Sulfuric Acid → Methyl 4-[2-fluoro-3-(methylsulfonyl)phenyl]piperazine-1-carboxylate

HRID 1879055Notes

Reaction equation

[F:1][C:2]1[C:7]([S:8][CH3:9])=[CH:6][CH:5]=[CH:4][C:3]=1[N:10]1[CH2:15][CH2:14][N:13]([C:16]([O:18][CH3:19])=[O:17])[CH2:12][CH2:11]1.[O-]O.[OH-:22].[Na+].S(=O)(=O)(O)[OH:25]>[O-][W]([O-])(=O)=O.[Na+].[Na+]>[F:1][C:2]1[C:7]([S:8]([CH3:9])(=[O:25])=[O:22])=[CH:6][CH:5]=[CH:4][C:3]=1[N:10]1[CH2:15][CH2:14][N:13]([C:16]([O:18][CH3:19])=[O:17])[CH2:12][CH2:11]1

Participants

Conditions

Temperature: 55 °C

Procedure

To an ice cooled solution of methyl 4-[2-fluoro-3-(methylthio)phenyl]piperazine-1-carboxylate (1.4 g, 4.9 mmol) in sulfuric acid (1 M, 10 ml) was added sodium tungstate (0.016 g, 0.05 mmol) in one portion followed by dropwise addition of hydroperoxide (30%, 1.25 ml, 12.2 mmol). The reaction mixture was warmed to 55° C. and was stirred for 20 h. The reaction mixture was brought to ambient temperature and aqueous sodium hydroxide (5 M, 50 ml) was added. The aqueous phase was extracted with ethyl acetate (2×50 ml). The combined organic phase was dried (MgSO4) and evaporated to dryness to give the title compound. Yield (1.1 g). MS m/z (rel. intensity, 70 eV) 316 (M+, 58), 296 (30), 228 (bp), 216 (38), 56 (71).

Workup

customwas brought to ambient temperature
extractionThe aqueous phase was extracted with ethyl acetate (2×50 ml)
dry with materialThe combined organic phase was dried (MgSO4)
customevaporated to dryness

Sources & evidence

ORD record: ord-5f84e1722d2d439b993b3c3a293ae8ea
Source dataset: uspto-grants-2012_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08314126B2

Reaction notes

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