Microwave-assisted TsOH/SiO2-catalyzed one-pot synthesis of novel fluoro-substituted coumarin hydrazones under solvent-free conditions

•Sixteen novel fluoro-substituted coumarin hydrazones were prepared and characterized.•One-pot method was found to be more convenient than the reported method.•The use of microwave reduced the reaction time.•Solvent-free conditions make the reaction greener.•Recovered TsOH/SiO2 is recyclable.

Sixteen novel fluoro-substituted coumarin hydrazones were synthesized from a series of ethyl 2-hydroxy-2-(trifluoromethyl)-2H-chromene-3-carboxylates with supported acid catalyst under microwave-assisted one-pot and solvent free conditions. The structures of synthesized compounds were confirmed by IR, 1H NMR, 13C NMR, HRMS and single crystal X-ray diffraction. Compared with the reported reaction conditions, the new method has the advantages of shorter reaction time, simple work-up procedure and environmental friendliness. The supported catalyst can be recovered easily and reused with little change in its activity.

Graphical abstractSixteen novel fluoro-substituted coumarin hydrazones were prepared with one-pot method under microwave-assistant and solvent-free conditions.Figure optionsDownload full-size imageDownload as PowerPoint slide