Stoffwechselprodukte von Mikroorganismen. 253. Mitteilung. Hormaomycin,ein neues Peptid-lacton mit morphogener Aktivität auf Streptomyceten

Hormaomycin, a Novel Peptide Lactone with Morphogenetic Activity on Streptomyces A culture identified as Streptomyces griseoflavus (strain W-384) has been found to produce a novel peptide-lactone antibiotic designated hormaomycin ( 6 ). The empirical molecular formula of the compound is established to be C₅₅H₆₉ClN₁₀O₁₄. The constituent amino acids of the antibiotic are suggested to be allothreonine ( 1 ; 1), isoleucine ( 2 ; 1), 3-methyl-phenylalanine ( 3 ; 2), and, for the first time identified from a natural source, 4-[(Z)-prop-1-enyl]-proline ( 4 ; 1) and 3-(2-nitrocyclopropyl)-alanine ( 5 ; 2). The amino acids were delivered by acidic hydrolysis and assigned by high-resolution- GC/MS analysis (after transformation to derivatives) in combination with extended 2D-NMR experiments of the antibiotic itself. From the latter, it became plausible that the N-terminus of the peptide chain is acylated by a Cl-containing derivative of 1H-pyrrol-2-carboxylic acid. Hormaomycin is active against some Gram-positive bacteria. In addition, the antibiotic exhibits potent aerial mycelium-inducing activity and effects the production of antibiotics.     

Stoffwechselprodukte von Mikroorganismen. 250. Mitteilung. Maduraferrin,ein neuartiger Siderophor aus Actinomadura madurae

Maduraferrin, a Novel Siderophore from Actinomadura madurae From a strain of Actinomadura madurae, a new siderophore was isolated. Maduraferrin is the Fe complex of an oligopeptide composed of salicylic acid, β-alanine, glycine, L -serine, N^δ-hydroxy-N^α-methyl-L -ornithine, and L -hexahydropyridazine-3-carboxylic acid. The complexing centers are a salicylamide moiety, a hydroxamic-acid group and an acid hydrazide group.     

Stoffwechselprodukte von Mikroorganismen. 237. Mitteilung. (2S, 3R, 4R, 6R)-2,3,4-Trihydroxy-6-methylcyclohexanon aus zwei Actinomyceten-Stämmen

(2S, 3R, 4R, 6R)-2,3,4-Trihydroxy-6-methylcyclohexanone from Two Strains of Actinomycetes A tetrazolium-blue positive compound was isolated from two strains of acinomycetes. Its constitution and relative configuration 1 were determined by spectroscopic methods, and the absolute configuration by degradation to (+)-(R)-methylsuccinic acid.     

Stoffwechselprodukte von Mikroorganismen. 190. Mitteilung. Über das 4-Oxo-homotyrosin,ein Abbauprodukt des Echinocandins B

D , L -4-Oxo-homotyrosine was synthesized by the acetylaminomalonic ester pathway. The optical resolution was carried out by means of the enzyme acylase I. The L -configuration of the enzymatically produced amino acid was confirmed by degradation to L -aspartic acid. 4-Oxo-homotyrosine obtained by degradation of the polypeptide antibiotic echinocandine B has D -configuration, but his optical purity is low. A hypothetical explanation for its formation from the (2 S, 3 S, 4 S)-3,4-dihydroxyhomotyrosine residue of echinocandine B is proposed.     

Stoffwechselprodukte von Mikroorganismen 198. Mitteilung Die Eurekansäure,ein Abbauprodukt von Flambamycin und Avilamycin: Konfigurationsbestimmung durch Röntgenstrukturanalyse und Abbau

Eurekanic Acid, a Degradation Product of Flambamycin and Avilamycin: Determination of the Configuration by X-Ray Structural Analysis and Degradation The relative configuration of methyl O-acetyleurekanate (6) , obtained by mild methanolysis of avilamycin A (2) and subsequent acetylation, was determined by an X-ray structural investigation. Methyl dihydroeurekanate (7) , similarly obtained from avilamycin C (3) and from reduced avilamycin A methyl ether, was degraded to L-threonolactone (14) which allowed to determine the chirality of eurekanic acid (4).     

Enantiospecific synthesis of (6R,7S,8aR)-dihydroxyindolizidine and (6R,7R,8S,8aR)-trihydroxyindolizidine from D-glucose.

Enantiospecific syntheses of (6R,7S,8aR)-dihydroxyindolizidine (1) and (6R,7R,8S,8aR)-trihydroxyindolizidine (2) from readily available methyl 2-azido-4,6-O-benzylidene-2-deoxy-α-D-altropyranoside (5) are described.     

N(a)-Demethylseredamin,ein neues Alkaloid aus Rauwolfia sumatrana; absolute Konfiguration von Seredamin. 140. Mitteilung über Alkaloide

From Rauwolfia sumatrana Jack (Apocynaceae) the two new indole alkaloids serpentinine and N_(a)-demethylseredamine were isolated. By chemical and spectroscopic evidence and by correlation experiments the latter was shown to have structure 2 . the exact position of the aromatic methoxyl group was established by an investigation of the brominated derivative 12 . The aromatic ORD. Cotton effect of N_(a)-acetyl-N_(a)-demethyl-seredamine ( 5 ) and its O-acetyl derivative 4 as well as the ketone Cotton effect of purpeline ( 9 ) suggest that all the alkaloids of the seredamine group have the same absolute stereochemistry as ajmaline ( 1 ). This was confirmed by a direct chemical correlation of seredamine ( 7 ) with ajmaline.     

Stoffwechselprodukte von Mikroorganismen. 101. Mitteilung. Synthese der trans-5-Hydroxy-3-methylpenten-(2)-säure (trans-Δ2-Anhydromevalonsäure)

trans-Δ²-Anhydromevalonic acid (XVII) was prepared by a Wittig reaction, starting from (4-tetrahydro-2-pyranyloxy)-2-butanone. On the other hand, the corresponding 4-acetoxy-2-butanone gave, under similar conditions, the cyclohexene derivative V, explainable by a twofold Michael addition of the Wittig reagent to methyl vinyl ketone, followed by an intramolecular alcol condensation.     

Isolation and Characterisation of (5R, 6S,5′R,8′R)- and (5R,6S,5′R,8′S)-Luteochrome from Brazilian Sweet Potatoes (Ipomoea batatas LAM.)

Luteochrome isolated from the tubers of a white-fleshed variety of sweet potato (Ipomoea batatas LAM .) has been shown by HPLC, ¹H-NMR and CD spectra to consist of a mixture of (5R,6S,5′R,8′R)- and (5R,6S,5′R,8′S)- 5,6:5′,8′-diepoxy-5,6,5′,8′-tetrahydro-β,β-carotene ( 1 and 2 , resp.). Therefore, its precursor is (5R,6S,5′R,6′S)-5,6:5′,6′-diepoxy-5,6,5′,6′-tetrahydro-β,β-carotene ( 4 ). This is the first identification of luteochrome as a naturally occurring carotenoid and, at the same time, gives the first clue to the as yet unknown chirality of the widespread β,β-carotene diepoxide. These facts demonstrate that the enzymic epoxidation of the β-end group occurs from the α-side, irrespective of the presence of OH groups on the ring.     

Total synthesis of (4R,5S,6E,14S)- and (4R,5S,6E,14R)-cystothiazoles F

Total synthesis of (4R,5S,6E,14S)- and (4R,5S,6E,14R)-cystothiazoles F 3 was achieved from the chiral bithiazole-type primary alcohols [(S)- and (R)-4-ethoxycarbonyl-2′-(1-hydroxymethylethyl)-2,4′-bithiazoles 8], which were obtained based on the enzymatic resolution of racemic alcohol 8 and its acetate 9. From a direct comparison by means of chiral HPLC between natural cystothiazole F 3 and synthetic compounds [(4R,5S,6E,14S)- and (4R,5S,6E,14R)-cystothiazoles 3], natural cystothiazole F 3 was found to be a 33:67 diastereomeric mixture [(4R,5S,6E,14S)-3:(4R,5S,6E,14R)-3 = 33:67].     

Inhaltsstoffe des Osmanthus-Absolues. 4. Mitteilung: Megastigma-5, 7 (E), 9-trien-4-on und Megastigma-5, 8 (E)-dien-4-on

Constituents of Osmanthus Absolute, 4th Communication. Megastigma-5, 7 (E), 9-triene-4-one and Megastigma-5, 8 (E)-diene-4-one In continuation of our communications on constituents of Osmanthus absolute, we now report on the occurrence of the two title compounds 1 and 2a in this natural substrate (0.01-0.02% each). Their structures were confirmed by synthesis starting from β-ionone via the common intermediate 4-oxo-β-ionol ( 9 ). Some further minor components bearing corresponding structural features are tabulated in view of possible biogenetic pathways leading to 1 or 2a , respectively. In order to clarify the olfactory behaviour, we also synthesized some analogous derivatives in the irone series, these substances being not yet found in nature.     

Heterotricyclodecane XX (+)-(1S, 3S, 6S, 8S)- und (−)-(1R, 3R, 6R, 8R)-2, 7-Dioxa-twista-4,9-dien

(+)-(1S, 3S, 6S, 8S)- and (?)-(1R, 3R, 6R, 8R)-2,7-dioxa-twista-4,9-diene. A synthesis and the determination of the sense of chirality of (+)-(1S, 3S, 6S, 8S)- and (?)-(1R, 3R, 6R, 8R)-2,7-dioxa-twista-4,9-diene ((+)- 5 and (?)- 5 , respectively) is described.     

Synthesis of (5R,8S,10R)-6-(Allyloxy)- and (5R,8S,10R)-6-(Propyloxy)ergolines from the 6-Methyl Precursors

Novel (5R,8S,10R)-6-(allyloxy)- and (5R,8S,10R)-6-(propyloxy)ergolines have been synthesized by use of a Meisenheimer [2,3]-sigmatropic rearrangement of a (5R,8S,10R)-6-allyl-ergoline N⁶-oxide as key step.     

Über Pterinchemie. 77. Mitteilung)Das (6R,S)-5-Formyl-6-methyl-5,6,7,8-tetrahydropterin: Synthese,chemische und physikalisch-chemische Eigenschaften

(6R,S)-5-Formyl-6-methyl-5,6,7,8-tetrahydropterine: Synthesis, Chemical and Physico-chemical Properties (6R, S)-5-Formyl-6-methyl-5,6,7,8-tetrahydropterine ( III ), a model substance for the biologically important 6-substituted 5-formyl-5,6,7,8-tetrahydropterines, was obtained for the first time by formylation of the corresponding tetrahydropterine with formic acid. Compound III , analogously to the other known 5-acyltetrahydropterines, exists in solution (except in DMSO) as a mixture of two rotamers IIIa and IIIb . The two H-C(7) in III have the same chemical shift and the same coupling constant to H-C(6), giving rise to a A,A',X,C-system. Conformational analysis of III , based on its ¹H-NMR,-spectrum, shows that the methyl group is pseudo-axial and the formyl group pseudo-equatorial. Moreover, the H(X)-C(6) bond lies nearly in the plane bisecting the C(6)-C(7)-H(A), C(6)-C(7)-H(A') dihedral angle; the C(6) and C(7) lie outside the N(5)-C(4a)-C(8a) plane and the tetrahydropyrazine cycle must be extremely strained, according to Dreiding models.