The present investigation involves (1) study of the chemistry of diazouracils, diazoazoles, diazopurines, their analogs and their derivatives of interest in cancer therapy and as antiviral agents, (2) preparation of many new classes of heterocyclic compounds, (3) definition of the behavior and utility of highly-delocalized heterocyclic carbenes and their products, (4) development of methods of synthesis and varied reactions of new heterocyclic systems and (5) provision of experimental quantities of products of interest as practical carcinostats. The specific objectives of this research are to (1) investigate synthesis and the behavior of 5- and 6-substituted-uracils, aziridinyluracils, cyclopropenouracils, cyclooctatetraenouracils, azoloazocines, azepinones, tropones and their derivatives, (2) prepare and determine the reactions of nitrogen-containing 8,6-, 8,5- and 8,3- and 7-membered heterocycles, varied polyazaazulenes and their analogs and (3) develop the chemistry of diazo-, azido- and diazomethylpyrimidines and purines, their carbenes and their nitrenes. Emphasis is to be given to the various reactions of diazouracils and nucleophiles in the presence of Rh(II) catalysts, the effects of acid- and base-catalysis on 1,3-dipolar cycloadditions of diazouracils to electronegatively- and electropositively-substituted olefins and acetylenes, thermal ring- expansion and sigmatropic rearrangement reactions of carbenes with arenes and hetarenes, generation of azolylidenes, purinylidenes and varied divalent intermediates by thermal conjugative 1,1-elimination processes, and synthesis and development of the chemistry of polyazaazulenes.