It is planned to continue with this project which involves the development of new methods for the direct replacement of nuclear hydrogen by desirable substituents in six-membered heteroaromatic compounds, starting with the N-oxide or the N-ylide of the compound. These new synthetic methods involve novel molecular rearrangements, and some make available in one step polycyclic compounds not readily synthesized by other means. This will provide very desirable synthetic tools for the medicinal chemist as well as make available many new heterocyclic compounds whose possible medicinal activity will be determined. In addition, pyridinium sulfonylmethylene ylides are used to introduce the function NuCh double bond (Nu triple bond nucleophile) into appropriate alpha, beta-unsaturated activated systems. These are then built up into novel ring systems of potential biological activity.