One-Pot Synthesis of 5-Alkoxy-4-amino-3-halo-2(5<i>H</i>)-furanones Containing Benzimidazole Moiety in the Absence of Metal Catalyst

In the presence of KF as base and THF as solvent, the tandem Michael addition-elimination reaction of different 5-alkoxy-3,4-dihalo-2(5H)-furanones with aminomethyl benzimidazoles at room temperature gave 21 target compounds simultaneously containing both bioactive benzimidazole and 2(5H)-furanone moieties in yields of 62-88 % (mostly over 71 %). The structures of all the newly synthesized compounds were elucidated and confirmed by FTIR, UV, 1H NMR, 13C NMR, mass spectroscopy and elemental analysis. The simple one-pot synthetic method provides a brief route for the introduction of the benzimidazole unit into 2(5H)-furanone derivatives under mild conditions without any metal catalysts. This transformation also affords an important synthetic strategy for the series 2(5H)-furanone derivatives, as well as a basis for the activity test of these potential drug molecules. Keywords: Benzimidazole, bioactive units, combination, Csp2-N bond formation, 2(5H)-furanone, metal-free catalysis, Michael addition-elimination reaction, one-pot synthesis.