Novoamauromine and ent-Cycloechinulin: two new diketopiperazine derivatives from Aspergillus novofumigatus.

Two new diketopiperazine metabolites, novoamauromine (1) and ent-cycloechinulin (2) have been isolated from Aspergillus novofumigatus CBS117520. The structures of 1 and 2 were established on the basis of spectroscopic and chemical investigation, including a detailed comparison of the spectroscopic and physico-chemical data of amauromine (3) and cycloechinulin (4).