7-(Aminoethyl) ether and thioether of daunomycinone

Abstract
One-step treatment of daunomycinone with excess 2-aminoethanethiol and 2-aminoethanol in trifluoroacetic acid afforded at C-7 the thioether (77% yield) and ether (30% after recycling), respectively. Stereoselectivity for the natural 7S over the 7R configuration was greater for the ether (97:3) than for the thioether (2.5:1). Esterification of daunomycin at C-7 with .beta.-alanine was accomplished through the mixed anhydride of Z(OMe)-.beta.-alanine. Preliminary biological tests suggest that the antitumor [mouse leukemia P388] and DNA interactive properties of the anthracyclines can be retained in such structures.