Sulfur trioxide → 3,4,5,5-Tetrafluorothiophen-2(5H)-one

HRID 2254316Notes

Reaction equation

HRID 2254316 reaction equation
S(=O)(=O)=[O:2].[F:5][C:6]1([F:15])[S:10][C:9](F)(F)[C:8]([F:13])=[C:7]1[F:14].[F-].FC1(F)SC(F)(F)C=C1>>[F:5][C:6]1([F:15])[S:10][C:9](=[O:2])[C:8]([F:13])=[C:7]1[F:14]

Participants

5

Reactant 4

HCID 24682Sulfur trioxideHCID 28179Fluoride IonHCID 10943363Thiophene, 2,2,3,4,5,5-hexafluoro-2,5-dihydro-HCID 12916665HCID 12916665, compound

Product 1

HCID 151220123,4,5,5-Tetrafluorothiophen-2(5H)-oneYield 25%

Procedure

Sulfur trioxide (128.0 g, 1.60 mol) was added rapidly to 77.6 g (0.40 mol) of hexafluoro-2,5-dihydrothiophene. After an initial exotherm, the mixture was refluxed for 30 min. and fractionated to give 121.9 g, bp 42°-55° C., shown to be mainly pyrosulfuryl fluoride by 19F NMR, and 29.5 g of crude tetrafluoro-2,5-dihydrothiophene, bp 77°-85° C. Redistillation of this product afforded 16.9 g (25%) of tetrafluoro-2,5-dihydrothiophene-2-one, bp 83° C. IR (CCl4): 1755 (C=O) and 1740 cm-1 (C=C). NMR (CCl4): 19Fφ-92.0 (d of d, JFF 14.7, 5.5 Hz, 2F, CF2),-133.5 (q, JFF 14.3 Hz, lF, CF), -144.3 (d of t, JFF 13.9, 5.5 Hz, lF, CF). MS: m/e 171.9615 (M+ ; calcd for C4F4OS, 171.9606), 143 9664 (M+ --CO; cald, 143,9657), 121.9641 (M+ --CF2 ; calcd, 121.9638). Anal. Calcd for C4F4OS: C, 27.91; S, 18.63 Found: C, 28.27; S, 19.16.

Workup

  1. temperatureAfter an initial exotherm, the mixture was refluxed for 30 min.
  2. customto give 121.9 g, bp 42°-55° C.
  3. distillationRedistillation of this product

Sources & evidence

ORD record
ord-4d0cbf1ec75241a889d07217254b3fd4
Source dataset
uspto-grants-1993_08
Patent number
US05235069

Reaction notes

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