Synthesis and Antimicrobial activities of some octahydroxanthen-1,8-dione derivatives

Abstract

Xanthenes are important group of compounds characterized by their certain biological activities. These compounds can be synthesized from the corresponding aldehydes. The carbonyl group in aldehydes is one of the versatile functional groups. Chapter one of this thesis deals basically with the chemistry of the aldehyde group with especial emphasis on their reactions as carbanions. This chapter deals also with xanthenes compounds together with a review of their biological importance, in addition, a short concise treatment of retrosynthesis analysis was covered. In this work nine octahydroxanthen-1,8-dione derivatives with their nine bisdimedone intermediates were designed and synthesized. The total synthesis was designed from the appropriate disconnections of the target molecules. Therefore the aldehyde was firstly condensed with dimedone in order to obtain the bisdimedone derivative, which followed by the acidic cyclization to form the 9-substituted-1,8-diketo octahydro xanthenes. The reaction course was followed with TLC technique. All the intermediates and the final compounds were subjected to UV and IR analysis. Further more most of the intermediates and the final octahydroxanthenes were analyzed with 1H and 13C-NMR. The corresponding hydrazones and oximes were prepared and their m.ps were recorded. Possible mechanistic explanation of the different synthetic routes together with their retrosynthetic analysis were dealt with in chapter three. The intermediates and the final compounds were scanned for their antibacterial activity against S. aureus, E. coli and P. aeruginosa, the compounds were found to possess some antimicrobial activity. The compounds were assayed for their antifungal activity against C. albicans.