Distribution of acetylenic thiophenes in the pectidinae

The distribution and quantitative significance of biosynthetically related di- and ter-thiophenes from 27 species representing seven genera of the Pectidinae (Heliantheae) was investigated by reverse-phase HPLC. Adenophyllum, Chrysactinia and Nicolletia, three previously unstudied genera, were found to contain thiophenes for the first time. Four derivatives, 5-(4-hydroxy-1-butenyl)-2,2′-bithiophene (1), 5-(4-acetoxy-1-butenyl)-2,2′-bithiophene (2), 5-(3-buten-1-ynyl)-2,2′-bithiophene (3) and 2,2′:5′,2″-terthiophene (4) were common constituents in most species of Adenophyllum, Chrysactinia, Dyssodia, Hymenatherum, Nicolletia and Porophyllum. One additional compound, 5-methyl-2,2′:5′,2″-terthiophene (5), was also present in extracts of Adenophyllum, Dyssodia and Hymenatherum, but was not detected in any other genus. Acetylenic thiophenes were not found in any of the 18 species of Pectis examined.