Synthetic and Mechanistic Study on the Microwave Assisted Fries Rearrangement of 1-Methylidene-3,4-dihydroisoquinoline-2(1H)-yl-methanones

Formerly, an unexpected acyl migration of 1-methylidene-3,4-dihydroisoquinoline- 2(1H)-yl-methanone derivatives was observed, and on this basis a microwave assisted synthetic method was developed for the preparation of members of the 2'-(3,4- dihydroisoquinoline-1-ylidene)-1-ethan-1-one family, potential CB2 receptor agonists and PDE7 inhibitors. The reaction mechanism was studied with experimental and theoretical methods in order to propose intra- and intermolecular radical pathways.