Contrasting behaviour of NBS towards 1,4-dihydrobenzothieno[3,2-b]pyridine 5,5-dioxides and 4,5-dihydro-1H-indeno[1,2-b]pyridines

Contemporary development in sequential Knoevenagel, Michael addition multicomponent reaction for the synthesis of 4-Aryl-5-oxo-5H-indeno[1,2-b]pyridine-3-carbonitrile

“…It has been evidenced that in most of the cases, the synthesis of the N-containing skeleton is carried out by using ammonium salts as an N-source, but in the absence of an ammonium salt, aromatic aldehyde, malononitrile, and 1,3-diketone react to give a pyran derivative [75][76][77]. There are similar reactions observed in the literature [78][79][80] with its own merits and demerits. Hence, to outwit these mentioned demerits of the previous reports herein, we successfully demonstrate a novel method by engaging the intramolecular carbonitrile N-atom as the Nsource for the selective synthesis of the indenopyridine skeleton altering the reported formation of indenopyran derivatives.…”