Alstoscholarisine L, a novel caged monoterpenoid indole alkaloid with antifungal activity from Alstonia scholaris.

Alstoscholarisine L is an architecturally complex monoterpenoid indole alkaloid with a unique ring fusion pattern, isolated from the leaves of Alstonia scholaris. The 6/5/5/6/6/6-membered rings contain two lactonic rings and one aminal carbon and possess seven contiguous aligned stereocenters, three of which are quaternary. Its structure was elucidated by extensive spectroscopic data analyses, quantum chemical computations, and single-crystal X-ray diffraction.

Heterocyclic pseudoguaianolide oligomers and seco-pseudoguaianolide derivatives from the inflorescence of Ambrosia artemisiifolia.

Two heterocyclic sesquiterpenoid oligomers (1, 2) and four previously undescribed seco-pseudoguaianolide derivatives (3-6) were isolated from the inflorescence of Ambrosia artemisiifolia. Ambrosiadimer A (1) is an unprecedented dimer featuring a hexahydropyrrolizine core scaffold and two pseudoguaianolide units. Ambrosiatrimer A (2) is a trimer formed from three pseudoguaianolide units via a pyrrolidine ring.

A new terpestacin-type sesterterpenoid with tricyclic 3/15/5 scaffold from an endophytic fungus sp. J019.

ABSTACTChemical investigation of an endophytic fungus, sp. J019, isolated from the plant species R. Br.

New ent-cleistanthanes and ent-pimaras diterpenoids with potential cytotoxicity from Phyllanthus franchetianus H. Lév.

Seven diterpenoids including five ent-cleistanthanes (1, 2, 4-6) and two ent-pimaranes (3, 7) were isolated for the first time from the aerial part of Phyllanthus franchetianus H. Lév. Their structures were elucidated on the basis of the extensive spectroscopic analyses, single-crystal X-ray diffraction and ECD analysis.

Isosativene and sativene sesquiterpene derivatives from Dendrobium nobile.

Two unusual isosativene sesquiterpene derivatives, named dendronobilol A (1) and dendronobilside A (2), and two unusual sativene sesquiterpene derivatives, named dendronobilsides B (3) and C (4), had been isolated from the stems of Dendrobium nobile. The structures of all the compounds were established using spectroscopic methods and by comparison with literature data, and their absolute configurations were confirmed via single-crystal X-ray diffraction data and electronic circular dichroism (ECD) calculations. Dendronobilol A (1) and dendronobilside A (2) possessed a unique tricyclo[4.

Selenium dioxide promoted selenylation/cyclization of leucosceptrane sesterterpenoids.

A novel selenium dioxide promoted selenylation/cyclization of leucosceptrane sesterterpenoids was reported. Two types of leucosceptrane derivatives with different valence states of selenium atoms (Se and Se) were obtained. The mechanisms of these two processes were proposed, and the selenium-containing derivates may serve as intermediates of Riley oxidation that could be trapped with appropriate substrates.

Silvaticusins A-D: ent-kaurane diterpenoids and a cyclobutane-containing ent-kaurane dimer from Isodon silvaticus.

Three new ent-kaurane diterpenoids, silvaticusins A-C (1-3), along with a new ent-kaurane dimer silvaticusin D (4) were isolated from the aerial parts of Isodon silvaticus. The structures of these new compounds were established mainly by comprehensive analysis of their NMR and MS data. The absolute configuration of compounds 1 and 4 were determined using a single-crystal X-ray diffraction and computational methods, respectively.

Structurally diverse ent-clerodanoids from the aerial parts of Isodon scoparius.

Scoparodane C (1), a diterpenoid with a rare 3,4-seco-3-nor-2,11-epoxy-ent-clerodane scaffold, was obtained from the aerial parts of Isodon scoparius, along with isocopariusines A-E (2-6), five ent-clerodanoids featuring a 5/6-fused ring system, and isocopariusines F-H (7-9), three common ent-clerodanoids. The structures of these previously undescribed compounds were established by a combination of spectroscopic analysis, X-ray diffraction, chemical derivatization, and quantum chemical calculation. Remarkably, isocopariusine B (3) showed strong resistance reversal activity against fluconazole-resistant Candida albicans.

Undobolins A-L, Ophiobolin-Type Sesterterpenoids from .

Twelve previously undescribed ophiobolin-type sesterterpenoids, undobolins A-L (-), were isolated from , and their structures were elucidated by spectroscopic analysis, ECD calculations, and single-crystal X-ray diffraction experiments. Compound was the second example of 20-nor-ophiobolin reported, while compounds - were notable for oxygenation of C-2, and compound showed significant inhibitory activity against ConA-induced T lymphocyte proliferation with an IC value of 2.3 μM, which suggests a promising new direction in the quest for immunosuppressive agents.

Isoxerophilusins A and B, Two Novel Polycyclic Asymmetric Diterpene Dimers from : Structural Elucidation, Modification, and Inhibitory Activities against α-Glucosidase.

Isoxerophilusins A () and B (), two unprecedented diterpene heterodimers biogenetically from -atisanes and abietanes, were isolated from the rhizomes of . Their structures were determined by extensive spectroscopic analysis and single-crystal X-ray diffraction. Selective esterification of generated 11 new derivatives.

Immunosuppressive leucosesterterpane and penta-nor-leucosesterterpane sesterterpenoids from Leucosceptrum canum.

Five undescribed leucosesterterpane sesterterpenoids, leucosceptrines A-E, two undescribed penta-nor-leucosesterterpane (C) sesterterpenoids, nor-leucosceptrines A and B, and three known analogues, were obtained from the aerial parts of Leucosceptrum canum of Chinese origin. Leucosceptrines A-C are the first examples of leucosesterterpane-type sesterterpenoids with unclosed dihydropyran rings and reverse configurations at chiral centers C-4 and/or C-12. Nor-leucosceptrines A and B possesses an unusual penta-nor-leucosesterterpane skeleton.

Thermally stable Ni foam-supported inverse CeAlO/Ni ensemble as an active structured catalyst for CO hydrogenation to methane.

Nickel is the most widely used inexpensive active metal center of the heterogeneous catalysts for CO hydrogenation to methane. However, Ni-based catalysts suffer from severe deactivation in CO methanation reaction due to the irreversible sintering and coke deposition caused by the inevitable localized hotspots generated during the vigorously exothermic reaction. Herein, we demonstrate the inverse CeAlO/Ni composite constructed on the Ni-foam structure support realizes remarkable CO methanation catalytic activity and stability in a wide operation temperature range from 240 to 600 °C.

Unified Strategy Enables the Collective Syntheses of Structurally Diverse Indole Alkaloids.

Natural products and their analogues are significant sources of therapeutic lead compounds. However, synthetic strategies for generating large collections of these molecules remain a significant challenge. The most difficult step in their synthesis is the design of a common intermediate that can be easily transformed into natural products belonging to different families.

Discovery and bioinspired total syntheses of unprecedented sesquiterpenoid dimers unveiled bifurcating [4 + 2] cycloaddition and target differentiation of enantiomers.

[4 + 2] cycloaddition has led to diverse polycyclic chiral architectures, serving as novel sources for organic synthesis and biological exploration. Here, an unprecedented class of cadinane sesquiterpene [4 + 2] dimers, henryinins A-E (1-5), with a unique 6/6/6/6/6-fused pentacyclic system, were isolated from . The divergent total syntheses of compounds 1-5 and their enantiomers (6-10) were concisely accomplished in eight linear steps using a protection-free approach.

Discovery of Natural Potent HMG-CoA Reductase Degraders for Lowering Cholesterol.

Exploitation of key protected wild plant resources makes great sense, but their limited populations become the major barrier. A particular strategy for breaking this barrier was inspired by the exploration of a resource-saving fungal endophyte Penicillium sp. DG23, which inhabits the key protected wild plant Schisandra macrocarpa.

Discovery and Biomimetic Semisynthesis of Spirophyllines A-D from .

Spirophyllines A-D (-), four new spirooxindole alkaloids all characterized by the spiro[pyrrolidin-3,3'-oxindole] core and a rare isoxazolidine ring, were isolated from . Their structures were determined by spectroscopic methods and confirmed by X-ray crystallography. Based on the biomimetic semisynthesis strategy, compounds - were synthesized in three steps via the key reactions of 1,3-dipolar cycloaddition and Krapcho decarboxylation from corynoxeine.

Pegriseofamines A-E: Five cyclopiazonic acid related indole alkaloids from the fungus Penicillium griseofulvum.

Five new cyclopiazonic acid related indole alkaloids, pegriseofamines A-E (1-5), were isolated from the fungus Penicillium griseofulvum. Their structures and absolute configurations were determined by NMR, HRESIMS, quantum-chemical calculation, and X-ray diffraction experiments. Among them, pegriseofamine A (1) possesses an undescribed 6/5/6/7 tetracyclic ring system generated by the fusion of an azepine and an indole unit via a cyclohexane, and the postulated biosynthetic origin of 1 was discussed.

Cyclobutane-Containing Meroditerpenoids, (+)-Isoscopariusins B and C: Structure Elucidation and Biomimetic Synthesis.

(+)-Isoscopariusins B () and C (), two meroditerpenoids containing a 6/6/4 tricyclic carbon skeleton and seven continuous stereocenters, were identified from . The structures were determined by nuclear magnetic resonance analysis and concise biomimetic syntheses from readily available alkene in seven and six steps, respectively. An intermolecular [2+2] photocycloaddition with cooperative catalysis of a Lewis acid and an Ir photocatalyst was used to construct a cyclobutane core with four stereogenic centers.

Cytotoxic C-20 non-oxygenated ent-kaurane diterpenoids from Isodon wardii.

Twenty new ent-kaurane diterpenoids, wardiisins A-T (1-20), along with two previously undescribed artefactual compounds (21 and 22) and twelve known analogues (23-34), were isolated from the aerial part of Isodon wardii. Their structures were elucidated by comprehensive analysis of spectroscopic data and single-crystal X-ray diffraction, and most of them were found to bear unusual C-12 oxygenation. Compounds 4, 7, 8, 19, 20, 21 exhibited remarkable cytotoxicity against the cancer cell lines HL-60, SMMC-7721, A-549, MDA-MB-231, and SW480, with IC values ranging from 0.

Anti-Neuroinflammatory Activity of New Naturally Occurring Benzylated Hydroxyacetophenone Analogs from the Endophytic Fungus Alternaria sp. J030.

Chemical studies on the culture broth of the endophytic fungus Alternaria sp. J030 led to the identification of three benzylated hydroxyacetophenone derivatives, bauvaroalterins A-C (1-3), and 34 structurally diverse metabolites (4-37). The new structures were elucidated by extensive spectroscopic analyses including UV, IR, 1D and 2D NMR, HR-ESI-MS, and further confirmed using single crystal X-ray diffraction.

Asperemestrins A-D, Emestrin Hybrid Polymers with Bridged Skeletons from the Endophytic Fungus .

Four emestrin hybrid polymers, asperemestrins A-D (, respectively), were isolated from the fungus . Asperemestrins A-C are the first examples of emestrin-sterigmatocystin heterodimers bearing a 7/5/6/6/5/5/6/6/6 nonacyclic system with a 2,5-diazabicyclo[2.2.

Scopariusicides D-M, ent-clerodane-based isomeric meroditerpenoids with a cyclobutane-fused γ/δ-lactone core from Isodon scoparius.

Scopariusicides D-M (1-10), ten new ent-clerodane-based meroditerpenoids with a cyclobutane-fused γ/δ-lactone core, were isolated from Isodon scoparius. Their structures were determined by comprehensive analysis of spectroscopic data, single-crystal X-ray diffraction, chemical transformation, and TDDFT ECD calculation. A plausible biosynthetic pathway of 1-10 was proposed in which the asymmetrical cyclobutane ring was formed via a crossed "head-to-tail" intermolecular [2 + 2] cycloaddition in anti/syn facial approaches between an ent-clerodane lactone and a cis-4-hydroxycinnamic acid.

Four undescribed ergostane-type steroids from Lasiodiplodia pseudotheobromae and their neuroprotective activity.

Four undescribed ergostane-type steroids, (22E,24R)-4α,5α-epoxyergosta-9α,14β-dihydroxy-7,22-diene-3,6-dione, (22E,24R)-4α,5α-epoxyergosta-9α,14α-dihydroxy-7,22-diene-3,6-dione, 12α-hydroxyergosta-7,22,24(28)-triene-3-one, and 3β,12α-dihydroxyergosta-7,24(28)-diene, along with a known congener (22E,24R)-9α,14β-dihydroxyergosta-4,7,22-triene-3,6-dione, were isolated from the fungus Lasiodiplodia pseudotheobromae. Their structures were elucidated using NMR, HRESIMS, ECD calculation, and X-ray diffraction analyses. (22E,24R)-4α,5α-epoxyergosta-9α,14β-dihydroxy-7,22-diene-3,6-dione and (22E,24R)-4α,5α-epoxyergosta-9α,14α-dihydroxy-7,22-diene-3,6-dione are a pair of C-14 epimers possessing an unusual epoxy group between C-4 and C-5, which was demonstrated using single-crystal X-ray diffraction analyses.

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

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. tuberculate. The structures of 1-4 were elucidated by comprehensive analysis of their spectroscopic data, quantum chemical calculations, as well as single-crystal X-ray diffraction.