Investigation of a number of new and novel reactions is proposed. These reactions provide facile conversions ad mechanistic information for processes which would be particularly useful in chemotherapeutic syntheses. In certain cases the pathways to be studied should lead to new understanding of enzyme function at a molecular level in a way which should be particularly useful for drug design. The use of alpha-heteroatom dipole-stabilized carbanions to achieve electrophilic substitution would provide a new method for conversion of alcohols, esters, amines, amides, sulfides, and thioesters to alpha-heteroatom substituted products. The same approach appears promising for substitution ortho to aromatic substituents previously considered susceptible to nucleophilic attack. The novel processes of heterophilic addition, the methylation of protomeric ambient nucleophiles and the specific synthesis of Beta-gamma unsaturated ketones should provide better conttrol of these potentially useful synthetic reactions. A hydrogen bonded model for the enzymatic introduction of a functional group at different sites on a fatty acid chain will be investigated. The hypothesis that the enzyme orotidine 5'-phosphate decarboxylase selectively binds a zwitterion will be investigated as part of a study to provide a rational design of inhibitors for this enzyme. The possibility that heterophilic addiction provides a model for the mechanism of flavin action will be studied with activated imines.