Calotropis ‐Glykoside, vermutliche Teilstruktur. . Glykoside und Aglykone, 321. Mitteilung

Reduction of uscharidin ( 19 ) with NaBH 4 gave a crystalline product C 29 H 42 O 9 which we formulate as β‐tetrahydro‐uscharidin ( 12 ), it was characterised as a crystalline tri‐O‐acetyl‐derivative 14 . The same compound 12 was obtained from calactin ( 18 ) and calotropin ( 18A ), thus confirming earlier results of H ESSE et al. about the close interrelationship of the three compounds. New formulae are suggested for the 7 Calotropis glycosides: calactin ( 18 ), calotropin ( 18A ), uscharidin ( 19 ), calotoxin ( 20 ), procerosid ( 21 ), uscharin ( 31 ), and voruscharin ( 32 ). These formulae are consistent with the chemical reactions and spectra of the mentioned compounds. They are constructed in analogy to the formula of gomphoside ( 11 ) advanced by W ATSON et al. with only an additional oxo group at C‐19.