Alkaloids which possess the rare hasubanan skeleton have been found to occur only in Stephania species. The structural elucidation of the first hasubanan ester alkaloid, stephavanine (from 2. abyssinica), has recently been reported.' We report herein the isolation and structural elucidation of a new hasubanan ester-ketal alkaloid, stephisoferuline (J_), and its interrelation with +demethylnorhasubanonine ((h).'
The defatted roots and rhizomes of 2. hernandifolia were extracted with methanol and then 30s aqueous methanol and the combined extracts were concentrated and triturated with 6% hydrochloric acid. The acid solution was extracted with ether and basified with ammonium hydroxide (pH 9). Extraction with chloroform gave the non-quaternary alkaloids, which were fractionated by continuous extraction with ether. The ether-soluble alkaloids were chromatographed on SilicAR-CC7 (Mallinckrodt). Elution with 2.5% methanol-chloroform gave fractions rich in stephisoferuline. Rechromatography on acid-washed alumina (Merck) with 2% methanol-chloroform as eluant followed by crystallization from chloroform-ether gave colorless needles of the chloroform solvate, CZ9H,,NCJ*2/3 CHCl,*: mp 133-135O (softens 101-1020); [a];+ 48' (c 0.82, MeOH); ,,KBr max 2.84, 2.98, 3.38, 5.89 (unsaturated ester) CL; ?~$p 229 rnw (sh) (E 18,020), 287 rnU. (e 15,100), 325 rnw (E 17,530); nmr (CDCl,) r 3.07-3.18 (3H, m, aromatic E from ester), 2.43 (lH, d (16), olefinic I$, 3.32 (lH, d (8.5)) and *All new crystalline compounds have been characterized by concordant elemental analyses.