Synthesis of Pyrrolo [2,1-a]isoquinolines using Cu NPs decorated microcrystalline cellulose in 2-Methyl-THF: A biodegradable heteregeneous nanocatalyst for the sustainable cascade approach

Abstract

Copper nanoparticles (Cu NPs) supported on microcrystalline cellulose (MCC) serve as an efficient and biodegradable heterogeneous nanocatalyst for the synthesis of pyrrolo [1,2a] isoquinoline under mild and sustainable reaction conditions through a cascade reaction involving condensation, addition, oxidation, and cyclization events. The catalyst underwent thorough characterization via various techniques, including FT-IR, PXRD, XPS, FE-SEM, EDX, TEM, and HR-TEM analysis. Optimized reaction conditions facilitated high-yield production of a diverse range of pyrrolo [1,2a] isoquinolines in 2-Me THF solvent, and the method demonstrated scalability with successful gram-scale synthesis. Notably, the catalyst exhibited reusability for up to five cycles without a significant decrease in activity. This approach aligns with eco-friendly principles, as evidenced by favorable green chemistry metrics for compound 4a, including low process mass intensity (7.83), a minimal environmental impact factor (6.83), a substantial atom economy (67.56 %), efficient reaction mass efficiency (60.76 %), high chemical yield (92.37 %), low mass intensity (1.64), notable mass productivity (60.97 %), considerable carbon efficiency (69.15 %), and optimum efficiency (89.93 %). These results highlight the sustainable and environmentally conscious nature of the developed synthetic methodology.