Michael addition of 4-methylquinazolines to chalcones: a greener protocol for C(sp3)-H functionalization using magnetically recoverable catalyst

C-H functionalization reactions are an important strategy to create carbon-carbon bonds due the atom- and step-economy of these processes. C(sp3)-H activation, specifically, have been widely studied lately and many Lewis acids have been used in this transformation, as for example, the functionalization of benzylic C–H bond in azaarenes by cobalt‐catalyzed 1,4‐addition to enones.
The use of metal supported on magnetic nanoparticles has been pointed as a sustainable alternative for conventional catalysts since they can be magnetically removed from reaction medium without filtration or centrifugation, preventing losses of the catalyst and increasing their reusability. Herein we report a greener catalyst to promote the Michael addition of 4-methylquinazolines to chalcones, using a magnetic cobalt nanoparticles. After a short screening of reaction conditions, the desired product was obtained in 55% yield using ethanol under microwave irradiation. This methodology can generate potential biologically active compounds, once quinazolines are known by their pharmacological properties.