Green and Efficient Construction of Chromeno[3,4-<i>c</i>]pyrrole Core via Barton–Zard Reaction from 3-Nitro-2<i>H</i>-chromenes and Ethyl Isocyanoacetate

Abstract

A regioselective one-pot method for the synthesis of 1-ethyl 2,4-dihydrochromene[3,4-c]pyrroles in 63–94% yields from available 2-phenyl-, 2-trifluoro(trichloro)methyl- or 2-phenyl-2-(trifluoromethyl)-3-nitro-2H-chromenes and ethyl isocyanoacetate through the Barton–Zard reaction in ethanol at reflux for 0.5 h, using K2CO3 as a base, has been developed.

Keywords

• 3-nitro-2<i>H</i>-chromenes
• ethyl isocyanoacetate
• Barton–Zard reaction
• 2,4-dihydrochromeno[3,4-<i>c</i>]pyrroles