Unprecedented Carbon Research Articles

A study on generation of embossed carbon nanopattern by induced microdomain alignments in PAN-based block copolymer under electric field

In this study, generation of a unique carbon nanostructure having embossed morphology was examined focusing on formation pathway under an external electric field. An ultrathin embossed carbon layer was prepared by exposing a polyacrylonitrile-based block copolymer (BCP) thin film to an electric field. A detailed investigation on formation process and window for experimental parameters such as field intensity and exposure time was performed systematically. An electric field was applied to prepared BCP thin films to induce regulated microdomain alignments, and subsequent thermal treatment produced an unprecedented carbon nanostructure having a unique morphology. Atomic force microscopy analysis showed that a critical field strength (ca. 10 V/μm) and exposure time (24 h) were required to obtain the carbon nanostructure. This article can provide important information for future studies on creation of nanopatterns with electric fields.

Unusual carbon nanomesh constructed by interconnected carbon nanocages for ionic liquid-based supercapacitor with superior rate capability

The exploration of various porous nanocarbon materials with an extraordinary electrochemical capacitive performance in ionic liquid (IL) electrolytes is urgently needed for development of the next-generation energy storage devices. Significant improvements in energy density have been achieved, however, supercapacitors with IL electrolytes usually suffer from issues related to low power density and large IR drop. Herein, we report an unprecedented carbon nanomesh that is made up of interconnected densely-packed carbon nanocages with ultrathin partially graphitic shells. The large specific surface area and well-developed mesopores combined with its unique structural features, make it a very competitive material for high-performance supercapacitor in IL electrolyte. Notably, this unique nanosheets morphology with lots of in-plane nanopores on their surface can provide fast cross-plane ion diffusion pathways, and meanwhile, the carbon nanocages with partially graphitic shells ensure the rapid electron transfer. The supercapacitor assembled with the optimized sample can deliver a high specific capacitance (up to 194 F/g at 1 A/g), superior rate capability (68% capacitance retention at 70 A/g), low IR drop (0.685 V at 70 A/g). Moreover, benefiting from the wide working voltage and high-rate capability, the energy densities can maintain at 56.1 Wh/kg even at an ultrahigh power density of 61.250 kW/kg. Strikingly, the as-assembled supercapacitor can successfully power a light-emitting diodes (LED, 2.2 V) module with 53 red LED lights demonstrating its great potential for practical applications in energy storage devices.

Xeniaphyllane-Derived Terpenoids from Soft Coral Sinularia nanolobata

A novel tetranorditerpenoid, sinubatin A (1) (having an unprecedented carbon skeleton), a new norditerpenoid, sinubatin B (2) (a 4,5-epoxycaryophyllene possessing an unusual methylfuran moiety side chain), and a known diterpenoid, gibberosin J (3) were isolated from soft coral Sinularia nanolobata. The structures of the new compounds were elucidated by extensive analysis of spectroscopic data.

Cajanusflavanols A-C, Three Pairs of Flavonostilbene Enantiomers from Cajanus cajan.

Three pairs of new flavonostilbene enantiomers, cajanusflavanols A-C (1-3), along with their putative biogenetic precursors 4-6, were isolated from Cajanus cajan. Compound 1 possesses an unprecedented carbon skeleton featuring a unique highly functionalized cyclopenta[1,2,3-de]isobenzopyran-1-one tricyclic core. Compounds 2 and 3 are the first examples of methylene-unit-linked flavonostilbenes. Their structures with absolute configurations were elucidated by spectroscopic analyses, X-ray diffraction, and computational calculations. Compounds 1 and 2 exhibited significant in vitro anti-inflammatory activities.

Aconicarmisulfonine A, a Sulfonated C20-Diterpenoid Alkaloid from the Lateral Roots of Aconitum carmichaelii.

A novel sulfonated C20-diterpenoid alkaloid with an unprecedented carbon skeleton and significant analgesic activity (46.7% inhibition at 0.1 mg/kg, i.p.), named aconicarmisulfonine A (1), was isolated from an aqueous extract of the lateral roots of Aconitum carmichaelii. Its structure was determined by comprehensive analysis of spectroscopic data, especially by 2D NMR spectroscopic data combined with ECD calculation and single-crystal X-ray diffraction. The plausible biosynthetic pathways of compound 1 are also discussed.

Fusarithioamide B, a new benzamide derivative from the endophytic fungus Fusarium chlamydosporium with potent cytotoxic and antimicrobial activities

Fusarithioamide B (6), a new aminobenzamide derivative with unprecedented carbon skeleton and five known metabolites: stigmast-4-ene-3-one (1), stigmasta-4,6,8(14),22-tetraen-3-one (2), p-hydroxyacetophenone (3), tyrosol (4), and fusarithioamide A (5) were separated from Fusarium chlamydosporium EtOAc extract isolated from Anvillea garcinii (Burm.f.) DC. leaves (Asteraceae). The structure elucidation and completeassignment of the isolated metabolites were performed mainly by the aid of various NMR and MS data. Fusarithioamide B (6) has been assessed for antibacterial and antifungal activities towards various microbial strains by disc diffusion assay. It exhibited selective antifungal activity towards C. albicans (MIC 1.9 µg/ml and IZD 14.5 mm), comparing to clotrimazole (MIC 2.8 µg/ml and IZD 17.9 mm). Also, it possessed high antibacterial potential towards E. coli, B. cereus, and S. aureus compared to ciprofloxacin. Furthermore, 6 was tested for the in vitro cytotoxic effect against KB, HCT-116, BT-549, MCF-7, SKOV-3, and SK-MEL cell lines. It had selective and potent effect towards BT-549, MCF-7, SKOV-3, and HCT-116 cell lines with IC50s 0.09, 0.21, 1.23, and 0.59 μM, respectively compared to doxorubicin (IC50s 0.046, 0.05, 0.321, and 0.24 μM, respectively). Fusarithioamide B may provide a lead molecule for future developing of antitumor and antimicrobial agents.

Synthesis of the Epimeric Secosteroids Strophasterols A and B.

Two epimeric rearranged ergostanes, strophasterols A and B, with an unprecedented carbon skeleton were synthesized from ergosterol, both in 17 steps via a common secosteroidal intermediate. The conversion of ergosterol into the pivotal intermediate involved an efficient acid-catalyzed double-bond migration from ring B to ring D, oxidative cleavage of the double bond, and a completely diastereoselective acyl radical cyclization to form an isolated cyclopentanone ring unique to this recently discovered family of steroidal compounds produced by mushrooms. The intermediate was transformed stereodivergently into two epimeric cyclopentane derivatives through hydrogenation using two types of catalysts. One epimer was elaborated into strophasterol B by utilizing peracid oxidation of an iodide to provide an epoxide directly, and the other epimer was elaborated into strophasterol A, which is known to be a suppressor of endoplasmic reticulum stress.

Synthesis of the Epimeric Secosteroids Strophasterols A and B

AbstractTwo epimeric rearranged ergostanes, strophasterols A and B, with an unprecedented carbon skeleton were synthesized from ergosterol, both in 17 steps via a common secosteroidal intermediate. The conversion of ergosterol into the pivotal intermediate involved an efficient acid‐catalyzed double‐bond migration from ring B to ring D, oxidative cleavage of the double bond, and a completely diastereoselective acyl radical cyclization to form an isolated cyclopentanone ring unique to this recently discovered family of steroidal compounds produced by mushrooms. The intermediate was transformed stereodivergently into two epimeric cyclopentane derivatives through hydrogenation using two types of catalysts. One epimer was elaborated into strophasterol B by utilizing peracid oxidation of an iodide to provide an epoxide directly, and the other epimer was elaborated into strophasterol A, which is known to be a suppressor of endoplasmic reticulum stress.

Rhodomollanol A, a Highly Oxygenated Diterpenoid with a 5/7/5/5 Tetracyclic Carbon Skeleton from the Leaves of Rhododendron molle.

A novel diterpenoid with an unprecedented carbon skeleton, rhodomollanol A (1), and a new grayanane diterpenoid, rhodomollein XXXI (2), were isolated from the leaves of Rhododendron molle. Their structures were elucidated using comprehensive spectroscopic methods and single-crystal X-ray diffraction. Compound 1 possesses a unique cis/trans/trans/cis/cis-fused 3/5/7/5/5/5 hexacyclic ring system featuring a rare 7-oxabicyclo[4.2.1]nonane core decorated with three cyclopentane units. The plausible biosynthetic pathway for 1 was proposed. Compound 1 exhibited moderate PTP1B inhibitory activity.

Abstract 3253: Targeting G-quadruplex nucleic acids: a series of β-carboline alkaloids with new skeletons from the seeds of Peganum harmala

Abstract G-quadruplexes are DNA secondary structures implicated in essential physiological and pathological processes, such as tumorgenesis. Small molecules which can stabilize or induce G-quadruplex formation have potential as antitumor agents through the alteration of oncogene expression levels or the disruption of telomere maintenance. Targeting G-quadruplex nucleic acids, we screened 17 medicinal plants for binding activity to a model G-quadruplex d(TTGGGTT)4 system by 1H NMR experiment. We found that the crude extract of Peganum harmala L. seeds showed the most potential binding activity and specific cytotoxicity against the PC-3 cancer cell line with an IC50 value of 13.65 μg/mL. Subsequently, 1H NMR and bioassay co-guided isolation of the extract of P. harmala L. was performed and obtained 21 new alkaloids, including 10 novel β-carboline alkaloids with unprecedented carbon skeletons, and 12 known analogues. Their structures including the absolute configurations were determined by extensive analysis of spectroscopic data, X-ray crystallography, ECD calculations, and ECD exciton chirality approaches. The antiproliferative activities and G-quadruplex binding activities were evaluated for these newly discovered and previously reported alkaloids. Some of the isolates showed pronounced cytotoxic effects with IC50 values below 10 µM and significant G-quadruplex binding activities. More interestingly, pegaharmine D (4), which showed the strongest G-quadruplex interaction, exhibited significant cytotoxic activity against HL-60, PC-3 and SGC-7901 cell lines, with IC50 values of 3.81 ± 0.32, 11.52 ± 0.62, and 15.16 ± 0.42 µM, respectively. The G-quadruplex interactions positively correlated with antiproliferative activities suggesting these β-carboline alkaloids may exert their anti-cancer effects through G-quadruplex interactions. This work contributed a practical strategy at first time for the discovery of novel G-quadruplex ligands from natural products and provided potential insights for using β-carboline alkaloids as anticancer lead compounds specifically targeting G-quadruplexes. Citation Format: Kaibo wang, Huiming Hua, Danzhou Yang. Targeting G-quadruplex nucleic acids: a series of β-carboline alkaloids with new skeletons from the seeds of Peganum harmala [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3253. doi:10.1158/1538-7445.AM2017-3253

Phase-Transition Nanodroplets for Real-Time Photoacoustic/Ultrasound Dual-Modality Imaging and Photothermal Therapy of Sentinel Lymph Node in Breast Cancer

Pathological status of lymph nodes (LNs) plays a critical role in staging and treatment for the patients with breast cancer. Sentinel lymph node biopsy has become the standard method in determining pathological status of axillary LNs. Therefore, the determination of sentinel lymph nodes (SLNs) and therapy of metastatic LNs are highly desirable in clinic. Herein, an unprecedented carbon nanoparticles (CNs)-incorporated liquid-gas phase-transition nanodroplets (CNPs) with strong near-infrared (NIR) absorption, good biocompatibility, excellent photoacoustic (PA) and ultrasound (US) contrast, and high photothermal-conversion efficiency are reported in this study. Upon laser irradiation, liquid-gas phase transition of the CNPs has been demonstrated to provide excellent contrasts for PA/US dual-modality imaging both in vitro and in vivo. Additionally, the CNPs are capable of staining lymph nodes, which can contribute significantly to the identification of LNs with naked eyes. With increased laser energy, the CNPs exhibit the high performance in killing the breast cancer cells both in vitro and in vivo, due to the photothermal effect induced from the CNs within CNPs. These results suggest that the developed multifunctional phase-transition nanodroplets have high potential to act as the theranostic agents in both SLNs detection and therapy of metastatic LNs.

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. Notably, 1-3 possessed a benzo[cd]indeno[2,1-f]indazol skeleton with a pyrazole-fused 6/5/6/6/5 pentacyclic ring system. Pyrazolofluostatin A (1) showed moderate antioxidation activity (EC50 48.6 μM).

A novel withanolide with an unprecedented carbon skeleton from Physalis angulata.

A novel withanolide, aromaphysalin A (1), possessing an exceptional C(11)-C(15) bond and an unprecedented 4,9-cyclized aromatic ring (ring A), is isolated from stems and leaves of Physalis angulata L. Its structure was determined by a combination of HRESIMS, 2D NMR spectra, and theoretical calculations. Compound 1 exhibited inhibitory activity on NO production with an IC50 value of 51.64 μM. A plausible biosynthetic pathway for 1 is also discussed.

Unprecedented carbon sub-microspheres with a porous hierarchy for highly efficient oxygen electrochemistry.

Developing efficient and robust electrocatalysts for bifunctional oxygen electrocatalysis is crucial for renewable energy technology. Herein, nitrogen and phosphorus co-doped carbon sub-microspheres with fascinating mesostructures are rationally synthesized through an effective soft-templating strategy. The unique features of substantial doping, large surface areas and well-defined porosity endow the dual-doped carbons with high-density electroactive sites, considerable active surface areas and improved mass transfer, ensuring impressive activity and durability in catalyzing oxygen reduction and evolution reactions, even competing with the noble metal benchmarks, thus assuring their use as an air cathode in a rechargeable Zn-air battery with low charge-discharge overpotential and remarkable long-term stability.

Commiphoranes A-D, Carbon Skeletal Terpenoids from Resina Commiphora.

Commiphoranes A-D (1-4), four novel aromatic terpenoids with unprecedented carbon skeletons, were isolated from Resina Commiphora. Their structures were identified by spectroscopic and crystallographic methods. Compounds 1 and 2 are dinorditerpenoids characteristic of a 6/6/6/6 ring system. In contrast, compounds 3 and 4 are sesquiterpenoids possessing a 5/6/7 backbone. Biological evaluation reveals that 3 could significantly attenuate overproduction of fibronectin, collagen I, and α-SMA in TGF-β1-induced rat renal proximal tubular cells.

Spirodalesol, an NLRP3 Inflammasome Activation Inhibitor.

Autoimmune and inflammatory diseases are associated with inappropriate activation of the NOD-like receptor protein 3 (NLRP3) inflammasome, but suitable inhibitors against such improper activations remain scarce. Here, spirodalesol (1) from Daldinia eschscholzii was structurally characterized and is biosynthetically proposed as an NLRP3 inflammasome activation inhibitor with an unprecedented carbon skeleton.

Synthesis of Novel Tetranorlabdane Derivatives with Unprecedented Carbon Skeleton

Synthesis of novel tetranorlabdane derivatives including hybride with terpeno-(1,2)-diazine units and dimers with an unprecedented carbon skeleton, was performed based on methyl 7-oxo-13,14,15,16-tetranorlabd-8-en-12-oate intermediate. The structures of the synthesized compounds have been fully confirmed, including by X-ray diffraction, and their antifungal and antibacterial activity was tested. A possible mechanistic pathway of the cycloaddition reaction is considered.

ChemInform Abstract: Merohyperins A—C, Meroterpenes from the Leaves of Hypericum chinense.

Abstract Two new C 15 meroterpenes with unprecedented carbon skeletons, merohyperins A ( 1 ) and B ( 2 ), were isolated from the leaves of Hypericum chinense together with a new C 13 meroterpene, merohyperin C ( 3 ). The structures of 1 – 3 were elucidated on the basis of spectroscopic analyses, chemical conversion, and calculations of the NMR spectra. Merohyperins A ( 1 ) and B ( 2 ) have a γ-lactone moiety and a tetrahydrofuran moiety, respectively. Merohyperin C ( 3 ) was obtained as a separable epimeric mixture and assigned as a decarbonyl analog of the known meroterpene, hyperolactone A.

Citrinovirin with a new norditerpene skeleton from the marine algicolous fungus Trichoderma citrinoviride

Citrinovirin (1), a novel norditerpene with an unprecedented carbon skeleton along with three known compounds, cyclonerodiol (2), 3-(2-hydroxypropyl)-4-(hexa-2E,4E-dien-6-yl)furan-2(5H)-one (3), and 5-hydroxy-3-hydroxymethyl-2-methyl-7-methoxychromone (4), was isolated from the culture of a marine brown alga-endophytic strain (cf-27) of Trichoderma citrinoviride. The structure and relative configuration of 1 were identified by spectroscopic methods, including 1D/2D NMR and MS. Its absolute configuration was established by analysis of ECD spectrum, aided by quantum chemical calculations. A plausible biogenetic pathway is proposed for 1, and it was evaluated to be active against Staphylococcus aureus.

Cephalotanins A–D, Four Norditerpenoids Represent Three Highly Rigid Carbon Skeletons from Cephalotaxus sinensis

Four polycyclic norditerpenoids, cephalotanins A-D (1-4) representing three unprecedented carbon skeletons with highly rigid ring systems, were isolated from Cephalotaxus sinensis and structurally characterized by a combination of various methods. Compounds 1 and 2 are new skeletal norditerpenoid trilactones, while 3 and 4 are two norditerpenoids featuring different new carbon skeletons. Biosynthetic pathways for 1-4 were proposed by involving diverse and very fascinating chemical events with the coexisting cephalotane troponoids as the precursors. Compound 1 exhibited good NF-κB inhibition with an IC50 value of 4.12±0.61 μΜ.