D-ribose based organo catalyst for the sustainable synthesis of bioactive biscoumarins

Herein, the reported work includes the design and synthesis of D-ribose containing DABCO (1,4-diazabicyclo[2.2.2]octane) sugar ionic liquid (DD-RSIL) via three steps and employed an organocatalyst for the synthesis of methylene or methine substituted biscoumarin analogues. The reaction involves the Knoevenagel condensation, proceeded by the Michael addition reaction. We demonstrated that the synthesized homogenous organocatalyst functioned effectively and could be reused through site-selective synthesis to produce a diverse array of bis-coumarin analogues with yields reaching up to 90 % in a one-pot and metal-free process. We assessed the DD-RSIL as an efficient, environmentally friendly, and sustainable organocatalyst, exhibiting a high atom economy of 96.26 %, an E-factor of 0.039, and 100 % carbon efficiency. A total of 31 derivatives were synthesized with yields reaching up to 90 % within 2 h of stirring at 70 °C under mild reaction conditions. A variety of biscoumarin derivatives were produced utilizing substituted aliphatic, aromatic, and heterocyclic aldehydes. The capacity for scalability is another significant benefit of this methodology. • Novel D-ribose based DABCO sugar ionic liquid(DD-RSIL) employed as an organocatalyst. • Sustainable synthesis of bioactive biscoumarin analogues. • Involves Knoevenagel condensation and Michael addition reaction via cascade process. • Developed reaction exhibits high atom economy, E-factor and 100 % carbon efficiency. • Chemo and regio selective reaction and wide functional group tolerance.