 This led to the suggestion that alizarin was a derivative of naphthalene, a C10 hydrocarbon, although Schunck pointed out that this did not explain the reactions of alizarin.He was vindicated when Graebe and Liebermann (1868) distilled alizarin with zinc dust to give anthracene, a C14 hydrocarbon, and subsequently (1869) synthesised alizarin from anthraquinone.Schunck showed that alizarin was not the major colour precursor component of fresh madder root, but it was a yellow, bitter, water-soluble component, which he called rubian.