ß-Nitro substituted carboxylic acids and their cytotoxicity.

ß-Nitro-substituted ethyl carboxylates are a new class of cytotoxic agents; they can be easily obtained in fair to good yields in a single-step reaction by a Pd-catalyzed asymmetric conjugate addition of aryl boronic acids to 2-nitro-acrylates. Of all the tested derivatives, 2-(4-chlorophenyl)-3-nitropropionic acid ethyl ester (6) is most cytotoxic especially against the human ovarian cancer cell line A2780 therefore making this compound an interesting candidate for further investigations.