Ru-Catalyzed C–H alkenylation on the arene ring of pirfenidone using pyridone as a directing group†
A method to functionalize the arene ring of pirfenidone has been demonstrated using pyridone as a directing group. Unlike the functionalization of the pyridone nucleus, the method demonstrated here is the alkenylation of the N-aryl ring of pirfenidone with internal alkynes using ruthenium catalyst. High functional group tolerance, simple reaction conditions and site-selective functionalization permit the synthesis of new analogues of drugs in a step-economical manner. The data of the control experiments suggest the possibilities of a base-assisted internal electrophilic substitution (BIES) pathway.