Reaction of ethyl acetoacetate and 2′-hydroxychalcones: Efficient route to 9-aryl-6H-benzo[c]chromen-6-ones

The reaction of ethyl acetoacetate and 2′-hydroxychalcones under atmospheric air to furnish a series of functionalized 6H-benzo[c]chromen-6-ones in moderate yields is reported. The reaction proceeds through trans-esterification, intra-molecular Michael addition, Robinson annulation and oxidative aromatization. KEY WORDS: 2′-Hydroxychalcones, Ethyl acetoacetate, 6H-Benzo[c]chromen-6-ones, Trans-esterification, Michael addition, Robinson annulation, Oxidative aromatization Bull. Chem. Soc. Ethiop. 2014, 28(2), 289-294.  DOI: http://dx.doi.org/10.4314/bcse.v28i2.1

GC-MS Analysis and Antimicrobial Activities of the Non-polar Extracts of Mundulea sericea

The composition of the non-polar extracts of the leaves, stem bark and twigs of Mundulea sericea (Fabaceae) were analyzed using GC-MS. Eight, five and eleven components were identified from the leaves, twigs and stem bark extract, respectively. The major components were identified as: caryophyllene (43.6 %) and cadina-3,9-diene (29.7 %) in the leaf extract, amorphene (34.4 %) and valencene (17.9 %) in the stem bark extract and isoledene (29.0 %) and α-gurjunene (22.4 %) from the twig extract. Sesquiterpenes were the major abundant components in the non-polar extracts. The leaf, stem bark and twig extracts showed weak antibacterial and antifungal activities.Keywords: Mundulea sericea, GC-MS, non-polar, sesquiterpenes, antimicrobia