Diarylheptanoids from the root bark of Juglans cathayensis

A new diarylheptanoid glucoside,（8R,9R）-17-methoxy-2-oxatricyclo[13.2.2.1^3.7]icosa-l（17）,3（20）,4,6, 15,18-hexaene-4,9,10-triol-9-O-β-D-glucopyranoside（1）,namely jugcathayenoside,together with two known diarylheptanoids,（+）-galeon（2） and 4-hydroxy-17-methoxy-2-oxatricyclo[13.2.2.1^3,7 ]icosa-1（17）,3（20）,4,6,15,18-hexaene-9-one（3）,were isolated from the root bark of Juglans cathayensis. Their structures were elucidated on the basis of extensive spectroscopic data analysis.     

Terpenoids from the dorid nudibranch cadlina luteomarginata

Methanol extracts of intact specimens of Cadlina luteomarginata, collected in Howe Sound and Barkley Sound, British Columbia, have been shown to contain sesquitepenoids and a degraded terpenoid. Albicanol (2) and its acetate 1 possess the drimane skeleton. Furodysin (4) and microcionin-2 (5) and microcionin-2 (6) are furanosesquiterpenoids of sponge origin. Luteone (8), the degraded terpenoid, represents a new carbon skeleton.     

Sesquiterpenoids from Ligularia virgaurea spp. oligocephala

Four novel eremophilane-type sesquiterpene lactones, 6β,10α-dihydroxy-1-oxoeremophila-7(11),8(9)-dien-12,8-olide (1), 6β-acetyl-2-oxoeremophila-1(10),7(11), 8(9)-trien-12,8-olide (2), 6β,8β-diacetyl-2-oxoeremophila-1(10),7(11)-dien-12,8-olide (3), dimeric eremophilane ligulolide B (5), and known sesquiterpenoid, 6β,8α-diacetyleremophila-1(10),7(11)-dien-12,8-olide (4), were isolated from an extract of the whole plant of Ligularia virgaurea spp. oligocephala. The structure of 1 was confirmed by NMR spectra and single crystal X-ray crystallography investigation, as well as 2, 3, and 5 were elucidated by spectroscopic methods including 1D and 2D NMR spectra. A discussion of biogenesis of 5 was described. Cytotoxicities of compound 1 were measured in vitro against selected cancer cells human promyelocytic leukemia (HL-60), human ovarian (HO-8910) and human lung epithehial (A-549).     

Synthesis of new chiral N-arylsulfonyl-1,3-oxazolidin-2-ones from α-amino acids

A variety of new chiral N-arylsulfonyl-1,3-oxazolidin-2-ones were prepared in three steps starting from (d)- and (l)-amino acid. N-Arylsulfonyl amino alcohols, derived from amino acids, were carbonylated with the bis-(trichloromethyl) carbonate (BTC), in the presence of triethylamine, to provide optically pure N-phenylsulfonyloxazolidin-2-ones 3a–f, N-naphthylsulfonyloxazolidin-2-ones 3g–j and N-tosylsulfonyloxazolidin-2-ones 3k–p in good yields.     

Chemical correlation of mortonins A,C and D sesquiterpenoids from mortonia genus

The structures of mortonins A (1), C (2a) and D (3) were previously deduced from chemical transformations and spectral data. The LAH reductions of mortonin A, mortonin C and their derivatives are discussed. Structure 2a, previously proposed for mortonin C, is proved by single crystal X-ray diffraction study. The transformation of Mortonin C (2a) into Mortonin A (1) and Mortonin D (3), proves the structure and stereochemistry proposed for all of them.     

New cytotoxic diterpenes from rondeletia panamensis (rubiaceae)

From the wood stem and stem bark of the Panamanian plant Rondeletia panamensis (Rubiaceae), three novel diterpenes have been isolated. The structure of oxidopanamensin (2) was determined by single crystal X-ray crystallography of the diacetate derivative. Panamensin (4) was correlated with oxidopanamensin (2) by epoxidation under alkali conditions and with rondeletin (6) by hydrogenation to 14,15-dihydrorondeletin (8). Of the three isolates, panamensin (4) and oxidopanamensin (2) were cytotoxic in the KB test system but rondeletin was inactive.     

Four new eremophilendiolides from Ligularia atroviolacea

From Ligularia atroviolacea, four new eremophilendiolides, 81$-hydroxy-eremophil-3,7 （11）-dien-12,8α（14,6α）-diolide （1）, 8β-methoxy-eremophil-3,7（11）-dien-12,8α（14,6α）-diolide （2）, 8α-hydroxy-eremophil-3,7（11）-dien-12,8lβ（14,6α）-diolide （3） and eremophil-3,7（11）,8-trien-12,8 （14,6α）-diolide （4）, as well as a known diolide （5） were isolated. Their structures were elucidated on the basis of 1D and 2D NMR as well as ESI-MS spectral data.     

New azaphilones from Chaetomium globosum isolated from the built environment

A strain of Chaetomium globosum (DAOM 240359) was isolated from an indoor air sample in Ottawa, Ontario, Canada. When fermented in liquid culture, this strain produced a number of known metabolites including chaetoglobosins A (6), C, and F (7), chaetomugilin D (5), chaetoviridin A (4), and three new nitrogenous azaphilones; 4′-epi-N-2-hydroxyethyl-azachaetoviridin A (1), N-2-butyric-azochaetoviridin E (2), and isochromophilone XIII (3). The structures were elucidated by spectroscopic analysis including; HRMS, 1D and 2D NMR, UV, and ORD. Compounds 2–7 were antimicrobial when tested using quantitative growth inhibition assays.     

Chemical studies of marine invertebrates—XXVIII: Diterpenes from clavularia inflata (coelenterata,octocorallia, stolonifera)

The presence of terpenoids in the order Stolonifera has been established by the isolation of three novel diterpenes, 1α,4β-dihydroxyclavular-17-ene (1), 4β-hydroxyclavulara-1(15),17-diene (2) and 3α.4β-dihydroxyclavulara-1(15), 17-diene (3) from Clavularia infiata. The structure of 1 has been determined by X-ray diffraction analysis and those of 2 and 3 by chemical intercorrelation with 1.     

Two new guaianolide-type sesquiterpenoids from Kadsura interior

Two new guaianolide-type sesquiterpenoids,4β,9β-dihydroxy-1α,5α-H-guaia-6,10(14)-dien(1) and 4β,9β,10α-trihydroxy-1α,5α-H-guaia-6-en(2),along with four known sesquiterpenoids(3a,3b,4 and 5),were isolated from Kadsura interior.Their structures and configurations were elucidated by spectroscopic methods including 2D-NMR and HR-MS techniques.Compounds 3a and 3b were obtained as a pair of enantiomers,and their structure and absolute configuration were established from their extensive NMR spectra and by single-crystal X-ray analysis.     

Two new cytotoxic sesquiterpenoids from Solanum lyratum

Two new sesquiterpenoids,attributable to eudesmane-type（1 and 2,named solajiangxins F and G）,were isolated from the whole plant of Solanum lyratum.Their structures were elucidated on the basis of integrated spectroscopic techniques.In vitro,compounds 1 and 2 were found to show signifcant cytotoxic activity against selected cancer cells,including P-388,HONE-1 and HT-29.     

Structures of six new compounds from Ligularia brassicoides

Four new eremophilane type sesquiterpenoids, a new bakkane type sesquiterpenoid, and a new secoeremophilane type sesquiterpenoid were isolated from Ligularia brassicoides Hand.-Mass. (Asteraceae) collected in China, and were an epoxy lactone derived from 6-acyloxyeuryopsin 1, 6-acyloxy-9-oxoeuryopsin 2, 6-acyloxy-9-oxofuranoeremophilane 3, 6-acyloxyeuryopsin 4, 6-acyloxy bakkane type epoxy lactone 5, and secovirgaurenol 6-O-(2′-hydroxymethyl)acrylate (6), respectively. All but one had a 2′-hydroxymethylacryloyloxy group at C-6. This is the first study to describe the chemical constituents of this species.     

Phenanthrenes from Juncus atratus with antiproliferative activity

The present study has focused on the isolation and structure determination of phenanthrenes from Juncus atratus Krock. Nine compounds, among them five phenanthrenes, have been isolated from the methanol extract of the plant. Two compounds [juncatrins A (1) and B (2)] are new natural products, three phenanthrenes [juncuenin B (3), effusol (4), and dehydroeffusol (5)], the flavones apigenin (7) and luteolin (8), the diterpene phytol and 13(R)-hydroxy-octadeca-(9Z,11E,15Z)-trien-oic acid (9) were isolated for the first time from the plant. Juncatrin A (1) is substitued with an acetyl group, while in case of juncatrin B (2), an unprecedented acetylene group is connected to the phenanthrene skeleton. The isolated phenanthrenes were evaluated for their antiproliferative activity against HeLa, SiHa and MDA-MB-231 human tumor cell lines. Four phenanthrenes (2, 3, 4 and 5) were more effective [IC₅₀s 3.48?μM (2), 2.91 (3), 3.68 (4), and 7.75?μM (5)] than cisplatin (IC₅₀ 12.43?μM) on HeLa cells.     

Enantioselective hydrolysis of (RS)-2-fluoroarylacetonitriles using nitrilase from Arabidopsis thaliana

The enzymatic resolution of 2-fluoroarylacetonitriles (RS)-3 using nitrilase from the plant Arabidopsis thaliana is described. Racemic 2-fluoronitriles 3 are easily accessible from O-silylated aromatic cyanohydrins 2 by reaction with DAST. The nitriles (RS)-3 were hydrolysed with the nitrilase as a catalyst, not to the expected 2-fluoroarylacetic acids but to the corresponding (R)-2-fluoroarylacetamides (R)-5 as the main products. After optimization of reaction conditions (pH 9, 7°C), the enantiomeric excesses of (R)-5a,c and f (R=H, 3-Me, 3-OMe) could be improved to >99% by one recrystallization. The acid catalysed hydrolysis of (R)-5a,5c and 5f afforded the corresponding (R)-2-fluoroarylacetic acids (R)-4a,4c and 4f without racemization.     

Mufolinin A,an unprecedented ring A-seco 10-ethyllimonoid from Munronia unifoliolata

Mufolinin A(1), a ring A-seco rearranged limonoid with an unprecedented ethyl at C-10 and novel 6/6/6/5 fused-ring skeleton, together with three new potential precursors(ring A-seco limonoids, 2–4) were isolated from Munronia unifoliolata. Their structures and absolute configurations were confirmed by nuclear magnetic resonance(NMR), high resolution electrospray ionization mass spectroscopy(HRESIMS), X-ray crystallography, electronic circular dichroism(ECD) calculations and NMR calculations with...     

Phomactins K–M,three novel phomactin-type diterpenes from a marine-derived fungus

Three novel diterpenes, phomactins K–M (1–3), were isolated from the cultures of an unidentified marine-derived fungus. The structures of 1–3 were elucidated from spectroscopic data (NMR, MS, IR), and the absolute configurations of 1, 2, and the relative configuration of 3 were determined by X-ray diffraction analysis.     

Antifungal variant bis(bibenzyl)s from the liverwort Asterella angusta

Bioassay-guided fractionation of the diethyl ether extract of the liverwort Asterella angusta led to the isolation of two antifungal bis(bibenzyl)s,riccardin I(1),and angustatin A(2).Their structures were established by spectroscopic analysis(1D NMR and 2D NMR,IR,MS).Compound 1 is a novel variant riccardin-type bis(bibenzyl),while compound 2 is the first nonheteratom-containing variant bis(bibenzyl)possessing a bibenzyl-phenanthrene skeleton.     

Two new myrinsol diterpenoids from Euphorbia dracunculoides Lam.

Two new myrinsol diterpenoids, euphordracunculins A(1) and B(2), together with three known analogues, euphorprolitherin B(3), proliferins A(4) and B(5),were isolated from the petroleum ether extract of the aerial parts of Euphorbia dracunculoides Lam. Their structures were elucidated by means of extensive spectroscopic analysis(NMR and ESI-MS) and comparison with data reported in the literature.     

Hyperbenzones A and B,two 1,2-seco and rearranged polycyclic polyprenylated acylphloroglucinols from Hypericum beanii

Two novel seco-polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperbenzones A (1) and B (2), were isolated from the roots of Hypericum beanii, together with one known biosynthetic congener 3. Compound 1 incorporates a 6/5/5 ring system with an unprecedented spiro[bicyclo[3.3.0]octane-3,1?-cyclohexane]-2,2??dione motif. The structures of 1 and 2 were determined by a combination of high resolution electrospray ionization mass spectroscopy (HRESIMS), nuclear magnetic resonance (NMR) spectroscopic analyses, gage-independent atomic orbital (GIAO) NMR chemical shift calculation with DP4+ analyses, electronic circular dichroism (ECD) calculation, and X-ray diffraction analysis. A 1,2-seco retro-Claisen rearrangement from a bicyclo[3.3.1]nonane PPAP precursor and following chemodivergent radical cascade cyclizations are proposed as the key steps in the biosynthetic pathway to yield compounds 1 and 2. Biological investigations indicated that compounds 1 and 3 could decrease intracellular lipid accumulation in a palmitic acid-induced nonalcoholic steatohepatitis (NASH) cell model.     

Melaleucadines A and B: Two rare benzylic phloroglucinol-terpene hybrids from Melaleuca leucadendron

Melaleucadines A and B (1 and 2), two rare benzylic phloroglucinol-terpene hybrids (meroterpenoids), have been isolated and identified from the branches and leaves of the Australian “tea tree” Melaleuca leucadendron L. Their structures including absolute configurations were determined by 1D/2D NMR, HR-MS, and the CD exciton chirality method. Compound 1 was a hybrid of a benzylic phloroglucinol and rearranged β-pinene via a rare 2,3,4,5-tetrahydrooxepine ring, and 2 was the adduct of a benzylic phloroglucinol and a humulene-type sesquiterpene via an oxa-heterocycle. Bioactivity screening revealed that compounds 1 and 2 exhibited neuroprotective effects at a concentration of 50.0?μM.