Synthesis of new synthons for organofluorine compounds from halothane containing sulfur functional groups.
To develop new synthons for the syntheses of organofluorine compounds, the treatment of Halothane, 2-bromo-2-chloro-1,1,1-trifluoroethane, (1) with 4-methylbenzenethiol (2) in the presence of sodium hydride gave 1-chloro-2,2,2-trifluoroethyl 4-methylphenyl sulfide (3), which was oxidized with m-chloroperbenzoic acid (m-CPBA) to the corresponding sulfoxide (4) and sulfone (5). Reaction of 3 and 5 with allyltributyltin in the presence of 2,2'-azobis(isobutyronitrile) (AIBN) gave 1-(trifluoromethyl)-3-butenyl compounds (9, 11). Sulfoxide 4 was decomposed in this condition. The treatment of 3 with allyltrimethylsilane in the presence of Lewis acids gave 1-(trifluoromethyl)-3-butenyl compounds (9) in good yield. This result suggests that 4-methylphenylthio substituent stabilizes the alpha-carbocation effectively, though the trifluoromethyl group destabilizes it strongly. Aromatic compounds similarly reacted with 3 in the presence of titanium(IV) chloride to give 2-aryl-1,1,1-trifluoro-2-(4-methylphenylthio)ethanes. Thus, sulfur compounds derived from Halothane were found to be useful new synthons for organofluorine compounds.
Kato
M
M
Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan.
Maeda
K
K
Sato
K
K
Omote
M
M
Ando
A
A
Kumadaki
I
I
D006221:Halothane / Q000737:chemistry*; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D013455:Sulfur / Q000737:chemistry*; D014220:Trialkyltin Compounds / Q000737:chemistry
D006845:Hydrocarbons, Fluorinated; D007202:Indicators and Reagents; D014220:Trialkyltin Compounds; C011559:tributyltin; D013455:Sulfur; D006221:Halothane