Reactivity of 4-Vinyl-2H-1-benzopyran-2-ones in Diels-Alder Cycloaddition Reactions: Access to Coumarin-Based Polycycles with Cdc25 Phosphatase-Inhibiting Activity

The reactivity of 4-(1-butoxyvinyl)-2H-chromen-2-one (1) and (E)-4-(2-butoxyvinyl)-2H-chromen-2-one (2) as diene in thermal Diels–Alder cycloaddition reactions with several electron-poor dienophiles is reported. Among several dienophiles used in this study 1,4-benzoquinone afforded cycloadducts 11-butoxy-1H-naphtho[1,2-c]chromene-1,4,5-trione (3e) and 1H-naphtho[1,2-c]chromene-1,4,5-trione (4g) that showed Cdc25 phosphatase-inhibition activity at low micromolar values, with both compounds more effective against Cdc25 A and Cdc25 C isoforms.