The Chemical Constitution of Rubrofusarin, a Pigment from Fusarium graminearum

Abstract

The zinc dust distillates of rubrofusarin, nor-rubrofusarin, and methylxanthones (1-, 2-, 3-, and 4-methylxanthones and l-methyl-3,6,8-trihydroxyxanthone) have been investigated.

On zinc dust distillation, rubrofusarin and nor-rubrofusarin afforded naphthalene and anthracene in low yield, but did not give methylxanthene expected from the formerly proposed structure of methylxanthone.

Methylxanthones are considered to give the corresponding methylxanthenes in the distillates; and it is true for 2-, 3-, and 4-methylxanthones. However, in the 1-methyl derivatives the main product was not 1-methylxanthene but anthracene. It has been found also that on that condition all methylxanthones examined did not give naphthalene that was a main zinc dust distillate in rubrofusarin.

Thus, we conclude that it is appropriate to assign the structure of naphthalene derivative for rubrofusarin instead of the so far proposed methylxanthone structure.