Highly efficient oxidative carbon-carbon coupling with SBA-15-support iron terpyridine catalyst.

SBA-15-Fe(terpy)(2+) complex efficiently catalyzed oxidative C-C cross-coupling reactions of tertiary amines with carbon nucleophiles in high product yields. The supported terpyridine ligand can be recycled by filtration.

Gold(III) porphyrin 1a inhibited nasopharyngeal carcinoma metastasis in vivo and inhibited cell migration and invasion in vitro.

A physiologically stable gold compound, gold(III) meso-tetraphenylporphyrin (gold-1a), has been shown to be effective in inducing apoptosis and prolonging the survival of hepatocellular carcinoma (HCC)-bearing rats as well as inhibiting the tumor growth of mice bearing nasopharyngeal carcinoma (NPC), neuroblastoma and colon carcinoma. In this study, we showed that gold-1a prolonged the survival of NPC metastasis-bearing mice and inhibited intrahepatic and lung metastasis. Histologically, gold-1a markedly reduced tumor microvessel formation.

Stable anticancer gold(III)-porphyrin complexes: effects of porphyrin structure.

In the design of physiologically stable anticancer gold(III) complexes, we have employed strongly chelating porphyrinato ligands to stabilize a gold(III) ion [Chem. Commun. 2003, 1718; Coord.

A water-soluble ruthenium glycosylated porphyrin catalyst for carbenoid transfer reactions in aqueous media with applications in bioconjugation reactions.

Water-soluble [Ru(II)(4-Glc-TPP)(CO)] (1, 4-Glc-TPP = meso-tetrakis(4-(beta-D-glucosyl)phenyl)porphyrinato dianion) is an active catalyst for the following carbenoid transfer reactions in aqueous media with good selectivities and up to 100% conversions: intermolecular cyclopropanation of styrenes (up to 76% yield), intramolecular cyclopropanation of an allylic diazoacetate (68% yield), intramolecular ammonium/sulfonium ylide formation/[2,3]-sigmatroptic rearrangement reactions (up to 91% yield), and intermolecular carbenoid insertion into N-H bonds of primary arylamines (up to 83% yield). This ruthenium glycosylated porphyrin complex can selectively catalyze alkylation of the N-terminus of peptides (8 examples) and mediate N-terminal modification of proteins (four examples) using a fluorescent-tethered diazo compound (15). A fluorescent group was conjugated to ubiquitin via 1-catalyzed alkene cyclopropanation with 15 in aqueous solution in two steps: (1) incorporation of an alkenic group by the reaction of N-hydroxysuccinimide ester 19 with ubiquitin and (2) cyclopropanation of the alkene-tethered Lys(6) ubiquitin (23) with the fluorescent-labeled diazoacetate 15 in the presence of a catalytic amount of 1.

Ruthenium catalyzed directing group-free C2-selective carbenoid functionalization of indoles by alpha-aryldiazoesters.

A directing group-free approach for C2-selective carbenoid functionalization of NH-indoles is presented. Using [RuCl(2)(p-cymene)](2) as catalyst and alpha-aryldiazoesters as carbenoid source, 2-alkylated indoles were obtained in up to 96% isolated yield. Similarly, a regioselective carbenoid functionalization of NH-pyrroles was also achieved.

Ligand-controlled enantioselective [2 + 2] cycloaddition of oxabicyclic alkenes with terminal alkynes using chiral iridium catalysts.

The first catalytic asymmetric [2 + 2] cycloaddition of oxabicyclic alkenes and terminal alkynes has been developed. This iridium-catalyzed enantioselective [2 + 2] cycloaddition allows the formation of four stereocenters in a single step with excellent enantioselectivity (94-->99% ee).

Silver(I)-mediated highly enantioselective synthesis of axially chiral allenes under thermal and microwave-assisted conditions.

Silver(I) salts mediated stereospecific transformation of optically active propargylamines to axially chiral allenes with excellent enantioselectivities (17 examples with 96-99% ee; one substrate with 91% ee) without subsequent racemization.

A selective oligonucleotide-based luminescent switch-on probe for the detection of nanomolar mercury(II) ion in aqueous solution.

An oligonucleotide-based luminescent platinum(II) switch-on probe has been developed for selective detection of nanomolar Hg(2+) ions.

Dual anti-angiogenic and cytotoxic properties of ruthenium(III) complexes containing pyrazolato and/or pyrazole ligands.

An oxo-bridged diruthenium(III) complex containing pyrazolato and pyrazole ligands is stable against ascorbic-acid reduction, induces apoptosis (60%, 48 h) against HeLa cells at 10 microM level and exhibits promising anti-angiogenic activity at its sub-cytotoxic concentrations. Other mononuclear ruthenium(III) complexes containing pyrazole ligands [Ru(pz)(4)X(2)](+) exhibit dual anti-angiogenic and cytotoxic properties.

Metal complexes in medicine with a focus on enzyme inhibition.

Since the clinical success of cisplatin and its derivatives, considerable effort has been expended by academics and pharmacological companies to the development of novel metal-based drugs. DNA is believed to be the main target of cisplatin, and there have been extensive studies on the binding between metal complexes and DNA targets. Recently, new light has been shed on the discovery of metal-based drugs that inhibit enzymatic activities or even target proteins directly.

A gold(III) porphyrin complex with antitumor properties targets the Wnt/beta-catenin pathway.

Gold(III) complexes have shown promise as antitumor agents, but their clinical usefulness has been limited by their poor stability under physiological conditions. A novel gold(III) porphyrin complex [5-hydroxyphenyl-10,15,20-triphenylporphyrinato gold(III) chloride (gold-2a)] with improved aqueous stability showed 100-fold to 3,000-fold higher cytotoxicity than platinum-based cisplatin and IC50 values in the nanomolar range in a panel of human breast cancer cell lines. Intraductal injections of gold-2a significantly suppressed mammary tumor growth in nude mice.

Backbone and side-chain 1H, 13C and 15N assignments of the ubiquitin-associated domain of human X-linked inhibitor of apoptosis protein.

X-linked inhibitor of apoptosis protein (XIAP), a leading member of the family of inhibitor of apoptosis (IAP) proteins, is considered as the most potent and versatile inhibitor of caspases and apoptosis. It has been reported that XIAP is frequently overexpressed in cancer and its expression level is implicated in contributing to tumorigenesis, disease progression, chemoresistance and poor patient-survival. Therefore, XIAP is one of the leading targets in drug development for cancer therapy.

Solution structure of an active mutant of maize ribosome-inactivating protein (MOD) and its interaction with the ribosomal stalk protein P2.

Ribosome-inactivating proteins (RIPs) are N-glycosidases that depurinate a specific adenine residue in the conserved sarcin/ricin loop of ribosomal RNA. This modification renders the ribosome unable to bind the elongation factors, thereby inhibiting the protein synthesis. Maize RIP, a type III RIP, is unique compared to the other type I and type II RIPs because it is synthesized as a precursor with a 25-residue internal inactivation region, which is removed in order to activate the protein.

Stabilization of G-quadruplex DNA with platinum(II) Schiff base complexes: luminescent probe and down-regulation of c-myc oncogene expression.

The interactions of a series of platinum(II) Schiff base complexes with c-myc G-quadruplex DNA were studied. Complex [PtL(1a)] (1 a; H(2)L(1a)=N,N'-bis(salicylidene)-4,5-methoxy-1,2-phenylenediamine) can moderately inhibit c-myc gene promoter activity in a cell-free system through stabilizing the G-quadruplex structure and can inhibit c-myc oncogene expression in cultured cells. The interaction between 1 a and G-quadruplex DNA has been examined by (1)H NMR spectroscopy.

Butyrate mediates nucleotide-binding and oligomerisation domain (NOD) 2-dependent mucosal immune responses against peptidoglycan.

The interaction between digestive tract microbiological flora and food has an important influence on human health. Butyrate is produced during the fermentation of dietary fibres by intestinal bacteria and plays an important role in the regulation of mucosal immunity. In this report, we studied the impact of butyrate on the defence mechanism against the bacterial membrane component peptidoglycan (PGN).

Graphite-supported gold nanoparticles as efficient catalyst for aerobic oxidation of benzylic amines to imines and N-substituted 1,2,3,4-tetrahydroisoquinolines to amides: synthetic applications and mechanistic study.

Selective oxidation of amines using oxygen as terminal oxidant is an important area in green chemistry. In this work, we describe the use of graphite-supported gold nanoparticles (AuNPs/C) to catalyze aerobic oxidation of cyclic and acyclic benzylic amines to the corresponding imines with moderate-to-excellent substrate conversions (43-100%) and product yields (66-99%) (19 examples). Oxidation of N-substituted 1,2,3,4-tetrahydroisoquinolines in the presence of aqueous NaHCO3 solution gave the corresponding amides in good yields (83-93%) with high selectivity (up to amide/enamide=93:4) (6 examples).

Highly enantioselective synthesis of chiral secondary amines by gold(I)/chiral Brønsted acid catalyzed tandem intermolecular hydroamination and transfer hydrogenation reactions.

A method for the synthesis of enantiomerically enriched secondary amines with excellent ee values through the tandem intermolecular hydroamination/transfer hydrogenation of alkynes using a "gold(I) complex-chiral Brønsted acid" protocol is developed. The catalysis works for a wide variety of aryl, alkenyl, and aliphatic alkynes as well as anilines with different electronic properties.

Palladium-catalyzed decarboxylative arylation of C-H bonds by aryl acylperoxides.

A Pd(OAc)(2)-catalyzed protocol for decarboxylative arylation of aromatic C-H bond was developed using aryl acylperoxides as inexpensive aryl sources. Substrates containing pyridyl, oxime, and oxazoline groups undergo effectively ortho-selective C-H arylation with excellent functional group tolerance. This arylation should begin by directing-group-assisted cyclopalladation, followed by the reaction of the palladacycle with aryl radicals generated in situ by thermal decomposition of the peroxides.

Metalloporphyrin-based oxidation systems: from biomimetic reactions to application in organic synthesis.

The oxidation of organic substrates catalyzed by metalloporphyrins constitutes a major class of biomimetic oxidation reactions used in modern synthetic chemistry. Ruthenium porphyrins are among the most extensively studied metalloporphyrin oxidation catalysts. This article provides a brief outline of the metalloporphyrin-based oxidation systems and is focused on the oxidation reactions catalyzed by ruthenium porphyrins performed in the author's laboratory.

Pluronic L-81 ameliorates diabetic symptoms in db/db mice through transcriptional regulation of microsomal triglyceride transfer protein.

Aim: To test whether oral L-81 treatment could improve the condition of mice with diabetes and to investigate how L-81 regulates microsomal triglyceride transfer protein (MTP) activity in the liver.

Methods: Genetically diabetic (db/db) mice were fed on chow supplemented with or without L-81 for 4 wk. The body weight, plasma glucose level, plasma lipid profile, and adipocyte volume of the db/db mice were assessed after treatment.

Ion desorption efficiency and internal energy transfer in carbon-based surface-assisted laser desorption/ionization mass spectrometry: desorption mechanism(s) and the design of SALDI substrates.

Ion desorption efficiency and internal energy transfer were probed and correlated in carbon-based surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using benzylpyridinium (BP) salt as the thermometer chemical. In a SALDI-MS experiment with a N(2) laser (at 337 nm) used as the excitation light source and with multiwalled carbon nanotubes (CNT), buckminsterfullerene (C(60)), nanoporous graphitic carbon (PGC), non-porous graphite particles (G), highly oriented pyrolytic graphite (HOPG), or nanodiamonds (ND) as the SALDI substrate, both the desorption efficiency in terms of ion intensity of BP and the extent of internal energy transfer to the ions are dependent on the type and size of the carbon substrates. The desorption efficiency (CNT approximately C(60) > PGC > G > HOPG > ND) in general exhibits an opposite trend to the extent of internal energy transfer (CNT < C(60) approximately PGC < G approximately HOPG < ND), suggesting that increasing the extent of internal energy transfer in the SALDI process may not enhance the ion desorption efficiency.