Synthesis of new 5-benzylidene-hydantoin esters

Compounds containing a hydantoin moiety are found in several medicines in clinical use. In this research, ethyl- and methyl-[2-(5-benzylidene)-2,4-dioxoimidazolidin-3-yl]acetyl esters are successfully synthesized over four reaction steps using conventional methods. The synthesis begins by subjecting hydantoin to a Knoevenagel condensation reaction with three different benzaldehydes to afford the penultimate products, which are further reacted with ethyl or methyl (bromoacetyl)alaninates, butanoates, valinates, and norvalinates to give the desired products as esters in low to moderate yields.