Microwave activation and solvent-free phase transfer catalysis for the synthesis of new benzylidene cineole derivatives as potential UV sunscreens

Microwave activation coupled with solvent-free phase transfer catalysis (PT C), as a green chemistry procedure, was applied to the synthesis of new ben zylidene cineole derivatives as potential UVA filters. Considerable improve ments over classical procedures are put into evidence when using KOH + K2CO 3 as the base and TBAB as the phase transfer agent. Comparison with convent ional heating in strictly the same conditions as under microwave revealed a n important specific non-thermal microwave effect. Preliminary studies to e valuate the photochemical behaviour of these new derivatives were carried o ut.