Neoadenoloside A, a highly functionalized diterpene C-glycoside, from Isodon adenolomus

Neoadenoloside A (1), an unprecedented diterpene C-glycoside with a unique C(26) framework, along with lasiokaurin (3) were isolated from the leaves of Isodon adenolomus. The absolute configuration of 2, a derivative of 1, was determined by spectroscopic methods and single-crystal X-ray diffraction analysis.     

713A, a new metabolite isolated from a fungal strain 713

A new compound named 713A was isolated from the fermentation broth of a fungal strain 713. The structure of 713A was elucidated by spectroscopic methods. In the screening for interleukin-6 (IL-6) receptor antagonist, 713A exhibited inhibitory activity to the binding of IL-6 and IL-6 receptor with an IC50 value of 8.6 microM.     

A novel xanthone dimer derivative with antibacterial activity isolated from the bark of Garcinia mangostana

A novel xanthone dimer derivative, garmoxanthone (1), together with 10 known compounds (2–11), were isolated from bark of Garcinia mangostana. Their structures were established through spectroscopic methods. Garmoxanthone exhibited strong inhibitory activities against MRSA ATCC 43300 and MRSA CGMCC 1.12409 (with MIC values of both 3.9 μg/mL) and moderate activities against tested strains of Vibrio (with MIC values ranging from 15.6 to 31.2 μg/mL). Garmoxanthone is a unique xanthone dimer with linkage of a fused 5/6 ring system and its absolute configuration was elucidated on the basis of experimental and calculated electronic circular dichroism. Garmoxanthone exhibited strong antibacterial activity which partially validated the ethnobotanical use of G. mangostana in the treatment of infections.     

Abyssomicin E, a highly functionalized polycyclic metabolite from Streptomyces species

Abyssomicin E (1), a new polycyclic metabolite with a C19 skeleton, was isolated from Streptomyces sp. (HKI0381). Its chemical structure was determined by comprehensive NMR and MS spectroscopic analyses. For the first time in this recently discovered class of compounds, the absolute stereochemistry was directly established by subsequent single-crystal X-ray diffraction study using anomalous dispersion with copper radiation.     

Candibirin A,a furano­coumarin dimer isolated from Heracleum candicans Wall.

Candibirin A [systematic name: 9,9′‐(1,4‐dioxane‐2,5‐diyldi­methyl­ene­dioxy)­di(7H‐furo­[3,2‐g]­chromen‐7‐one)], a new furano­coumarin dimer, was isolated from Heracleum candicans Wall . ¹H NMR and MS spectra had indicated that the title compound was a dimer of heraclenin or heraclenol, but the linkage structure and its chirality were undetermined. The dioxane linkage, having the R,R configuration, has now been elucidated from di­methyl sulfoxide‐solvated crystals, C₃₂H₂₈O₁₀·2C₂H₆OS. Candibirin A is thus a dimerization product from heraclenin formed by reaction at the epoxy group. Di­methyl­form­amide‐solvated crystals, C₃₂H₂₈O₁₀·C₃H₇NO, adopt a different conformation, with a folded structure that differs from the extended structure in the dimethyl sulfoxide solvate. However, the puckering of the dioxane linker unit is very similar in the two conformers. This result shows that the rotation of the ether bonds, in the linker between the furano­coumarin and dioxane moieties, causes the conformational flexibility of (I).     

Boletunones A and B, highly functionalized novel sesquiterpenes from Boletus calopus

Highly functionalized novel sesquiterpenes, named boletunones A and B, were isolated from the methanolic extract of the fruiting body of the mushroom Boletus calopus. Their structures and relative stereochemistry were established by various spectral analyses. [structure: see text]     

Total synthesis of (+)-ampullicin and (+)-isoampullicin: two fungal metabolites with growth regulatory activity isolated from Ampulliferina sp. 27.

The total synthesis of the growth regulators (+)-ampullicin 1 and (+)-isoampullicin 2 from (R)-(-)-carvone 5 was accomplished by application of an 18-step sequence with 4.5% overall yield. The crucial step of the synthetic strategy lies on the internal displacement of tosylate 13 by means of the lactone enolate. In this way, access was opened to the tricyclic core present in these biologically active sesquiterpenic amides. A Horner-Emmons reaction between the carbaldehyde 16 and the phosphonate 22 led us to the stereoselective preparation of (+)-ampullicin 1. Standard transformation of 1 into the thermodynamically more stable geometric isomer (+)-isoampullicin 2 was trivial. The absolute configuration of both amides was established by X-ray analysis of a sample of synthetic (+)-isoampullicin 2.     

Secondary metabolites isolated from Piper chimonantifolium and their antifungal activity

In this study, the CH(2)Cl(2) extract from leaves of Piper chimonantifolium was subjected to several chromatographic separation procedures to afford one chromene (gaudichaudianic acid) as a major compound as well as two flavonoids (dihydrooroxylin and pinocembrin) and three steroids (sitosterol, sitosteryl palmitate and stigmasterol). The structures of all determined compounds were characterised by spectrometric analysis, mainly mass spectrometry and NMR, as well as their optical properties. This article describes the first phytochemical study of the leaves of P. chimonantifolium and an evaluation of the antifungal activity of its major compounds.     

Synthesis of cascadol,a highly branched functionalized polyether

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2394–2395, October, 1989.     

A new furanosteroid from Talaromyces sp. lgt-4, a fungal endophyte isolated from Tripterygium wilfordii

Wortmannolol (1), a new furanosteroid, along with five known compounds, wortmannolone (2), ergosterol (3), p-hydroxyphenyl ethanol (4), trans-6-dodecene (5), (2Z, 4E) -5-(8-hydroxy-1,5-dimethyl-3-oxo-6-oxabicyclo [3.2.1] octan-8-yl) -3-methylpenta-2,4-dienoic acid (6) were isolated from a fungal endophyte Talaromyces sp. lgt-4. Their structures were elucidated by IR, MS, 1D and 2D NMR spectra. Compound 1 show weak monoamine oxidase inhibitory activity.     

A highly selective tandem cross-coupling of gem-dihaloolefins for a modular, efficient synthesis of highly functionalized indoles

A highly efficient method of indole synthesis using gem-dihalovinylaniline substrates and an organoboron reagent was developed via a Pd-catalyzed tandem intramolecular amination and an intermolecular Suzuki coupling. Aryl, alkenyl, and alkyl boron reagents are all successfully employed, making for a versatile modular approach. The reaction tolerates a variety of substitution patterns on the aniline leading to indoles with group at C2-C7. The orthogonal approach of the sequential copper- and palladium-mediated synthesis of 1,2-diarylindoles exploited the wide availability of diverse organoboron reagents.     

Synthesis and characterization of a highly fluorescent benzofuran dimer derived from estradiol

Pd-catalyzed cyclization of a fluorescent dimer in which two cores of the potent estrogenic estradiol are bridged by the 1,4-diethynil benzene moiety led to a steroid dimer bearing the 1,4-di(benzofuran-2-yl)benzene. The obtained compound showed an intense blue fluorescence characterized by a broad emission band between 350 and 550 nm, with four maxima at 384, 403, 435, and 456 nm. The benzofuran dimer showed an 18-fold increased quantum yield compared with that of its synthetic precursor.     

A new route to optically pure highly functionalized tetrahydro-isoquinolines with a quaternary carbon stereocenter

A facile synthesis of highly substituted, optically pure tetrahydro-isoquinolines with a quaternary carbon stereocenter is described. Glycolic cleavage of 1,2-dihydroxy-hexahydro-pyrrolo-isoquinolines 1 affords a mixture of cyclic hemiacetals, which can be converted via intramolecular chemoselective Cannizzaro reaction into respective β-amino alcohols, whereas the IBX oxidation gives N-formyl aldehydes. We have demonstrated the utility of such synthons by the synthesis of (+)-6,7-dimethoxy-salsoline-1-carboxylic acid and its new 1-phenyl analogue.     

A peroxide-bridged imidazole dimer formed from a photochromic naphthalene-bridged imidazole dimer

2,4,5-Triphenylimidazole (lophine) is known as the first chemiluminescence substrate, and its oxidized derivative, the 2,4,5-triphenylimidazolyl radical, corresponds to the coloured species in the photochromic reaction of hexaarylbiimidazole (HABI). We report the first direct observation of the O(2) adduct of the imidazolyl radical that forms the end-on peroxide-bridged imidazole dimer. The ring-opening reaction of the peroxide-bridged imidazole dimer leading to the formation of an N-benzoylbenzamidine derivative supports the presence of the 4,5-epidioxide of lophine as a reaction intermediate of its chemiluminescence.     

A pimpinellin monomer and dimer isolated from the roots of Esenbeckia grandiflora

X‐ray diffraction studies carried out on single crystals of the monomeric, viz. 5,6‐di­methoxy‐2H‐furo­[2,3‐h][1]benzo­pyran‐2‐one, C₁₃H₁₀O₅, and dimeric, viz. 5,5′,6,6′‐tetra­methoxy‐3,3′,4,4′‐tetra­hydro‐2H,2′H‐3,3′:4,4′‐bi­(furo­[2,3‐h][1]benzo­pyran)‐2,2′‐dione, C₂₆H₂₀O₁₀, forms of pimpinellin have revealed that, following cyclo­dimerization, the carbonyl groups are head‐to‐head with respect to one another. In the monomer, the heterocyclic ring is planar, but it exhibits a twisted‐boat conformation in the dimer. Both the monomer and the dimer interact through C—H⋯O interactions.     

Physicochemical characteristics and antitumor activities of a highly branched fungal (1----3)-beta-D-glucan, OL-2, isolated from Omphalia lapidescens.

Physicochemical properties and antitumor activities of a fungal (1----3)-beta-D-glucan, OL-2, isolated from Leiwan (Omphalia lapidescens) were examined. OL-2 showed sharp signals on carbon-13 nuclear magnetic resonance spectrum in dimethylsulfoxide-d6 as a solvent, and these signals were significantly reduced by the addition of distilled water to the concentration of 20%. This phenomenon is consistent with the general property of the gel forming (1----3)-beta-D-glucan. Binding of OL-2 to Congo red induced a significant change of lambda max to a longer wavelength, and the concentration to induce gel to sol transition was about 0.7 N; in contrast, the concentration was about 0.2 N in the cases of SPG and curdlan. These observations suggested that the gel structure would be significantly stabilized in the case of OL-2. OL-2 showed no or low antitumor activity against the solid form of Sarcoma 180 by intraperitoneal and intralesional administrations; however, it was effective on the ascites form of Sarcoma 180. Of interest, OL-2 also showed significant antitumor activity against the ascites form of MH-134 when administered with 5-fluorouracil. These results indicated that OL-2 showed characteristic features regarding its physicochemical properties and antitumor activity.     

Woodfordin C, a macro-ring hydrolyzable tannin dimer with antitumor activity, and accompanying dimers from Woodfordia fruticosa flowers

Three new dimeric hydrolyzable tannins, woodfordins A, B and C, along with seven known hydrolyzable tannins, including oenothein B, a dimer exhibiting marked host-mediated antitumor activity, were isolated from an Indonesian crude drug, Sidowayah [dried flowers of Woodfordia fruticosa (L.) Kurz (Lythraceae)]. The structures of the new tannins were elucidated based on chemical and spectral evidence. Woodfordin C, having a macro-ring structure, was also found to exhibit a significant antitumor activity.