Abstract
An efficient organocatalytic route has been developed to synthesize novel substituted thioxanthenes (2a–2v) starting from diaryl thioether alcohols (1a–1v) using the intramolecular Friedel–Crafts reaction. The starting materials were obtained in two stages via a coupling reaction followed by the Grignard reaction. In this study, we tried for the first time to use some organic Brønsted acids as organocatalysts (3a–3h) in the intramolecular Friedel–Crafts cyclization reaction of thioether alcohols. The synthesis of original substituted thioxanthenes was achieved within 15 minutes by using N-triflylphosphoramide (3h) with quantitative yields in THF at room temperature.
Graphical Abstract
Supplementary information
Experimental details, analytical data for all compounds and copies of 1H NMR, 13C NMR spectra, GC-MS and elemental analysis are provided.
Acknowledgments
This work was supported by Istanbul University, Scientific Research Projects, project number BYP-2017-24039.
Disclosure statement
No potential conflict of interest was reported by the author.