Acromelic acid isolation

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. 

Acromelic acid A (260), isolated from Clitocybe acromelaga, displays the most potent polarizing effect of aU known kainoids. By application of the same intramolecular aziridine thermolysis route described above, Takano et al. (80) outlined a concise entry into such compounds. Thermolysis of the chiral aziridine 261, derived from (5)-0-benzylglycidol in 1,2-dichlorobenzene at 200 °C, furnished the single reaction product 262 in 73% yield. The complete control over the... 

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... 

The acromelic acid A 5 obtained had physical properties (including specific rotation) identical to natural material, the overall yield from tran.s-4-hydroxy-L-proline 34 being 9%. Initial experiments led to the isolation of 60 mg of purified 5 although this synthetic route would be amenable to preparation on a significantly larger scale. 

Ishida, M., and Shinozaki, H. 1988. Acromelic acid is a much more potent excitant than kainic acid or domoic acid in the isolated rat spinal cord. Brain Res 474, 386-389. 

The toxic symptoms of this poisonous mushroom are extremely unpleasant. Discomfort starts several hours after a meal, followed by severe pain at the extremities, which occurs after several days following digestion. This pain continues for more than a month (sometimes for three months). Whether the new alkaloids, acromelic acids A and B, which were isolated and characterized, are the main toxic compounds is uncertain [1].These alkaloids share the same pyrrolidine ring and the side chains at the C-2 and C-3 positions with kainic acid. In addition, kainic acid was transformed into acromelic acid A by changing the side chain at the C-4 position without changing the stereochemistry at C-4. Consequently, the absolute stereochemistry of acromelic acid was concluded to be the same as that of kainic acid [2]. 

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