Tailored SnO2@MWCNTs efficient and recyclable nano-catalyst for selective synthesis of 4, 5-dihydropyrrolo [1, 2-a] quinoxalines via Pictet–Spengler reaction

Heterocyclic compounds have a wide range of applications, and Pictet–Spengler reaction is effectual in the synthesis heterocyclic such as quinoline isoquinoline. The present work describes an effective Pictet–Spengler-type protocol for selective quinoxaline derivatives from substituted pyrroles diverse aromatic aldehydes over tailored SnO2 nanoparticles anchored multi-walled carbon nanotubes (SnO2@MWCNTs) nano-catalyst under greener condition. An elementary process (chemical synthesis) oxidation MWCNTs followed by uniform dispersion used to synthesize SnO2@MWCNTs catalyst. catalyst was then characterized using modern spectroscopic analytical techniques. activity investigated toward formation quinoxaline. progressed with 100% conversion 93–80% yield desired product at ambient operating conditions just 2.30–3.30 h time. effect different parameters temperature, time, loading on MWCNTs, were also discussed detail. displayed high tolerance functionalities respect form efficient way gave excellent yield. Plausible mechanistic pathway proposed. It believed that provided sufficient Lewis acidic sites selectively obtain final product. Additionally, recyclability studied which demonstrated could be efficiently reused six successive cycles without significant loss its activity. provides approach derivative preparation selectivity (free oxidized side product)