Abstract
A microwave irradiated magnetically separable nano cobalt ferrite catalyzed green method for the synthesis of 4-phenyl-4H-pyrano[3,2-h]quinolin-2-amine and 2-amino-4-phenyl-4H-pyrano[3,2-h] quinoline-3-carbonitrile derivatives through cyclization of aromatic aldehyde, acetonitrile/malononitrile and 8-hydoxyquinoline is developed and presented in this paper. The cubic magnetic cobalt ferrite nano particles were synthesized by sol-gel citrate precursor method and characterized by FT-IR, XRD, SEM and TEM techniques and the structures of the synthesized pyranoquinoline derivatives were assigned by IR, MASS and 1H NMR techniques. The reaction is carried out in a domestic microwave oven with a heat-resistant microwave safe glass container with a lid.
Highlights
Microwave irradiation is a powerful tool and efficient method for the synthesis of biological active compounds due to selective absorption of microwave energy by polar molecules [1]
Multicomponent reactions play an important role in organic chemistry due to their excellent yields, ideal atom efficiency, convergence, exploratory power leading to the straight forward synthesis of some heterocyclic compounds [4] and they have wide applications in combinatorial synthesis [5]-[7]
The procedure involves multi-component one pot cyclization reaction between aromatic aldehyde, acetonitrile/malononitrile and 8-hydoxyquinoline is described as a model reaction shown in Scheme 1
Summary
Microwave irradiation is a powerful tool and efficient method for the synthesis of biological active compounds due to selective absorption of microwave energy by polar molecules [1]. Several methods have been reported for the synthesis of pyranoquinoline derivatives such as Lanthanide chloride [18], Potassium fluoride-alumina [19], Triethylamine [20], Imino DielsAlder reactions catalyzed by Antimony (III) sulfate [21], Molten tetra-n-butylphosphonium bromide under solvent-free conditions [22], Piperdine [23], Iodine [24], Phosphorous oxy chloride [25], Ultrasound assisted green synthesis [26], Sodium acetate [27], Ethanol:pyridine (1:1) [13], Egg shell [28], Trifluoroborane-silica [29], 1,4-diazabicyclo[2,2,2]octane [30] and Indium chloride [31] Even though these methods have their own merits but some limitations are observed like longer reaction times [33], usage of toxic reagents [23] and difficulty of separation of catalyst [20]. We are reporting an efficient improved procedure for one-pot multi-component synthesis of 4H-pyrano [3,2-h]quinoline derivatives through aromatic aldehyde, malononitrile/acetonitrile and 8-hydroxyquinoline in presence of magnetically separable nano cobalt ferrite catalyst under microwave irradiation (Scheme 1)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
