New amino acids, L-3-(2-carboxypyrrolyl)-alanine (D and L-3-(2-oxo-5-pyridyl)-alanine (L)# were isolatedfrom m e and their structtues were deduced by spectral data and biogenesis and coyirmed by syntheses. Stisolobic acid (5) was also found in thisjkngus. Clitocybe acromelalga (Japanese name ; dokusasako) is a poisonous mushroom found only in Japan. The accidental ingestion of this mushroom causes a violent pain and a marked reddish edema in hand and foot after several days and it continues for about a month. These characteristic physiological properties prompted us to study the toxin of the fungus. We have already isolated several principles so far. They are clitidine,l) clitioneine?) 4-amino quinolinic acidf) and acromelic acids A (3) and B 0.4) Further and continuous investigation led to the isolation of new amino acids 1,s) 2 and stizolobic acid a.6) In this paper, we wish to describe the isolation of 1.2 and 5, the determination of structures and syntheses of 1 and 2 which are biosynthetically close to acromelic acids A and B, probably.4s 7)The water extracts of frozen fruit bodies were diluted by acetone to give precipitates which were dialysed against water. Dialyzate was fractionated by chromatography and paper electrophoresis monitoring the lethal effect in mice. Amino acids, 1 and 2, were isolated from a poisonous fraction. A fraction showed depolarizing activity in the preparation of new born rat spinal cord. The active compound of this fraction was found to be stizolobic acid a whose uniqe activity on neurons of vertebrate and invertebrate was recently reported.9The weakly acidic property of 1 was obvious from its behavior on ion-exchange column chromatography and paper electrophoresis. The molecular formula, C8HloO4N2, was deduced from the [M+I-Ij+ peak of HR-FAB mass spectrum. IH-NMR and *%XVMR spectra of 1 in D20 indicated the presence of two aromatic protons [6 6.48, IH, brs and 6.80, lH, brs], four carbons of aromatic ring [6 115.9 (d), 118.3 (s), 121.6 (s) and 123.7 (d)], an alanine side chain [6 2.89, lH, dd, J=5.1, 14.5; 2.98, lH, dd, J=7.2, 14.5; 3.78, lH, dd, J=5.1, 7.2. 6 28.6 (t), 56.4 (d) and 176.5 (s)] and a carboxyl group on the aromatic ring [6 163.8 (s)]. The chemical shifts of two singlet peaks due to aromatic protons and those of four signals due to aromatic carbonsimplied a 2,~~su~dm~ pyrroge structute. Fyrrole and furan exhibit fluky signals of their protons aud carbons at quite different chemical shifts. The W spectrum also supported above impkation.On the other hand, t ELNMR spectrum of 2 in J&,0 showed also the presence of alanine side chain p 2.68, lH, dd, 52'7.0, 14.5; 2.80, 1% dd, Jt4.9, 14.5; 3.41, 1H, dd, J-Q-9, 7.03 and three aromatic proton signals [S 6.39, IH, d, J=S.S, 7.36, lH, brd, J28.5; 7.64, lH, brs]. The W spectra of 2 exhibited two maxima around at 225 and 300 urn which were very similar to those of S-methyl-2-pyridone. Furthermore, the coupling constants and chemical shifts of three aromatic protons in the 1%NMR spectrum suggested 5 substitute-2-p~doue structure.These abservation and biogenetic conside~tion implied strnctums 1 and 2 for the newly isolated amino acids (Scheme 1). The biogenesis was previously f&u& for acromehc acids aud formation of 1 and 2 could be involved in this scheme. Due to a small amount of the sample the structures 1 and 2 were coufiied by syntheses.The synthesis of 1 was pe~~~~ starting from Poole-2-car~Kylic acid 2 whose methyl ester was treated with Viismeier reagent to afford an aldehyde & The aldehyde & was converted to au a~-unsaturated ester 2 with Homer-Emmons reagent @I after protection of the imino group. Hy~genation of the double bond of 2 was carried out with NaBFQ assisted by NiC12-6H2O.lo) Removal of protective gr&rpslt) furnished racemic amino acid 1 (Scheme 2).Next, the synthesis of 2 was achieved starting from 6-hydroxy nicotinic acid. Reduction of ester 13 with DIBAH followed by oxidation with manganese dioxide gave an aldehyde fi which was converted to n in the similar way to those employed in the synthesis of 1. Removal of protective groups afforded a racemic amino acid 2 (Scheme 3).Synthetic 1 and 2 underwent optical resolution employing TLC with chiral plate u: Rf=O.56 and 0.65,2: Rf=O.42 and 0.35 MeOH/H~O/MeCN=1/1/4).12) CD spectra of both 1 and 2 showed (+) Cotton effect for the faster moving compounds and (-) for the slower moving ones. Since L-amino acid exhibits usually (+) Cotton effect in CD spectrum,l3) the compounds with Rf 0.65 for 1 and Rf 0.42 for 2 should be L-isomer. The NMR and CD spectra, HPLC retention time and TLC (chiral plate) Rf value of the synthetic L-amino acids were completely coincident with those of natural products.In the biogenesis of acromelic acids, the fission of DOPA at an outside and an inside of diol (a and b respectively) was assumed so far (Scheme 1). In this study the fission at another outside of diol (c) was also concerned. Acromelic acid C14) is probably derived from 2 via similar route to the biogenesis of the acromelic acids A and B. But we found that acromelic acid B underwent decarboxylation under one year preservation in a refrigerator. The pyrrolyl alanine 1 may be derived from pyridone 2 or the pyridone related to stizolobic acid. Thus, it can be assumed that all compounds of acromelic acid family obtained from this mushroom are biosynthetically derived from DOPA. The biological activities of 1 and 2 are now under investigation.