Talaromycins C,D,E,and F

Four new spiroketal talaromycins have been isolated from T. stipitatus and, by equilibration with acid, have been structurally correlated with the previously identified talaromycins A and B.     

Simultaneous high-performance liquid chromatographic determination of altersolanol A, B, C, D, E and F

A high-performance liquid chromatographic model for the simultaneous determination of altersolanol A–F by using a reversed-phase column with an acetonitrile-water gradient elution system is described. The analysis can be completed within 13 min, the detection limits are 0.2–0.5 pmol per injection (5 μl) and the relative standard deviations are 0.90–1.34%. The method was applied satisfactorily to the determination of altersolanols in culture media of a strain of Alternaria solani without any prepurification.     

Triterpene glycosides ofCaltha polypetala glycosides A,B, D,E, and F

Five individual triterpene glycosides — A, B, D, E, and F — which are hederagen-in mono- and biosides, have been isolated from the roots ofCaltha polypetala (Great Marsh Marigold), familyRanunculaceae. Glycosides E and F proved to be new compounds for which, on the basis of the results of acid and alkaline hydrolyses, methylation, methanolysis, and physicochemical methods of investigation, the following structures are proposed: E — hederagenin 3-0-D-glucopyranoside, 28-O-L-rhamnopyranoside; and F — heteragenin 28-O-[O-L-rhamnopyranosyl-(1→ 6)-D-glucopyranoside].     

The structures of pukeleimides A,B, D,E, F,and G

Structures for pukeleimides A, B, D, E, F, and G, six novel pyrrolic compounds from a shallow-water variety of the marine blue-green alga bar|Lyngbya majuscula, are proposed from spectral data.     

Total synthesis of maremycins A,B, C1/C2, D1, and D2

The total synthesis of maremycins A, B, C₁/C₂, D₁, and D₂ is achieved starting from the natural amino acids l-isoleucine and S-methyl-l-cysteine, in which the total synthesis of maremycins B, C₁/C₂, and D₂ is accomplished for the first time. The synthesis features a position-selective intramolecular bromination process for the synthesis of key chiral building block, a Pd-catalyzed indole synthesis for the preparation of (2S,3S)-β-methyltryptophan and hydroxylation of oxindoles by molecular oxygen. In addition, the protocol for conversion of maremycins A and B to maremycins C and D was improved.     

Triterpene glycosides ofCaltha polypetala glycosides A, B, D, E, and F

Five individual triterpene glycosides — A, B, D, E, and F — which are hederagen-in mono- and biosides, have been isolated from the roots ofCaltha polypetala (Great Marsh Marigold), familyRanunculaceae. Glycosides E and F proved to be new compounds for which, on the basis of the results of acid and alkaline hydrolyses, methylation, methanolysis, and physicochemical methods of investigation, the following structures are proposed: E — hederagenin 3-0-D-glucopyranoside, 28-O-L-rhamnopyranoside; and F — heteragenin 28-O-[O-L-rhamnopyranosyl-(1 6)-D-glucopyranoside].I. G. Kutateladze Institute of Pharmacochemistry, Academy of Sciences of the Georgian SSR, Tbilisi. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 712–716, November–December, 1986.     

The sesquiterpene lactones from achillea fragrantissima,I. Achillolide A and B,two novel germacranolides

With the aid of one- and two-dimensional multipulse NMR techniques the structure of two novel sesquiterpene lactones from Achillea fragrantissima growing in Israel were elucidated and their conformational behaviour investigated. Although both compounds are closely related in their structures their CD spectra indicate that they belong to different enantiomeric series.     

Chaxines B, C, D, and E from the edible mushroom Agrocybe chaxingu

Four novel compounds, chaxines B (1), C (2), D (3), and E (4), were isolated from an edible mushroom Agrocybe chaxingu. The structures of 1-4 were determined by the interpretation of spectroscopic data. Compounds 1 and 2 suppressed the formation of osteoclast.     

A modular total synthesis of aculeatins A, B, E, F and 6-epi-aculeatins E, F

The total synthesis of aculeatins A, B, E and F confirming the assigned absolute configuration of recently isolated aculeatins E and F is documented. A convergent approach has been designed by the addition of both the terminal units (phenol and side chain) at an advanced stage. The central 1,3,5-triol unit with the requisite stereochemistry was prepared from the commercially available α-d-glucoheptonic-γ-lactone. Selective O-debenzylation during the hydrogenolysis of the diyne intermediate and the one pot phenolic oxidation with concomitant spiroketalization highlight the accomplished total syntheses.     

Medicinal flowers. XXI. Structures of perennisaponins A, B, C, D, E, and F, acylated oleanane-type triterpene oligoglycosides, from the flowers of Bellis perennis

Six new acylated oleanane-type triterpene oligoglycosides, perennisaponins A (1), B (2), C (3), D (4), E (5), and F (6), were isolated from the flowers of Bellis perennis (Daisy flower) together with 14 saponins, nine flavonoids, and two glycosides. The structures of 1-6 were elucidated on the basis of chemical and physicochemical evidence.     

Rastronole A,B, C,D, E,F, G und H; eine Gruppe multioxygenierter Diterpenbitterstoffe der ent-Kauran-Reihe aus Englerastrum scandens ALSTON

Rastronols A, B, C, D, E, F, G, and H, a group of multioxygenated bitter principles with ent-kaur-16-en-15-one structure from Englerastrum scandens ALSTON (Labiatae) We have isolated from the leaves of Englerastrum scandens from Kenya eight new, highly oxygenated ent-kaur-16-en-15-ones named rastronol A, B, C, D, E, F, G, and H, and determined their structures mainly by spectroscopic techniques as 1, 8, 14, 17, 20, 29, 39 , and 51 respectively.     

Ilwensisaponins A,B, C,and D: Triterpene Saponins from Scrophularia ilwensis

From the aerial parts of Scrophularia ilwensis, four new triterpene saponins, ilwensisaponins A–D ( 1 – 4 ) were isolated. The structures of the compounds were elucidated using chemical and spectral data as 13β, 28-epoxy-3-β-{{[β-D -glucopyranosyl-(1→2)]-[α-L -rhamnopyranosyl-(1→4)-β-D -glucopyranosyl-(1→3)]-β-D -fucopyranosyl}-oxy} olean-11-en-23-ol ( 1 ), 3-β-{{[β-D -glucopyranosyl-(1→2)]-[α-L -rhamnopyranosyl-(1→4)-β-D -glucopyranosyl-(1→3)]-β-D -fucopyranosyl}oxy}olena-11, 13(18)-diene-23, 28-diol ( 2 ), 3-β-{{[β-D -glucopyranosyl-(1→2)]-[α-L -rhamnopyranosyl-(1→4)-β-D glucopyranosyl-(1→3)]-β-D fucopyranosyl}oxy}-11α-methoxyolean- 12-ene-23, 28-diol (3) , and 3-β-{{[β-D -glucopyransoyl-(1→2)]-[α-L -rhamnopyranosyl-(1→4)-β-D -glucopyranosyl-(1→3)]-β-D -fucopyranosyl}oxy}olean-12-ene-11α,23,28-triol (4) .     

Novel Trinor-eremophilanes (Dendryphiellin B,C, and D), Eremophilanes (Dendryphiellin E,F, and G), and Branched C9-Carboxylic Acids (Dendryphiellic Acid A and B) from the Marine Deuteromycete Dendryphiella salina (SUTHERLAND) PUGHet NICOT

Further investigation of global extracts from cultures of the marine deuteromycete Dendryphiella salina leads to the isolation of three novel trinor-eremophilanes esterified by branched C₉-carboxylic acids, dendryphiellin B (= (+)-(1R*,2S*,7R*,8aR*)-1,2,6,7,8,8a-hexahydro-7-hydroxy-1,8a-dimethyl-6-oxonaphthalen-2-yl (6R*, 2E, 4E)-6-hydroxy-6-methylocta-2,4-dienoate; (+)- 2 ), dendryphiellin C (=(+)-(1R*, 2S*, 7R*, 8aR*)-1,2,6,7,8,8a-hexa-hydro-7-hydroxy-1,8a-dimethyl-6-oxonaphthalen-2-yl (6S, 2E, 4E)-6-methylocta-2,4-dienoate; (+)- 3 )), and dendryphiellin D (=(+)-(1R*, 2S*, 7R*, 8aR*)-1,2,6,7(8,8a-hexahydro-7-hydroxy-1,8a-dimethyl-6-oxonaphthalen-2-yl (6R*,2E,4E)-6-(hydroxymethyl)octa-2,4-dienoate; (+)- 4 ). An intact eremophilane, dendryphiellin E ( 5 ), and its ethanolysis product dendryphiellin F whose absolute configuration is represented by structural formula (+)- 6 are also isolated from the above extracts. Dendryphiellin E exists as an open form 5a in equilibrium with a closed form 5b . A similar equilibrium exists between the open form 8a and the closed form 8b of a non-esterified eremophilane, dendryphiellin G ( 8 ), which is isolated too from the above extracts and proves structurally related to the cyclic portion of 5 . Finally, the free, branched C₉-carboxylic acids dendryphiellic acid A ((+)- 9 ) and B ((+)- 10 ) which correspond to side chains of the above esterified terpenes are also isolated from the above extracts.     

Araguspongines B, C, D, E, F, G, H, and J, new vasodilative bis-1-oxaquinolizidine alkaloids from an okinawan marine sponge, Xestospongia sp

Nine new vasodilative alkaloids, araguspongines A, B (1), C (2), D (3), E (4), F (5), G (6), H (7), and J (8), were isolated from an Okinawan marine sponge, Xestospongia sp. On the basis of chemical and physicochemical evidence, the absolute stereostructures of araguspongines B, D, E, F, G, H, and J were determined respectively as 1, 3, 4, 5, 6, 7, 8, and the relative stereostructure of araguspongine C was determined as 2 having two 1-oxaquinolizidine moieties. Araguspongines B, D, and E each comprised a pair of the enantiomers, 1a and 1b, 3a and 3b, and 4a and 4b, respectively.