Complanadine B, obscurumines A and B, new alkaloids from two species of Lycopodium

A new dimer of C₁₆N₂ type alkaloid, complanadine B (1), and two new C₁₆N type alkaloids, obscurumines A (2) and B (3), have been isolated from the club moss Lycopodium complanatum and L. obscurum, respectively. The structures and stereochemistry of 1-3 were elucidated by combination of 2D NMR spectra and chemical transformation. Complanadine A (4) isolated together with 1 induced secretion of neurotrophic factors from human astrocytoma cells.     

Quinoxaline-annelated Z-shaped quadruple-bridged orthocyclophanes: synthesis and crystal structures

A three-step synthesis of nineteen Z-shaped quadruple-bridged [6,6] and [6,4]orthocyclophanes comprising two quinoxaline-based sidewalls are described. The synthesis began from the bis-Diels−Alder adducts B1-B3 followed by ruthenium-promoted oxidation of dichloroetheno-bridges in the adducts to generate a bis-α-diketones, which were then condensed with various arene-1,2-diamines (9a-g) to construct sidewalls (phane parts) of Z-shaped quadruple-bridged orthocyclophanes D1-3, D2g, and D3g. Single-crystal structures of six orthocyclophanes (D1a, D2a, D2f, D3f, D2g-α, and D3g-α) were obtained and revealed that the C_Ar−H?π and π?π stacking interactions between N-containing arene rings are the major driving force for molecular assembly and crystal packing, in addition to the interactions involving the polar OCH₃ groups and the solvate molecules.     

New phlegmarane-type, cernuane-type, and quinolizidine alkaloids from two species of Lycopodium

Two new phlegmarane-type alkaloids, cermizines A (1) and B (2), three new quinolizidine alkaloids, cermizine C (3) and senepodines G (4) and H (5), and a new C₁₆N₂ type alkaloid consisting of a quinolizidine and a piperidine ring, cermizine D (6), as well as two new cernuane-type alkaloids, cernuine N-oxide (7) and lycocernuine N-oxide (8), have been isolated together with cernuine (9) and lycocernuine (10) from the club moss Lycopodium cernuum and L. chinense. The relative stereochemistry of 1-4 and 6, and the absolute stereochemistry of 5, 7, and 8 were elucidated by combination of NOESY correlations, modified Mosher's method, chemical transformations, and computational methods. Cermizine D (6) might be a biosynthetic intermediate of cernuane-type alkaloids such as 7-10.     

Vincamajorines A and B,monoterpenoid indole alkaloids with new carbon skeletons from Vinca major

Two new monoterpenoid indole alkaloids, vincamajorines A (1) and B (2), were isolated from Vinca major. Their structures were elucidated by means of 1D and 2D NMR, and HREIMS spectroscopic data. The relative and absolute configurations were deduced by comparing the experimental ¹³C NMR, ECD spectra, and OR data with those theoretically calculated. Vincamajorine A (1) represents a new C₂₀ carbon skeleton arranged compactly in seven rings, and vincamajorine B (2) is an alkaloid with an unprecedented 6/5/7/5/6 pentacyclic ring system. A possible biosynthetic pathway was also proposed for the formation of 1 and 2.     

Ecionines A and B, two new cytotoxic pyridoacridine alkaloids from the Australian marine sponge, Ecionemia geodides

Chemical investigations of the Australian marine sponge Ecionemia geodides resulted in the isolation of two new pyridoacridine alkaloids, ecionines A (1) and B (2), along with the previously isolated marine natural products, biemnadin (3) and meridine (4). Compounds 1 and 2 both contain an imine moiety, which is rare for the pyridoacridine structure class. The chemical structures of 1 and 2 were determined by extensive 1D and 2D NMR and MS data analyses. All compounds were tested against a panel of human bladder cancer cell lines, the increasingly metastatic TSU-Pr1 series (TSU-Pr1, TSU-Pr1-B1 and TSU-Pr1-B2) and the superficial bladder cancer cell line 5637. Ecionine A (1) displayed cytotoxicity against all cell lines, with IC₅₀ values ranging from 3 to 7 μM. This is the first report of chemistry from the sponge genus Ecionemia.     

Lyconadins C and F, new Lycopodium alkaloids from Lycopodium complanatum

New Lycopodium alkaloids, lyconadins C (1) and F (2), were isolated from the club moss Lycopodium complanatum. Lyconadin C (1) is a new C₁₆N₂-type Lycopodium alkaloid possessing unique fused-tetracyclic ring system consisting of a cycloheptene ring fused to a decahydroquinoline and pyridone rings. Lyconadin F (2) possesses a primary amide moiety in its molecular, which is the first example of Lycopodium alkaloids. Biogenetically, lyconadins C (1) and F (2) might be related to lyconadins A (4) and B (5). The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. The absolute stereochemistry of 2 was elucidated by chemical correlations with lyconadin B (5) through hemiaminal form of lyconadin F (3).     

Total synthesis of eurypamides, marine cyclic-isodityrosines from the Palauan sponge Microciona eurypa

Total synthesis of eurypamides A, B, and D, 1, 2, and 4, has been successfully accomplished. The Tl(NO₃)₃ (TTN) oxidation of the halogenated bisphenols, 14a, 14b, 24, and 43, effected regio-controlled cyclization to provide the corresponding diaryl ethers, 15a, 15b, 25, and 46. This investigation revealed a structural revision of eurypamide A as to possess (2″S,3″R,4″S)-configuration (47), along with the spectral data of pure 2 and 4, which were previously characterized in a mixture.     

Yojironins A−D, meroterpenoids and prenylated acylphloroglucinols from Hypericum yojiroanum

Two new meroterpenoids, yojironins A (1) and B (2), were isolated from the whole plants of Hypericum yojiroanum, together with two new prenylated acylphloroglucinols, yojironins C (3) and D (4). Their structures were elucidated by spectroscopic data. Yojironins A (1) and B (2) are biogenetically unique meroterpenoids, which seem to be composed of two acetate units with a 2-methylbutanoyl group and three isoprene units. Yojironin A (1) exhibited antimicrobial activity.     

Syntheses,crystal structures,and magnetic and luminescent properties of a series of lanthanide coordination polymers with chelidamic acid ligand

A series of lanthanide(III) complexes with chelidamic acid ligand, [Ln(C₇H₂NO₅)·3H₂O]_n·nH₂O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd₂(C₇H₂NO₅)₃·4H₂O]_n·2nH₂O (5) and [Ce(C₇H₂NO₅)·1.5H₂O]_n (6), have been synthesized by hydrothermal method and structurally characterized by single-crystal X-ray diffraction. Complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (4⁴) topology 2D network. The variable-temperature magnetic properties of 3 and 5 have been investigated. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied.     

Metal-organic coordination architectures of azole heterocycle ligands bearing acetic acid groups: Synthesis, structure and magnetic properties

Four new coordination complexes with azole heterocycle ligands bearing acetic acid groups, [Co(L¹)₂]_n (1), [CuL¹N₃]_n (2), [Cu(L²)₂·0.5C₂H₅OH·H₂O]_n (3) and [Co(L²)₂]_n (4) (here, HL¹=1H-imidazole-1-yl-acetic acid, HL²=1H-benzimidazole-1-yl-acetic acid) have been synthesized and structurally characterized. Single-crystal structure analysis shows that 3 and 4 are 2D complexes with 4⁴-sql topologies, while another 2D complex 1 has a (4³)₂(4⁶)-kgd topology. And 2 is a 3D complex composed dinuclear μ_1,1-bridging azido Cu^II entities with distorted rutile topology. The magnetic properties of 1 and 2 have been studied.     

New pyridoacridine alkaloids from the purple morph of the ascidian Cystodytes dellechiajei

Two new pyridoacridine alkaloids, 13-didemethylaminocycloshermilamine D (1) and demethyldeoxyamphimedine (2), were isolated from the purple chromotype of the Western Mediterranean ascidian Cystodytes dellechiajei. This morph also contained the known shermilamine B (3), kuanoniamine D (4), N-deacetylshermilamine B (5), N-deacetylkuanoniamine D (6), styelsamines C (7), and D (8). The structures of new compounds were elucidated on the basis of spectroscopic data. A hypothetic biosynthetic pathway from the tetracyclic styelsamine D (8) was proposed for both compounds 1 and 2 and their antimicrobial potential was evaluated.     

Kehokorins A-C, novel cytotoxic dibenzofurans isolated from the myxomycete Trichia favoginea var. persimilis

Kehokorins A (1)-C (3), three novel dibenzofurans, have been isolated from field-collected fruit bodies of the myxomycete, Trichia favoginea var. persimilis, and their structures were elucidated by spectral data. Kehokorin A (1) was a α-l-rhamnopyranoside of kehokorin B (2), while kehokorin C (3) was a 1-demethoxy analog of 2. Kehokorin A (1) was cytotoxic against HeLa cells with an IC₅₀ value of 1.5 μg/mL.     

Three novel nortriterpenoids from Notochaete hamosa Benth. (Labiatae)

Three nortriterpenoids, notohamosin A (1), B (2) and C (3) with novel skeleton, and eight known compounds were isolated from the ethanol extract of the whole plants of Notochaete hamosa Benth. (Labiatae). On the basis of spectral evidence including 1D, 2D NMR, IR and MS data, their structures were elucidated. The relative configurations of compounds 1, 2 and 3 were determined according to NOESY experiments.     

Novel cyclopropyl diketones and 14-membered macrolides from the soil fungus Hamigera avellanea BCC 17816

Two novel cyclopropyl diketones, hamavellone A (1) and B (2), and two new 14-membered nonaketide macrolactones, hamigeromycin A (3) and B (4), together with six known compounds, 89-250904-F1 (radicicol analogue A, 5), pseurotin A (6), emodin (7), ω-hydroxyemodin (8), and emodin bianthrones (9 and 10) were isolated from the soil fungus Hamigera avellanea BCC 17816. The structures of the new compounds were defined by analysis of NMR and MS data. The absolute stereochemistry of 3 was addressed by chemical correlation to 5. Hamavellone B (2) exhibited antimalarial activity with an IC₅₀ of 5.2 μg/mL, whereas it also showed comparable cytotoxicity.     

Three new diterpenoids, tricalysiolide H and tricalysiones A and B, from Tricalysia dubia

Three new diterpenoids, tricalysiolide H (1) and tricalysiones A (2) and B (3), with novel structural features were isolated from the wood of Tricalysia dubia, together with a known compound, cafestol (4). The structures of 1-3 were elucidated on the basis of 2D NMR spectroscopy and X-ray crystallographic analysis.     

Excavatoids A-D, new polyoxygenated briaranes from the octocoral Briareum excavatum

Three polyoxygenated briaranes, including two new compounds, excavatoids A (1) and B (2), and a known metabolite, briaexcavatin I (3), were isolated from the cultured octocoral Briareum excavatum. Moreover, the wild type B. excavatum, collected off southern Taiwan coast, yielded two new 5,6-epoxybriaranes, excavatoids C (4) and D (5). The structures of new compounds 1, 2, 4, and 5 were determined by spectroscopic methods and the structure of 1 was further confirmed by X-ray diffraction data analysis. The X-ray structure for briaexcavatin I (3) was also reported for the first time. Excavatoid A (1) is the first briarane which possesses six hydroxy groups and a 17-methoxy group. Excavatoid C (4) is the first 12,13-secobriarane which possesses a novel pentacyclic skeleton with an ?-lactone. Excavatoid D (5) displayed moderate inhibitory effects on superoxide anion generation and elastase release by human neutrophils.     

Bisleuconins A-D: a pair of epimeric ent-kauranoid dimers and two new asymmetric analogues isolated from Isodonleucophyllus

A phytochemical investigation of Isodon leucophyllus led to the isolation of four novel ent-kauranoid dimers: bisleuconins A-D (1-4), and one known compound, rabdoloxin A (5). It was interesting that the structures of bisleuconins A (1) and B (2) were elucidated as a pair of epimeric ent-kauranoid dimers with unique linkage pattern C-16→C-17′ to connect two monomers. Bisleuconins C (3) and D (4) were two new asymmetric ent-kauranoid dimers. A possible biogenetic pathway of 1 and 2 was also proposed.     

Novel cytotoxic constituents of Orthosiphon diffusus

Chemical investigation on Orthosiphon diffusus resulted in the isolation of four relatively rare, novel polychiral furanopyrans, orthodiffenes A-D (1-4) which were characterized from detailed studies of their 1D and 2D NMR spectra. The X-ray crystallographic analysis of orthodiffene A (1) was accomplished. The in vitro cytotoxic activity of orthodiffenes A-C (1-3) was tested against Jurkat and HL-60 cells using camptothecin as a positive control. Orthodiffenes A (1) and B (2) showed comparable activity to camptothecin against HL-60 and Jurkat cells, respectively.     

Bioactive rearranged limonoids from the Chinese mangrove Xylocarpus granatum Koenig

Two new pyridine-containing limonoids, xylogranatopyridines A and B (1 and 2) and their formal precursor, prexylogranatopyridine (3) were isolated from the twigs and leaves of the Chinese mangrove, Xylocarpus granatum. Xylogranatopyridine B (2) possesses an unprecedented rearranged B-ring together with a seco-ring A, supporting the biogenetic connection of 1–2 with 3. The chemical structures were elucidated by means of detailed spectroscopic analysis and X-ray single-crystal diffraction. The absolute configurations were assigned using electronic solid-state circular dichroism (ECD) supported by time-dependent density functional theory (TDDFT) ECD calculations and X-ray analysis. Xylogranatopyridine A (1) exhibited a significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with an IC₅₀ value of 22.9 μM. This is the first report of PTP1B inhibitory activity of limonoids.     

N-Hydroxypyridone alkaloids,chromone derivatives,and tetrahydroxanthones from the scale-insect pathogenic fungus Orbiocrella sp. BCC 33248

Six new compounds, an N-hydroxypyridone glucoside, orbiocrellin A (1), its aglycone orbiocrellin B (2), chromone glucosides 3 and 4, a dihydrochromone 5a/5b, and a chromone 6, were isolated from the scale-insect pathogenic fungus Orbiocrella sp. BCC 33248. Orbiocrellin A (1) exhibited antimalarial activity against Plasmodium falciparum K1 (IC₅₀ 3.1 μg/mL) while it was non-cytotoxic. In contrast, orbiocrellin B (2) showed both antimalarial (IC₅₀ 2.1 μg/mL) and cytotoxic (NCI-H187 cells, IC₅₀ 0.70 μg/mL) activities.