1685 cm-1, Amax. (EtOH) < 220 and 260 nm (slight inflection, E ca. 1000) ; for n.m.r. and mass spectral data see Discussion section; m / e 260-1166 ( M -S,, C&16N@3 requires 260.1161) and 91.0548 (C,H, requires 91.0548) (Found: C, * Partially racemized didethio-products were isolated in some runs. The cis t-butyl ethers derived from them displayed low positive optical rotations. t trans-Didethiohyalodendrin t-butyl ether, a minor product in some runs, was readily separated by chromatography. ' + Added in proof-The circular dichroism curve of hyalodendrin was kindly determined by Dr. J. A. Verpoorte and Dr. A. Taylor: c.d. (c 0.376 in MeOH, 1 min cell) 234 nm (A c 22.5), 252 (0), 264 (-8.36), and 310 (0). The absolute configurationof the bridged dioxopiperazine system t h w corresponds to that of chaetocin and verticillin A, and is antipodal to that of gliotoxin, the sporidesmins, and the aranotins.G. M. Strunz and M. Kakushima, unpublished data.

Spectroscopic studies and chemical correlation with hyalodendrin show that a new metabolite of Hynlodetidrot~ sp. is bisdethiodi(methylthio)hyalodendrin (3-benzyl-6 hydroxymethyl-l,4-dimethyl-2,sdioxo-3,6-di(methy1 thi0)piperazine).Les t t i~d e s spectroscopiques et une correlation chinlique avec I'hyalodendrine dkmontrent q u ' i~n mttabolite nouveau d'une esptce d'Hynlorlet~rl,oti est la bisdethiodi(mtthylthio)hyalodendrine (3-benzyl-6-hydroxymtthyl-l,4-dim~thyl-2,5-dioxo-3,6-di(m~thylthio) piperazine).Can. J. Chem., 52,325 (1974) A recent addition to the group of biologically gens give rise to multiplets at 6 7.12 (2H) and active epidithiodiketopiperazine fungal metab-7.26 p.p.m. (3H). A n AB quartet centered at 6 olites (1) is hyalodendrin (I),' produced by a 3.44 (2H, J = 14 Hz) represents the benzylic Hyalodendron sp. (2, 3). We report here the protons, and demonstrates the tetrasubstituted isolation and identification of a new, related character of the neighboring carbon atom. metabolite, bisdethiodi(methylthio)hyalodendl.in Coupling with the hydroxyl proton ( J = 6 and (2), produced in culture by this organism.7 Hz), as well as geminal coupling ( J = 12 Hz) is observed for the two hydrogens attached to C y 3 0 the primary carbinol center, and they appear asdoublets The hydroxyl of doublets proton at 6 is 3.14 manifested and 3.85 p.p.m. as a broadened unsymmetrical "triplet" a t 6 1.43; as o 2~~expected, irradiation at 314 Hz collapsed the 1 signal for the carbinol protons to a n AB quartet ( J = 12 Hz). Singlets (3H each) a t 6 3.03 and and -CH20H functionality, as well as the two Comparison of the spectroscopic charac-meth~lthio groups was confirmed by the mass teristics of the new metabolite, C,6H22N203S2, spectral fragmentation Pattern (see Ex~erimen-with those of hyalodendrin (I), indicated that tal section). Ions a t n.l/e 132 and 72 can be the former compound is also an N-methylserine-rationalized in terms of the cleavages indicated N-methylphenylalanine diketopiperazine, bear-in Scheme 1 (c.f. ref. 8). ing substitution at the 3 and 6 positions.Correlation with hyalodendrin corroborated 2 displayed i.r. absorption indicative of amide the formulation 2. Thus, treatment of the former and hydroxyl functionality, as well as peaks with sodium borohydride in the presence of attributable to a monosubstituted phenyl group methyl iodide and ~~r i d i n e (5) at 0" gave a (see Experimental section) (2, 4). In the n.m.r. di(methylthi0) ether, identical in all respects spectrum (220 MHZ, CDCI,), the phenyl hydro-with the metabolite 2. Sodium borohydride For personal use only.

Spectroscopic and chemical studies, including correlation with pestalotin (LL-P880a), show that a new metabolite isolated from cultures of an unidentified fungus is 5-hydroxy-3-methoxy-6-0x0-2-decenoic acid 6-lactone.Les Ctudes spectroscopiques et chimiques, contenant une correlation avec la pestalotine (LL-P880a), dCmontrent qu'un nouveau mitabolite, isolC de cultures d'un champignon nonidentifiC est le &-lactone de I'acide 5-hydroxy-3-mCthoxy-6-0x0-2-decenoique.Can. J. Chem., 52,825 (1974) Tamura and co-workers (1) recently described the isolation and structure elucidation of pestalotin (I), a new 5,6-dihydro-2-pyrone displaying gibberellin synergism, produced by the phytopathogenic fungus Pestalotia cryptomeriaecola. The same compound, designated LL-P880a, was isolated from an unidentified Penicillium species by Ellestad et al. (2), and these workers further demonstrated the configuration at C-6 and -1' to be S. We report here on the closely related substance 2 isolated, together with 1, from culture filtrates of an unidentified fungus. ' The new metabolite, C , ,Hl,O4, displayed i.r. absorption (CCI,) at 1728 and 1630 cm-' and U.V. I , , , 233 nm ( E 10 600). These features, together with n.m.r. signals corresponding to an olefinic hydrogen at 6 5.17 (lH, s) and methyl ether protons at 6 3.78 (3H, s), suggested a 4-methoxy-5,6-dihydro-2-pyrone (1-5). In the mass spectrum, the base peak at m/e 127 (M' -85) and an ion at mle 85 (C5H90+) result from cleavage of an n-pentanoyl chain; further evidence for this structural element was found in the i.r. absorption at 1740 crn-' (CO), and the appropriate methyl and methylene signals in the 220 MHz n.m.r. spectrum. A signal at 6 4.80 (IH, dd, J,, + J,, -14 Hz) was attributed to the C-6 hydrogen by virtue of its low-field IThe fact that the organism could not be induced to sporulate has rendered identification impossible so far but suggests that it is neither a Pestalotia nor a Penicillium species. We thank Dr. L. P. Magasi of this laboratory for providing the culture, IT-6, and for discussions relating to its identification. position and m~ltiplicity,~ and this assignment also defines the location of the side chain. These data are readily interpreted in terms of structure 2. C H 3 y 3Conversion of 2 into the corresponding pyrone, 3, corroborated the assigned formulation. This transformation was effected directly (without isolation of a bromine-containing intermediate) by treatment of 2 with N-bromosuccinimide. To facilitate comparison with a simple model, 4-methoxy-6-methyl-2-pyrone, the carbonyl group in the side chain of 3 was reduced with sodium borohydride. The spectroscopic characteristics of the product, 4, indeed showed a gratifying similarity to those of the model a-pyrone. Thus, 4 displayed (besides broad hydroxyl absorption at 3390 cm-') i.r. peaks (CC1,) at 1737, 1650, and 1242 cm-' ; and U.V. I , , , (EtOH) 211 ( E 7420) and 282 nm 'The signal for the C-6 proton changed in a manner consistent with the assigned structure on reduction of the ketone func...

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