Solvent-Free, One-Pot, Multicomponent Synthesis of Xanthene Derivatives

An efficient and environmentally benign one-pot condensation of cyclic diketones, aldehydes and naphthols was achieved with 1,4-diazabicyclo[2-2-2]octane supported on Amberlyst-15 as a novel catalyst, producing a variety of benzoxanthenones in good to excellent yields. The advantages of this multicomponent reaction include the use of a heterogeneous catalyst, solventless conditions and a simple methodology that is atom-economical and results in low E-factor values. A total of 17 xanthene derivatives, including two novel molecules, were synthesized and then characterized. Aromatic aldehydes carrying an electron-withdrawing group provided excellent yields. Appreciable results were also obtained using aliphatic aldehydes. The catalyst is fully recyclable and can be reused up to six times.

Automated summary

An efficient and environmentally benign one-pot condensation reaction was achieved using 1,4-diazabicyclo[2-2-2]octane supported on Amberlyst-15 as a novel catalyst. The reaction involved cyclic diketones, aldehydes, and naphthols, resulting in the synthesis of various benzoxanthenones with good to excellent yields. The advantages of this reaction include the use of a heterogeneous catalyst, solventless conditions, atom-economical methodology, and low E-factor values. Seventeen xanthene derivatives, including two novel molecules, were synthesized and characterized. Aromatic aldehydes with electron-withdrawing groups showed excellent yields, and aliphatic aldehydes also gave appreciable results. The catalyst exhibited full recyclability and could be reused up to six times.