Curassavine, the major alkaloid of Heliotropium curassavicum Linn. is shown to be an ester of trachelanthamidine with 3-carboxy-4-methylhexane-2,3-diol (homoviridifloric acid), the first example of a monocarboxylic necic acid with a C, skeleton; the minor alkaloids, coromandalin and heliovicine are esters of trachelanthamidine with ( + ) -viridifloric and ( - )-trachelanthic acids, respectively, the former providing the first example of natural occurrence of a (+)-viridiflorate.