Phosphinic Dehydrodipeptides: Diversification of the P1′ Residue with the Morita–Baylis–Hillman Acetates and Inhibition of Alanyl Aminopeptidases

Abstract

Activated allyl acetates (the Morita–Baylis–Hillman acetates) were confirmed as convenient electrophilic precursors of the P1′ fragment of phosphinic dehydrodipeptides, and then, their selected saturated analogs were obtained in the subsequent reduction. This approach is particularly appropriate for structurally complex side chains and thus is an alternative to the addition of α-substituted acrylates with aminoalkylphosphinic acids. While phosphinic dehydrodipeptides were found to be good inhibitors of two mammalian alanyl metalloaminopeptidases, the saturated compounds showed higher activities than their structurally constrained counterparts. Docking calculations and molecular modeling showed that conformational freedom allowed for the favorable binding of distinct stereoisomers of phosphinates, while the presence of the double bond was more restrictive.