Amides,Isoquinoline Alkaloids and Dipeptides from the Aerial Parts of Piper mullesua

One undescribedamide,pipermullesine A,twoundescribed isoquinoline alkaloids,pipermullesinesBand C,and six undescribed dipeptides,pipermullamides A–F,along with 28 known compounds,were isolated from the aerial parts of Piper mullesua.The structures of the undescribed compounds were elucidated based on the analysis of 1D and 2D NMR and MS data.Furthermore,the structures of pipermullesines A–Cwere confirmed by single crystal X-ray diffraction analysis.All isolates were evaluated for inhibitory activity against platelet aggregation induced by thrombin(IIa)or platelet-activating factor(PAF).(-)-Mangochinine,pellitorine,and(2E,4E)-N-isobutyl-2,4-dodecadienamide showed weak inhibitory activity against rabbit platelet aggregation induced by PAF,with IC_(50)values of 470.3μg/mL,614.9μg/mL,and 579.7μg/mL,respectively.

Sesquilignans and sesquiterpenoid from the stem barks of Illicium simonsii and their anti-AChE activity

Three new sesquilignans,1-3,a new sesquiterpenoid,4,and three known compounds were isolated from the stem barks of Illicium simonsii.The structures of new compounds(1-4)were elucidated by spectroscopic methods.A biosynthetic pathway was proposed for simonsienols A-C(1-3).Anti-AChE activity and anti-BuChE activity were evaluated for all compounds except forα-cadinol ethyl ether(4).As a result,isodunnianol(7)exhibited anti-AChE activity with an IC50 value of 13.0μM.

Lignans and sesquiterpenoids from the stems of Schisandra bicolor var. tuberculata

A pair of new tetrahydrofuran lignan enantiomers,(±)-schibiculatin A[(±)-1],a new enedione lignan,schibiculatin B(2),two new cadinane-type sesquiterpenoids,schibiculatins C(3)and D(4),along with two known seco-cadinane-type sesquiterpenoids(5 and 6)and seven known miscellaneous lignans(7-13)were isolated from the stems of Schisandra bicolor var.tuberculata.The structures of 1-4 were elucidated by comprehensive analysis of their spectro-scopic data,quantum chemical calculations,as well as single-crystal X-ray diffraction.A few isolated compounds were tested for their protective activities against corticosterone-induced apoptosis in PC12 cells.Among them,compounds 5 and 6 showed moderate activities.

Two New Compounds from Schisandra propinqua var.propinqua

Schisanpropinoic acid(1),a new bergamotane sesquiterpenoid,and schisanpropinin(2),a new tetrahydrofuran lignan with a rare epoxyethane unit,were identified from the stems and leaves of Schisandra propinqua var.propinqua.Their structures were determined based on comprehensive spectroscopic and mass spectrometric analysis.The absolute configuration of 1 was determined by X-ray analysis.Compounds 1 and 2 were tested for their cytotoxic activity against five human tumor cell lines.

Four new indole alkaloids from Plantago asiatica

Four new indole alkaloids,plasiaticines A-D(1-4),together with two known ones,were isolated from the seeds of Plantago asiatica.The structures of the new compounds were elucidated on the basis of comprehensive analysis of spectroscopic data.All compounds were tested for their cytotoxic activity,and all compounds except 4 were tested for their acetylcholinesterase(AChE)inhibitory activities.

Lactam Triterpenoids from the Bark of Toona sinensis

Three new limonoid-type triterpenoids,namely toonasins A–C(1–3)with a rare lactam E ring,along with six known compounds(4–9)were isolated from the barks of Toona sinensis.The structures of new compounds were elucidated by interpretation of spectroscopic data,and the relative configuration of compound 1 was further characterized by X-ray crystallographic analyses.The isolated compounds were evaluated for their cytotoxic activities against five human tumor cell lines(HL-60,SMMC-7721,A-549,MCF-7 and SW480),and compounds 3 and 5 showed weak cytotoxicities.

(±)-Evodiakine,A Pair of Rearranged Rutaecarpine-Type Alkaloids From Evodia rutaecarpa

(±)-Evodiakine(1a and 1b),a pair of rearranged rutaecarpine-type alkaloids with an unprecedented 6/5/5/7/6 ring system,were isolated from the nearly ripe fruits of Evodia rutaecarpa.Separation of the enantiomers have been achieved by chiral HPLC column.The structures of(±)-evodiakine were unambiguously elucidated by 1D and 2D NMR spectra,mass spectrometry,and single-crystal X-ray diffraction.Their absolute configurations were determined by comparison of experimental and calculated electronic circular dichroism spectra.A hypothetical biogenetic pathway for(±)-evodiakine was also proposed.Compounds 1a,1b,and the racemate(1)were tested for their cytotoxic and anti-inflammatory activities.

Four new diterpenoids from Isodon eriocalyx var.laxiflora

Four new diterpenoids,laxiflorins S-V(1-4),bearing four different types,and one known compound,laxiflorin O(5),were isolated from Isodon eriocalyx var.laxiflora.Compound 1 was the first example of ent-kauranoids bearing a unique C_(24) carbon framework and compound 4 was the first example of 3,4-seco-ent-abietane diterpenoids from the Isodon genus.Their structures were determined by spectroscopic methods(UV,IR,MS,NMR).

Dendrowardol C, a novel sesquiterpenoid from Dendrobium wardianum Warner

Dendrowardol C(1)-a novel sesquiterpenoid,with an unprecedented 4/5/6/6 tetracyclic carbon backbone,together with two known cyclopacamphane-type sesquiterpenoids;dendronobilin I(2)and dendrobane A(3)were isolated from the stems of Dendrobium wardianum Warner.The structure of 1 was established on the basis of spectroscopic data and the absolute configuration was determined by single-crystal X-ray diffraction crystallography.The hypothetical biosynthetic pathway of 1 was postulated.Compound 1 showed no cytotoxic activity against human tumor cell lines HL-60,SMMC-7721,A-549,MCF-7,and SW480.

Lyconadins G and H,Two Rare Lyconadin-Type Lycopodium Alkaloids from Lycopodium complanatum

Two rare lyconadin-type Lycopodium alkaloids,lyconadins G(1)and H(2),together with four known ones(3–6),were isolated from Lycopodium complanatum.The structures were determined on the basis of their spectroscopic analyses,and the absolute configuration of 1 was established by an X-ray crystallographic analysis.It is the first time to establish the absolute configuration of lyconadin-type Lycopodium alkaloid by an X-ray diffraction experiment.In addition,these findings may provide more information for the biosynthesis of lyconadins.

Daphmacrodins A and B, alkaloids from Daphniphyllum macropodum

Two new daphnicyclidin-type Daphniphyllum alkaloids,daphmacrodins A and B(1 and 2)were isolated from the leaves and stems of Daphniphyllum macropodum.Their structures were elucidated by extensive spectroscopic techniques,including 2D NMR spectroscopy and mass spectrometry.The relative configuration of 1 was further confirmed by a single-crystal X-ray diffraction analysis.Their cytotoxic activities against five human cancer cell lines,pesticidal activities against brine shrimp(Artemia salina),and antibacterial activities against five standard bacterial and fungal strains were evaluated.The structure of 1 was successfully transformed to 2 by a chemical method.

Three new nortriterpenoids from Schisandra wilsoniana and their anti-HIV-1 activities

Three new highly oxygenated nortriterpenoids,wilsonianadilactones D-F(1-3),were isolated from the leaves and stems of Schisandra wilsoniana.Their structures were established by means of spectroscopic analysis.Compounds 1-3 showed weak anti-HIV-1 activity with the therapeutic index(TI)values(CC50/EC50)greater than 8.16,14.7,and 17.5,respectively.

Arthrinins E-G, Three Botryane Sesquiterpenoids from the Plant Endophytic Fungus Arthrinium sp. HS66

Arthrinins E-G(1-3),three new sesquiterpenoids possessing non-isoprenoid botryane skeleton,were isolated from the fermentation of an endophytic fungus named Arthrinium sp.HS66 which colonized in the stems of Isodon xerophilus.Their structures were determined by extensive spectroscopic methods.Furthermore,the structure of 1 was unambiguously confirmed by X-ray diffraction,while those of 2 and 3 were verified through quantum chemical calculation of NMR data and ECD spectra.

Five new 2-(2-phenylethyl)chromone derivatives and three new sesquiterpenoids from the heartwood of Aquilaria sinensis, an aromatic medicine in China

Five new 2-(2-phenylethyl)chromone derivatives,(5S,6R,7R,8S,7ʹR)-7ʹ-hydroxyagarotetrol(1),(5S,6R,7R,8S,7ʹS)-7ʹ-hydroxyagarotetrol(2),(6S,7S,8R)-2-[2-(4-methoxyphenyl)ethyl]-6,7,8-trihydroxy-5,6,7,8-tetrahydrochromone(3),(6S,7S,8R)-2-(2-phenylethyl)-6,7,8-trihydroxy-5,6,7,8-tetrahydrochromone(4),(5S,6R,7S,8R)-2-(2-phenylethyl)-5,6,7-trihydroxy-5,6,7,8-tetrahydro-8-[2-(2-phenylethyl)-7-methoxychromonyl-6-oxy]chromone(5),three new sesquiterpenoids,(4S,5S,7S,8S,10S,13R)-7,8,13-trihydroxyrotunda-1,11-dien-3-one(6),(4S,5S,7S,8S,10S,13S)-7,8,13-trihydroxyrotunda-1,11-dien-3-one(7),and(4R,5S,7S,8S,10S,13S)-7,8,13-trihydroxyrotunda-1,11-dien-3-one(8),along with 14 known compounds were isolated from the resinous heartwood of Aquilaria sinensis(Thymelaeaceae).The chemical structures of these new compounds were elucidated by 1D and 2D NMR and MS data,single-crystal X-ray diffraction analysis,and electronic circular dichroism(ECD)calculations.The neuroprotective activities of these isolates were evaluated using an in vitro model of rat adrenal pheochromocytoma(PC12)cell injury induced by corticosterone.At concentrations from 5 to 40μM,compounds 4 and 6,agarotetrol(9),and 6-hydroxy-2-(2-phenylethyl)chromone(17)showed significant protective activities against corticosterone-induced PC12 cell injury(P<0.001).

Isorosthornins A-C,new ent-kaurane diterpenoids from Isodon rosthornii

Three new ent-kauranoids,isorosthornins A-C(1-3),and a new natural product,dihydroponicidin(4),together with five known ones were isolated from the aerial parts of Isodon rosthornii.The structures were determined by means of extensive spectroscopic analysis.All diterpenoids isolated were evaluated for their cytotoxicity against HL-60,SMMC-7721,A-549,MCF-7,and SW480 cell lines,and compounds 5 and 7 showed significant inhibitory effects on all cell lines.

Dual activation and C-C coupling on single atom catalyst for CO_(2) photoreduction

An excellent single-atomic photocatalyst,Ti@C_(4)N_(3),is theoretically found to effectively convert CO_(2) to C_(2)H_(6) by density functional theory(DFT)calculations and non-adiabatic molecular dynamics(NAMD)simulations.The Ti@C_(4)N_(3) photocatalyst has remarkable stability both thermally,chemically,and mechanically.Electronically,it has strong absorption properties(λ=327.77 and 529.61 nm),suitable band positions,and a long photogenerated electron lifetime(τ_(e)=38.21 ps),allowing photogenerated electrons to migrate to the surface.Notably,the high-valence active site effectively activates two CO_(2) through dual activation:Under light irradiation,the weakly adsorbed CO_(2) undergoes photo-induced activation by the photoelectron of conduction band minimum(CBM);without light,the high Lewis acidity of the Ti site induces CO_(2) activation through back-donatingπ-bond.Contrast simulation results uncovered that dual activation of CO_(2) is attributed to the thermal and photonic synergy.Furthermore,two activated CO_(2) species under light easily couple to form oxalate with the barrier of 0.19 eV,and further reduced to C_(2)H_(6) with a low activation energy of 1.09 eV.

Improvement of the stability of Hg/AC catalysts by CsCl for the high-temperature hydrochlorination of acetylene

Activated carbon-supported mercuric chloride（HgCl2） is used as an industrial catalyst for acetylene hydrochlorination. However, the characteristic of easy sublimation of HgCl2 leads to the deactivation o the catalyst. Here, we showed that the thermal stability of the Hg/AC catalyst can be evidently improved when Cs Cl is added into the Hg/AC catalyst. Compared with the pure Hg/AC catalyst, the sublimation rate of HgCl2 from the Hg–Cs/AC catalyst decreased significantly and the Hg–Cs/AC catalyst showed bette catalytic activity and stability in the reaction. This promoting effect is related to the existence of cesium mercuric chlorides（CsxHgyCl（x＋2y）） highlighted by XRD, HR-TEM and EDX analyses. Thus, reacting HgCl2 with alkali chlorides to form alkali-mercuric chlorides may be a key to design highly efficient and thermally stable mercuric chloride catalyst for hydrochlorination reactions.

Two new guaianolide-type sesquiterpenoids from Kadsura interior

Received 22 November 2012 Received in revised form 25 December 2012 Accepted 2B December 2012 Available online 4 February 2013

Pestaloamides A and B,two spiro-heterocyclic alkaloid epimers from the plant endophytic fungus Pestalotiopsis sp.HS30

Pestaloamides A and B(1 and 2),two novel alkaloids featuring an unprecedented spiro[imidazothiazoledione-alkylidenecyclopentenone]scaffold,were obtained from the cultures of an endophytic fungus Pestalotiopsis sp.HS30 which inhabited the stems of Isodon xerophilus.Their planar structures and absolute configurations were fully determined by extensive spectroscopic analysis and X-ray crystallography.In addition,both compounds 1 and 2 showed the latent tumor immunotherapy activity through markedly promoting the cell surface engagement of NKG2 D ligands involving MICA/B and ULBP1 in HCT116 cells.

Visible-light photoredox-mediated oxidation of N-methyl tertiaryamines under catalyst free conditions:Direct synthesis of methylene-bridged bis-1,3-dicarbonyl compounds

Mediated by visible light-induced photoredox catalysis and free of other catalysts, a new and efficient synthesis of methylene-bridged bis-l,3-dicarbonyl derivatives has been developed. A variety of N-methyl tertiaryamines and 1,3-dicarbonyl compounds were investigated in this reaction.