Acta Pharm. 49 (1999) 257-266
Fusion of 2,4-dihydroxyacetophenone, 1, and ethyl cyanoacetate furnished coumarin 3. Compound 3 on refluxing with acetic anhydride or propionic anhydride yielded the corresponding coumarins 4a,b, respectively. Coumarins 3 and 4a reacted with elemental sulphfur in ethanol/piperidine to yield thieno[3,4-c]coumarins 6a,b. 4-Styrylcoumarins 7a,b were obtained through interaction of 4a with aromatic aldehydes. When coumarin 4a was refluxed with arylidenemalononitriles in ethanol/piperidine, benzo[c]coumarins 8a-d were obtained. Compound 8a reacted with acetic anhydride, propionic anhydride, phenyl isothiocyanate and formamide to yield the corresponding coumarins 11, 12, 14 and 15, respectively. Some of these compounds were screened in vitro for their antibacterial activities.
Keywords: polyfunctionally substituted coumarins, synthesis, antibacterial agents