Selective binding of elliptinium acetate onto the 3'-terminal ribose of diribonucleosides monophosphates

We report the full structure of two elliptinium diribonucleosides monophosphate adducts: the oxidized form of this antitumor agent alkylates very selectively the pX ribose of ApX (X = G or U) leading to a spiro derivative, where the C10 atom of ellipticine skeleton is linked to both sugar oxygen atoms 2' and 3'. No other adducts could be detected, specially the expected ones corresponding to the usual alkylation sites of bases.