Alkaloids of Aconitum yesoense Nakai

Alkaloids of Aconitum yesoense Nakai.—Sakai and co-workers42 have reported the isolation and elucidation of the structure of three new C19 diterpenoid alkaloids from Aconitum yesoense Nakai. These minor bases, ezochasmanine, ezo-chasmaconitine, and anisoezochasmaconitine, were isolated together with pseudo-kobusine (92), chasmanine (59), and jesaconitine (93). Ezochasmanine (94) (C25H41N07 m.pt 115—118 °C) formed a mixture of the monoacetate (95) and the diacetate (96) when treated with acetic anhydride in pyridine. The reaction of 

Reagents i, BzCl, pyridine, ii, Cl3CCH2OCOCl, iii, Ac20, p-TsOH iv, Zn, AcOH v, S02C12 vi, H2, Pt vii, OH- 

14-acetyl derivative (99) of chasmanine from the H and 13C n.m.r. spectral data and by the conversion of chasmanine into (99). The presence of the aroyl groups at C-8 and acetyl groups at C-14 in (98) and (99) is unique in the C19 diterpenoid alkaloids. The correlation of these new bases with chasmanine and the previous X-ray crystallographic analysis of 14-benzoylchasmanine hydrochloride43 establishes the indicated stereochemical assignments. 

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