Agelasines are 7,9-dialkylpurinium salts isolated from marine sponges (Agelas sp.) and asmarines are neutral purine derivatives isolated from Raspaila sp. sponges. These two classes of purine natural products are structurally related; they both contain terpenoid side chains. Up till now only a few agelasines and no asmarines have been synthesized. High activity against Mycobacterium tuberculosis (the bacterium that causes tuberculosis) has been found for some agelasines and analogs. Tuberc ulosis (TB) is the major cause of death from a single infectious agent among adults in developing countries and there is estimated that 30 million people will die from TB in the next 10 years. However no new drug directed specifically against TB have been introduced the last 30 years even though multi-drug resistant TB is a growing problem. In this project, we will develop selective syntheses of agelasines and analogs. We will continue to screen the agelasines and analogs formed for antimycobacterial acti vity and try to determine their mode of action as antibacterials. We are also interested in exploring activity against other microorganisms as well cytotoxicity (potential as anticancer compounds) and ability to act as antifouling agents. Little is known about bioactivity of asmarines. We will develop methodology for construction of the 7-membered ring in the asmarines, and try to synthesize simple asmaine analogs. The asmarine analogs formed will be subjected to the same bioactivity studies as described for the agelasine derivatives.