Abstract: The minute amount of toxic principles, acromelic acids A (a. 110 pg) and B (ca. 40 gg), was isolated from a poisonous mushroom Clitocybe acromelalga. Spectral analyses and biogenetic consideration led to the structures 1 and 2 for acromelic acids A and B, respectively. The syntheses of 1 and 2 starting from La-kainic acid 3 established the proposed structures. Both amino acids show extremely potent neuroexcitatory action.
