Small, strained rings have rigid, defined conformations and unique electronic properties. For these reasons, many groups seek to use these subunits to form biologically active molecules. We report a generally applicable approach to attach small rings to a wide range of aromatic compounds by palladium-catalyzed α-arylation of cyclopropyl, cyclobutyl and azetidinyl esters. The direct α-arylation of cyclopropyl esters and cyclobutyl esters is achieved in high yield by ensuring that the rate of coupling exceeds the rate of Claisen condensation. The α-arylation of azetidines is achieved without ring opening of the strained saturated heterocycle by conducting the reactions with an azetidine derivative bearing a benzyl protecting group on nitrogen. Mechanistic studies show that the α-arylation of small rings is challenging because of the weak acidity of α C-H bond (cyclopropanes), strong sensitivity of the strained esters to Claisen condensation (cyclobutatanes), or facile decomposition of the enolates (azetidinyl esters).

A novel traceless protecting strategy is presented for the long-standing challenge of conducting the palladium-catalyzed α-arylation of carboxylic aids and secondary amides with aryl halides. Both of the presented coupling processes occur with a variety of carboxylic acids and amides and with a variety of aryl bromides containing a broad range of functional groups, including base-sensitive functionality like acyl, alkoxycarbonyl, nitro, cyano, and even hydroxyl groups. Five commercial drugs were prepared through this method in one step in 81-96% yield. Gram-scale synthesis of medication Naproxen and Flurbiprofen with low palladium loading further highlights the practical value of this method.

The enantioselective construction of carbon-heteroatom and carbon-carbon bonds that are alpha to ketones leads to the formation of substructures that are ubiquitous in natural products, pharmaceuticals and agrochemicals. Traditional methods to form such bonds have relied on combining ketone enolates with electrophiles. Reactions with heteroatom-based electrophiles require special reagents in which the heteroatom, which is typically nucleophilic, has been rendered electrophilic by changes to the oxidation state. The resulting products usually require post-synthetic transformations to unveil the functional group in the final desired products. Moreover, different catalytic systems are typically required for the reaction of different electrophiles. Here, we report a strategy for the formal enantioselective α-functionalization of ketones to form products containing a diverse array of substituents at the alpha position with a single catalyst. This strategy involves an unusual reversal of the role of the nucleophile and electrophile to form C-N, C-O, C-S and C-C bonds from a series of masked ketone electrophiles and a wide range of conventional heteroatom and carbon nucleophiles catalysed by a metallacyclic iridium catalyst.

Although much effort has been spent on the enantioselective synthesis of tertiary alkyl fluorides, the synthesis of compounds containing such a stereogenic center within an array of stereocenters, particularly two vicinal ones, remains a synthetic challenge, and no method to control the configuration of each stereogenic center independently has been reported. We describe a strategy to achieve such a stereodivergent synthesis of vicinal stereogenic centers, one containing a fluorine atom, by forming the connecting carbon-carbon bond with a catalyst system comprising an iridium complex that controls the configuration at the electrophilic carbon and a copper catalyst that controls the configuration at the nucleophilic fluorine-containing carbon. These reactions occur with alkyl- and aryl-substituted allylic esters and the unstabilized enolates of azaaryl ketones, esters, and amides in high yield, diastereoselectivity, and enantioselectivity (generally >90% yield, >20:1 dr, 97-99% ee). Access to all four stereoisomers of products demonstrates the precise control of the two configurations independently. This methodology extends to the stereodivergent construction of vicinal quaternary and tertiary stereocenters in similarly high yield and selectivity. DFT calculations uncover the origin of stereoselectivity of copper enolate in allylic substitution.

A methyl group on an arene, despite its small size, can have a profound influence on biologically active molecules. Typical methods to form a methylarene involve strong nucleophiles or strong and often toxic electrophiles. We report a strategy for a new, highly efficient, copper and iodide co-catalyzed methylation of aryl- and heteroarylboronic esters with the mild, nontoxic reagent trimethylphosphate, which has not been used previously in coupling reactions. We show that it reacts in all cases tested in yields that are higher than those of analogous copper-catalyzed reactions of MeOTs or MeI. The combination of C-H borylation and this methylation with trimethylphosphate provides a new approach to the functionalization of inert C-H bonds and is illustrated by late-stage methylation of four medicinally active compounds. In addition, reaction on a 200 mmol scale demonstrates reliability of this method. Mechanistic studies show that the reaction occurs by a slow release of methyl iodide by reaction of PO(OMe)₃ with iodide catalyst, rather than the typical direct oxidative addition to a metal center. The low concentration of the reactive electrophile enables selective reaction with an arylcopper intermediate, rather than nucleophilic groups on the arylboronate, and binding of tert-butoxide to the boronate inhibits reaction of the electrophile with the tert-butoxide activator to form methyl ether.

Background

There is a growing realization that COPD, or at least emphysema, involves several processes presenting in aging and cellular senescence. Endothelial progenitor cells (EPCs) contribute to neovascularization and play an important role in the development of COPD. The gene for p16^Ink4a is a major dominant senescence one. The aim of the present study was to observe changes in lung function, histomorphology of lung tissue, and expression of p16^Ink4a in lung tissue and bone marrow-derived EPCs in emphysematous mice induced by cigarette-smoke extract (CSE), and further to search for a potential candidate agent protecting against emphysema induced by CSE.

Materials and methods

An animal emphysema model was induced by intraperitoneal injection of CSE. 5-Aza-2'-deoxycytidine (5-Aza-CdR) was administered to the emphysematous mice. Lung function and histomorphology of lung tissue were measured. The p16^Ink4a protein and mRNA in EPCs and lung tissues were detected using Western blotting and quantitative reverse-transcription polymerase chain reaction, respectively.

Results

CSE induced emphysema with increased p16^Ink4a expression in lung tissue and bone marrow-derived EPCs. 5-Aza-CdR partly protected against emphysema, especially in the lung-morphology profile, and partly protest against the overexpression of p16^Ink4a in EPCs and lung tissue induced by CSE.

Conclusion

5-Aza-CdR partly protected against emphysema in mice via suppressing p16^Ink4a expression in EPCs and lung tissue.

Background

A major issue with the current management of psoriasis is our inability to predict treatment response.

Objective

Our aim was to evaluate the ability to use baseline molecular expression profiling to assess treatment outcome for patients with psoriasis.

Methods

We conducted a longitudinal study of 46 patients with chronic plaque psoriasis treated with anti-TNF agent etanercept, and molecular profiles were assessed in more than 200 RNA-seq samples.

Results

We demonstrated correlation between clinical response and molecular changes during the course of the treatment, particularly for genes responding to IL-17A/TNF in keratinocytes. Intriguingly, baseline gene expressions in nonlesional, but not lesional, skin were the best marker of treatment response at week 12. We identified USP18, a known regulator of IFN responses, as positively correlated with Psoriasis Area and Severity Index (PASI) improvement (P = 9.8 × 10^-4) and demonstrate its role in regulating IFN/TNF responses in keratinocytes. Consistently, cytokine gene signatures enriched in baseline nonlesional skin expression profiles had strong correlations with PASI improvement. Using this information, we developed a statistical model for predicting PASI75 (ie, 75% of PASI improvement) at week 12, achieving area under the receiver-operating characteristic curve value of 0.75 and up to 80% accurate PASI75 prediction among the top predicted responders.

Conclusions

Our results illustrate feasibility of assessing drug response in psoriasis using nonlesional skin and implicate involvement of IFN regulators in anti-TNF responses.

Background

Stroke is the leading cause of mortality in China, with limited evidence of in-hospital burden obtained from nationwide surveys. We aimed to monitor and track the temporal trends and rural-urban disparities in cerebrovascular risk factors, management and outcomes from 2005 to 2015.

Methods

We used a two-stage random sampling survey to create a nationally representative sample of patients admitted for ischaemic stroke in 2005, 2010 and 2015. We sampled participating hospitals with an economic-geographical region-stratified random-sampling approach first and then obtained patients with a systematic sampling approach. We weighed our survey data to estimate the national-level results and assess changes from 2005 to 2015.

Results

We analysed 28 277 ischaemic stroke admissions from 189 participating hospitals. From 2005 to 2015, the estimated national hospital admission rate for ischaemic stroke per 100 000 people increased (from 75.9 to 402.7, P_trend<0.001), and the prevalence of risk factors, including hypertension, diabetes, dyslipidaemia and current smoking, increased. The composite score of diagnostic tests for stroke aetiology assessment (from 0.22 to 0.36, P_trend<0.001) and secondary prevention treatments (from 0.46 to 0.70, P_trend<0.001) were improved. A temporal decrease was found in discharge against medical advice (DAMA) (from 15.2% (95% CI 13.7% to 16.7%) to 8.6% (8.1% to 9.0%); adjusted P_trend=0.046), and decreases in in-hospital mortality (0.7% in 2015 vs 1.8% in 2005; adjusted OR (aOR) 0.52; 95% CI 0.32 to 0.85) and the composite outcome of in-hospital mortality or DAMA (8.4% in 2015 vs 13.9% in 2005; aOR 0.65; 95% CI 0.47 to 0.89) were observed. Disparities between rural and urban hospitals narrowed; however, disparities persisted in in-hospital management (brain MRI: rural-urban difference from -14.4% to -11.2%; cerebrovascular assessment: from -20.3% to -16.7%; clopidogrel: from -2.1% to -10.3%; anticoagulant for atrial fibrillation: from -10.9% to -8.2%) and in-hospital outcomes (DAMA: from 2.7% to 5.0%; composite outcome of in-hospital mortality or DAMA: from 2.4% to 4.6%).

Conclusions

From 2005 to 2015, improvements in hospital admission and in-hospital management for ischaemic stroke in China were found. A temporal improvement in DAMA and improvements in in-hospital mortality and the composite outcome of in-hospital mortality or DAMA were observed. Disparities between rural and urban hospitals generally narrowed but persisted.