1,274,825. Cardanolides; cardenolides. DEUTSCHE AKADEMIE DER WISSENSOHAFTEN U BERLIN. 20 Feb., 1970, No. 8286/70. Heading C2U. A mixture comprising a 20(22)-cardenolide and either a cardanolide or a 14,21-epoxycardanolide is separated by treatment with a base in an aqueous organic solvent mixture at 0-50‹ C., the pH of the reaction mixture being maintained at 10-11, and subsequently separating the 20(22)-cardenolide (which is unchanged by this treatment) from the reaction mixture by extraction or by chromatography. The extraction may be effected with an organic solvent preferably after adjustment of the reaction mixture pH to 11-12À5, and conventional working up of the extract yields the pure 20(22)- cardenolide. The cardanolide or 14,21-epoxycardanolide (which is cleaved by the treatment to a γ-hydroxycarboxylic acid) may be isolated from the residual reaction mixture by acidification thereof to a pH of 3-4 (an organic solvent extraction preferably being first performed at pH 8) followed by extraction with an organic solvent and working up of the extract. The aforesaid chromatography is effected by passing the reaction mixture, preferably after adjustment thereof to pH 8, through an anionexchange column and eluting with an aqueous organic solvent. Acidification and extraction of the eluate yields the pure 20(22)-cardenolide. Subsequent elution of the column with an alkali metal salt in aqueous-organic solution (preferably after an intermediate elution with aqueous methanol), acidification and extraction of the eluate and working up of the extract yields the pure cardanolide or 14,21-epoxycardanolide. Specified products are digitoxin, dihydrodigitoxin, 16-epigitoxin and dihydro-16-epigitoxin.
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