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Chemical composition screening of octocoral Briareum stechei , collected from Okinawan waters, led to the isolation of 10 briarane-type diterpenoids, including four previously-undescribed metabolites, briastecholides G–J (1 – 4), in addition to six known analogues, brianodin A (5), briarlides G (6) and P (7), and violides G, O, and P (8 – 10). The structures of 1 – 10 were elucidated by spectroscopic methods. Briastecholide D (1) was found to possess an unprecedented 10/6/5/5-fused tetracyclic scaffold. Furthermore, the stereochemistry of brianodin A (5) was elucidated directly by the single-crystal X-ray diffraction analysis for the first time in this study. Briaranes 2 and 5 – 8 reduced the release of iNOS to 17.01, 37.95, 28.76, 1.21 and 26.66%, respectively, at a concentration of 10 μM. [Display omitted] • Four new briaranes, briastecholides G–J (1 – 4) was isolated from an octocoral Briareum stechei. Briastecholide D (1) was found to possess a 10/6/5/5-fused tetracyclic scaffold. • The absolute configuration of brianodin A was confirmed by single-crystal X-ray diffraction analysis. • Briaranes reduced the release of iNOS. [ABSTRACT FROM AUTHOR]

Four low‐spin {FeNO}6 complexes, [Fe(NO)(PS2)(PS2H)] (1, PS2H2 = bis(2‐dimercaptophenyl)phenylphosphine) with a pendant thiol, [Fe(NO)(PS2)(PS2CH3)] (2) bearing a pendant thioether, and [Fe(NO)(PS2)(RPS)] (RH, 4a; RTMS, 4b) without the noncovalent thiol/thioether group are spectroscopically and structurally characterized. In comparisons of the νNO, absorption energy in UV/vis spectra and structural parameters from single X‐ray diffraction studies, the four iron‐nitrosyl‐thiolato compounds share similarity in electronic structure. Complex 1 with a pendant thiol leads to NO and HNO production upon exposure to the light. Photolysis of 2 bearing a pendant thioether only affords NO. Effective detection of HNO or NO from 1 or 2 is achieved by the employment of [MnIII(TMSPS3)(DABCO)]. In contrast, 4a and 4b show inertness toward visible‐light stimulus. Photolysis and having pendant thiol/thioether group play key roles in NO production from these iron‐nitrosyl‐thiolato complexes, that is, the Fe‐NO bond is weakened by exposure to light and the noncovalent SH of 1 or SCH3 of 2 can serve as an incoming ligand to interact with Fe atom, resulting in a transient with intramolecular [RS⋅⋅⋅Fe⋅⋅⋅NO] interaction (RH and CH3) which could facilitate NO dissociation. [ABSTRACT FROM AUTHOR]

[Display omitted] A novel cembranoid, (1 R ,7 R ,8 R ,11 R ,12 R)-7,8:11,12-bisepoxycembrene A (1), was isolated from an octocoral Sinularia sp. The structure of 1 was elucidated using spectroscopic methods, and its absolute configuration was confirmed by a single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

C‐shaped ortho‐benzodipyrrole‐based A‐DNBND‐A non‐fullerene acceptors (NFAs), derived from the removal of the A′ thiadiazole moiety in Y6, emerge as a new class of structurally simplified A‐D‐A‐type NFAs. In this work, a selenium‐substitution strategy is applied to the central DNBND ladder‐π‐core, yielding asymmetric CB‐Se and symmetric CB‐2Se. Asymmetric CB‐Se demonstrates a less ordered 3D trapezoid‐like packing structure, which promotes a more favorable intermixed donor‐acceptor morphology with PM6 polymer, achieving a higher power conversion efficiency (PCE) of 17.87% in organic photovoltaics (OPVs). This value represents the highest reported value among the selenium‐incorporated A‐D‐A‐type NFAs. Symmetric CB‐2Se forms a kaleidoscope‐like 3D single‐crystal structure with enhanced intermolecular interactions. This enables the development of a single‐crystal‐like solution‐processed thin film, which transitions from a kinetically trapped face‐on π–π stacking orientation to a thermodynamically stable edge‐on configuration upon thermal annealing. The CB‐2Se‐based organic field‐effect transistor (OFET) achieved a remarkable electron mobility of 1.18 cm2 V−1 s−1 with exceptional n‐type air stability, which outperformed the corresponding A‐DNA′ND‐A‐type Y6‐based materials by two orders magnitudes and represents the highest reported value for solution‐processed n‐type OFETs utilizing A‐D‐A‐type small molecules. [ABSTRACT FROM AUTHOR]

A d10 Cu(I) two‐dimensional (2D) metal–organic framework (MOF) with chemical formulas, {[Cd(L)(tcm)(H2O)]⋅2H2O}n (1) (L = 1,3,5‐tris(4‐pyridylethynyl)benzene; tcm−1 = tricyanomethanide) was synthesized and structurally characterized by single crystal X‐ray diffraction method. In 1, the coordination geometry of Cu(I) ion is distorted tetrahedral coordinated to four N atoms from three L and one tcm− ligands. A 2D puckered honeycomb‐like layer is formed via the bridges of Cu(I) ions and L ligands with tris‐monodentate coordination mode. Two 2D layers are mutually interpenetrated via the π–π stacking interaction between benzene ring of L ligand and pyridyl ring of neighboring L ligand to form a two‐fold interpenetrated 2D net and then arranged orderly to construct its 3D supramolecular network. Thermal stability and in‐situ temperature‐dependent structural variations of 1 are performed by TG analysis associated with temperature‐dependent PXRD measurement. The water vapor ad‐/de‐sorption isotherm and CO2 adsorption isotherm of 1 are measured and discussed. [ABSTRACT FROM AUTHOR]

During the chemical screening of the sea whip octocoral Junceella fragilis , five chlorine-containing briarane-type diterpenoids featuring with an s-cis -Δ3(E),5(16)-diene conjugated diene system, were discovered. Of these compounds, two are entirely novel entities: (−)-frajunolide H (1) and fragilide Y (2). Additionally, three known analogs were identified: fragilide P (3), junceellolide B (4), and junceellolide C (5). To determine the absolute structures of 1 and 3 , single-crystal X-ray diffraction analysis was utilized. On the other hand, 2D NMR experiments in combination with data from the literature enabled accurate verification of the structure of 2. Moreover, an evaluation of the conformations of previously-discovered briaranes such as frajunolide H and junceellolide B and C was carried out. Among these newly-discovered compounds, fragilide Y possessed anti-inflammatory activity that reduced the expression of cyclooxygenase-2 (COX-2) to 88.70% at a concentration of 10 μM. Altogether, this study yielded valuable information about the unique chemistry and promising pharmacological properties of chlorine-containing briarane diterpenoids from sea whip octocoral. [Display omitted] • Two new chlorine-containing briaranes, (−)-frajunolide H and fragilide Y, were isolated from Junceella fragilis. • The structures, including the absolute configurations, of (−)-frajunolide H and fragilide P, were determined by X-ray diffraction analysis. • The conformation of Δ3(E),5(16)-conjugated diene moiety in frajunolide H, junceellolides B and C, were revised. [ABSTRACT FROM AUTHOR]

A 3Fe4S cluster related to M‐cluster of Mo‐nitrogenase is reported. [K(THF)5][Fe3(μ‐bdt)2(μ‐PPh2)(CO)5] (1) is synthesized from photo‐assisted structural rearrangement of [K(THF)2][(μ,κ2‐bdt)Fe2(μ‐PPh2)(CO)5] under visible light irradiation. The molecular structure of 1 consists of a Fe3 core bearing one dithiolate bridge and the second dithiolate group capping onto the metallic plane. The structural motif of 1 is analogous to that of Mo‐participated 3Fe4S unit in M‐cluster of Mo‐nitrogenase, with the similar Fe‐Fe and Fe‐S bond distances. Upon protonation in 193 K, a Fe‐hydride species (1H) is generated and characterized to possess the bridging hydride group (δ = −12.57 ppm) by 1H‐NMR spectroscopy and DFT calculation. In CH3CN solution, complex 1 exhibits a reversible reduction and oxidation process at E1/2red = −1.94 V and E1/2ox = −0.18 V, respectively, at 273 K. The reduction behavior of 1 in CH2Cl2 solution at 243 K displays a slight modification in the presence of trifluoroacetic acid, revealing a moderate anodic potential shift (~50 mV). The current amplitude of the reduction wave is linearly increased with the increasement of acid added, indicative of the catalytic event. [ABSTRACT FROM AUTHOR]

Two d10 M(II) (M = Cd and Zn) coordination polymers (CPs) with chemical formulas, {[Cd(L1)(NCS)2(H2O)]⋅C2H5OH}n(1), and {[Zn(L1)(NCS)2]⋅C2H5OH⋅0.5H2O}n(2) (L1 = 1,3,5‐tris(4‐pyridylsulfanylmethyl)‐2,4,6‐trimethylbenzene) were synthesized and structurally characterized by single‐crystal x‐ray diffraction method. In compound 1, the coordination environment of Cd(II) ion is distorted octahedral bonded to three nitrogen donors from three L1 ligands located in a facial‐position, two nitrogen donors from NCS− and one water molecule. The L1 acts as a bridge ligand with tris‐monodentate coordination mode in a cis‐cis‐cis structural conformation, connecting the Cd(II) to form a two‐dimensional (2D) zigzag‐like layered metal‐organic frameworks. Adjacent 2D layers are then arranged orderly in an ABAB manner to complete its three‐dimensional (3D) supramolecular architecture. In compound 2, the coordination environment of Zn(II) ion is distorted tetrahedral bonded to two nitrogen donors from two L1 ligands and two nitrogen donors from two NCS− ligands. The L1 acts as a bridge ligand with bis‐monodentate coordination mode in a cis‐cis‐cis structural conformation, connecting the Zn(II) ions to form a one‐dimensional (1D) zigzag‐like polymeric chain. Adjacent chains are arranged orderly in an alternate ABAB manner to generate a 2D framework and then further arranged in an AAA manner to complete its 3D supramolecular architecture. The structural characterization as well as thermal‐stability and solvents de‐/ad‐sorption behavior of 1 and 2 are studied and discussed in details. [ABSTRACT FROM AUTHOR]

Three new polyacetoxybriarane diterpenoids, briavioids A–C (1 – 3), as well as two known analogues, briaexcavatin M (4) and excavatolide F (5), were isolated from a cultured soft coral Briareum violaceum. The structures and relative stereochemistry of new metabolites 1 – 3 were assigned on the basis of NMR studies. Single-crystal X-ray diffraction analysis was performed to identify the structure of 1. Briaranes 1 – 5 were assessed in terms of their inflammation activity by screening their inhibition abilities against iNOS protein in LPS-stimulated RAW264.7 macrophage cells. [Display omitted] • Three previously-undescribed briaranes, briavioids A–C (1 – 3), were isolated from a cultured octocoral Briareum violaceum. • The structure of briavioid A was confirmed by a single-crystal X-ray diffraction analysis. • Excavatolide F reduced the release of iNOS. [ABSTRACT FROM AUTHOR]

The reaction of potassium (aza-15-crown-5)dithiocarbamate (KO4NCS2) and (Me2S)AuCl gave the dinuclear complex [Au(O4NCS2)]2, which underwent structural transformation upon heating to rearrange into the hexanuclear complex [Au(O4NCS2)]6. Under similar reaction conditions, KO4NCS2 reacted with AgNO3 or [Cu(CH3CN)4]ClO4 to give the 1-D coordination polymer [Ag(O4NCS2)]n (1) and the tetranuclear complex [Cu(O4NCS2)]4 (2), respectively. It is noted that upon heating a similar structural transformation process occurs from tetranuclear complex 2 to the octanuclear complex [Cu(O4NCS2)]8 (2′), connected by a weak Cu⋯S contact of 2.846 Å, and it has been isolated and corroborated by powder and single-crystal X-ray diffraction studies as well. Moreover, a variety of MO4NCS2 salts (M = Li+, Na+, K+ and Rb+) were used to react with AgNO3 to construct a series of coordination architectures: [LiAg(O4NCS2)2(μ-H2O)0.5]2 (3), {Na[Ag(O4NCS2)2]}n (4), {K[Ag(O4NCS2)2]}n (5) and {Rb[Ag(O4NCS2)2]}n (6). The smallest Li+ ion only coordinates with four oxygen atoms from the same azacrown ether ring and one H2O molecule, leading to a 1-D hydrogen-bonded chain with another azacrown ether ring for complex 3. The larger Na+ ion coordinates with seven oxygen atoms from two different crown ether rings, leading to a 1-D chain for complex 4. However, the largest K+ and Rb+ ions constitute a 1-D framework, except that each metal ion coordinates with eight oxygen atoms from two different crown ether rings, featuring a 1-D helical chain for complexes 5 and 6. Hence, the different sizes of alkaline metal ions exert a dramatic effect on the structural motifs of complexes 3–6. Remarkably, the dithiocarbamate moieties adopt μ2-bridging ([Au(O4NCS2)]2 and [Au(O4NCS2)]6), μ3- and μ4-bridging (1–2) and chelate forms (3–6) in the structural backbones. [ABSTRACT FROM AUTHOR]

Molybdenum trioxide (MoO3) with a theoretical specific capacity of 1117 mA h g−1 is widely considered a promising anode material for lithium-ion batteries. However, the irreversible conversion reactions, low electrical conductivity, and detrimental volume expansion upon Li intercalation between the one-dimensional layered structures of MoO3 hinder its practical implementation. Herein, we report a facile synthetic protocol that allows surficial modification by replacing the terminal and bridging oxo groups of molybdenum oxide clusters. Successful organoimido functionalization resulted in a large cathodic shift in Mo(VI / V) reduction by 0.6 V, pronounced electronic communication between the organic moiety and the metal–oxide unit, and significant increase in electrical conductivity (80–100 Ω interfacial charge-transfer resistance). Combined with the enlarged active surface area due to the structural hindrance induced by the organic functionality, the steady specific capacity of the organoimido-modified molybdenum oxide clusters was greater than 1200 mA h g−1 at 900 mA g−1 at the end of 360 cycles, where the best value of 1653 mA h g−1 was achieved for the nitroaniline-substituted species. The steady capacity of 480 mA h g−1 was achieved in the fast charge–discharge process (3000 mA g−1) over 1400 cycles. The results indicate that the surficial modification of metal oxides with organo moieties using our facile synthetic method has broad application potential for metal oxides to be used as high-capacity electrode materials in the future. [ABSTRACT FROM AUTHOR]

• Cu(II) coordination polymer and trinickel EMACs were synthesized and structurally characterized using the unsymmetrical pyrazine-modulated Hppza ligand. • Magnetic interaction parameters for 3 (J = −199.2 cm−1) and 4 (J = −178.0 cm−1) support superexchange pathways along metal cores. • Due to the electron-withdrawing effect of pyrazine, the nickel strings of Hppza are readily reduced, retarding oxidation. • The activities of ligands and their nickel string complexes against various proteins were compared with theoretical calculations, and then the ADME/T properties of molecules were examined. • The interactions occurring in the molecular docking calculation were examined in detail with the Protein-Ligand Interaction Profiler (PLIP) service. The unsymmetrical pyrazine-modulated ligand, N-(pyridine-2-yl)pyrazin-2-amine (Hppza) (1), its 1D straight-chain copper (II) coordination polymer [Cu 2 (Hppza) 2 ∙(NO 3) 4 ] n (2) and trinuclear metal string [Ni 3 (µ 3 -ppza) 4 Cl 2 ] (3) and [Ni 3 (µ 3 -ppza) 4 (NCS) 2 ] (4) complexes have been successfully synthesized and structurally characterized. The free ligand Hppza (1) exhibits anti-syn conformation. In an asymmetric unit of 2 , there are two kinds of Cu(II) atoms, both of which have elongated octahedral coordination geometry, and the copper(II) centers are linked by oxygen atoms of one nitrate anion. There are only minor differences in Ni...Ni bond lengths between pyrazine-modulated ligand complexes of [Ni 3 (μ 3 -ppza) 4 × 2 ] (X = Cl− (3), NCS− (4)) and their unmodulated analogs, while the distances between the terminal nickel atoms and the axial ligands 3 and 4 are shorter. The results of magnetic susceptibility measurements showed an antiferromagnetic exchange constant (J) of about J = –199.2 cm–1 for 3 and J = –178.0 cm–1 for 4. The electrochemical properties of nickel strings of Hppza differ significantly from their unmodulated counterparts. The activities of ligands and their metal complexes against various proteins that are AChE (PDB ID: 4M0E), BChE (PDB ID: 5NN0), α-Gly (PDB ID: 1UAS), hCA I (PDB ID: 2CAB), and hCA II (PDB ID: 3DC3) were compared, and then the ADME/T properties of molecules were examined. Afterward, the interactions occurring in the docking calculation were examined in detail with the Protein-Ligand Interaction Profiler (PLIP) service. These complexes were inhibitors of BChE, hCA I and II, α-glycosidase and AChE enzymes for complex 3 and 5 with Ki values of 12.65 and 42.95 μM for hCA I, 3.64 and 15.84 μM for hCA II, 5.44 and 50.07 μM for BChE, 15.85 and 4.77 μM for α-glycosidase and 8.58 and 86.24 μM for AChE, respectively. The unsymmetrical pyrazine-modulated ligand, N-(pyridine-2-yl)pyrazin-2-amine (Hppza) (1), its straight chain copper (II) coordination polymer [Cu 2 (Hppza) 2 (NO 3) 4 ] n (2) and trinickel string complexes [Ni 3 (µ 3 -ppza) 4 Cl 2 ] (3) and [Ni 3 (µ 3 -ppza) 4 (NCS) 2 ] (4) have been successfully synthesized and structurally characterized. The activities of ligands and their metal complexes against various proteins were compared with theoretical calculations, and then the ADME/T properties of molecules were examined. Afterward, the interactions occurring in the docking calculation were examined in detail with the Protein-Ligand Interaction Profiler (PLIP) service. [Display omitted] [ABSTRACT FROM AUTHOR]

It is well known that phonon-induced relaxation processes play a significant role in accelerating magnetization relaxation in the low-temperature regime. Unfortunately, many SIMs (single-ion magnets) suffer from being quenched by these mechanisms such that neither out-of-phase signals nor magnetization hysteresis can be readily observed. Nevertheless, because it involves molecular motions at low-frequency (low-energy) levels, methods for synthetically controlling this factor have not yet been addressed by chemists. In this study, we prepared a series of three compounds in which one contains a rigid chelating ligand, and the other two contain analogous ligands that can coordinate more liberally. To our surprise, compound 1, with a rigid chelating ligand, displayed promising SIM behavior with out-of-phase signals up to 11 K in a zero d.c. magnetic field at an a.c. frequency of 1000 Hz. The other two (2 and 3) with dangling ligands failed to show significant out-of-phase signals until an extra d.c. field was applied. The results of magnetization relaxation studies suggest that the phonon-induced relaxation processes play an essential role in 2 and 3, even at very low temperatures. Nevertheless, the rigid chelating ligand in 1 prevents the molecule from being involved in phonon-induced relaxation processes that seriously interfere with the magnetization relaxation up to 5.6 K. Therefore, we concluded that the presence of a rigid chelating ligand can efficiently change the phonon-induced relaxation processes at low temperatures. [ABSTRACT FROM AUTHOR]

Graphene, as one of the carbon-based materials, is considered to be a potential replacement for platinum and has been widely used as a counter electrode in dye-sensitized solar cells to achieve low-cost and high electrocatalytic materials. In this work, we synthesized a nitrogen-sulfur-coordinated iron complex as a source of heteroatoms, and prepared iron-nitrogen-sulfur co-doped reduced graphene oxide (FeNS-rGO) composite material by mixing with different mass ratios of graphene oxide (GO) and thermal annealing under nitrogen at 400 °C. The sintered GO was transformed into rGO, which increased the conductivity of materials, while the doping of nitrogen and sulfur atoms enhanced the carrier mobility and conductivity of the material. The distribution of Fe on graphene also improved the catalytic performance of material. FeNS-rGO (5:1), used as the CE in DSSC, showed superior reduction catalytic activity for I−/I 3 − compared to platinum and demonstrated an excellent power conversion efficiency of 8.17 %, which outperformed platinum. This proves that the graphene composite material doped with iron, nitrogen, and sulfur has excellent performance and can be used as a substitute for platinum. [Display omitted] • A planar nitrogen-sulfur coordinated iron complex as a heteroatom dopant. • The iron-nitrogen-sulfur co-doped reduced graphene oxide (FeNS-rGO) improves the conductivity and catalytic performance. • The FeNS-rGO exhibits excellent electroactivity for the reduction of triiodide ions (I 3 −) in DSSCs. • The DSSCs incorporating the FeNS-rGO as counter electrodes demonstrate high power conversion efficiencies. [ABSTRACT FROM AUTHOR]

• A novel sterol was isolated from the soft coral Lobophytum durum. • The absolute configuration of sterol 3 was determined through X-ray analysis. • The soft coral Lobophytum durum is a rich source of marine sterols. Chromatographic investigation on the ethyl acetate extract of the soft coral Lobophytum durum collected from the waters of Guishan Island in northeast Taiwan resulted in the isolation of three sterols 1 – 3 , including one new sterol, 3 β -hydroxy-25-methylene-5-cholesten-7-one (1), and two previously reported sterols, 7-oxogorgosterol (2), and (24 R)-ergostane-3 β ,5 α ,6 β ,25-tetraol 25-monoacetate (3). The structures of sterols 1 – 3 were determined by extensive spectroscopic data analysis and by comparison with literatures. Additionally, the 24 R -configuration of sterol 3 was identified by a single-crystal X-ray diffraction analysis and 13C chemical shifts for first time. The anti-inflammatory activities of sterols 1 – 3 were evaluated by examining their inhibitory effects on the generation of superoxide anions and the release of elastase against activated human neutrophils. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • An uncommon spiroketal steroid, 24-dehydrohippuristaol (1), was isolated from Isis hippuris. • 24-Dehydrohippuristaol is the first Δ24(28)-hippuristanol derivative. • 24-Dehydrohippuristaol showed cytotoxicity towards DLD-1 and LoVo cells. Chemical screening of a Formosan sea bamboo octocoral Isis hippuris have led to the isolation of nine spiroketal steroids, including a new metabolite, 24-dehydrohippuristanol (1), a new natural product, hippuristanol 11-one (2), as well as seven known analogs, hippuristanol (3), 22- epi -hippuristanol (4), hippurin-1 (5), 22- epi -hippurin-1 (6), 3-acetyl-22- epi -hippurin-1 (7), 3α-acetoxy-11β-hydroxy-24-methyl-22,25-epoxy-5α-furostan-18,20β-lactone (8) and (22 S)-3α-acetoxy-11β,18α-dihydroxy-24-methyl-18,20β;22,25-diepoxy-5α-furostane (9). The structures of steroids 1 – 9 were corroborated by 2D NMR experiments and comparison with literature data. The configurations of steroids 3 , 4 , 6 and 9 , obtained in previous studies, were reported for the first time in this study by single-crystal X-ray diffraction analysis. Steroid 1 exhibited cytotoxic effects against DLD-1 and LoVo cancer cells with IC 50 values of 5.54 and 6.89 μM, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • A rare 7β,8β-epoxybriarane, briavioid D (1), was isolated from Briareum violaceum. • The structure of briarane 1 was determined by a single-crystal X-ray diffraction analysis. • Briavioid D is the first example of briarane analog possessing a 7,8‑epoxy group in the γ-lactone moiety. A rare 7β,8β-epoxybriarane, briavioid D (1), has been isolated from a cultured octocoral Briareum violaceum. The structure of 1 was deduced by extensive 2D NMR studies. Single-crystal X-ray diffraction analysis was performed to identify the structure of 1 and this compound was found to reduce the release of iNOS to 85.77 %, at a concentration of 10 μM. [ABSTRACT FROM AUTHOR]

[Display omitted] • 17,20-epoxysteroids, hippuristeroketal B (1), hippuristerones A (2) and I (3), were isolated from octocoral Isis hippuris. • The absolute stereochemistry of steroids 1 – 3 was determined by single-crystal X-ray diffraction analysis. • Hippuristerone A (2) exhibited cytotoxic effect against HT-29 and DLD-1 cancer cells. Three 17,20-epoxysteroids, including a new metabolite, hippuristeroketal B (1), as well as two known compounds, hippuristerones A (2) and I (3), have been isolated from octocoral Isis hippuris collected off the waters of Taiwan. The structure of steroid 1 was deduced by extensive 1D and 2D NMR studies. The absolute stereochemistry of steroids 1 – 3 was determined by single-crystal X-ray diffraction analysis. Steroid 2 exhibited cytotoxic effect against HT-29 and DLD-1 cancer cells with IC 50 values of 11.39 and 12.86 μM, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two new 8,17-epoxybriaranes, briastecholides K and L, were obtained from octocoral Briareum stechei. • The absolute configuration of excavatolide E was confirmed by single-crystal X-ray diffraction analysis. Octocorals belonging to genus Briareum were proven to be rich sources of briarane-type diterpenoids. Three 8,17-epoxybriaranes, including a known metabolite, excavatolide M (1), as well as two new compounds, briastecholides K (2) and L (3), have been isolated from octocoral Briareum stechei collected off the waters of Taiwan. In this study, the absolute configuration of 1 was determined by single-crystal X-ray diffraction analysis for the first time. Moreover, the structures and stereochemistry of briaranes 2 and 3 were established based on spectroscopic analysis and comparison with those of 1. [ABSTRACT FROM AUTHOR]

Two novel chlorine-containing cembranoids, chlorofurancembranoids A (1) and B (2), were isolated from an octocoral identified as Sinularia sp. The structures of 1 and 2 were elucidated using spectroscopic methods, and the absolute configuration of 1 was further confirmed by single-crystal X-ray diffraction analysis. Cembranoid 2 showed cytotoxicity towards human promyelocytic leukemia HL-60 cells, with an IC 50 value of 3.67 μM. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Four manzamine-type alkaloids, including a novel compound, manzamine A 27- N -oxide (1), as well as three previously reported analogues, manzamines A (2), E (3), and 8-hydroxy- manzamine A hydrochloride (4) were isolated from the organic extract of marine sponge Neopetrosia proxima. The structures of 1 – 4 were determined based on spectroscopic data and 1 was proved to be the first manzamine alkaloid possessing the 27- N -oxide moiety. The structures, including absolute configurations of 1 and 4 , were established using single X-ray diffraction analysis. Compounds 1 – 3 showed cytotoxicity towards Hep3B (IC 50 = 10.1, 3.8, 5.8 μM), SC-M1 (IC 50 = 11.7, 3.7, 5.6 μM) and MCF-7 (IC 50 = 10.6, 4.1, 4.2 μM) tumor cells. [ABSTRACT FROM AUTHOR]