• 1 Department of Chemistry, University of Malaya , 50603 Kuala Lumpur, Malaysia
J Nat Prod, 2012 May 25;75(5):942-50.
PMID: 22559995 DOI: 10.1021/np300120p


Three new bisindole alkaloids of the macroline-macroline type, perhentidines A-C (1-3), were isolated from the stem-bark extract of Alstonia macrophylla and Alstonia angustifolia. The structures of these alkaloids were established on the basis of NMR and MS analyses. The absolute configurations of perhentinine (4) and macralstonine (5) were established by X-ray diffraction analyses, which facilitated assignment of the configuration at C-20 in the regioisomeric bisindole alkaloids perhentidines A-C (1-3). A potentially useful method for the determination of the configuration at C-20 based on comparison of the NMR chemical shifts of the bisindoles and their acetate derivatives, in these and related bisindoles with similar constitution and branching of the monomeric units, is also presented.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.