- Synthesis of 3β,14-Dihydroxy-5β,14β-pregnan-20-one C-3 Derivatives: Ozonolysis of Digitoxin and Digitoxigenin and their Derivatives followed by Zinc-Acid Reduction to the C-21 Methyl Ketone
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Ozonolysis of digitoxin, digitoxin tetraacetate, digitoxin tetrakis-(2,2,2-trichloroethyl carbonate), digitoxigenin, digitoxigenin acetate, digitoxigenin hemisuccinate and digitoxigenin 2,2,2-trichloroethyl carbonate followed by treatment with excess of zinc in acetic acid gave either the corresponding 21-hydroxy ester after 5 min or the 21-methyl ketone after 20 h.This procedure is more efficient than methods previously reported for the conversion of the α,β-unsaturated γ-lactone into an acetyl group and is applicable to the cardiac glycosides directly to give 14β-hydroxypregnan-20-one derivatives.Acidic hydrolysis of 14,21-dihydroxy- and 14-hydroxy-3β-tris(digitoxosyloxy)-5β,14β-pregnan-20-one is reported.Structures are based on 1H and 13C NMR assignments.
- Templeton, John F.,Ling, Yangzhi,Jin, Jichun,Boehmer, Mark A.,Zeglam, Talal H.,LaBella, Frank S.
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p. 823 - 829
(2007/10/02)
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