Convenient synthesis and isolation of trifluoromethylthio-substituted building blocks

• Published in: Journal of fluorine chemistry 2011-12, Vol.132 (12), p.1241-1246
• Main Authors: Harsányi, Antal, Dorkó, Éva, Csapó, Ágnes, Bakó, Tibor, Peltz, Csaba, Rábai, József
• Format: Article
• Language: English
• Subjects: Balloons; CF 3I solution; Chains; Equivalence; Radicals; Raw materials; Sodium; Steam-distillation; Sulfides; Synthesis (chemistry); Trifluoromethyl sulfides; Trifluoromethylation
• ISSN: 0022-1139; 1873-3328
• DOI: 10.1016/j.jfluchem.2011.07.008

The reaction of CF 3I and arenethiols gave trifluoromethyl sulfides, which were isolated by steam-distillation. [Display omitted] ► Synthesis of trifluoromethyl sulfides from CF 3I and mercaptanes. ► Using of CF 3I stock solutions in DMF or DMSO as S-alkylating reagents. ► Steam-distillation as a means of choice for isolation of aryl/alkyl trifluoromethyl sulfides. Various aryl-, heteroaryl-, and alkyl mercaptanes (RSH, 1a– r) were treated with a slight excess of NaH suspended in DMF to make the appropriate sodium thiolates (RSNa), which then reacted with 1.3 equivalent of CF 3I at room temperature for overnight to afford the appropriate trifluoromethyl sulfides (CF 3SR, 2) in fair to good yields. The radical chain alkylation reaction was effective without the use of UV irradiation with all but three substrates (thiosalicylic acid, 1k; 2-mercaptobenzimidazole, 1q; and 3-mercaptopropionic acid, 1r). Steam-distillation was found as an effective and easy to upscale means for the isolation of these volatile and water immiscible sulfides. The CF 3I reagent gas was conveniently weighed and delivered to the reaction mixture by the balloon technique or as a preliminary made stock solution in DMF or DMSO. The sulfides 2 obtained here were assayed by GC and characterized by 1H, 13C, 19F NMR and MS spectroscopy.