Talauxins: Hybrid Phenalenone Dimers from <i>Talaromyces stipitatus</i>
Nirmal Chaudhary, Andrew Crombie, Daniel Vuong, Ernest Lacey, Andrew M. Piggott, Peter Karuso
Abstract
Cultivation and extraction of the fungus Talaromyces stipitatus led to the isolation of five new oxyphenalenone–amino acid hybrids, which were named talauxins E, Q, V, L, and I based on the corresponding one-letter amino acid codes, along with their putative biosynthetic precursor, duclauxin. The rapid reaction of duclauxin with amino acids to produce talauxins was demonstrated in vitro and exploited to generate a small library of natural and unnatural talauxins. Talauxin V was shown to undergo spontaneous elimination of methyl acetate to yield the corresponding neoclauxin scaffold. This process was modeled using density functional theory calculations, revealing a dramatic change in conformation resulting from the syn elimination of methyl acetate.