~t r a t e s~'~.~-~] .It therefore seemed an attractive reagent for the transformations 1 + 2.Hydrolysis of la-f catalyzed by porcine liver esterase proceeded in 0.1 M phosphate buffer suspensions. The initial saponification was indicated by the decrease of pH, which was maintained at pH 7 or 8 by addition of 1 N NaOH. Only one ester group is saponified. After acidification, 2a-f are recovered by extraction (EtzO). Diastereomeric purities (to check for possible isomerizations) were determined by GC after reacidification (MeOH/ HC(OMe)3). Enantiomeric ratios were determined on the crude products by 250 MHz 'H-NMR spectroscopy with ( + )-(R)-a-methylbenzylamine, independent of, usually unreliable, rotational data of derivatives (Table 1).The absolute configuration of 2aI7] was known, that of 2b was determined by selective base (NaH/dimethyl sulfoxide) isomerization to the known trans-enantiomer 4b, and that of 2c by conversion to the known['b1 lactones 3c/ ent-k. The absolute configurations of le, f were known from X-ray structure determinations ['].
I**] This work was supported by the Fonds der Chemischen lndustrie Angen. Chem. Inr. Ed. Engl. 25 (1986) No. 5 0 VCH Verlogsgesellschafr mbH. 0-6940 Weinheim. 1986 0570-0833/86/0505-0463 $ 02.50/0 [lo] The d ' configurated Cp2Zr-C=C-R subunit in the bonding situation found here is isolobal to an ally1 radical. Therefore, there is a formal analogy between 5 and delocalized (single minimum) Cope systems; a) W. von E. Doering, C . A. Troise, 3. Am. Chew. Sor. 107 (1985) 5739, and Angew. Chem. Int. Ed. Engl. 25 11986) No. 5 0 V C H Verlagsgesellschaji mbH. 0.6940 Weinheim. 1986 0570-0833/86/0505-0464 . % 02.50/0 references cited therein; b) R. Hoffmann, W: D. Stohrer, ibid. 93 (1971) 6941; M.
Fruchtkorper zeigen beim Betiipfeln rnit waBriger FeC13-Lasung121 eine intensiv blauviolette Farbreaktion, die uns veranlaBte, die dafiir maBgeblichen Substanzen zu untersuchen.Nach Extraktion der frischen Pilzel3I rnit Methanol, Eindampfen der Liisung und Verteilen des Riickstandes zwischen Wasser und Essigester verbleiben die FeCl,-positiven Verbindungen in der waBrigen Phase. Durch wiederhoke Gelchromatographie an verschiedenen Trennmedien konnen zwei Verbindungen rein erhalten werden, welche die Farbreaktion bewirken.Die in geringeren Anteilen (0.01-0.02%) vorhandene Substanz, Fp= 104-106"C, envies sich als identisch rnit N'-Hydroxy-N,N-dimethylhamstoff 1I4I, einer bisher in der Natur nicht gefundenen Verbindung. den DNA-Stoffwechsel eingreifen["I, ist vor dem GenuB des WeiBen Raslings zu warnen. 1 kg Pilze enthalten immerhin
I Diese Arbeit wurde vom Fonds der Chemischen lndustrie gefordert 456 0 V C H Verlagsgesell.whafi mbH. 0-6940 Weinheim. 1986 0044-8249/86/0505-0456 0 02.50/0 Angew. Chem. 98 (1986) Nr. 5 Soc. 93 (1971) 7201; c) Versuche zur experimentellen Realisierung bei rein organischen Systemen siehe z. B.: C. Schnieders, H.4. Altenbach. Engl. 20 (1981) 93; d) siehe auch: D. Cremer, E. Kraka. 1. Am. Chern. Soc. 107 (1985) 3800; D. B. Brown: Mixed-Valence Compounds. D. Reidel. Dordrecht 1980. Angew. Chem. 98 (1986) Nr. 5 0 V C H Verlagsgesellschaff mbH. 0-6940 Weinheim. 1986 0044-8249/86/0505-0457 S 02.50/0
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