This award supports cooperative research between Joseph Dannenberg of Hunter College at the City University of New York (CUNY) and Oscar Ventura of the University of the Republic in Montevideo, Uruguay. They will study the theory of boron anionic heterocycles derived from hydroxamic acids. Molecular orbital calculations will be used to model the tautomerism (interconversion of structural isomers) of substituted hydroxamic acids. These acids are inhibitors of urease but not in the presence of boric acid so the reaction between this acid and hydroxamic acid will be studied. This is a project of fundamental interest to chemists and the two collaborators are well qualified and productive. Both have a history of effective international collaboration. Dannenberg's experimental skills complement the theoretical ones of the Uruguayan. Therefore this project represents a cooperation in frontier chemistry between U.S. and Latin American scientists and a good example of fulfillment of the goals of the Science in Developing Countries program.