Microwave assisted synthesis of naphthopyrans catalysed by silica supported fluoroboric acid as a new class of non purine xanthine oxidase inhibitors

Sahil Sharma, Kirti Sharma, Ritu Ojha, Dinesh Kumar, Gagandip Singh, Kunal Nepali, P. M.S. Bedi

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31 Citations (Scopus)


A series of naphthopyrans was synthesized employing silica supported fluoroboric acid under solvent free conditions in a microwave reactor. The catalytic influence of HBF4-SiO2 was investigated in detail to optimize the reaction conditions. The synthesised compounds were evaluated for in vitro xanthine oxidase inhibitory activity for the first time. Structure-activity relationship analyses have also been presented. Among the synthesised compounds, NP-17, NP-19, NP-20, NP-23, NP-24, NP-25 and NP-26 were the active inhibitors with an IC50 ranging from 4 to 17 μM. Compound NP-19 with a thiophenyl ring at position 1 emerged as the most potent xanthine oxidase inhibitor (IC50 = 4 μM) in comparison to allopurinol (IC50 = 11.10 μM) and febuxostat (IC50 = 0.025 μM). The basis of significant inhibition of xanthine oxidase by NP-19 was rationalized by its molecular docking at MTE binding site of xanthine oxidase.

Original languageEnglish
Pages (from-to)495-500
Number of pages6
JournalBioorganic and Medicinal Chemistry Letters
Issue number2
Publication statusPublished - Jan 15 2014
Externally publishedYes



  • Fluoroboric acid
  • Microwave
  • Naphthopyrans
  • Silica
  • Xanthine oxidase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmaceutical Science
  • Drug Discovery
  • Clinical Biochemistry
  • Organic Chemistry

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