3-Hydroxy-22,26-epiminocholestane

Hapepunine (72), occurring in Fvitillavia aamtsahataensis, is the first natural 166-hydroxy-22,26-epiminocholestane derivative encountered (Mitsuhashi et al., Tetrahedron Letters, 1978, 2099). Anrakorinine, from the same source, affords a tosylate which on reduction (LiAlH ) yields hapepunine (72). In its pmr-spectrum it lacks a methyl singlet at 6 0.96 ppm (present in hapepunine), but has an AB quartet (2H) at 3.62 and 3.88 ppm. Consequently it is formulated as 18-hydroxyhapepunine (73) idem, Phytochem., 1981, M, 157). Several indolizidine bases, also related to Solarium Alkaloids, have been encountered in the Fritil-laria group. Camtschatcanidine, for example, from F. aamtsohatoensis, is (74), on the basis of spectral comparison with solanidine on reduction (LiAlHi ) of its 0-tosyl-derivative solanidine (75) is formed (Mitsuhashi et al.. 

Veralozidine (97) (C27H43NO2 mp 153-155° [a] —92.2° in ethanol) was isolated from the green part of Veratrum lobelianum 69). The mass spectrum of veralozidine exhibited a fragmentation pattern indicative of a 22,26-epiminocholestane skeleton. The UV spectrum of this alkaloid showed a maximum attributable to the C=N double bond. Veralozidine displayed IR absorption due to a hydroxy, a 3jS-hydroxy-5-ene, and a C=N group. 

It was reported earlier that 16g-hydroxy-22,26-epiminocholestane derivatives such as solaverbascine (16) were oxidised smoothly by manganese dioxide to yield spirosolane derivatives such as sola-... 

The hydroxy-group absorption in the i.r. spectra of 16-hydroxylated 22,26-epiminocholestanes has been examined." Absorption maxima consistent with seven-membered-ring hydrogen bonding between the amino-function and hydroxy-group at C-16 was observed for both the 16a- and 16 -series. The i.r. absorptions of several acetylated derivatives were also studied. 

Extraction of Fritillaria camtschatcensis, a known source of solanidine, has yielded tomatidenol (34), solasodine (16a), and a new alkaloid hapepunine, C2sH47N02. Hapepunine was assigned the N-methyl 22,26-epiminocholestane structure (35 a) on the basis of spectroscopic studies similar to those described above for teinemine. This structure proposal was proved by the partial synthesis of hapepunine from tomatidenol (34) via the desmethyl derivative (35b). Hapepunine (35 a) is the first natural 16j8-hydroxy-22,26-epiminochoIestane derivative. ... 

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