Digoxin oxidized product

Claim 1

The material obtainable by: (a) selectively oxidising digoxin at the 15'- and 16'-positions of the terminal digitoxose residue thereof using sodium periodate; (b) reacting the product of step (a) with tyrosine methyl ester; and (c) selectively reducing with sodium borohydride the product of step (b); which material (i) absorbs at a wavelength of 254 mμ when in solution in the mixture methanol:chloroform, 1:9 (v/v); (ii) is homogeneous by thin layer chromatography using alumina plates and the solvent system methanol:chloroform, 2:8 (v/v) and has Rf 0.60 in this system; (iii) gives positive reactions with Pauly's reagent (for tyrosine) and Raymond's reagent (for cardenolides) and has a phenol to cardenolide ratio of 1:1; (iv) has an infrared absorption spectrum substantially as shown in FIG. 2; and (v) whereof the nuclear magnetic resonance spectrum recorded at 100 MHz in deuterochloroform/hexadeuterodimethylsulphoxide has the following features: ______________________________________ Observed chemical Protons shifts (ppm) Characteristics ______________________________________ Phenolic 6.95 doublet Phenolic 6.75 doublet Lactone 5.95 singlet Angular CH.sub.3 0.80 and 0.92 singlets ______________________________________ where ppm (parts per million) is with reference to tetramethylsilane internal standard.