Strophanthidin 3-6-

ZnCl2 is essential. The reaction was utilized in the synthesis of strophanthidin. Only the q, /3-alkene in the a, fi- and 7, (5-unsaturated ketone 51 is reduced selectively[47], Triethoxysilane is another reducing agent of the enone 52 and simple alkenes[48]. 

Kass, R.S., Tsien, R.W. and Weingart, R. (1978). Ionic basis of transient inward current induced by strophanthidin in cardiac Purkinje fibres. J. Physiol. 281, 209-226. 

Blaustein MP, Golovina VA 2001 Structural complexity and functional diversity of endoplasmic reticulum Ca2+ stores. Trends Neurosci 24 602-608 Boyett MR, Hart G, Levi A J 1986 Dissociation between force and intracellular sodium activity with strophanthidin in isolated sheep Purkinje fibres. J Physiol 381 311—331... 

In their synthesis of convallatoxin, Reichstein and coworkers16 made some minor modifications in the Meystre-Miescher procedure. Because of the low solubility of strophanthidin (2) in benzene, the anhydrous aglycon was dissolved in a small volume of absolute p-dioxitne. Pure, dry silver carbonate was introduced and, under efficient stirring, a solution of the halide in benzene was added over a period of three hours, while distillation was maintained at a rate equal to that of the addition, thus keeping the volume of the solution in the flask at a constant (and small) volume. After addition of the halide was complete, a small volume of absolute benzene was added dropwise over a period of one hour, with distillation maintained as in the foregoing. By this procedure, the yield of tri-O-acetylcopvalla-toxin amounted to 44%. 

Following this work, Reichstein and coworkers15 effected the first partial synthesis of a naturally occurring cardenolide, convallatoxin. Convalla-toxin [3/3-0-(6-deoxy-a-n-mannopyranosyl) strophanthidin (9)] is considered to be the most potent of all the known, naturally occurring cardenolides, and is obtained from the blossoms of the lily-of-the-valley (Convallaria majalis). The coupling of strophanthidin (2) with 2,3,4-tri-0- acetyl-6-deoxy-a- L-mannosyl bromide was performed using silver car-... 

Because of the expensive nature of the bromide (30), pilot experiments were carried out by using the known" 2,3,4,6-tetrarO-acetyl-a-D-mannosyl bromide (31) in order to establish optimum conditions for the coupling of (30) with (2). Coupling of the acetylated D-mannosyl bromide (31) with strophanthidin (2) was performed in 1,2-dichloroethane with exclusion of light, using freshly prepared silver carbonate. The water was removed azeotropically in the usual manner, and the reaction products... 

Fourteen yean later, R. Mauli and C. Tamm, [Heh. Chim. Acta, 40, 299 (1967)] isolated strophanthidin 0-D-glucoeide (6b) from Periploca nigrescent. 

Perhaps the strongest support for the argument, that enhancement of cardiotonic activity by the carbohydrate component is a function of hydroxylation, may be gained by inspection of the potencies of the completely deoxygenated 3-tetrahydropyranyl derivatives of digitoxigenin (1) and of strophanthidin (2) (see Table I). In each case, the value ob-... 

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