Clitocybe acromelalga Acromelic acids

A number of kainoids have been isolated from the poisonous Japanese mushroom, Clitocybe acromelalga. Acromelic acid A 5 and acromelic acid B 6 were isolated from this source by Shirahama and co-workers6 in 1983, their structures being confirmed from total syntheses by Takano et al.7,8 and semisynthetic approaches by Shirahama.9-11 More recently, an additional three acromelates have been isolated acromelic acids C... 

Alkaloids derived from glutamic acid, other than y-aminobutyric acid (GABA), include kainic acid isolated from Digenea simplex, domoic acid isolated from Chondria armata, acromelic acids isolated from Clitocybe acromelalga, ibotenic acid isolated from Amanita strobiliformis Amanita pantherina), and tricholomic acid isolated from Tricholoma musucaria, and are described in this chapter. 

Structurally rather complicated target molecules can be synthesized with the aid of thi-olate 1,6-addition reactions to acceptor-substituted dienes as well. For example, a richly functionalized proline derivative with a 2,4-pentadienal side chain was converted into the corresponding 6-phenylthio-3-hexen-2-one derivative by 1,6-addition of phenylthiolate, treatment of the adduct with methyl lithium and oxidation (equation 46)127. The product was transformed into acromelic acid A, the toxic principle of clitocybe acromelalga ichimura. Similarly, the 1,6-addition reaction of cesium triphenylmethylthiolate to methyl 2,4-pentadienoate served for the construction of the disulfide bridge of the macrobicyclic antitumor depsipeptide FR-901,228128. 

From recent literature it must be coneluded that mushrooms of the genera Inocybe and Clitocybe contain toxic components that are different from muscarine. The severe symptoms reported of an Israeli ehild poisoned with /. tristis therefore departed from what is known of musearine poisoning (Amitai et al., 1982). The toxic activities of C. acromelalga and C. amoenolens, two Clitocybe species containing clitidine and acromelic acid A, respectively, were studied in rats (Fukuwatari et al., 2001 Saviuc et al., 2003). 

Hashimoto, K., Konno, K., Shirahama, H., and Matsumoto, T., Synthesis of acromelic acid B, a toxic principle of Clitocybe acromelalga, Chem. Lett., 1399, 1986. 

Yamano K, Shirahama H. New amino acids from Clitocybe acromelalga. Possible intermediates in the biogenesis of mushroom toxins, acromelic acids. Tetrahedron 1993 49(12) 2427-2436. 

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