Tabernaelegantinines C and D, two new bisindole alkaloids containing a cyano group from Tabernaemontana elegans stapf. Part 2.

Abstract

Tabernaelegantinines C and D, isolated from the root bark of Tabernaemontana elegans, have been shown by spectroscopic data and chemical correlation to be ‘dimer’ alkaloids composed of a dregamine unit and an isovoacangine unit connected through a linkage involving C(3) of the former and C(12′) or C(10′) of the latter, respectively. The isovoacangine unit of both compounds contains an extra cyano-group at C(3′) and the configuration at this centre is (S).