Isolation, Structural Determination and Synthesis of Biologically Active Substances Produced by Fungi

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1. Dokusasako (a poisonous mushroom)-neuroexcitatory amino acids and their chemical development. Clitidine, clithioneine, acromelic acids A and B, and 4-amino quinolinic acid were isolated from the mushroom but other new poisonous principles must be contained in this fungus. We have tried to isolate them and a new amino acid and a new fraction acting as a neuroexcitant have been found. The structure of the new amino acid was deduced from spectroscopic data and its biogenesis and confirmed by the synthesis. 4-(2-Carboxypyrrolyl)-3-alanine was synthesized from 4-formylpyrrol-2- carboxylic acid ester and found to be identical with the new natural amino acid. The synthetic compound was optically resolved with a chiral plate and their CD were measured. Rf value on the chiral plate and CD sign of the natural product was coincided with synthetic L-acid. A new neuroexcitatory fraction was also found and undergoing its structural studies now. As the acromelic acids were recognized as a tool of … More neuropharmacological studies, so many requests for supplying the reagents were received. Design of the reagent which is so active as the acromelic acids and more easily accessible and development of the synthetic method of such reagents have been studied. The highly stereoselective construction of pyrrolidine ring with C4 substituent by a photo-induced Diels-Alder reaction was successfully carried out to give a new methoxyphenyl kainoid which was stronger neuroexcitant than acromelic acid itself. Furthermore, stereoselective substitution reaction of tosylate group on the C4 position of proline was smoothly performed and the easier general procedure for various kainoid was established. 2. Ohwaraitake (a poisonous mushroom)-a neuroexcitant and stereochemistry of gymnopilin. A previously isolated bitter principle gymnopilin A10 and/or All is probably new neuroexcitants. We sought for neuroexcitatory constituents in this toadstool testing depolarizing activity of a rat spinal cord and reached to the above conclusion. It is very rare and interesting that such a chain origoisoprenoid alcohol shows neuroexcitatory activity. Stereochemistry 6 or 7 quarternary carbon or the gymnopilin was under investigation by synthesis. 3. Hanaiguchi (an eddible mushroom)-a lipid peroxidation inhibitor. The title compound was isolated from the mushroom and its structure was determined as 1-acetoxy-2-geranylgeranyl-4, 6-dihydroxybenzene by spectral studies. Less