Synthesis of coumarin-linked naphthoquinone fused pyrrole derivatives by HFIP-mediated multicomponent reaction

A straightforward and effective method for synthesizing coumarin-linked pyrrole derivatives fused with naphthoquinone has been reported by the one-pot reaction of aryl glyoxal, 4-hydroxycoumarin and 2-amino-1,4-naphthoquinone in hexafluoroisopropanol (HFIP) under reflux conditions. The main features of this methodology are simple reaction conditions, no use of metal or additional catalyst, less reaction time, use of recrystallization technique for purification, avoid of column chromatography, good yields of the products, creation of three new bonds (2 C-C and 1 C-N) in one-pot and occurrence of three biologically import moieties namely pyrrole, naphthoquinone and coumarin in the product. Spectroscopic techniques such as FTIR, ¹H NMR, ¹³C NMR, and HRMS were used to characterize all of our synthesized products. To further confirm the structure of the product, single crystal XRD of one compound was recorded.

Graphical Abstract

A convenient and step-economical methodology has been described for the synthesis of coumarin-linked pyrrole derivatives fused with naphthoquinone from readily available starting materials such as aryl glyoxal, 4-hydroxycoumarin and 2-amino1,4-naphthoquinone by HFIP mediated multicomponent reaction.