Studies on the antibacterial action of novel gem-diphenyl-spiro-cyclopropano- oxazolones and 2-aryl(alkyl)-4-ylidene-oxazol-5-ones.

The preparation and in vitro antibacterial activity of a novel series of gem-diphenyl-spiro-cyclopropano-oxazolones (cis-1,2,2,5-tetraphenyl 6-oxa-4-azaspiro[2.4]hept-4-en-7-one) are described. The overall activity of these compounds was higher than that of the 2-aryl(alkyl)4-ylidene-oxazol-5-ones (azlactones). The gem-diphenyl-spiro-cyclopropano-oxazolones 1-4 have emerged as the most potent derivatives when tested against bacteria.