Cycloechinulin, a Trp-Ala-derived alkaloid from the fungus Aspergillus ochraceus

The structure of the Trp-Ala-derived, non-basic alkaloid cycloechinulin from the mycelial mat of the fungus Aspergillus ochraceus is described; systematic name: (3S)-2,3,8,9-tetrahydro-11-methoxy-3,8,8-trimethylpyrazino[1',2' :1,2]azocino-[5,4-b]indole-1,4-dione-methanol (4/1), C20H21N3O3.0.25-CH4O. There are four independent molecules plus one methanol molecule in the asymmetric unit. The conformations of molecules 1-3 are almost identical, while molecule 4 shows a different conformation in the fused 8-6 ring moiety.