Polyacetylenes of Dahlia

Two Dahlia sherffii strains and three Dahlia pinnata strains and Dahlia rudis Sorensen have been investigated for polyacetylenes. A great number of acetylenic compounds, characterized earlier from other Dahlia species was determined. The two Dahlia sherffii strains and the three Dahlia pinnata strains contain 1-phenylhept-5-ene-1,3-diyne and 1-phenyl-hepta-1,3,5-triyne and derivatives which have previously been found in one Dahlia coccinea strain and in a horticultural form. A comparison between this group of dahlias with others previously investigated, show characteristic differences in the chemical pattern. Dahlia rudis is thus closer to the D. imperialis and the D. tenuicaulis and three of the Dahlia coccinea strains. Dahlia merckii exhibits a quite unique pattern of polyacetylenes.