Thiophene, 2,2,3,4,5,5-hexafluoro-2,5-dihydro- → 3,4-Difluorofuran-2,5-dione
Reaction equation
[F:1][C:2]1[C:6](=[O:7])S[C:4](=[O:8])[C:3]=1[F:9].FC1(F)SC(=[O:16])C(F)=C1F.FC1(F)SC(F)(F)C(F)=C1F>>[F:1][C:2]1=[C:3]([F:9])[C:4]([O:7][C:6]1=[O:16])=[O:8]Participants
Procedure
Both difluoro-2,5-dihydrothiophene-2,5-dione and tetrafluoro-2,5-dihydrothiophene-2-one are made by the reaction of SO3 with hexafluoro-2,5-dihyrothiophene (Example 3, infra). Thus reaction of the hexafluoro-2,5-dihydrothiophene with SO3 under reaction conditions less vigorous than those reported herein that produce difluoromaleic anhydride will produce difluoro-2,5-dihydrothiophene-2,5-dione and/or tetrafluoro-2,5-dihydrothiophene-2-one. Less vigorous conditions include one or more of lower reaction temperatures, shorter reaction times, lesser amounts of SO3 and the absence of catalysts. Since difluoro-2,5-dihydrothiophene-2,5-dione and tetrafluoro-2,5-dihydrothiophene-2-one are both intermediates in the reaction of hexafluoro-2,5-dihydrothiophene with SO3 to produce difluoromaleic anhydride, reaction of either difluoro-2,5-dihydrothiophene-2,5-dione or tetrafluoro-2,5-dihydrothiophene-2-one with SO3 under conditions described herein will yield difluoromaleic anhydride.
Workup
- customunder reaction conditions less vigorous than
Sources & evidence
- ORD record
- ord-20592a817cf549b5868b7c66ff6a164c
- Source dataset
- uspto-grants-1993_08
- Patent number
- US05235069
Reaction notes
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