100:0 to 92:8, to give the title compound. MS: m/z=340 (M+1).

Workup

customMost of the acetone was removed by concentration in vacuo
extractionextracted with EtOAc (2×100 mL)
washThe combined organic layers were washed with brine (40 mL)
dry with materialdried over Na2SO4
filtrationfiltered
concentrationconcentrated in vacuo
customThe crude product was purified by silica gel chromatography
washeluting with a gradient of CH2Cl2

Sources & evidence

ORD record: ord-b37d316b97fe46ba80df035e06e260df
Source dataset: uspto-grants-2011_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07893079B2

Reaction notes

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