Studies on fungal products. Part XXXIII. Structures of new indoloditerpenes, possible biosynthetic precursors of the tremorgenic mycotoxins, penitrems, from Penicillium crustosum.

Along with the tremorgenic mycotoxins, penitrems A (3), B (4), D (6), E (7), and F (8), the minor metabolites 1 and 2 were isolated from the mycelia of Penicillium crustosum THOM, which was found contaminating bread intended for school lunches in Tokyo city. The structures of 1 and 2 were determined on the basis of spectroscopic and chemical investigations. these compounds (1 and 2) might be biosynthetic precursors of penitrems.