Functionalization of the corrole ring: the role of isocorrole intermediates.

Bromination of 3-nitro-5,10,15-triarylcorrole selectively provides two regioisomers, depending on the reaction pathway. An isocorrole species is the key intermediate to drive the reaction towards the 2-Br-17-nitro regioisomer.

Isolation and structure determination of a sesquiterpene lactone (vernodalinol) from Vernonia amygdalina extracts.

Context: Vernonia amygdalina Del. (VA; Asteraceae or Compositae) is a small tree growing throughout tropical Africa. It is widely used for food and medicinal purposes by local people.

Effect of inclining strain on the crystal lattice along an extended series of lanthanide hydroxysulfates Ln(OH)SO4 (Ln = Pr-Yb, except Pm).

A series of trivalent lanthanide hydroxysulfates, Ln(OH)SO(4), (Ln = Pr through Yb, except radioactive Pm) has been synthesized via hydrothermal methods from Ln(2)(SO(4))(3)·8H(2)O by reaction with aqueous NaOH at 170 °C in Teflon lined Parr steel autoclaves, and were characterized by single crystal X-ray diffraction and FT-IR spectroscopy. Two types of arrangements were found in the solid state. The lighter (Ln = Pr-Nd, Sm-Gd) and heavier lanthanide(III) hydroxysulfates (Tb-Yb) are each isostructural.

Binding and selectivity aspects of an expanded azamacrocycle for anions.

An expanded azamacrocycle L, containing four secondary and two tertiary amines was synthesized, and its binding ability towards chloride, bromide, iodide, sulfate, nitrate and perchlorate were determined by (1)H NMR titrations in D(2)O at pH 1.7. The results suggest that the ligand is capable of forming a complex with each of the anions examined, showing the selectivity for sulfate in water.

One-pot synthesis of meso-alkyl substituted isocorroles: the reaction of a triarylcorrole with Grignard reagent.

The reaction of 5,10,15-tritolylcorrole with EtMgBr opens the way for novel functionalizations of the corrole ring. DDQ oxidation of the macrocycle, followed by addition of the Grignard reagent, led to the formation of 5- and 10-alkyl substituted isocorroles in satisfying yields. Together with the one-pot formation of these isocorrole isomers, the use of such a nucleophile evidenced the competitive reactivity of the macrocycle β-positions, leading to the formation of 2-bromo- and 3-bromo-5,10,15-tritolylcorrole.

Antileishmanial Germacranolides from Calea zacatechichi.

Phytochemical study of the leaves and stems of Calea zacatechichi Schl. (Asteraceae) led to the isolation of a series of six germacranolides (1-6) with significant antileishmanial activity. The structure of a new compound named by us as calealactone D (1) was determined by NMR and MS, and its absolute configuration by X-ray crystallography.

(Acetato-κ2O,O')dihydroxidoytterbium(III) hemihydrate.

The title compound, [Yb(C(2)H(3)O(2))(OH)(2)]·0.5H(2)O, was obtained via hydrothermal reaction of Yb(CH(3)COO)(3)·H(2)O with NaOH at 443 K. The compound forms two-dimensional layers with six crystallographically independent Yb(III) atoms.

A rod packing microporous metal-organic framework with open metal sites for selective guest sorption and sensing of nitrobenzene.

A microporous MOF [Zn(4)(OH)(2)(1,2,4-BTC)(2)] (1,2,4-BTC = Benzene-1,2,4-tricarboxylate) with two immobilized open metal Zn(2+) sites was obtained by solvothermal reaction, which exhibits highly selective guest sorption and sensing of nitrobenzene.

Anion recognition and sensing by a new macrocyclic dinuclear copper(II) complex: a selective receptor for iodide.

A macrocyclic dinuclear copper complex, [Cu(2)(II)(1)Br(3)(H(2)O)]Br, has been synthesized and characterized by X-ray crystallography, in which the macrocycle is folded to form a bowl-shaped cavity. The sensing ability of the receptor has been studied for halides by UV-vis spectroscopy in water-acetonitrile (1:3, v/v) and water. The results indicate that the new receptor exhibits a strong affinity and selectivity for iodide.

Dibenzocyclooctadiene lignans from Magnolia and Talauma (Magnoliaceae): their absolute configuration ascertained by circular dichroism and X-ray crystallography and re-evaluation of previously published pyramidatin structures.

Twelve pyramidatins, i.e., dibenzocyclooctadiene-type lignans, together with Machilin G, were isolated from the dichloromethane extracts of aerial material of Talauma gloriensis, Magnolia fraseri, and Magnolia pyramidata (Magnoliaceae).

Structure-activity relationship studies on derivatives of eudesmanolides from Inula helenium as toxicants against Aedes aegypti larvae and adults.

An Aedes aegypti larval toxicity bioassay was performed on compounds representing many classes of natural compounds including polyacetylenes, phytosterols, flavonoids, sesquiterpenoids, and triterpenoids. Among these compounds, two eudesmanolides, alantolactone, and isoalantolactone showed larvicidal activities against Ae. aegypti and, therefore, were chosen for further structure-activity relationship study.

Cooperative NH⋯O and CH⋯O interactions for sulfate encapsulation in a thiophene-based macrocycle.

A thiophene-based macrocycle containing four secondary and two tertiary amines has been synthesized and its binding affinity has been investigated toward sulfate anion in solution and solid states. Structural analysis of the sulfate salt suggests that the ligand in its hexaprotonated form, is capable of encapsulating one sulfate within the cavity through cooperative NH⋯O and CH⋯O interactions. As investigated by (1)HNMR titrations, the lignad forms a 1:1 complex with sulfate in water at pH 2.

Superbasic amidine monodentate ligands in fac-[Re(CO)3(5,5'-Me2bipy)(amidine)]BF4 complexes: dependence of amidine configuration on the remote nitrogen substituents.

Addition of various RNH(2) to fac-[Re(CO)(3)(5,5'-Me(2)bipy)(CH(3)CN)]BF(4) (1) converts the acetonitrile ligand to the amidine ligand (a superbase) in fac-[Re(CO)(3)(5,5'-Me(2)bipy)(HNC(CH(3))NHR)]BF(4) products. Each complex has four conceivable isomers (E, E', Z, and Z') because the amidine CN bonds have double-bond character, and the two remote NHR group substituents are different. The reaction of 1 in acetonitrile is complete in 6 to 96 h (25 degrees C) and forms fac-[Re(CO)(3)(5,5'-Me(2)bipy)(HNC(CH(3))NHR)]BF(4) E' and Z isomers.

Effect of overall charge and charge distribution on cellular uptake, distribution and phototoxicity of cationic porphyrins in HEp2 cells.

Five cationic porphyrins bearing one to four -N(CH(3))(3)(+) groups linked to the p-phenyl positions of 5,10,15,20-tetraphenylporphyrin (TPP) were synthesized in order to study the effect of overall charge and its distribution on the cellular uptake, phototoxicity and intracellular localization using human carcinoma HEp2 cells. The di-cationic porphyrins DADP-o and DADP-a accumulated the most within cells and preferentially localize within vesicular compartments and in mitochondria. Of these two only DADP-a was phototoxic to the cells (IC(50)=3 microM at 1 J/cm(2)).

Bioactive 1,4-dihydroxy-5-phenyl-2-pyridinone alkaloids from Septoria pistaciarum.

Four new 1,4-dihydroxy-5-phenyl-2-pyridinone alkaloids (1-4) were isolated from an EtOAc extract of a culture medium of Septoria pistaciarum. The structures of these compounds were determined by spectroscopic methods, and the absolute configuration of the major compound (1) was determined by X-ray crystallographic analysis. Compound 1 exhibited moderate in vitro antiplasmodial (antimalarial) activity against chloroquine-sensitive (D6) and -resistant (W2) strains of Plasmodium falciparum and cytotoxic activity to Vero cells.

A new hexaaminomacrocycle for ditopic binding of bromide.

A hexaaminomacrocycle L, containing four secondary and two tertiary amines has been synthesized and crystallized with hydrobromic acid. Structural analysis of the bromide complex suggests that the ligand in its tetrtaprotonated form, is involved in coordinating two bromides from both sides via hydrogen bonding interactions with N…Br(-) distance of 3,351 Å, forming a ditopic complex. The other two bromides are outside the cavity, and singly bonded to the macrocycle.

Constituents of Calamintha ashei: effects on Florida sandhill species.

Chemical constituents of the perennial shrub Calamintha ashei have been characterized as part of our investigation of the allelopathic properties of this plant. Besides the known monoterpenes, (+)-evodone, (-)-calaminthone and (+)-desacetylcalaminthone, fresh aerial parts of C. ashei provided six new menthofurans, two new germacrane sesquiterpenes, and the six, known flavonoids: 5-desmethoxynobiletin, 5-hydroxy-6,7,8,4'-tetramethoxyflavone, 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone, thymonin, 5,4'-dihydroxy-6,7-dimethoxyflavone and 6-hydroxy-7,3'-dimethoxyluteolin.

Synthesis and characterization of free-base, copper, and nickel isocorroles.

A series of free-base and metalated isocorroles represented as (TT-n-iso-Cor)H(2) and (TT-n-iso-Cor)M(II), where n = 5 or 10 and M = Ni or Cu, were synthesized and characterized by electrochemistry and spectroelectrochemistry in CH(2)Cl(2) containing 0.1 M tetra-n-butylammonium perchlorate. The metalation of the free-base macrocycles with Co(II), Mn(III), or Zn(II) was also attempted but was unsuccessful.

Charge-assisted encapsulation of two chlorides by a hexaprotonated azamacrocycle.

A chloride complex of a hexaprotonated azamacrocycle has been isolated, and its structure has been determined by X-ray crystallography showing two encapsulated chloride anions in the cavity. The two internal guests are coordinated at two binding sites on the opposite side of the macrocycle through trigonal recognition by hydrogen-bonding interactions. The other four chlorides are located outside the cavity, each with a single hydrogen bond from secondary amines.

Formation of an Amine-Water Cyclic Pentamer: A New Type of Water Cluster in a Polyazacryptand.

Structural analysis of an adduct of a thiophene-based cryptand with tosylic acid shows the formation of a hybrid amine-water cyclic pentamer composed of four water molecules and one protonated amine in the charged hydrophobic cavity. The bulky tosylate groups remain outside the cavity, making the ligand favorable for hosting water molecules. Ab initio calculations based on density functional theory (DFT) confirm that the hybrid amine-water pentamer is stabilized inside the hydrophobic cavity of the cryptand.

{4-Phenyl-1-[1-(1,3-thia-zol-2-yl)ethyl-idene]-thio-semicarbazidato}{4-phenyl-1-[1-(1,3-thia-zol-2-yl)ethylidene]-thio-semi-carbazide}nickel(II) chloride mono-hydrate.

In the title compound, [Ni(C(12)H(11)N(4)S(2))(C(12)H(12)N(4)S(2))]Cl·H(2)O, the Ni(II) ion is chelated by two 2-acetyl-thia-zole-3-phenyl-thio-semicarbazone ligands, forming a distorted octa-hedral complex. The metal ion is coordinated via the thia-zole nitro-gen, imine nitro-gen and thione sulfur atoms from each thio-semicarbazone ligand, and two coordinating units lie almost perpendicular to each other give dihedral angle = 81.89 (1)°].

Facile iterative synthesis of 2,5-terpyrimidinylenes as nonpeptidic alpha-helical mimics.

A facile iterative synthesis of 2,5-terpyrimidinylenes that are structurally analogous to alpha-helix mimics is presented. Condensation of amidines with readily prepared alpha,beta-unsaturated alpha-cyanoketones gives 5-cyano-substituted pyrimidines. Iterative transformation of the 5-cyano group into an amidine allows synthesis of 2,5-terpyrimidinylenes with variable groups at the 4-, 4'-, and 4''-positions.

Anticancer activities of the ruthenium carboxylato, amido and pyridine complexes.

Ruthenium complexes [1-3] with oxalato, amido and pyridine ligands have been synthesized and characterized. Biological tests showed that the ruthenium complexes 2 and 3 have modest cytotoxicity on both murine cell line NIH3T3 and human cancer colon cell lines HCT116 and HT29 while complex 1 has no obvious growth defect. We further tested why complexes 2 and 3 exhibit modest cytotoxicity.