The yellow pigments of <i>Beauveria</i> species. Structures of tenellin and bassianin

Abstract

Tenellin and bassianin are deduced from chemical and spectroscopic evidence to be the 3-[(E,E)-4,6-dimethylocta-2,4-dienoyl] and 3-[(E,E,E)-6,8-dimethyldeca-2,4,6-trienoyl] derivatives of 1,4-dihydroxy-5-(p-hydroxyphenyl)-2(1H)-pyridone. Spin–spin coupling information in the 1 H and 13 C nuclear magnetic resonance spectra after biosynthetic enrichment of tenellin with 13 C and 15 N isotopes was a valuable aid in elucidating the structure.