2,5-dialkylfurans and nitroalkanes as source of 2,3,5-trialkylpyrroles

Abstract

The synthesis of 2,3,5-trialkylpyrroles can be easily achieved by conjugate addition of nitroalkanes to 2-alken-1,4-dione (prepared by oxidative cleavage of 2,5-dialkylfuran) in acetonitrile with DBU as base, followed by chemoselective hydrogenation (10% Pd/C as catalyst) of the C-C double bond of the enones obtained by the elimination of nitrous acid from the Michael adduct. The Paal-Knorr reaction, performed on a bed of basic alumina and in the absence of a solvent, completes the formation of the title compounds.