Chiral BN-Heteroacenes Embedded with B←N Coordination: Acid-Triggered Reversible Bond Switching and Optical Limiting Behavior.

Boron-nitrogen coordination (B←N) bonds have emerged as a versatile motif for engineering π-conjugated systems with tunable optoelectronic properties. Herein, we report the synthesis, structures, and properties of chiral heteroacenes (-) featuring B←N coordination within highly twisted π-frameworks. - were synthesized via a four-step approach, where the final cyclization simultaneously forged six- and five-membered rings bearing both B-N covalent and B←N dative bonds.

Unsaturated lactones from .

A new -unsaturated lactone, 2-(1-hydroxy-2-methylpropyl)-4-isopropylfuran-1(4)-one (), along with nine known compounds (-), was isolated from . The structure of compound was elucidated based on comprehensive spectroscopic analysis, including 1D and 2D NMR (HSQC, COSY, HMBC), and HR-ESI-MS spectrometry. The absolute configuration was determined by comparison of the experimental and time-dependent density functional theory (TDDFT)-calculated electronic circular dichroism (ECD) spectra.

Valence state engineering in multi-heteroatom-doped PAHs: a strategy for tunable photophysical properties and phototheranostic potentials.

Precise modulation of the electronic structures in heteroatom-doped polycyclic aromatic hydrocarbons (hetero-PAHs) is essential for advancing organic optoelectronic materials. Herein, we report a facile synthetic strategy for hetero-PAHs co-doped with N, O, and S/Se, achieved acid-catalyzed Pictet-Spengler reactions and thermally induced -substitution. Systematic π-extension results in a large redshift in optical absorption/emission and enhances fluorescence quantum yield ( ) from 4.

"Two-in-One" DPP Building Blocks for Ambipolar Conjugated Polymers in Flexible Transistors.

Advancements in conjugated donor-acceptor (D-A) polymers with superior semiconducting performance and reliability are pivotal to the evolution of flexible electronics. However, the development of electron-accepting building blocks has lagged far behind that of electron-donating ones, hindering the progression of ambipolar and n-type semiconductor polymers-especially ambipolar types-and thereby limiting the construction of logic circuits and p-n heterojunctions. In this study, we introduce a new electron-accepting building block, , meticulously engineered for semiconducting polymers tailored to flexible electronics applications.

Two new sesquiterpene eudesmanolides from the Raeusch.

Two new sesquiterpene eudesmanolides, 5-hydroxy-eudesman-7(11)-en-8(12)-olide (), and 5-hydroxy-7(11)-en-8-oxo-eudesmane (), along with six known sesquiterpene eudesmanolides, were isolated from the leaves and twigs of Raeusch. The structures of these compounds were established basis on NMR and MS spectroscopic analyses. The cytotoxic activities of the isolated compounds were evaluated.

Penicisteckins A-F, Isochroman-Derived Atropisomeric Dimers from HNNU-5B18.

Penicisteckins A-D (-), two pairs of atropodiastereomeric biaryl-type hetero- and homodimeric bis-isochromans with 7,5'- and 7,7'-linkages and a pair of atropodiastereomeric 2-(isochroman-5-yl)-1,4-benzoquinone derivatives [penicisteckins E () and F ()], were isolated from the HNNU-5B18. Their structures including the absolute configuration were determined by extensive spectroscopic and single-crystal X-ray diffraction analysis and TDDFT-ECD calculations. Both the bis-isochromans and the isochroman/1,4-benzoquinone conjugates represent novel biaryl scaffolds containing both central and axial chirality elements.

A -Baeyer-Villiger oxidation: one-step transformation of tellurophene into chiral tellurinate lactone.

Baeyer-Villiger (BV) oxidation is a fundamental organic reaction, whereas the hetero-BV oxidation is uncharted. Herein, a -BV oxidation is discovered. By oxidizing a tellurophene-embedded and electron-rich polycycle () with CPBA or Oxone, an oxygen atom is inserted into the Te-C bond of the tellurophene to form tellurinate lactone .

Two novel nornemoralisin-type diterpenoids from Aphanamixis polystachya (Wall.) R. Parker.

Two novel heptanornemoralisin-type diterpenoids nornemoralisins A (1) and B (2), together with two known compounds nemoralisin (3) and nemoralisin A (4), were isolated from the stem bark and leaves of Aphanamixis polystachya (Wall.) R. Parker.

Endoplasmic reticulum stress mediated the xanthohumol induced murine melanoma B16-F10 cell death.

Xanthohumol (XN) exerts a specific cytotoxicity in B16-F10 melanoma cells with cytoplasmic vacuoles formation. Further investigation showed XN inhibited cell proliferation in a time- and dose-dependent manner along with down-regulation of mitogen-activated protein kinase and up-regulation of the endoplasmic reticulum (ER) stress marker Bip, CHOP and protein ubiquitination, which was relieved by the ER-stress inhibitor 4-PBA. Whereas no early apoptosis characteristics was identified during XN induced cell death.

Isopimarane-type diterpenoids from .

A new isopimarane-type diterpenoid, crolaevinoid A, along with four known analogues was isolated from the twigs and leaves of . The structures of the isolated compounds were established on the basis of NMR and MS spectroscopic analyses. The isolated compounds were examined the antibacterial activities.

Chemical constituents from common vetch ( L.) and their antioxidant and cytotoxic activities.

L. (common vetch) is a potential food source for both human beings and animals because of its abundant nutritional composition. There is a lack of phytochemical study on the whole plant, and thus the objective of this study was to investigate the isolation of phytochemicals and evaluate their biological activities.

Iridoid Derivatives with Cytotoxic Activity from Pedicularis uliginosa Bunge.

Three new iridoids, rel-(4aR,7S,7aS)-7-hydroxy-7-methyl-1,4a,5,6,7,7a-hexahydrocyclopenta[c]pyran-4-carbaldehyde (1), 1-methoxy-7-methyl-1,3,5,6-tetrahydrocyclopenta[c]pyran-4-carbaldehyde (2), and rel-(1R,4S,4aS,7R,7aR)-7-methylhexahydro-1,4-(epoxymethano)cyclopenta[c]pyran-3(1H)-one (3), together with seven known analogues, were isolated from the 95 % EtOH extract of the whole plants of Pedicularis uliginosa Bunge. Their structures were elucidated via extensive NMR spectroscopy and mass spectral data. In terms of inhibitory effects on human tumor cells, compounds 1, 2, 6, 7, and 8 exhibited better inhibitory activities against ACHN cells than the positive control (vinblastine).

Molecular basis of dimer formation during the biosynthesis of benzofluorene-containing atypical angucyclines.

Lomaiviticin A and difluostatin A are benzofluorene-containing aromatic polyketides in the atypical angucycline family. Although these dimeric compounds are potent antitumor agents, how nature constructs their complex structures remains poorly understood. Herein, we report the discovery of a number of fluostatin type dimeric aromatic polyketides with varied C-C and C-N coupling patterns.

Pyrazolofluostatins A-C, Pyrazole-Fused Benzo[a]fluorenes from South China Sea-Derived Micromonospora rosaria SCSIO N160.

Pyrazolofluostatins A-C (1-3), three new benzo[a]fluorenes with an unprecedented carbon skeleton, were obtained from the South China Sea-derived Micromonospora rosaria SCSIO N160. Their structures were elucidated by extensive spectroscopic analyses. The structure of pyrazolofluostatin A (1) was confirmed by X-ray crystallographic analysis.

Terpenoids from Euphorbia pekinensis.

Euphorpekone A (1) and euphorpekone B (2), two new diterpenoids, 3β-hydroxy-25-methyloxylanosta-8,23-diene, a new triterpenoid (3), together with a known triterpenoid, 3β,25-dihydroxylanosta-8,23-diene (4), were isolated from Euphorbia pekinensis Rupr. Their structures were elucidated on the basis of UV, IR, 1D ((1)H, (13)C, NOE) and 2D ((1)H-(1)H COSY, HSQC, HMBC) NMR, HR-ESI-MS, X-ray diffraction analysis, and CD method.

Pyrone derivatives from the endophytic fungus Alternaria tenuissima SP-07 of Chinese herbal medicine Salvia przewalskii.

Three new pyrones, solanapyrones P-R (1-3), were afforded by the extracts of the endophytic fungus Alternaria tenuissima SP-07 isolated from the fresh root of Chinese herbal medicine Salvia przewalskii, along with the known solanapyrones (4-6) and benzopyrones (7-9). Solanapyrones P (1) and Q (2) possess an unprecedented nor-solanapyrone skeleton as natural products. Their structures were determined on the basis of NMR and HR-ESI-MS analysis.

A new benzopyran derivative from Pseuduvaria indochinensis Merr.

From the twigs and leaves of Pseuduvaria indochinensis Merr., a new benzopyran derivative, pseudindochin (1), was isolated together with three known compounds, oligandrol (2), (6E,10E)-isopolycerasoidol (3) and polycerasoidol (4). The structure of compound 1 was elucidated on the basis of extensive spectroscopic data interpretation, including 1D, 2D NMR, HR-ESI-MS, UV and IR.

The antiangiogenic activity of Kushecarpin D, a novel flavonoid isolated from Sophora flavescens Ait.

Aims: Kushecarpin D (KD) is a novel flavonoid isolated from the traditional Chinese herbal medicine Kushen (the dried root of Sophora flavescens Ait). As part of our continuous effort to explore Chinese traditional medicinal herbs and to identify novel natural anticancer products, the antiangiogenic properties of KD were examined in vitro using a human umbilical vein endothelial cell line (ECV304).

Main Methods: The SRB and Trypan Blue exclusion assays were used to evaluate the effect of KD on cell proliferation.

A novel flavonoid isolated from Sophora flavescens exhibited anti-angiogenesis activity, decreased VEGF expression and caused G0/G1 cell cycle arrest in vitro.

Kushen, the dried root of Sophora flavescens Ait, is a traditional Chinese herbal medicine. Kushen alkaloids have been developed in China as anticancer drugs, and more potent antitumor activities have been identified in kushen flavonoids than in kushen alkaloids. In this study, the anti-angiogenic properties of (2S)-7,2',4'-triihydroxy-5-methoxy-8-dimethylallyl flavanone (Compound 1, a novel flavonoid isolated from Kushen), were examined using the human umbilical vein endothelial cell line (ECV304) in vitro.

Tirucallane-type triterpenoids from Dysoxylum lenticellatum.

Ten new tirucallane-type triterpenoids, represented by a rearranged skeleton dysolenticin A (1), dysolenticin B (2), a rare trinortriterpenoid dysolenticin C (3), three tirucallane triterpenoid derivatives with a hemiketal moiety dysolenticins D-F (4-6), dysolenticins G-I (7, 9, 10), and the new alkaloid dysolenticin J (12), together with seven known analogues were isolated from the twigs and leaves of Dysoxylum lenticellatum. Their structures were elucidated by extensive spectroscopic methods, and those of compounds 1, 3, 4, 6, and 10 were confirmed by single-crystal X-ray diffraction experiments. Dysolenticin J (12) showed significant vasodilative effects on intact rat aortic rings with a diastolic degree of 87.

A new iridoid compound from Patrinia rupestris (Pall.) Juss.

Extraction of roots of Patrinia rupestris (Pall.) Juss. gave a new iridoid compound, 1β,3α-diethyloxy-7-hydromethyl-4-(3-methyl-butyryloxymethyl)-cyclopenta-4(4a),7(7a)-diene[c]pyran-6-one (1), together with a known compound, (1α,4aα, 6α,7β,7aα)-[4a,5,6,7,7a-hexahydro-6,7-dihydroxy-1-(3-methyl-1-oxobutoxy) cyclopenta[c]pyran-4,7-diyl]bis(methylene) 3-methyl-butanoic acid ester (2).

Chemical constituents of Gentiana macrophylla Pall.

A novel dimeric secoiridoid glucoside, gentimacroside (1), and six known compounds (2-7) were isolated from the roots of Gentiana macrophylla Pall. Their structures were established on the basis of spectroscopic analysis, especially by means of 1D-, 2D-NMR and HRESIMS analyses.

Alkaloids from Sophora flavescens Aition.

Although the quinolizidine alkaloids and flavonoids, the main active components of the traditional Chinese medicine Sophora flavescens, have been largely investigated, a new matrine alkaloid derivative 9alpha-hydroxy-7,11-dehydromatrine (1) and a rare 1,4-diazaindan-type alkaloid flavascensine (17), together with 15 known alkaloids, were isolated from S. flavescens. The structures were established on the basis of spectroscopic techniques.

A novel trinorguaiane-type sesquiterpene from Dictamnus radicis.

A novel trinorguaiane-type sesquiterpene named radicol (1), together with a known sesquiterpene dictamnol (2), was isolated from the petroleum ether-EtOAc-MeOH extracts of the root of Dictamnus radicis Cortex. The structure of 1 was elucidated as 1 alpha,5 alpha-dimethyl-4 alpha,10 alpha-bicyclo[3.5.