IBX, 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (2iodoxybenzoic acid 1), has been known for more than a century, although its presence on the scene of organic synthesis has remained limited primarily due to its remarkable insolubility in most organic solvents. 1,2b,3a

The ultracentennial 10-1-4 iodinane oxide IBX (3; o-iodoxybenzoic acid; 1-hydroxy-1,2-benziodoxol-3(lif)-one 1-oxide) represents a new oxidizing reagent that successfully joins to the large family of known oxidants. IBX, in contrast to other valuable oxidants, is inexpensive to prepare and easy to handle, can tolerate moisture and water, and generally gives very good yields. Furthermore, IBX is mild and chemoselective (primary alcohols are converted into aldehydes with no overoxidation to acids; 1,2-diols are converted to -ketols or a-diketones without oxidative cleavage; amino alcohols are oxidized to amino carbonyls, without protection of the amino group; sensitive heterocycles are not affected; various other functional groups are compatible with IBX oxidation). IBX is versatile (it works in various solvents and it is highly sensitive to temperature variations), and its solutions in DMSO are stable enough to carry out the oxidation reaction easily.

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The design, synthesis, and biological properties of novel inhibitors of the Na(+),K(+)-ATPase as potential positive inotropic compounds are reported. Following our model of superposition between cassaine and digitoxigenin, digitalis-like activity has been elicited from a non-digitalis steroidal structure by suitable modifications of the 5alpha,14alpha-androstane skeleton. The strong hydrophobic interaction of the digitalis or cassaine polycyclic cores can be effectively obtained with the androstane skeleton taken in a reversed orientation. Thus, oxidation of C-6 and introduction in the C-3 position of the potent pharmacophoric group recently introduced by us, in the 17 position of the digitalis skeleton, namely, O-(omega-aminoalkyl)oxime, led to a series of substituted androstanes able to inhibit the Na(+),K(+)-ATPase, most of them with an IC(50) in the low micromolar level, and to induce a positive inotropic effect in guinea pig. Within this series, androstane-3,6,17-trione (E,Z)-3-(2-aminoethyl)oxime (22b, PST 2744) induced a strong positive inotropic effect while being less arrhythmogenic than digoxin, when the two compounds were compared at equiinotropic doses.