“…Nitrogen-, oxygen- and sulfur-based heterocyclic compounds are contributing extensively in the current medicinal chemistry because of their wide applications in drug discovery and development [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. As the potentially privileged scaffolds, pyridine-fused heterocycles have attracted attention due to their effective and widespread biological properties for the treatment of different diseases such as cancer, diabetes, hyperpigmentation, tuberculosis, hyperplasia and ulcer [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ].…”