Adriamycin analogs. Periodate oxidation of adriamycin

Adriamycin is selectively cleaved in high yield at the C13-C14 bond by 1 equiv of sodium metaperiodate to yield carboxylic acid 3. The corresponding methyl ester 4 is obtained by Fischer esterification. Spectral studies indicate that 3 and 4 bind to calf thymus DNA in a manner similar to adriamycin and daunomycin but Tm measurements suggest that less stable complexes are formed. Ester 4 inhibits DNA and RNA synthesis in cultured L1210 cells at levels comparable to adriamycin but acid 3 is much less effective. Both new compounds are moderately effective as antitumor agents against P388 lymphocytic leukemia in the mouse.