Dimethylformamide → 2',4'-Difluorobiphenylsulfonyl chloride
Reaction equation
[F:1][C:2]1[CH:7]=[C:6]([F:8])[CH:5]=[CH:4][C:3]=1[C:9]1[CH:14]=[CH:13][C:12](S(O)(=O)=O)=[CH:11][CH:10]=1.CN(C=[O:23])C.[S:24]([Cl:27])(Cl)=[O:25]>>[F:1][C:2]1[CH:7]=[C:6]([F:8])[CH:5]=[CH:4][C:3]=1[C:9]1[C:10]([S:24]([Cl:27])(=[O:25])=[O:23])=[CH:11][CH:12]=[CH:13][CH:14]=1Participants
4
Procedure
2′,4′-Difluorobiphenyl-4-sulphonic acid (12.1 g, 47 mmol) was suspended in thionyl chloride (100 mL). The mixture was heated at reflux for 30 minutes, when a catalytic amount of dry DMF was added and the reaction mixture was heated at reflux for a further 4 hours. The reaction mixture was then cooled, the thionyl chloride evaporated and the residue was then azeotroped with toluene (3×10 mL). The resulting yellow/orange gum was taken up into EtOAc (250 mL) and washed with water (50 mL) and brine (50 mL), and dried over MgSO4. Filtration and evaporation gave the title compound as a brown oil which crystallized on standing (11 g).