B. Maleki
Jan 2, 2016
Citations
1
Influential Citations
31
Citations
Journal
Organic Preparations and Procedures International
Abstract
The increasing concern for the environment has led modern academic and industrial chemists to develop chemical processes with maximize yields and minimize cost while using non-toxic reagents and solvents. Multi-component reactions (MCRs) constitute such processes that combine economic aspects with the environmental ones and are powerful tools for the construction of novel and structurally complex molecules in a singlepot reaction. This ensures high atom economy, good yields and low costs, in short reaction times, minimization of waste, labor, energy, and avoidance of tedious purification processes. 2-Amino-4H-benzo[g]chromenes are an important class of compounds. In particular, they are a common heterocyclic scaffold in biologically active and medicinally significant compounds including anti-cancer, anti-inflammatory, anti-malarial, and as pesticides. Some of hydroxynaphthalene-1,4-dione derivatives are fluorescent compounds and are of interest as emitters for electroluminescent devices, as molecular probes for biochemical research, and as fluorescent whitening agents. The diverse biological activities of some 2-amino-4H-benzo[g]chromene derivatives have prompted considerable attention to their preparation. To the best of our knowledge, a few procedures have been used for the synthesis of 2-amino-4H-benzo[g]chromenes such as triethylbenzylammonium chloride (TEBA), DMF/AcOH under microwave irradiation, Et3N, 18 DBU, ionic liquids, Zn(L-Proline)2, 24 potassium phthalimide-Noxyl and urea. However, a number of these methods suffer from certain drawbacks such as prolonged reactions times at high temperatures, the use of volatile or hazardous organic solvents, tedious work-up procedures, utilization of alternative energy source (microwave) and the use of corrosive, toxic and non-reusable catalysts in large amounts, which creates difficulties in the separation of the products. Therefore, it seemed desirable to develop a more efficient and a general method for the synthesis of these 2-amino-4Hbenzo[g]chromenes. In continuation of our efforts toward the development of greener methodologies, we report a simple, efficient, and green synthesis of 2-amino-4H-benzo[g]chromene derivatives 4 by reaction of various aldehydes, malononitrile, and 2-hydroxy-1,4-naphthoquinone in the presence of o-benzenedisulfonimide (OBS) as a reusable acid catalyst