Acta Pharm. 49 (1999) 257-266

Synthesis of novel polyfunctionally substituted coumarins as antibacterial agents

MOHAMED S. A. EL-GABY,^1*  MOUSTAFA M. GHORAB,²  and   SOAD M. ABDEL-GAWAD³

¹Department of Chemistry, Faculty of Science, Al-Azhar University at Assiut, Assiut 71524, Egypt
²Department of Drug Radiation Research, National Center for Radiation Research and Technology, P. O. Box 29, Nasr City, Cairo, Egypt
³Department of Chemistry, Faculty of Science (Girl's), Al-Azhar University, Cairo, Egypt

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