On the structure of fistulosin

We describe our investigation into the purported structure of the Welsh onion metabolite "fistulosin".This compound was assigned as 2-octadecyl-3-hydroxyindole, which might also exist as 2-octadecylindoxyl.Our results show that the corresponding 2-octadecyl-1-(phenylsulfonyl)indoxyl, which we synthesized from 1-(phenylsulfonyl)indole, undergoes facile conversion to alkyl 2-(1-oxononadecyl)aminobenzoate, which supports the work of Sderberg in that fistulosin is actually 2-(1-oxooctadecyl)aminobenzoic acid.