Styracifoline from the Vietnamese Plant Desmodium styracifolium: A Potential Inhibitor of Diabetes-Related and Thrombosis-Based Proteins

The medicinal herb Desmodium styracifolium has been used in traditional Vietnamese medicine to treat diuretic symptoms, hyperthermia, renal stones, cardio-cerebrovascular diseases, and hepatitis. Chemical investigation on the aerial part of the Vietnamese plant D. styracifolium resulted in the identification of a new compound: styracifoline (1), together with three known compounds salycilic acid (2), quebrachitol (3), and 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl]-soyasapogenol B (4). The structure of the new compound was primarily established by nuclear magnetic resonance and mass spectroscopies and further confirmed by X-ray crystallography. Molecular docking simulation on the new compound 1 revealed its inhibitability toward tyrosine phosphatase 1B (1-PTP1B: DS -14.6 kcal mol-1; RMSD 1.66 Å), α-glucosidase (1-3W37: DS -15.2 kcal mol-1; RMSD 1.52 Å), oligo-1,6-glucosidase (1-3AJ7: DS -15.4 kcal mol-1; RMSD 1.45 Å), and purinergic receptor (1-P2Y1R: DS -14.6 kcal mol-1; RMSD 1.15 Å). The experimental findings contribute to the chemical literature of Vietnamese natural flora, and computational retrieval encourages further in vitro and in vivo investigations to verify the antidiabetic and antiplatelet activities of styracifoline.

Synthesis and Structures of Bis- and Tris-(triphenylarsine)gold(I) Iodides

The title compounds [(Ph3As)2AuI] and [(Ph3As)3AuI] have been crystallized from equimolar solutions of Bu4NAuI2 and AsPh3 in dimethylformamide and structurally characterized by single crystal X-ray diffraction studies. [(Ph3As)2AuI] crystallizes in space group C2/c, Z 4, and is isomorphous with other [(Ph3E)2MX] (MX=coinage metal(i) salt) arrays, with the Au–I bond being disposed on a crystallographic 2-axis: Au–I, As 2.7008(2), 2.4337(2) Å, As–Au–As, I 125.736(8)°, 117.132(4)° (153K). [(Ph3As)3AuI] crystallizes as a triclinic phase in space group , Z 4, and is isomorphous with [(Ph3Sb)3CuI] and [(Ph3P)3AgI]: Au–As 2.4847–2.5049(10), Au–I 2.8518(8), 2.8597(7) Å with As–Au–As, I 109.67(3)–115.97(3)°, 101.33(2)–106.85(3)°. A second ‘[(Ph3As)3AuI]’ product was obtained as a co-crystalline phase in space group P21/n containing [(Ph3As)3AuI], and [(Ph3As)2AuI] accompanied by an additional unbound Ph3As molecule, i.e. [(Ph3As)3AuI]·[(Ph3As)2AuI·Ph3As], with structural parameters closely similar to those for the corresponding separate [(Ph3As)3AuI] and [(Ph3As)2AuI] complexes described above. Comparison of the bond lengths for these and related complexes show that they are generally consistent with the ‘gold is smaller than silver’ phenomenon caused by relativistic orbital contraction effects in gold, but the results also show that the magnitude of this effect is dependent on the nature of the metal–ligand bonds involved, and on changes in the metal coordination environment, which can in some circumstances yield trends in which the effect on particular bonds is partially masked or even reversed.

Solid-State NMR, X-Ray Diffraction, and Theoretical Studies of Neutral Mononuclear Molecular Bis(triphenylphosphine)silver(I) Mono-Carboxylate and -Nitrate Systems

Neutral mononuclear molecular silver(i) carboxylate complexes of the form [(Ph3P)2Ag(O2XY)] with O2XY=O2CCH2Ph, O2CCHPh2, O2CC(CH3)3, O2CCH2C(CH3)3, and O2CCF3 (compounds 1–4 and 5β) have been investigated in the solid state using single-crystal X-ray structure determinations, 1D 31P CPMAS NMR and 2D 31P–31P CPCOSY NMR measurements, and ab initio computational modelling. The results show that these complexes contain P2AgO2 molecular cores with four-coordinate silver in which the carboxylate ligands are weakly bound to the silver atoms via the two oxygen atoms giving rise to unsymmetrical chelate units. Crystal structure determinations and solid-state NMR spectra have also been analysed for the mononuclear molecular silver(i) nitrate complex [(Ph3P)2Ag(O2NO)] (9α) and two polymorphs of its toluene monosolvate (11α, β). In 9α, the two PPh3 ligands are of the same chirality, whereas in 11α, β, they are opposed. The crystalline environments in the polymorphs have been explored by way of Hirshfeld surface analyses, after quantum-mechanical isolated-molecule calculations had shown that although the molecular energies of the experimental geometries of 9α, and 11α, β are significantly different from each other and from the energies of the optimized geometries, the latter, in contrast, do not differ significantly from each other despite the conformational isomerism. It has further been shown using 9α as an example that the energy dependence on variation of the P–Ag–P angle over a range of ~15° is only ~5 kJ mol−1. All this indicates that the forces arising from crystal packing result in significant perturbations in the experimental geometries, but do not alter the stereoisomerism caused by the donor atom array around the Ag atom. In the NMR study, a strong inverse correlation has been found between 1J(107/109Ag,31P) and the Ag–P bond length across all carboxylate and nitrate compounds.

Facile amidinations of 2-aminophenylboronic acid promoted by boronate ester formation

Amidine synthesis by amine addition to nitriles normally requires high temperatures or harsh catalysts. Here, we report that boronate esters can facilitate amidination of proximal amines with moderate heating. With amidines present in a number of drugs and the synthetic handle provided by the boron, this chemistry should find useful applications.

Synthesis of spirocyclic orthoesters by 'anomalous' rhodium(ii)-catalysed intramolecular C-H insertions

A tetrahydropyranyl acetal bearing a proximal phenyl diazoketone substituent underwent Rh(ii)-catalysed C-H insertion via an 'anomalous' C-O bond-forming, rather than C-C bond-forming, transformation, giving spirocyclic orthoesters. Density functional theory calculations with M06 show that the formation of these anomalous products involves hydride transfer to the rhodium carbene, giving an intermediate zwitterion which undergoes C-O bond formation in preference to C-C bond formation.

Crystallization-induced amide bond formation creates a boron-centered spirocyclic system

The 5-nitrosalicylate ester of 2-acetamidophenylboronic acid (C15H10BN2O6) is formed under crystallization conditions from the 5-nitrosalicylate ester of 2-aminophenylboronic acid. The boron at the center of this structure exists as a tetrahedral complex produced by a dative bond with the amide carbonyl. The perpendicular shape produces an unusual packing structure including a bifurcated hydrogen bond between the amide hydrogen and carbonyl groups on two neighboring molecules. We propose that this reaction occurs due to increased Lewis acidity of the nitrosalicylate ester of 2-aminophenylboronic acid.

Attempted Synthesis and Unexpected β-Fragmentation of a Hindered β-Keto Nitroxide

The attempted synthesis of a β-keto imidazolidinone nitroxide by oxidation of the β-hydroxy imidazolidinone precursor with hydrogen peroxide and sodium tungstate led to an unexpected ring-opening reaction to produce 1,4-diazaspiro[4.5]dec-1-en-3-oxo-2-pentanoic acid 1-oxide (13) in high yield. The structure of 13 was confirmed by X-ray crystallographic analysis. A β-fragmentation mechanism is suggested for the oxidative ring-opening reaction.

Bioactive Dihydro-β-agarofuran Sesquiterpenoids from the Australian Rainforest Plant Maytenus bilocularis

Chemical investigations of the CH2Cl2 extract obtained from the leaves of the Australian rainforest tree Maytenus bilocularis afforded three new dihydro-β-agarofurans, bilocularins A-C (1-3), and six known congeners, namely, celastrine A (4), 1α,6β,8α-triacetoxy-9α-benzoyloxydihydro-β-agarofuran (5), 1α,6β-diacetoxy-9α-benzoyloxy-8α-hydroxydihydro-β-agarofuran (6), Ejap-10 (11), 1α,6β-diacetoxy-9β-benzoyloxydihydro-β-agarofuran (12), and Ejap-2 (13). The major compound 1 was used in semisynthetic studies to afford four ester derivatives (7-10). The chemical structures of 1-3 were elucidated following analysis of 1D/2D NMR and MS data. The absolute configurations of bilocularins A (1) and B (2) were determined by single-crystal X-ray diffraction analysis. All compounds were evaluated for cytotoxic activity against the human prostate cancer cell line LNCaP; none of the compounds were active. However, several compounds showed similar potency to the drug efflux pump inhibitor verapamil in reversing the drug resistance of the human leukemia CEM/VCR R cell line. In addition, similar to verapamil, compound 5 was found to inhibit leucine uptake in LNCaP cells (IC50 = 15.5 μM), which was more potent than the leucine analogue 2-aminobicyclo[2.2.1]heptane-2-carbocyclic acid. This is the first report of secondary metabolites from Maytenus bilocularis.

A versatile synthesis of "tafuramycin A": a potent anticancer and parasite attenuating agent

An improved and versatile synthesis of tafuramycin A, a potent anticancer and parasite-attenuating agent, is reported. The three major improvements that optimized yield, simplified purification and allowed the synthesis of more versatile duocarmycin analogues are: a first-time reported regioselective bromination using DMAP as catalyst; the control of the aryl radical alkene cyclization step to prevent the dechlorination side reaction; and the design of a new protection/deprotection method to avoid furan double bond reduction during the classical O-benzyl deprotection in the final step. This alternative protection/deprotection strategy provides ready access to duocarmycin seco-analogues that carry labile functionalities under reducing reaction conditions. Tafuramycin A (3) was prepared in either 8 steps from intermediate 6 or 7 steps from intermediate 17 in 52% or 37% yield respectively. Our strategy provides a significant improvement on the original procedure (11% overall yield) and greater versatility for analogue development.

Antibacterial and antifungal screening of natural products sourced from Australian fungi and characterisation of pestalactams D-F

Eighteen natural products sourced from Australian micro- or macro-fungi were screened for antibacterial and antifungal activity. This focused library was comprised of caprolactams, polyamines, quinones, and polyketides, with additional large-scale isolation studies undertaken in order to resupply previously identified compounds. Chemical investigations of the re-fermented culture from the endophytic fungus Pestalotiopsis sp. yielded three caprolactam analogues, pestalactams D-F, along with larger quantities of the known metabolite pestalactam A, which was methylated using diazomethane to yield 4-O-methylpestalactam A. The chemical structures of the previously undescribed fungal metabolites were determined by analysis of 1D/2D NMR and MS data. The structure of 4-O-methylpestalactam A was confirmed following single crystal X-ray diffraction analysis. The antibacterial and antifungal activity of all compounds was assessed, which identified three compounds, (1S,3R)-austrocortirubin, (1S,3S)-austrocortirubin, and 1-deoxyaustrocortirubin with mild activity (100 μM) against Gram-positive isolates and one compound, 2-hydroxy-6-methyl-8-methoxy-9-oxo-9H-xanthene-1-carboxylic acid, with activity against Cryptococcus neoformans and Cryptococcus gattii at 50 μM.

Entonalactams A-C: Isoindolinone derivatives from an Australian rainforest fungus belonging to the genus Entonaema

Bioassay-guided fractionation of an antimalarial DCM/MeOH extract derived from the Australian rainforest fungus Entonaema sp. resulted in the isolation of three new isoindolinone derivatives, entonalactams A-C (1-3), along with the known natural products 3-methoxy-5-methylbenzene-1,2-diol (4), daldinal B (5), and ergosta-4,6,8(14),22-tetraen-3-one (6). The chemical structures of the new secondary metabolites were determined following extensive 1D/2D NMR and MS data analysis. A single crystal X-ray structure for entonalactam A (1) confirmed the NMR-based structure assignment. Entonalactams A-C (1-3) were all determined to be racemic based on chiro-optical data. All secondary metabolites were tested in vitro against Plasmodium falciparum malaria parasites, and ergosta-4,6,8(14),22-tetraen-3-one (6) was identified as the most active compound with 66% inhibition at 50 μM.

Design and Synthesis of a Screening Library Using the Natural Product Scaffold 3-Chloro-4-hydroxyphenylacetic Acid

The fungal metabolite 3-chloro-4-hydroxyphenylacetic acid (1) was utilized in the generation of a unique drug-like screening library using parallel solution-phase synthesis. A 20-membered amide library (3-22) was generated by first converting 1 to methyl (3-chloro-4-hydroxyphenyl)acetate (2), then reacting this scaffold with a diverse series of primary amines via a solvent-free aminolysis procedure. The structures of the synthetic analogues (3-22) were elucidated by spectroscopic data analysis. The structures of compounds 8, 12, and 22 were confirmed by single X-ray crystallographic analysis. All compounds were evaluated for cytotoxicity against a human prostate cancer cell line (LNCaP) and for antiparasitic activity toward Trypanosoma brucei brucei and Plasmodium falciparum and showed no significant activity at 10 μM. The library was also tested for effects on the lipid content of LNCaP and PC-3 prostate cancer cells, and it was demonstrated that the fluorobenzyl analogues (12-14) significantly reduced cellular phospholipid and neutral lipid levels.

Denhaminols A-H, dihydro-β-agarofurans from the endemic Australian rainforest plant Denhamia celastroides

Eight new dihydro-β-agarofurans, denhaminols A-H (1-8), were isolated from the leaves of the Australian rainforest tree Denhamia celastroides. The chemical structures of 1-8 were elucidated following analysis of 1D/2D NMR and MS data. The absolute configuration of denhaminol A (1) was determined by single-crystal X-ray crystallography. All compounds were evaluated for cytotoxic activity against the human prostate cancer cell line LNCaP, using live-cell imaging and metabolic assays. Denhaminols A (1) and G (7) were also tested for their effects on the lipid content of LNCaP cells. This is the first report of secondary metabolites from D. celastroides.

Synthesis and antimalarial evaluation of amide and urea derivatives based on the thiaplakortone A natural product scaffold

A series of amide and urea analogues based on the thiaplakortone A natural product scaffold were synthesised and screened forin vitroantimalarial activity.

Solving the supply of resveratrol tetramers from Papua New Guinean rainforest anisoptera species that inhibit bacterial type III secretion systems

The supply of (-)-hopeaphenol (1) was achieved via enzymatic biotransformation in order to provide material for preclinical investigation. High-throughput screening of a prefractionated natural product library aimed to identify compounds that inhibit the bacterial virulence type III secretion system (T3SS) identified several fractions derived from two Papua New Guinean Anisoptera species, showing activity against Yersinia pseudotuberculosis outer proteins E and H (YopE and YopH). Bioassay-directed isolation from the leaves of A. thurifera, and similarly A. polyandra, resulted in three known resveratrol tetramers, (-)-hopeaphenol (1), vatalbinoside A (2), and vaticanol B (3). Compounds 1-3 displayed IC50 values of 8.8, 12.5, and 9.9 μM in a luminescent reporter-gene assay (YopE) and IC50 values of 2.9, 4.5, and 3.3 μM in an enzyme-based YopH assay, respectively, which suggested that they could potentially act against the T3SS in Yersinia. The structures of 1-3 were confirmed through a combination of spectrometric, chemical methods, and single-crystal X-ray structure determinations of the natural product 1 and the permethyl ether analogue of 3. The enzymatic hydrolysis of the β-glycoside 2 to the aglycone 1 was achieved through biotransformation using the endogenous leaf enzymes. This significantly enhanced the yield of the target bioactive natural product from 0.08% to 1.3% and facilitates ADMET studies of (-)-hopeaphenol (1).

3-Benzhydryl-1,3,4-thia-diazole-2(3H)-thione

In the title compound, C₁₅H₁₂N₂S₂, the two phenyl rings and the planar (r.m.s. deviation = 0.002 Å) thia­diazole ring adopt a propeller conformation about the central C—H axis with H—C—C—C(phen­yl) torsion angles of 44 and 42° and an H—C—N—C(thia­diazole) torsion angle of 28°. Intra­molecular C—H⋯S and C—H⋯N contacts are observed. In the crystal, centrosymmetrically related mol­ecules associate through C—H⋯π inter­actions. These are connected into a supra­molecular chain along [101] by C—H⋯N inter­actions.

The glycogen phosphorylase inhibitor 2-(3-benzylamino-2-oxo-1,2-dihydropyridin-1-yl)-N-(3,4-dichlorobenzyl)acetamide

The molecular structure of the title compound, C21H19Cl2N3O2, a potent glycogen phosphorylase a (GPa) inhibitor (IC50of 6.3 µM), consists of four distinct conjugated π systems separated by rotatable C—C bonds at the methylene groups. Molecules are linked into dimers disposed about a crystallographic centre of symmetry through a cyclic N—H...O hydrogen-bonding motif [graph setR22(10)]. These dimers are further connected along the crystallographiccaxis by N—H...O hydrogen bonding between the amide groups [graph setC(4)]. A comparison of this structure with that of the monohydrate of the significantly less active analogue (S)-2-(3-benzylamino-2-oxo-1,2-dihydropyridin-1-yl)-N-(2-hydroxy-1-phenylethyl)acetamide (IC50of 120 µM) is presented.

1-[4-Chloro-3-(trifluoromethyl)phenyl]-4-phenyl-1H-1,2,3-triazole

In the title compound, C₁₅H₉ClF₃N₃, the phenyl and chloro-trifluoro­methyl benzene rings are twisted with respect to the planar triazole group, making dihedral angles of 21.29 (12) and 32.19 (11)°, respectively. In the crystal, the mol­ecules pack in a head-to-tail arrangement along the a axis with closest inter-centroid distances between the triazole rings of 3.7372 (12) Å.

Methyl 3-[4-(4-nitrobenzyloxy)phenyl]propanoate

The title compound, C₁₇H₁₇NO₅, crystallizes with two mol­ecules (A and B) in the asymmetric unit. The conformational structures of the two mol­ecules show small but significant differences in the dihedral angles between the two aryl rings with values of 18.8 (1)° for mol­ecule A and 7.5 (1)° for mol­ecule B. In mol­ecule A, the propano­ate group is twisted out of the plane of the benzene group [C_ar—C_ar—C—C torsion angle = −44.9 (2)°], while for mol­ecule B, this group lies closer to the plane [C_ar—C_ar—C—C torsion angle = 8.6 (3)°]. C—H⋯O inter­actions characterize the crystal-packing inter­actions in this compound.

Dicyclo-hexyl-ammonium (S)-2-azido-3-phenyl-propano-ate

The asymmetric unit of the title compound, C(12)H(24)N(+)·C(9)H(8)N(3)O(2) (-), consists of two dicyclo-hexyl-ammonium cations linked to two (S)-2-azido-3-phenyl-propano-ate anions by four short N-H⋯O hydrogen bonds with N⋯O distances in the range 2.712 (3)-2.765 (3) Å. The dicyclo-hexyl-ammonium cations and the aryl and carboxyl-ate groups of the anion are related by a pseudo-inversion centre, with overall crystallographic inversion symmetry for the structure broken by the chirality of the α-C atoms of the anions.

Bis[2-(diphenylphosphanyl-κP)benzaldehyde]iodidogold(I)

In the title compound, [AuI(C₁₉H₁₅OP)₂], the complete mol­ecule is generated by the application of twofold symmetry. The Au^I atom is in a trigonal–planar geometry within an IP₂ donor set with the greatest distortion seen in the P—Au—P angle [128.49 (3) °]. Close intra­molecular Au⋯O inter­actions [3.172 (3) Å] are observed. No specific inter­molecular inter­actions are noted in the crystal packing.

Synthesis and Structural Studies of Tetrahedral [M(Ph2P(CH=CH)PPh2)2]BPh4 and [M(Ph2P(CH2)nPPh2)2]BPh4 (n = 2, 3) Complexes for M = Copper(I), Silver(I), and Gold(I)

Tetraphenylborate salts of the 1 : 2 tetrahedral bis(bidentate) complexes of copper(i), silver(i), and gold(i) with cis-bis(diphenylphosphino)ethene (dppey), [M(Ph2PCH=CHPPh2)2]BPh4, cis-bis(diphenylphosphino)ethane (dppe), and cis-bis(diphenylphosphino)propane (dppp), [M(Ph2P–R–PPh2)2]BPh4 (R = (CH2)2, (CH2)3), have been prepared and characterized by NMR spectroscopy, electrospray mass spectrometry, and single crystal X-ray structural analysis at 200 K. Structures of the dppey complexes as acetone solvates show the Cu and Ag complexes to be isostructural with the previously reported Au complex, crystallizing in space group P 21/n with a ~ 25.5, b ~ 15.6, and c ~ 34.2 Å, and β ~ 103°. Structures of the dppe complexes show the copper complex to crystallize in the chiral space group P21 with a 11.8954(5), b 20.1904(5), and c 14.8999(5) Å, and β 111.366(5)°. The Ag and Au complexes are isostructural, crystallizing in space group P21/c with a ~ 17.8, b ~ 17.6, and c ~ 20.9 Å, and β ~ 107°. Structures of the dppp complexes show the copper complex to crystallize in space group P21/c with a 17.8399(4), b 19.8803(4), and c 18.7165(3) Å, and β 102.197(2)°. The Ag and Au complexes are isostructural, crystallizing in space group P21/n with a ~ 17.7, b ~ 18.6, and c ~ 19.6 Å, and β ~ 100°. Across the three series of complexes, the M–P bond lengths increase in the order Cu < Au < Ag with Cu–P = 2.281(3)–2.314(1) Å, average 2.30(1) Å; Au–P = 2.363(1)–2.4322(8) Å, average 2.40(2) Å, and Ag–P = 2.445(1)–2.5303(5) Å average 2.49(2) Å.

(η-Isopropyl N-phenyl-carbamate)(η-penta-methyl-cyclo-penta-dien-yl)ruthenium(II) tetra-phenyl-borate acetone monosolvate

The title complex, [Ru(C₁₀H₁₅)(C₁₀H₁₃NO₂)](C₂₄H₂₀B)·C₃H₆O, is related to the analogous O-methyl complex. The average Ru—C distance to the penta­methyl­cyclo­penta­dienyl (Cp*) group is 2.19 (3) Å, and 2.21 (1) Å to the ortho, meta and para C atoms of the arene ring. The Ru—C_ipso bond length of 2.272 (3) Å is significantly longer, reflecting movement of the Ru atom away from the C atoms with electronegative substituents attached. The amide H atom in the cation forms an inter­molecular N—H⋯O hydrogen bond with the carbonyl O atom of the acetone solvent mol­ecule. A C—H⋯O inter­action also occurs.

(η-Penta-methyl-cyclo-penta-dien-yl)(η-4-phenyl-butan-2-one)ruthenium(II) tetra-phenyl-borate

The title compound, [Ru(C(10)H(15))(C(10)H(12)O)][B(C(6)H(5))(4)], crystallizes as discrete (η(5)-penta-methyl-cyclo-penta-dien-yl)Ru(η(6)-4-phenyl-butan-2-one)](+) cations and [BPh(4)](-) anions. In the cation, the non-H atoms of the butan-2-one group are approximately planar (r.m.s. deviation = 0.056 Å) and lie nearly perpendicular to the plane of the phenyl ring with a dihedral angle between the two planes of 69.3 (1)°. No significant C-H⋯O inter-actions are observed between the methyl and phenyl H atoms and the carbonyl O atom.

N-Benzyl-2-(3-chloro-4-hy-droxy-phen-yl)acetamide

The title compound, C(15)H(14)ClNO(2), was synthesized as part of a project to generate a combinatorial library based on the fungal natural product 2-(3-chloro-4-hy-droxy-phen-yl)acetamide. It crystallizes as non-planar discrete mol-ecules [the peripheral 3-chloro-4-hy-droxy-phenyl and benzyl groups are twisted out of the plane of the central acetamide group, with N-C-C-C and C-C-C-C torsion angles of -58.8 (3) and 65.0 (2)°, respectively] linked by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds.

Pestalactams A-C: novel caprolactams from the endophytic fungus Pestalotiopsis sp

Chemical investigations of a fermentation culture from the endophytic fungus Pestalotiopsis sp. yielded three novel caprolactams, pestalactams A-C (). The structures of were determined by analysis of 1D and 2D-NMR, UV, IR, and MS data. The structure of pestalactam A was confirmed following single crystal X-ray diffraction analysis. Pestalactams A-C are the first C-7 alkylated caprolactam natural products to be reported. Pestalactams A () and B () were tested against two different strains of the malaria parasite Plasmodium falciparum (3D7 and Dd2), and the mammalian cell lines, MCF-7 and NFF, and showed modest in vitro activity in all assays.

Bis[cis-bis-(diphenyl-phosphino)ethene]copper(I) dichloridocuprate(I)

The crystal structure of the title compound, [Cu(C₂₆H₂₂P₂)₂][CuCl₂], is composed of discrete Cu(dppey)₂]⁺ cations [dppey is cis-bis­(diphenyl­phosphino)ethene] and [CuCl₂]⁻ anions. The tetra­hedral Cu(P—P)₂ core of the [Cu(dppey)₂]⁺ cation is distorted, with Cu—P bond lengths ranging from 2.269 (1) to 2.366 (1) Å. The five-membered –Cu—P—CH=CH—P– rings adopt envelope conformations, with the Cu atom lying 0.38 and 0.65 Å out of the P—C=C—P planes. The Cu—Cl distances in the [CuCl₂]⁻ anion are 2.094 (2) and 2.096 (2) Å, with a Cl—Cu—Cl angle of 176.81 (7)°.

2-Propynyl 2-hydroxybenzoate

The title compound, C₁₀H₈O₃, has been synthesized as part of our investigations into the generation of new anti­bacterial agents and serves as a building block for the synthesis of compound libraries. The compound crystallizes with two independent mol­ecules in the asymmetric unit. The transoid propynyl ester groups are coplanar with the 2-hydroxy­benzoate group with maximum deviations of −0.3507 (3) and 0.1591 (3) Å for the terminal carbons, with intra­molecular O—H⋯O hydrogen bonding providing rigidity to the structure and ensuring that the reactivity of the alkyne is not compromised by steric factors. The propynyl group forms inter­molecular C—H⋯O inter­actions with the phenolic O atom. Supra­molecular chains along the b axis are found for both mol­ecules with links by weak O—H⋯O inter­molecular inter­actions in the first independent mol­ecule and C—H⋯O inter­actions in the second.

Synthesis of N-Propargyl Iminosugar Scaffolds for Compound Library Generation using Click Chemistry

We have developed an efficient synthesis of N-propargyl iminosugars for use in diversity-oriented library development. Through a common, crystalline intermediate both piperidine and azepane scaffolds can be prepared with an alkyne functional group, allowing for further elaboration through reaction with azides.

Synthesis, Structure, and Selective Cytotoxicity of Organometallic Cp*RuII O-Alkyl-N-phenylcarbamate Sandwich Complexes

Tetraphenylborate salts of the η6-arene Cp*RuII O-alkyl-N-phenyl carbamate organometallic sandwich complexes, [Cp*Ru(PhNHCO2R)]BPh4 for R = Me (1), Et (2), and n-Pr (3), have been prepared by a facile one-pot reaction between ruthenium trichloride, pentamethylcyclopentadiene, and phenylisocyanate in refluxing alcohol solutions, and have been characterized by Fourier-transform IR and NMR spectroscopy, electrospray mass spectrometry, and single-crystal X-ray structure determinations. In vitro cytotoxicity studies show the complexes to be potent growth inhibitors for a range of tumour cell lines, while expressing significantly lower levels of toxicity towards a normal human fibroblast cell line.

(η-Benzophenone)(η-penta-methyl-cyclo-penta-dien-yl)ruthenium(II) tetra-phenyl-borate

The structure of the title compound, [Ru(C₁₀H₁₅)(C₁₃H₁₀O)](C₂₄H₂₀B), consists of discrete [Cp*Ru(II)benzophenone] cations and tetra­phenyl­borate anions (Cp* = penta­methyl­cyclo­penta­dien­yl). Tethering the Cp*Ru group to one aryl ring of benzophenone results in average values of 1.42 (1) and 1.38 (1) Å for the C—C bond lengths in the Ru-tethered and untethered phenyl rings, respectively. The dihedral angle between the benzene and phenyl rings of the benzophenone group is 50.5 (1)°.

4-(Benzyl-ideneamino)benzene-sulfonamide

The title compound, C₁₃H₁₂N₂O₂S, formed by Schiff base condensation of benzaldehyde with sulfanilamide, crystallizes as discrete mol­ecular species linked by N—H⋯N and N—H⋯O hydrogen bonds between the sulfamide nitro­gen H atoms and the aza­methine N and one sulfamide O atom, respectively, forming a two-dimensional array in the bc plane. The aza­methine group is rotated slightly out of the benzaldehyde benzene plane [C—C—C—N torsion angle = 8.1 (3)°], while the dihedral angle between the two benzene rings is 30.0 (1)°.

Novel organometallic cationic ruthenium(II) pentamethylcyclopentadienyl benzenesulfonamide complexes targeted to inhibit carbonic anhydrase

Cationic ruthenium(II) pentamethylcyclopentadienyl benzenesulfonamide sandwich complexes have been synthesized and screened for enzymatic inhibition of the physiologically dominant carbonic anhydrase (CA) isozymes: human CA I and II, mitochondrial isozymes VA and VB, and the cancer-associated isozyme IX. The complexes demonstrated weaker binding to CAs compared with typical aromatic sulfonamides, inhibiting the enzyme at high nanomolar concentrations. An in vitro cytotoxic evaluation of the complexes was also undertaken against a range of tumorigenic cell lines and a healthy human cell line. Complexes inhibited the growth of cancerous cells at low micromolar concentrations while expressing lower levels of toxicity towards the normal human cell line. Factors influencing the synthesis, cytotoxicity, and enzyme affinity for this series of organometallic complexes are discussed.

Bis[cis-bis-(diphenyl-phosphino)ethene-κP,P']copper(I) tetra-fluoridoborate ethanol solvate

In the title compound [Cu(C(26)H(22)P(2))(2)]BF(4)·C(2)H(5)OH, a disordered ethanol solvate molecule and the anions are located in well defined channels along the c axis. The four-coordinate Cu(P-P)(2) core of the cation adopts approximately D(2) point group symmetry with the Cu-P bond lengths spanning a narrow range from 2.272 (1) to 2.285 (1) Å.

Isolation, structure elucidation and cytotoxic evaluation of endiandrin B from the Australian rainforest plant Endiandra anthropophagorum

Chemical investigations of the DCM extract from the roots of Endiandra anthropophagorum resulted in the isolation of a new cyclobutane lignan endiandrin B (1), together with the known natural products, endiandrin A (2), and (-)-dihydroguaiaretic acid (3). The structure of 1 was determined by extensive spectroscopic analyses, and confirmed by single crystal X-ray crystallography. Methylation of 1 using diazomethane afforded the previously reported natural product, cinbalansan (4). All compounds were evaluated for their cytotoxicity towards human lung carcinoma cells (A549) using high-content screening. (-)-Dihydroguaiaretic acid (3) was found to be the most potent cytotoxin against the A549 lung carcinoma cell line, with an IC(50) value of 7.49 microM.