Synthesis and antibacterial evaluation of typharin analog: 6,8-dihydroxy-7-methyl-3-styryl-3,4-dihydroisocoumarin

J Asian Nat Prod Res. 2013;15(2):130-5. doi: 10.1080/10286020.2012.751978. Epub 2013 Jan 17.

Abstract

Synthesis of the 6-hydroxy-7-methyl analog of typharin (8-dihydroxy-3-styryl-3,4-dihydroisocoumarin) isolated from the rhizomes of Typha capensis has been described. Direct condensation of 3,5-dimethoxy-4-methylhomophthalic acid (1) with cinnamoyl chloride at elevated temperature under inert conditions afforded 6,8-dihydroxy-7-methyl-3-styrylisocoumarin (2). Hydrolysis of isocoumarin to keto acid (3) followed by reduction and cyclodehydration of hydroxy acid analog (4) afforded ( ± )-6,8-dimethoxy-3-(4-methoxyphenyl)-3,4-dihydroisocoumarin (5). Demethylation of the latter using anhydrous aluminum chloride/ethane thiol furnished the title isocoumarin (6). Compounds (1-6) were screened for in vitro antibacterial activity against a representative panel of Gram-positive and Gram-negative bacteria using levofloxacin as the reference drug.

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / isolation & purification*
  • Anti-Bacterial Agents / pharmacology*
  • Gram-Negative Bacteria / drug effects
  • Gram-Positive Bacteria / drug effects
  • Isocoumarins / chemical synthesis*
  • Isocoumarins / chemistry
  • Isocoumarins / pharmacology*
  • Levofloxacin
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Ofloxacin / pharmacology
  • Rhizome / chemistry
  • Typhaceae / chemistry

Substances

  • 6,8-dihydroxy-7-methyl-3-styryl-3,4-dihydroisocoumarin
  • Anti-Bacterial Agents
  • Isocoumarins
  • typharin
  • Levofloxacin
  • Ofloxacin