A green approach for the multicomponent synthesis of polyhydroquinolines and 6-unsubstituted dihydropyrimidinones using novel highly proficient acidic ionic liquid [CEMIM][MSA] as a reusable catalyst

Carboxylic acid functionalized imidazolium based novel acidic ionic liquid [CEMIM][MSA] was synthesized using economically feasible raw materials under very mild condition. The cost effective and sustainable synthesis of polyhydroquinoline and 6-unsustituted dihydropyrimidinone derivatives in green media was first time carried out very effectively using [CEMIM][MSA] catalyst. Acidic ionic liquid catalyst [CEMIM][MSA] with carboxylic acid group was easily separated and reused up to five cycles without much loss in its catalytic activity and stability. The introduced catalyst had showed a better catalytic performance in aqueous medium to obtain described compounds with excellent yields in shorter time. Purification free isolation of pure polyhydroquino-lines and 6-unsustituted dihydropyrimidinones derivative makes the revealed protocol attractive and ecological.

Automated summary

This study successfully synthesized a carboxylic acid functionalized imidazolium-based acidic ionic liquid, which was used as a catalyst for cost effective and sustainable synthesis of polyhydroquinoline and 6-unsustituted dihydropyrimidinone derivatives in green media. The catalyst showed excellent catalytic performance, stability, and could be easily separated and reused up to five cycles. It achieved high yields of the desired compounds in shorter time in an aqueous medium, with purification-free isolation of pure products.