The isolation and characterization of the major crystalline alkaloids of three Crinum species, C. defixum, C. scabrum, and C. latifolium, are reported. A new alkaloid, 5a-hydroxyhomolycorine (1) has been isolated from C. defixum. The latter plant also contains an alkaloid identified as 9-0-demethylhomolycorine which differs in physical properties from that previously reported for this compound. Evidence is provided for the structure of 9-0-demethylhomolycorine by ' H and 13C NMR studies. In the latter, the exploitation of long-range ' H coupling in the 13C spectra of lactones in this series is found to be diagnostically useful in assigning aromatic substitution patterns. A survey of the CD spectra of lactone alkaloids of the benzopyrano[3,4-g]indole system indicates that this technique can provide useful structural information.The Crinum genus of the amaryllidaceae has a wide geographical distribution in the temperate and subtropical regions. The species C. defixum Ker-Gawl, C. latifolium L., and C. scabrum Herb. are indigenous to the Indian subcontinent. Several preliminary reports2 have established the presence of lycorine in each of these species and a more definitive study3 of C. defixum has shown the presence of caranine, crinamine, crinine, galanthamine, galanthine, haemanthamine, and hippeastrine from C. defixum grown in Holland.
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