According to life-history theory, investment in reproduction is associated with costs, which should appear as decreased survival to the next reproduction or lower future reproductive success. It has been suggested that oxidative stress may be the proximate mechanism of these trade-offs. Despite numerous studies of the defense against reactive oxygen ...

This article reports a systematic study of the seed-mediated growth of Au@Pd core-shell nanocrystals with a variety of controlled sizes and morphologies. The key to the success of this synthesis is to manipulate the reaction kinetics by tuning a set of reaction parameters, including the type and concentration of capping ...

An efficient and controlled means to achieve a rare cine substitution of arenes is reported. The methodology relies on the strategic use of aryl O-carbamates as readily removable directing groups for arene functionalization. The removal of aryl carbamates is achieved by employing an air-stable Ni(II) precatalyst, along with an inexpensive ...

Asymmetric syntheses of both 1-deoxy-6,8a-di-epi-castanospermine and 1-deoxy-6-epi-castanospermine, polyhydroxylated indolizidine-alkaloids that act as selective glycosidase inhibitors, have been accomplished in seven steps. The key feature of our unique syntheses includes the stereoselective introduction of the C-3 and C-4 hydroxyl groups utilizing the aza-Claisen rearrangement-induced ring-expansion of 1-acyl-2-alkoxyvinyl pyrrolidine and a substrate-controlled ...

The ring-opening polymerization of two caprolactone monomers catalyzed by zinc undecylenate (ZU) is reported. Polymerizations were performed in bulk with benzyl alcohol (BnOH) as an initiator at 90 and 110 °C, respectively. A slower polymerization rate was observed for γ-octyloxy-ϵ-caprolactone as compared to ϵ-caprolactone. Diblock copolymers were synthesized by the ...

An efficient, scalable, and stereocontrolled synthesis of the entire carbon framework of an actin binding dimeric macrolide rhizopodin has been accomplished in its protected form. The key features of our synthesis include a titanium catalyzed anti acetal aldol reaction, a substrate controlled diastereoslelective prenyl stannylation, a Mukaiyama aldol reaction, an ...

Catalytic or stoichiometric amount of Lewis acids were found to be very effective alpha-directing additives in the stereoselective glycosylations of diverse 2,3-O-caobonate protected glucose and galactose thioglycoside donors by preactivation protocol. The poor stereoselectivities of 4,6-di-O-acetyl-2,3-O-carbonate protected thioglycoside donors 2 and 5 in glycosyl coupling reactions were greatly improved, and ...

Compounded trilostane capsules (15 mg, 45 mg, or 100 mg) were purchased from eight pharmacies and assayed for content and dissolution characteristics. Capsules made in-house containing either inert material or 15 mg of the licensed product and proprietary capsules (30 mg and 60 mg) served as controls. Findings were compared ...

Although oxidative stress is considered the underlying mechanism by which dysfunctional metabolism occurs in obese subjects, there are few studies on oxidative stress in overweight subjects. The objective of this study was to verify the influence of metabolic syndrome (MetS) on oxidative stress and antioxidant defense in overweight subjects. There ...

OBJECTIVE: The purpose of this study was to examine the status of folate and vitamin B12 (B12) in relation to serum homocysteine (HCY) and oxidative stress indices in patients with type 2 diabetes (T2DM). METHODS: This case-control study involved 100 Omani adults (50 patients newly diagnosed with T2DM and 50 ...

Airway inflammation and related respiratory complaints are common symptoms among waste management workers (WMWs). This study investigated the relationship between exposure to municipal solid waste (MSW) and the levels of inflammatory markers and oxidative stress among WMW of Ogun State, South West Nigeria. A total of 280 subjects consisting of ...

An oxidative γ-functionalization of enals under N-heterocyclic carbene (NHC) catalysis to give unsaturated δ-lactones is disclosed. Enantioselectivity control involving the relatively remote enal γ-carbon was achieved via Lewis acid [Sc(OTf)3 or combined Sc(OTf)3/Mg(OTf)2] and NHC cooperative catalysis.

A novel dithioester control agent [dimethyltetrathioterephtalate (DMTTT)] is presented for the thioketone-mediated radical polymerization (TKMP) of n-butyl acrylate. The rate of polymerization is significantly decreased in the presence of DMTTT indicating formation of dormant radical species. During polymerization, molar masses increase linearly with monomer conversion with reasonably narrow initial molar ...

The highly selective mono-C-allylation of oligoglycinates such as a diethylenetriaminepentaacetate, an iminodiacetate and an ethylenediaminetetraacetate via insertion of a vacuum operation between the N-allylation and C-migration steps is reported. It is contrastive that one-pot N-allylaion-C-allylation procedure gave a mixture including multi-allylated products. In the reaction with N-ylides, gem-C-diallylation and alpha,alpha'-C-diallylation ...

Several metals undergo redox cycling, producing free radicals and generating oxidative stress. The purpose of this study was to investigate in-vitro oxidative stress of orthodontic archwires made of various alloys. Mouse fibroblast cells L929 were exposed to 6 types of archwires, and the concentration of the oxidative stress marker 8-hydroxy-2'-deoxyguanosine ...

A Jacobsen epoxidation protocol using H(2)O(2) as oxidant was designed for the large-scale preparation of various epoxy vinyl sulfones. A number of cocatalysts were screened, and pH control led to increased reaction rate, higher turnover number, and improved reliability.

Going all the way: The first total synthesis of (±)-kopsihainanine A has been achieved in ten steps with a 12 % overall yield from commercially available 1,2,3,4-tetrahydrocarbazol-4-one. This synthesis features an intramolecular conjugate addition of the iminium ion formed in situ with the amide and a substrate-controlled diastereoselective α-hydroxylation. Furthermore, ring D ...

Computational study of the mechanisms and stereoselectivities of a dual amino-catalyzed synthesis of cyclohexenones containing all carbon γ-quaternary and ∂-tertiary stereocenters is reported. Extensive conformational search with density functional theory optimizations, the high accuracy SCS-MP2/cc-pV∞Z energies, and PCM solvation corrections were used to characterize all intermediates and transition states. Six ...

A new class of narrowly dispersed nanosize hexagonal MOF rods from Mn(iii)-porphyrin and In(iii) was obtained. The length of MOF rods was controlled by simple change of reaction times. Furthermore, the oxidation of styrene has been successfully demonstrated with Mn(iii)-porphyrin MOF rods and their reusability has been also tested.

Heme oxygenase-1 (HMOX-1) is activated by oxidative stress, and gene responsiveness is reportedly determined by the number of dinucleotide (GT(n)) repeats in its highly polymorphic promoter region. "Short" (S; GT(n)<25) alleles reportedly associate with higher response, lower oxidative stress, lower risk of type 2 diabetes mellitus (type 2DM), and better ...

"Matching" and "mismatching" effects in the doubly diastereoselective conjugate additions of the antipodes of lithium N-benzyl-(N-α-methylbenzyl)amide to enantiopure cis- and trans-dioxolane containing α,β-unsaturated esters have been investigated. High levels of substrate control were established first upon conjugate addition of achiral lithium N-benzyl-N-isopropylamide to both tert-butyl (S,S,E)-4,5-O-isopropylidene-4,5-dihydroxyhex-2-enoate and tert-butyl (4R,5S,E)-4,5-O-isopropylidene-4,5-dihydroxyhex-2-enoate. However, ...

A palladium-catalyzed decarboxylative cyclopropanation of γ-methylidene-δ-valerolactones with aromatic aldehydes has been developed to give 4-oxaspiro[2.4]heptanes with high selectivity. The site of nucleophilic attack to a π-allylpalladium intermediate has been controlled with a sterically demanding phosphine ligand. The course of the reaction is highly dependent on ligands and solvents, and selective ...

Three in one: A highly efficient and mild Pd(II) -catalyzed carboesterification of alkenes with carboxylic alkyne derivatives proceeds through a domino-type alkyne-alkene coupling/CO-bond formation. The stereoselectivity is controlled by the choice of substrates and temperature. The reaction provides a convenient method for the construction of naturally occurring biologically active compounds ...

A zinc or indium-mediated Barbier-type allylation of aldehydes with 3-bromomethyl-5H-furan-2-one in aqueous solvents was developed to provide an efficient route to α-methylene-γ-butyrolactone, which is synthetically very useful. The desired products were obtained in moderate to high yields in aqueous solvents. Excellent drs were achieved, among which the best diastereomeric ratios ...

Reactions of the allyltin trichloride generated from (4S)-4-benzyloxypent-2-enyl(tributyl)stannane with imines prepared from glyoxylates proceed with useful levels of 1,5-stereocontrol in favour of (4E)-2,6-anti-2-(alkylamino)-6-benzyloxyhept-4-enoates . This stereoselectivity, controlled by the chirality of the stannane, dominates over any intrinsic stereochemical bias of the imine although a small amount of matching and mis-matching ...

We report extremely fast tandem ring-opening/ring-closing metathesis polymerization of a monomer containing two rather unreactive functional groups: cyclohexene and a terminal alkyne. When a third-generation Grubbs catalyst was used at low temperature, this tandem polymerization produced polymers with controlled molecular weights and narrow polydispersity indices. In order to explain this ...

A stereoselective synthesis of the macrolactone core of the potent anticancer agent neopeltolide is disclosed. The key steps of the synthesis include asymmetric allylation using Krische' protocol, conjugate reduction using MacMillan's methodology, and an asymmetric hetero-Diels-Alder reaction using Jacobsen's catalyst. Substrate controlled diastereoselective 1,3-anti reduction of a keto alcohol, Luche ...

3-Alkenylation or 3-alkylation of indole with propargylic alcohols could be efficiently controlled by the catalyst. In the presence of triflic acid, 3-alkenylation of indole occurred and 3,4-dihydrocyclopenta[b]indole skeleton was effectively constructed in moderate to excellent yields via a cascade process. In the presence of Cu(OTf)2, 3-alkylation of indole resulted in ...

Synthesis of the C1-C6 and C7-C23 fragments of the proposed structure of iriomoteolide 1a has been accomplished. Key steps include a cross metathesis to form the C15-C16 E olefin and a chelation controlled Grignard addition to form the tertiary alcohol at C14. Notably, 7 of the 9 stereocenters of the ...

Autism spectrum disorders (ASDs) are rarely diagnosed in children younger than 2 years, because diagnosis is based entirely on behavioral tests. Oxidative damage may play a central role in this pathogenesis, together with the interconnected transmethylation cycle and transsulfuration pathway. In an attempt to clarify and quantify the relationship between ...

The two-directional desymmetrization of prochiral precursors with α,β-unsaturated branches by catalyst-controlled 1,4-addition of silicon and likewise boron nucleophiles allows for a general enantioselective access to syn,anti-triols with 1,n + 1,2n + 1 (n = 2 and 3) substitution patterns. The utility is demonstrated in the synthesis of the C17-C25 fragment ...

A protective association between bilirubin and atherosclerosis/ischemic heart disease clearly exists in vivo. However, the relationship between bilirubin and in vivo oxidative stress parameters in a clinical population remains poorly described. The aim of this study was to assess whether persons expressing Gilbert syndrome (GS; i.e., unconjugated hyperbilirubinemia) are protected ...

In contrast to previously studied reactions of ethynyl lithium reagents, the reactions of propynyl and hexynyl lithium with N(3)P(3)F(6) lead to predominantly nongeminal isomers. A modest cis stereo selectivity was observed. The sequential addition of a lithio acetylene reagent which follows a predominately geminal pathway (lithiophenylacetylene) and an aryl lithium ...

The feasibility of kinetic resolutions of racemic monosubstituted cyclohex-2-enones by Rh/binap-catalyzed reactions was investigated. 1,2-Addition of AlMe(3) to the 5-substituted derivatives furnished allylic alcohols in the matched case, while the less reactive enantiomers were either left over or transformed into trans-3,5-disubstituted cyclohexanones in parallel or sequential 1,4-additions. Altogether, these represent ...

Chronic obstructive pulmonary disease (COPD) is associated with cerebrovascular abnormalities and an overproduction of reactive oxygen species. We hypothesized that COPD patients have oxidant-related cerebrovascular dysfunction. The main objective was to evaluate cerebrovascular reactivity and its relationship to oxidative stress in females with COPD.We studied eight females with moderate-COPD, and ...

A simple, mild, cost effective and green approach for the reductive mono N-alkylation of nitroarenes has been developed. HOAc/Zn are utilized as the reducing system together with a carbonyl compound as an alkyl source in methanol. Excellent yields were obtained with stoichiometric control of mono over dialkylated products. Application to ...

The catalytic efficiency of mixed Cu(I)-Cu(II) system in situ generated by partial reduction of CuSO4 with glucose in ethanol (non-anhydrous) under open air has been explored. With this catalysis, the multicomponent cascade reaction of A3-coupling of heterocyclic amidine with aldehyde and alkyne, 5-exo-dig cycloisomerization, and prototropic shift has afforded an ...

We demonstrated that single-crystalline cobalt monoxide (CoO) hollow spheres and octahedra could be selectively synthesized via thermal decomposition of cobalt(ii) acetylacetonate in 1-octadecene solvent in the presence of oleic acid and oleylamine. The morphologies and sizes of as-prepared CoO nanocrystals could be controlled by adjusting the reaction parameters. Cobalt oxide ...

The 5'-phosphorylated oligonucleotides (5'-pONs) are currently synthesized using expensive and sensitive modified phosphoramidite reagents. In this work, a simple, cost-effective, efficient, and automatable method is presented, based on the controlled oxidation of the 5'-terminal alcohol followed by a β-elimination reaction. The latter reaction leads to the removal of the terminal ...

The factors that control the chemoselectivity of palladium-catalyzed cyclization reactions of (2-iodoanilino)carbonyl compounds have been explored by an extensive experimental computational (DFT) study. It was found that the selectivity of the process, that is, the formation of fused six- versus five-membered rings, can be controlled by the proper selection of ...

The first enantioselective total synthesis of the proposed structure of aldingenin B is reported in 16 steps from known compounds. The stereochemistry at C5 and C6 were established by an asymmetric acetal aldol. Following a ring-closing metathesis, a selective, substrate-controlled hydrogen bond-mediated dihydroxylation provided control of the C2 and C3 ...

Background and Aims: Many studies have focused on the role of pathogen infection in hypertension (HT). It has been postulated that increased vascular tonus in HT is basically related to the imbalance between vasodilator, such as nitric oxide (NO), and vasoconstrictor, such as endothelin-1 (ET-1), substances secreted by endothelium. The ...

The synthesis of the macrolactone core of (+)-neopeltolide has been achieved. The key synthetic strategy involves the highly diastereoselective synthesis of the 2,6-cis-disubstituted tetrahydropyran ring by a transannular cyclization of δ-hydroxy alkene using mercuric trifluoroacetate. Two of the six stereocenters C-5 and C-11 were realized from l-malic acid, while the ...

Using a Pt/Si catalytic nanodiode, we externally control the rate of CO oxidation on a Pt nanofilm. The catalytic reaction can be turned on and off by alternating between bias states of the device. Additionally, the reaction rate is sensitive to photocurrent induced by visible light. The effects of both ...

1-Vinylcycloalkenes undergo highly regio- and enantioselective (>98% ee) 1,4-hydrovinylation (HV) when treated with ethylene (1 atmosphere) at room temperature in the presence of [(S,S)-2,4-bis-diphenylphosphino-pentane(BDPP)]CoCl2 (0.05 equiv.) and methylaluminoxane. The minor 1,2-HV products, seen only in 1-vinylcyclohexene (~14%) and 1-vinylcycloheptene (2%), are formed as racemic mixtures. The corresponding Ni(II)-catalyzed HV reactions ...

Oxazolidinones are powerful promoters of the Nazarov reaction, enabling the cyclization of conventionally resistant substrates to be achieved under mild conditions. They exert excellent regio- and torquoselective control in both the conventional Nazarov reaction giving cyclopentenones and in the "interrupted" Nazarov reaction, giving more highly substituted multistereocenter containing products.

The total oxidative status (TOS)/total anti-oxidative status (TAS) ratio can provide information on an individual's absolute oxidative stress index (OSI). We investigated the alterations in the oxidant-antioxidant balance by measuring the oxidant parameters OSI, TOS, and malondialdehyde (MDA) together with the antioxidant parameters such as TAS, and superoxide dismutase (SOD) ...

Lewis acid-catalyzed quaternary ammonium salt-mediated highly regioselective ring opening of chiral activated aziridines and azetidines with alcohols to non-racemic β- and γ-amino ethers is developed. The reaction mainly proceeds via an SN2 pathway and the partial racemization of the starting substrate was effectively controlled by using quaternary ammonium salts. β- ...

An efficient and convergent synthesis of the C5-C18 fragment of Halichomycin was reported in this note. Butanolide fragment 6 was readily prepared stereoselectively from (R)-Roche ester through catalyst control; dienylic bromide domain 7 was synthesized from (S)-serine by substrate control. C5-C18 fragment 2 was rapidly assembled through a stereoselective alkylation ...

Angiotensin II contributes to myocardial tissue remodeling and interstitial fibrosis through NADPH oxidase-mediated generation of oxidative stress in the progression of heart failure. Recent data suggest that nebivolol, a third generation β-blocker, improves diastolic dysfunction by targeting nitric oxide and metabolic pathways that decrease interstitial fibrosis. We sought to determine ...