Three new two-dimensional metal-organic coordination polymers derived from bis(pyridinecarboxamide)-1,4-benzene ligands and 1,3-benzenedicarboxylate: Syntheses and electrochemical property

Three new metal-organic coordination polymers, [Co(3-bpcb)(1,3-BDC)]·H₂O (1), [Co(4-bpcb)(1,3-BDC)]·2H₂O (2) and [Cu(4-bpcb)(1,3-BDC)]₂·0.5(4-bpcb) (3), have been hydrothermally synthesized using N,N′-bis(3-pyridinecarboxamide)-1,4-benzene (3-bpcb) or N,N′-bis(4-pyridinecarboxamide)-1,4-benzene (4-bpcb) and 1,3-benzenedicarboxylate (1,3-H₂BDC) mixed ligands and characterized by elemental analyses, IR, TG, XRPD and single-crystal X-ray diffraction. Complexes 1–2 exhibit the similar two-dimensional (2D) network with different undulation degrees and dimensions, owing to different N positions from the 3-bpcb and 4-bpcb ligands. 1,3-BDC ligand in complexes 1 and 2 shows two coordination modes. The adjacent 2D layers for 1–2 are further linked by hydrogen bonding interactions to form a three-dimensional (3D) supramolecular network. Complex 3 possesses infinite 3-fold interpenetrating 2D network composed of three kinds of Cu-4-bpcb one-dimensional (1D) chains and 1,3-BDC ligands, in which 1,3-BDC only shows one coordination mode. The 2D network is further extended into 3D supramolecular framework by hydrogen bonding interactions. The non-coordinated 4-bpcb ligands existing in the 2D network connect with adjacent 2D layers through the hydrogen bonding interactions. In addition, the electrochemical behaviors and the fluorescence property of complexes 1–3 have been reported.     

A new eudesmane sesquiterpene glycoside from Parepigynum funingense

A new eudesmane sesquiterpene glycoside,1α,6β-dihydroxy-5,10-bis-epi-eudesm-4(15)-ene-6-O-β-D-glucopyranoside(2), together with a known analogue compound,1α,6β-dihydroxy-5,10-bis-epi-eudesm-3-ene-6-O-β-D-glucopyranoside(1),were isolated from the roots of Parepigynumfuningense.The structure of 2 was determined by 1D and 2D NMR spectroscopy.Compound 1 was isolated from this plant for the first time.     

New azaphilones from Chaetomium globosum isolated from the built environment

A strain of Chaetomium globosum (DAOM 240359) was isolated from an indoor air sample in Ottawa, Ontario, Canada. When fermented in liquid culture, this strain produced a number of known metabolites including chaetoglobosins A (6), C, and F (7), chaetomugilin D (5), chaetoviridin A (4), and three new nitrogenous azaphilones; 4′-epi-N-2-hydroxyethyl-azachaetoviridin A (1), N-2-butyric-azochaetoviridin E (2), and isochromophilone XIII (3). The structures were elucidated by spectroscopic analysis including; HRMS, 1D and 2D NMR, UV, and ORD. Compounds 2–7 were antimicrobial when tested using quantitative growth inhibition assays.     

Polyketides and nitrogenous metabolites from the endophytic fungus Phomopsis sp. D15a2a

Three new polyketides, phomopones A−C (1–3), one new cyclic tetrapeptide, 18-hydroxydihydrotentoxin (4), and a new amide, 6-hydroxyenamidin (5) together with a known derivative, enamindin (6) were obtained from the endophytic fungus Phomopsis sp. D15a2a isolated from the plant Alternanthera bettzickiana. The structures of the new compounds were elucidated by 1D, 2D NMR and HRMS data. The absolute configurations of the isolated metabolites were determined either by X-ray crystallography, Marfey’s method or by converting the compounds to Mosher esters.     

The structure and luminescence properties of three complexes based on bifunctional imidazole-dicarboxylate connector

To study the diverse coordination modes of the H₂btib,three new coordination architectures,namely, [Ag（Hbtib）CH₃CN]_n（1）,)[Ag（Hbtib）]_n（2） and[Pb（btib）（CH₃OH）₂]_n（3）（where H₂btib=4-（（2-butyl-5-（2- carboxy-3-（thiophen-2-yl）prop-1-enyl）-1H-imidazol-1-yl）methyl）benzoic acid） have been synthesized and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction.Complex 1 exhibits 1D single chain structure,while 2 shows 1D double metal chain motif,and 3 features a 2D layer topology.Also,1,2 and 3 display strong emission band in the solid state at room temperature.     

Guianofruits C–I from fruit oil of andiroba (Carapa guianensis,Meliaceae)

Two novel chukrasone-type limonoids, named Guianofruits C and D (1 and 2), a guianolide derivative named Guianofruit E (3), and four novel phragmalin–type limonoids named Guianofruits F–I (4–7), were isolated from the fruit oil of Carapa guianensis AUBLET (Meliaceae), a traditional medicine in Brazil and Latin American countries. Their structures were mainly elucidated based on spectroscopic analyses using 1D and 2D NMR techniques. The effects of compounds 1–6 on the production of NO by LPS-activated mouse peritoneal macrophages were investigated. Two new chukrasone-type limonoids, Guianofruits C (1) and D (2), exhibited moderate inhibitory activities.     

Synthesis of mono- and dihydroxy-substituted 2-aminocyclooctanecarboxylic acid enantiomers

(1R,2S,6R)-2-Amino-6-hydroxycyclooctanecarboxylic acid (?)-10 was synthesized from (1R,2S)-2-aminocyclooct-5-enecarboxylic acid (+)-2 via an iodolactone intermediate, while (1R,2S,3R,4S)-2-amino-5,6-dihydroxycyclooctanecarboxylic acid (?)-12 was prepared by using the OsO₄-catalyzed oxidation of Boc-protected amino ester (?)-5. The stereochemistry and relative configurations of the synthesized compounds were determined by 1D and 2D NMR spectroscopy (based on 2D NOE cross-peaks and ³J(H,H) coupling constants) and X-ray crystallography.     

Biogenetically related caged ent-kaurane diterpenoids from Isodon eriocalyx var. laxiflora

Two novel caged ent-kauranoids, neolaxiflorins D (1) and E (2), along with three other new ent-kauranoids, neolaxiflorins F–H (3–5), and a known one, eriocalyxin B (6), were obtained from Isodon eriocalyx var. laxiflora. Neolaxiflorin D (1) is the first 15,16-seco-16,17-dinor-ent-kaurane diterpenoid, and neolaxiflorin E (2) is the first 15,16-seco-17-homo-ent-kauranoid. The absolute configurations of ent-kauranoids 1 and 2 were determined by single-crystal X-ray diffraction analyses. Structural analysis of intermediate compounds 3–5 indicated that eriocalyxin B (6) is a biogenetic precursor of caged ent-kauranoids 1 and 2 as illustrated. The cytotoxic activity of the new compounds was evaluated by an MTT assay.     

A novel 10-membered macrocyclic lactone from the mangrove-derived endophytic fungus Annulohypoxylon sp.

A novel 10-membered macrolactone, hypoxylide (1), was isolated from the endophytic fungus Annulohypoxylon sp. that was obtained from the Mangrove plant Rhizophora racemosa. The structure and absolute configuration of 1 were unambiguously elucidated by comprehensive 1D and 2D NMR, as well as by HRESIMS and ECD spectroscopic analyses. Hypoxylide (1) features an unprecedented polyketide skeleton comprised of a trihydroxynaphthalene-dione moiety fused to a decalactone ring. A plausible biosynthetic pathway of this novel metabolite is proposed.     

Physalinol A,a 1,10-seco-physalin with an epidioxy from Physalis alkekengi L. var. franchetii (Mast.) Makino

Physalinol A (1), a novel 1, 10-seco-physalin with a peroxy bridge, was isolated from the organic extracts of Physalis alkekengi L. var. franchetii (Mast.) Makino. The structure was determined on the basis of 1D and 2D NMR spectra and HR-ESI-MS data. The absolute configuration of 1 was evidenced by X-ray diffraction data and further confirmed by ECD calculations. The isolated compound 1 has no cytotoxicity against HCT-116 and PC-3 cancer cell lines and a weak antimicrobial activity against Escherichia coil. In addition, compound 1 also exhibited a weak anti-inflammatory action in lipopolysacaride (LPS)-induced RAW 264.7 macrophages with an IC₅₀ value of 57.3?±?1.03?μM.     

Stereoselective enzymatic synthesis of monoglucosyl-myo-inositols with in vivo anti-inflammatory activity

The monoglucosyl-inositols α-d-glucopyranosyl-(1→4)-4d-myo-inositol 3 and α-d-glucopyranosyl-(1→1)-1d-myo-inositol 4 were synthesized by a combined enzymatic transglucosylation and hydrolysis strategy, using cyclodextrin glucosyl transferase (CGTase) from Thermoanaerobacter sp., followed by hydrolysis with Aspergillus niger glucoamylase. The glucosides were separated by preparative HPLC and fully characterized by extensive 1D and 2D NMR studies. The structure of the regioisomer 4 was confirmed by X-ray crystallography of its perbenzoylated derivative 4a. Both isomers demonstrated in vivo anti-inflammatory activity at comparative levels to corticosterone on mouse ear oedema induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) and in rat hind paw oedema induced by carrageenan.     

Constituents from Bupleurum montanum (Coss. & Dur.) (Apiaceae)

A chemical investigation of the aerial parts of Bupleurum montanum (Coss. & Dur.) (Apiaceae) afforded five compounds, quercitin 1, tamarexetin 2, isorhamnetin-3-rutinoside 3, kaempferol-3-O-β-rutinoside 4, and 3,4-dihydroxybenzoic acid (Protocatechuic acid) 5. The structural elucidation was performed mainly by MS, 1D and 2D NMR spectrum data.     

New borrelidin derivatives from an endophytic Streptomyces sp.

Three new borrelidin-type macrolactones, designated as borrelidins J?L (4–6), together with borrelidin A (1), borrelidin E (2), and 12-desnitrile-12-carboxyl-borrelidin (3) were isolated from a plant endophytic Streptomyces sp. NA06554. Their structures were determined by extensive spectroscopic analysis including HRESIMS, 1D and 2D NMR data. The antibacterial activities for compounds 1–6 were examined. Borrelidins A (1) and L (6) showed potent and moderate antibacterial activity against Micrococcus luteus, respectively, whereas other derivatives (2–5) are almost inactive, which allows us to propose a plausible structure-activity relationship.     

Lycogladines A-H,fawcettimine-type Lycopodium alkaloids from Lycopodium complanatum var. glaucum Ching

Five new fawcettimine-type alkaloids (1–5) and three new natural products (6–8), along with four known analogues, fawcettimine (9), fewcettidine (10), lycopoclavamine B (11), and lycopladine B (12), were isolated from the whole plant of Lycopodium complanatum var. glaucum Ching. The structures of lycogladines A-H (1–8) were determined based on HRESIMS, 1D and 2D NMR spectroscopic analysis, as well as single-crystal X-ray diffraction. Compound 1 possesses a new ring system that is formed through the linkage of C-13-OC-2, which is rarely present in Lycopodium alkaloids (LAs). Compounds 1–8 were tested for their β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) and acetylcholinesterase (AChE) inhibitory activities.     

Polybrominated diphenyl ethers from Dysidea herbacea,Dysidea chlorea and Phyllospongia foliascens

The marine sponges Dysidea herbacea, D. chlorea and Phyllospongia foliascens were differentiated with difficulty in the field. D. herbacea contained 2-(2',4'-dibromophenoxy)-3,4,5-tribromophenol (1), 2-(2',4'-dibromophenoxy)-4,5,6-tribromophenol (2) and 2-(2',4'-dibromophenoxy)-3,5-dibromophenol (6). D. chlorea contained only 2-(2',4'-dibromophenoxy)-4,6-dibromophenol(3), a compound previously reported as a metabolite of D. herbacea. Phyllospongia foliascens contained 2-(3',5'-dibromo-2'-methoxy-phenoxy)-3,5-dibromoanisole (7) and a 1:2 mixture of 2-(3',5'-dibromo-2'-hydroxyphenoxy)-3,5,6-tribromophenol (8) and 2-(3',5'-dibromo-2'-hydroxyphenoxy)-3,4,5,6-tetrabromophenol (9).     

Saxifraganoids A and B,two novel cucurbitane triterpenoid glycosides from Saxifraga umbellulata var. pectinata

Two novel cucurbitane triterpenoid glycosides, named saxifraganoids A (1) and B (2), were isolated from Saxifraga umbellulata var. pectinata. Their structures including absolute configurations were elucidated based on the analysis of spectroscopic data (1D, 2D NMR and HRMS), and single-crystal X-ray diffraction. Compound 1 represents the first example of cucurbitane triterpenoid with a Δ¹⁷⁽²⁰⁾, and compound 2 contained an unusual N-acetylglucosamine at C-16. The protective effects against liver injury induced by carbon tetrachloride (CCl₄) in the human embryonic-liver L-02 cells of these two compounds were evaluated.     

A pair of epimeric cassane-type diterpenoids and a new labdane-type derivative from Caesalpinia decapetala

Caesaldecins A and B (1a/1b), a pair of epimeric cassane-type diterpenoids containing an ether linkage between C-6 and C-20 and an α,β-butenolide ring in the northern hemisphere, were isolated from the leaves of the medicinal plant Caesalpinia decapetala (Roth) Alston, along with a new labdane-type diterpenoid, termed as 8(17),11(Z),13(E)-trien-15,18-dioic acid (2). Structures of 1 and 2 were established by extensive spectroscopic analyses, including HRESIMS, 1D and 2D NMR, and electronic circular dichroism (ECD) calculations. The in vitro antibacterial and inhibitory activities against a panel of bacteria and cancer cell lines were evaluated, respectively. Compound 2 displayed moderate antibacterial activity against the methicillin-resistant Staphylococcus aureus subsp. aureus (MRSA) with an MIC₅₀ value of 5.99?μg?mL^?1.     

Phloroglucinol derivatives and a chromone glucoside from the leaves of Myrtus communis

Seven new phloroglucinol derivatives, myrtucommunins A–D (1–4), 6-methylisomyrtucommulone B (5), 4-methylmyrtucommulone B (6), and 2-isobutyryl-4-methylphloroglucinol 1-O-β-d-glucopyranoside (7), and one new chromone derivative, undulatoside A 6′-O-gallate (8), were isolated from the leaves of Myrtus communis (Myrtaceae). Myrtucommunins A–D (1–4) were conjugates of polymethylated acylphloroglucinol and flavonol rhamnoside. The absolute configurations of the rhamnosyl moieties for 1–4 were confirmed to be l in each case by HPLC analyses, while those of the aglycones were assigned by comparisons of the experimental and TDDFT calculated ECD spectra. 6-Methylisomyrtucommulone B (5) and 4-methylmyrtucommulone B (6) were assigned as 6/6/6 tricyclic acylphloroglucinol derivatives with a racemic nature. Antimicrobial activities of 1–8 and related known compounds were evaluated.     

Synthesis and structures of two novel non-centrosymmetric metal-organic polymers containing 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylic acid ligands

Two novel non-centrosymmetric coordination polymer, [Zn₂(PIDC)(H₂O)Cl]_n (1) and {[Mn(HPIDC)H₂O]·2H₂O}_n (2) have been synthesized through hydrothermal method and characterized by IR, elemental analysis and single-crystal X-ray diffraction. Complex 1 crystallized in a chiral space group P2₁2₁2₁ has a 2D network structure. Complex 2 is a 3D open framework with 1D channel where 1D zigzag water chains are reside through hydrogen-bonding interactions and crystallized in a chiral space group C_c. Both 1 and 2 display a strong second harmonic generation (SHG) response.     

Biyoulactones D and E,meroterpenoids from Hypericum chinense

Two new meroterpenoids, biyoulactones D (1) and E (2), were isolated from the roots of Hypericum chinense, and their structures were elucidated on the basis of spectroscopic data and conformational analysis. Biyoulactones D (1) and E (2) are structurally unique tricyclic meroterpenoids having an octahydroindene ring, a γ-butyrolactone ring, and a β-diketone moiety.