A novel basic dicationic molten salt based on 4, 4'-bipyridine for synthesis of 1, 8-dioxooctahydroxanthene and 1, 8-dioxodecahydroacridine derivatives under solvent-free conditions

A novel basic dicationic molten salt based on 4, 4'-bipyridine for synthesis of 1, 8-dioxooctahydroxanthene and 1, 8-dioxodecahydroacridine derivatives under solvent-free conditions Xanthene and acridine derivatives are important classes of heterocyclic compounds exhibiting remarkable pharmacological activities. In this study, a versatile and efficient catalytic protocol was developed for the synthesis of 1,8-dioxooctahydroxanthene and 1,8-dioxodecahydroacridine derivatives. The reactions were promoted by a novel dicationic Brönsted molten salt catalyst, 1, 1'-sulfinyl bis(4, 4'-bipyridinium)dichloride ([(BPy) 2 SO][Cl] 2 ) under solvent-free conditions. The catalytic system proved to be highly efficient, affording 1, 8-dioxooctahydroxanthene derivatives in 30 min-60 min with 80%-95% yield, and 1, 8-dioxodecahydroacridine derivatives in 50 min-70 min with 83%-92% yield. Moreover, the catalyst showed outstanding reusability and could be recycled for at least six consecutive runs without any noticeable loss of activity. Keywords basic dicationic molten salt, bipyridine, 1, 8-dioxooctahydroxanthene derivatives, 1, 8-dioxodecahydroacridine derivatives, solvent-free, multi-component reaction