We reported a novel series of pyrano-pyrido-carbazol derivatives (PPCDs) 6(a-o), synthesized via the reaction of 4-hydroxypyridocarbazolone (3), aryl/heteroaryl aldehyde (4), and malononitrile (5), in water using Fe 3 O 4 magnetite nanoparticles (Fe 3 O 4 MNPs) as a heterogeneous novel catalyst at room temperature just in 60 mins under ultrasound. For this propose, Fe 3 O 4 MNPs with particle size 23.4 � 0.9 nm was successfully synthesized via a one-step novel coprecipitation method in aqueous medium by the use of a new alkaline agent i. e. 2-(ethylamino) ethanol and systematically characterized using field emission scanning electron microscopy (FESEM), highresolution transmission electron microscopy (HRTEM), energy dispersive analysis of X-ray (EDAX), X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared (FTIR). Fe 3 O 4 MNPs show remarkably dramatic dispersion stability as evident from zetapotential (ζ) value of À 38.9 mV and hydrodynamic diameter (HD) of 238 nm and excellent specific surface area of 185 m 2 /g. Additionally, Fe 3 O 4 MNPs was easily separated after completion of the reaction, from the reaction mixture using the external magnet, and can be reused seven times without any considerable loss of its activity. The use of ultrasound made homogeneous dispersion of MNPs in water which accelerated the rate of reaction for the synthesis of PPCDs. This protocol has notable advantages like the synthesis of novel PPCDs with high yield in short reaction time, inexpensive catalyst, eco-safe, and also favour green chemistry protocol.

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