title: Total synthesis and antibacterial screening of ( ± )-7-butyl-6,8-dihydroxy-3-pentyl-3,4-dihydroisochromen-1-one.
abstract: A new total synthesis of ( ± )-7-butyl-6,8-dihydroxy-3-pentyl-3,4-dihydroisochromen-1-one, isolated as R-enantiomer from Geotrichum sp., has been described. Reaction of 4-butyl-3,5-dimethoxyhomophthalic anhydride with hexanoyl chloride in the presence of 1,1,3,3-tetramethyl guanidine and triethyl amine afforded 7-butyl-6,8-dimethoxy-3-pentylisochromen-1-one, which was converted into corresponding 3,4-dihydroisochromen-1-one by successive ring opening and reduction. Final demethylation to furnish the natural product was achieved using anhydrous aluminum chloride in ethanethiol. The target compound and the intermediates were subjected to antibacterial evaluation against 10 bacterial strains using levofloxacin as standard.
authors.affiliation: a Department of Chemistry , Quaid-i-Azam University , Islamabad , 45320 , Pakistan.
authors.forename: Aamer
authors.initials: A
authors.lastname: Saeed
authors.forename: Hummera
authors.initials: H
authors.lastname: Rafique
authors.forename: Muhammad
authors.initials: M
authors.lastname: Arshad
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D005848:Geotrichum / Q000737:chemistry; D049934:Isocoumarins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D064704:Levofloxacin / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013237:Stereoisomerism
chemical_list: C586004:7-butyl-6,8-dihydroxy-3-pentyl-3,4-dihydroisochromen-1-one; D000900:Anti-Bacterial Agents; D049934:Isocoumarins; D064704:Levofloxacin