Microwave-Assisted Mannich Reaction of 2-Hydroxy-chalcones

Abstract

A series of Mannich base derivatives of 2-hydroxy-chalcones were obtained expediently in good to excellent yields by microwave-assisted Mannich reaction. The regioselectivity of the reaction occurred preferentially at the C-3 position of the 2-hydroxy-chalcone backbone. In comparison with conventional results, results from microwave possesses give better yields in shorter times. Further vasorelaxation assay showed that 2-hydroxy-3-((4-methylpiperazin-1-yl)methyl)-4,6-dimethoxymethoxy-3′-bromo-chalcone 8 significantly decreased maximal PE-induced contraction (Emax = 100 ± 5.97%, EC₅₀ = 10.2 ± 0.51 µM).

Keywords:

• 2-Hydroxy-chalcones
• Mannich reaction
• microwave-assisted
• vasorelaxation

ACKNOWLEDGMENTS

We thank the College of Science Zhejiang University for ¹H NMR, ¹³C, NMR, and elemental analyses, and the experimental center of the College of Pharmaceutical Sciences Zhejiang University, for supporting the microwave reactor.

Notes

^a Ratio of 18 (C3-position product) to 19 (C5-position product) is 3:1.