Straightforward Functionalizationof 3,5-Dichloro-2-pyrazinones under Simultaneous Microwaveand Ultrasound Irradiation

Heck reactions and Suzuki-Miyaura cross-couplings with relatively poorly reactive 3,5-dichloro-2-pyrazinones were studied at the same temperature under conventional heating, dielectric heating (MW) and simultaneous MW/US irradiation. This comparative study showed a synergic effect of combined MW and US irradiation resulting in a much higher reaction yield, at the same time avoiding side reactions and partial degradation that is otherwise observed under conventional heating.