Reported herein is the development of the first enantioselective monodentate ligand assisted Pd‐catalyzed domino Heck carbonylation reaction with CO. The highly enantioselective domino Heck ...carbonylation of N‐aryl acrylamides and various nucleophiles, including arylboronic acids, anilines, and alcohols, in the presence of CO was achieved. A novel monodentate phosphoramidite ligand, Xida‐Phos, has been developed for this reaction and it displays excellent reactivity and enantioselectivity. The reaction employs readily available starting materials, tolerates a wide range of functional groups, and provides straightforward access to a diverse array of enantioenriched oxindoles having β‐carbonyl‐substituted all‐carbon quaternary stereocenters, thus providing a facile and complementary method for the asymmetric synthesis of bioactive hexahydropyrroloindole and its dimeric alkaloids.
Domino reaction: A new monodentate phosphoramidite ligand, Xida‐Phos, was used in the enantioselective Pd‐catalyzed domino Heck carbonylative reaction for the synthesis of oxindoles having β‐carbonyl‐substituted all‐carbon quaternary centers. The reaction was used in the asymmetric synthesis of bioactive hexahydropyrroloindole (HPI) and its dimeric alkaloids.
Asymmetric hydroxycarbonylation is one of the most fundamental yet challenging methods for the synthesis of carboxylic acids. Herein, we reported the development of a palladium‐catalyzed highly ...enantioselective Markovnikov hydroxycarbonylation of vinyl arenes with CO and water. A monodentate phosphoramidite ligand L6 plays vital role in the reaction. The reaction tolerates a range of functional groups, and provides a facile and atom‐economical approach to an array of 2‐arylpropanoic acids including several commonly used non‐steroidal anti‐inflammatory drugs. The catalytic system has also enabled an asymmetric Markovnikov hydroalkoxycarbonylation of vinyl arenes with alcohols to afford 2‐arylpropanates. Mechanistic investigations suggested that the hydropalladation is irreversible and is the regio‐ and enantiodetermining step, while hydrolysis/alcoholysis is probably the rate‐limiting step.
A Pd‐catalyzed highly enantioselective Markovnikov hydroxycarbonylation of vinyl arenes with CO and water for the synthesis of 2‐arylpropanoic acids has been developed. Several non‐steroidal anti‐inflammatory drugs including ibuprofen, naproxen, flurbiprofen, fenoprofen, and ketoprofen were synthesized in high yields and ees in gram scale.
Has the geography of intergenerational mobility in the United States changed over time? Constructing a large historical linked sample, I show that upward mobility in the early twentieth century was ...greater for those who grew up in the coastal and industrial regions, in contrast to more recent times, where mobility is higher among persons who were raised in the middle of the country. The historical patterns are not driven by imperfections in record linkage or measurement error in economic status.
Palladium and CO.: The title reaction proceeds in the presence of CO, thus providing a synthesis for 1,3‐oxazin‐6‐ones (see scheme; DABCO=1,4‐diazabicyclo2.2.2octane, DMF=N,N‐dimethylformamide). The ...reaction tolerates a variety of functional groups on both the aryl ring and the amide of the substrate. Initial mechanistic studies suggest the activation of the alkenyl CH bond to be a key step.
In contrast to the kinetically favored outward isomerization‐hydrocarbonylation of alkenes, the disfavored inward isomerization‐hydrocarbonylation of alkenes remains an important challenge. Herein, ...we have developed a novel and effective palladium‐catalyzed inward isomerization‐hydroaminocarbonylation of unactivated alkenes and aniline hydrochlorides for the formation of synthetically valuable α‐aryl carboxylic amides in high yields and high site‐selectivities. The high efficiency of the reaction is attributed to a relay catalysis strategy, in which the Markovnikov‐favored PdH‐PtBu3 catalyst is responsible for inward isomerization, while the PdH‐Ruphos catalyst is responsible for hydroaminocarbonylation of the resulting conjugated aryl alkenes. The reaction exhibits highly functional group tolerance and provides a new method for formal carbonylation of remote C(sp3)−H bond.
A novel palladium‐catalyzed inward isomerization and hydraminocarbonylation of unactivated alkenes for the synthesis of α‐aryl carboxylic amides has been developed. The combination isomerization‐responsible catalyst and hydrocarbonylation‐responsible catalyst was found to be a highly effective strategy to render the reaction feasible. The reaction shows highly functional group compatibility and site‐selectivity.
Long-term exposure to ambient and household particulate matter (PM2.5) causes death and health loss, and both are the leading risk factor to global disease burden. We assessed spatiotemporal trends ...of ambient and household PM2.5 attributable burdens across various diseases at the global, regional, and national levels from 1990 to 2017.
Data on PM2.5-attributable disease burdens were extracted from the Global Burden of Disease (GBD) study 2017. Numbers and age-standardized rates (ASRs) of deaths, disability-adjusted life years (DALYs) and corresponding estimated annual percentage change (EAPC) were estimated by disease, age, sex, Socio-demographic Index (SDI), locations.
Exposure to PM2.5 contributed to 4.58 million deaths and 142.52 million DALYs globally in 2017, among which ambient PM2.5 contributed to 64.2% deaths and 58.3% DALYs. ASRs of deaths and DALYs in 2017 decreased to 59.62/105 persons with an EAPC of −2.15 (95% CI: 2.21 to −2.09) and 1856.61/105 persons with an EAPC of −2.58 (95% CI: 2.64 to −2.51), respectively compared to those in 1990. Ambient PM2.5-attributable Non-communicable diseases (NCDs) have dominated major concern in middle and low SDI countries especially in South Asia and East Asia, while household PM2.5-attributable lower respiratory infections (LRIs) still caused the largest burden in low SDI countries in Africa and Asia. Those under 5 and over 70 years old had the largest burdens in PM2.5 attributable LRI and NCDs, respectively.
In conclusion, ambient PM2.5-attributable NCDs have threatened public health in middle and low SDI countries, while household PM2.5-attributable LRI still caused the largest burden in low SDI countries. More positive strategies should be tailored to reduce PM2.5-attributable burdens considering specific settings globally.
•PM2.5-attributed disease burdens transitioned from LRI to NCDs, with the greatest burden in regions with lower SDI.•Although ASR of death and DALY decreased, overall PM2.5-attributed disease burdens remain heavy.•Increasing ambient PM2.5-attributed non-communicable diseases primarily imperiled the health of older people.•Decreasing household PM2.5-attributed lower respiratory infection still dominated in children under 5 in low SDI regions.
Intelligent actuating materials have drawn enormous attention because of their potential applications in soft robots, smart sensors, bionics, etc. Aiming to integrate light, thermal, and humidity ...stimuli deformations and self-healing function into a single polymer, a smart actuating polyurethane material CPPU-50 is designed and successfully synthesized through co-polymerization of azobenzene-containing Azo-C
, polyethylene glycol 200 (PEG200), and 4,4'-diphenylmethane diisocyanate (MDI) at a ratio of 1:1:2. The obtained polyurethane CPPU-50 exhibits good photoinduced bending, thermal responsive shape memory effect, humidity triggered deflections and self-healing properties. Furthermore, an actuator combining light and thermal stimuli is created and the self-healing CPPU-50 film can withstand the object of 1800 times without tearing. This work can pave a way for further development of long-lived multi-stimuli-responsive actuating devices and intelligent materials.
A novel and efficient Fe-catalyzed radical cycloaddition of 2H-azirines and enamides for the synthesis of substituted pyrroles has been developed. The radical cycloaddition reaction proceeded through ...a conceptually new Fe(II)-catalyzed homolytic cleavage of C–N bond of 2H-azirines sequential radical cyclization with enamides. The reaction used readily available starting materials, tolerated various functional groups, and afforded valuable triaryl-substituted pyrroles in good to high yields under mild reaction conditions.
In the present work, polyethylenimine-capped CdS quantum dots (PEI-CdS QDs) with bright green fluorescence were synthesized and applied for sensitively and selectively detecting the nitrite in ...vegetable and water samples. Highly fluorescent and environment-friendly PEI-CdS QDs (quantum yield about 8%) with diameters of ca. 5 nm were easily synthesized by using hyperbranched PEI as functional polymer. Formation of the PEI-CdS QDs was verified by transmission electron microscopy and UV–vis spectroscopy. The fluorescence intensity of the as-synthesized PEI-CdS QDs was enhanced pronouncedly by the increasing amount of PEI and was stable when the pH ranged from 5.0 to 9.0. Our results demonstrated that the fluorescence of the PEI-CdS QDs was effectively quenched by the nitrite in a rather wide linear range of 1.0 × 10–7–1.0 × 10–4 M while efficiently avoiding the interferences from nitrate ions and other commonly coexisting anions of nitrite in the vegetable samples. The detection limit of the present method was lower than the maximum limit of nitrite in drinking water (6.5 × 10–5 M) ruled by the World Health Organization, which is significant to the application of the method.
Idiopathic pulmonary fibrosis (IPF) is the most common type of idiopathic interstitial pneumonia and has one of the poorest prognosis. However, the molecular mechanisms underlying IPF progression ...remain largely unknown. In this study, we determined that IL-24, an IL-20 subfamily cytokine member, was increased both in the serum of IPF patients and the bronchoalveolar lavage fluid (BALF) of mice following bleomycin (BLM)-induced pulmonary fibrosis. As a result, IL-24 deficiency protected mice from BLM-induced lung injury and fibrosis. Specifically, loss of IL-24 significantly attenuated transforming growth factor β1 (TGF-β1) production and reduced M2 macrophage infiltration in the lung of BLM-induced mice. Mechanistically, IL-24 alone did not show a perceptible impact on the induction of M2 macrophages, but it synergized with IL-4 to promote M2 program in macrophages. IL-24 suppressed IL-4-induced expression of suppressor of cytokine signaling 1 (SOCS1) and SOCS3, through which it enhanced signal transducer and activator of transcription 6/peroxisome proliferator-activated receptor gamma (STAT6/PPARγ) signaling, thereby promoting IL-4-induced production of M2 macrophages. Collectively, our data support that IL-24 synergizes with IL-4 to promote macrophage M2 program contributing to the development of pulmonary fibrosis.
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