Anticancer Prodrug Studies: Diels - Alder Chemistry of 1-Methylthio-1-(p-tolylsulfonyl)ethene

Abstract

The reactivity of 1-methylthio-1-(p-tolylsulfonyl)ethene (1) as a dienophile in Diels–Alder chemistry is investigated. Cycloaddition reactions were carried out with a range of pyran-2-ones and isobenzofurans. The initial Diels–Alder adducts have the potential of undergoing fragmentation in chemistry that is relevant to the design of anticancer intercalator prodrugs. The nature of the final products of the reactions provided insights into both the cycloaddition reactions and fragmentation pathways of the adducts. By comparison with a thioether group, the sulfonyl substituent of the dienophile was found to decrease the reactivity and regioselectivity of the cycloaddition chemistry and to facilitate fragmentation of the initial adducts by the elimination of p-toluenesulfinic acid.