Synthesis of tetrahydrobenzo[b]pyrane derivatives using nano magnetic graphene-oxide functionlized with triethylene tetramine 

Alinezhad H.1, Boroumand H.1, Tarahomi M.1, Mohseni Tavakkoli S.1 

1 Faculty of Chemistry, University of Mazandaran, Babolsar, Iran, P.O. Box 47416-95447
Email: heshmat@umz.ac.ir

Graphene oxide (GO), a member of the carbonaceous nano material family, is a two-dimensional wrinkle structure with one-atom-thick carbon sheet, presenting abundant O-containing functional groups on the edges and surfaces [1]. In addition, graphene oxides are rich in hydroxyl and carboxyl groups, so they are easier to be functionalized. Magnetic graphene composite can be easily separated from solution by a magnet, which exhibits excellent performance in the enrichment and separation of small molecule pollutants in the environment [2]. 
Multicomponent reactions (MCRs), performed with heterogeneous nanocatalysts have undergone an explosive growth in recent years.Compounds having pyran annulated heterocycles exhibit a wide range of biological activities, such as diuretic, analgesic, anticancer, anti-tumoral, and anti-HIV and etc [3]. An efficient one-pot three-component procedure has been developed for the preparation of tetrahydrobenzo[b]pyrans using Nano magnetic graphene-oxide functionlized with amines such as triethylene tetramine (MGO-TET) as catalyst in solvent-free condition. Three-component reactions of aryl aldehydes, malononitrile and dimedone in solvent-free condition were proceeded. This methodology has number of advantages such as: high yields, simple workup, short reaction times and reusability of the catalyst. The catalyst was readily separated using an external magnet and reusable without significant loss of its catalytic efficiency. The catalyst was characterized by FT-IR, SEM and EDAX analysis.

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