Microwave-Accelerated Synthesis of Flavanones through Oxidative Cyclization of 2'-Hydroxychalcones Using Acetic Acid as a Sole Catalyst

Authors

  • Gan B. Bajracharya Laboratory of Catalysis and Frontier Molecules, Faculty of Science, Nepal Academy of Science and Technology (NAST), Khumaltar, Lalitpur, Nepal.
  • Rabina Dhakal Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Ghantaghar, Kathmandu, Nepal.
  • Sulochana Timalsina Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Ghantaghar, Kathmandu, Nepal.

DOI:

https://doi.org/10.3126/jncs.v44i1.62688

Keywords:

Catalysis, Flavonoids, Green Chemistry, Michael reaction, Microwave synthesis, Oxygen Heterocycles

Abstract

Under microwave irradiation conditions, 2'-hydroxy chalcones 1a-c underwent AcOH-mediated cyclization in an oxa-Michael addition manner to afford flavanones 2a-c in acceptable yields (up to 82%). These reactions proceeded in a shorter reaction time (~ 30 min) through microwave activation; otherwise, the reaction would take several days and even weeks, if a conventional heating process was employed. For example, cyclization of (E)-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one (1a) has required 4 days of stirring with AcOH (0.25 M), under conventional heating at 100 °C, to produce 2-phenylchroman-4-one (2a), in 75% yield; while under microwave conditions, the reaction has yielded 82% of compound 2a, after 30 min. Thus obtained products 2a-c were fully characterized by recording of melting point together with UV, 1H NMR, and 13C NMR spectra.

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Published

2024-02-21

How to Cite

Bajracharya, G. B., Dhakal, R., & Timalsina, S. (2024). Microwave-Accelerated Synthesis of Flavanones through Oxidative Cyclization of 2’-Hydroxychalcones Using Acetic Acid as a Sole Catalyst. Journal of Nepal Chemical Society, 44(1), 143–152. https://doi.org/10.3126/jncs.v44i1.62688

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Section

Research Article