Alkaloids related to 20-piperidyl-5a-pregnane

aallium contains two glycoalkaloids which on hydrolysis afford 25-isosolafloridine (50) and solacallinidine (51), respectively. These have been investigated spectrally and the hydrochloride of the former subjected to an X-ray diffraction analysis (Bird et al.. Tetrahedron Letters, 1976, 3653 Acta Cryst., 1977, 33B, 3782). A chemical correlation between the pair has been established idem. Austral. 

Solaverbascine, occurring in S. verbasoifolium leaves, has been assigned structure (57) from spectral study and because it is formed by reductive ring-cleavage of solaso-dine (44) (G. Adam et al., Phytochem., 1980, 1, 1002) conversely it affords solasodine on manganese dioxide oxidation (Adam and H. T. Huong, Tetrahedron Letters, 1980, 21, 1931 J. prakt. Chem., 1981, 323, 839). The latter reaction occurs via 22-n double bond formation followed by spontaneous cyclization. 

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