A New Synthesis of Enantiopure Amine Fragment: An Important Intermediate to the Anti-HIV Drug Lenacapavir.

Herein, we describe a new seven-step approach to prepare ()-1-(3,6-dibromopyridin-2-yl)-2-(3,5-difluorophenyl)ethan-1-amine (()-) from the inexpensive 2-(3,5-difluorophenyl)acetic acid. The key steps in the sequence include (1) the Weinreb amide-based ketone synthesis to provide an entry point to the core structure; (2) simple functional group transformations to afford the racemic amine -; and (3) dynamic kinetic resolution (DKR) to access the chiral amine ()-. This seven-step process delivered the enantiopure amine ()- in an overall isolated yield of approximately 15%.

The effect of air pollutants on COPD-hospitalized patients in Lanzhou, China (2015-2019).

Background: Lanzhou is the largest heavy industrial city in northwest China and it is a typical geographical valley-like city. However, there are few studies on the relationship between air pollutants and COPD, and their respective sample sizes are small, resulting in inconsistent results. The aim of this study is to analyze the effects of air pollutants on COPD hospitalizations in Lanzhou, China.

Practical Synthesis of 7-Bromo-4-chloro-1-indazol-3-amine: An Important Intermediate to Lenacapavir.

7-Bromo-4-chloro-1-indazol-3-amine is a heterocyclic fragment used in the synthesis of Lenacapavir, a potent capsid inhibitor for the treatment of HIV-1 infections. In this manuscript, we describe a new approach to synthesizing 7-bromo-4-chloro-1-indazol-3-amine from inexpensive 2,6-dichlorobenzonitrile. This synthetic method utilizes a two-step sequence including regioselective bromination and heterocycle formation with hydrazine to give the desired product in an overall isolated yield of 38-45%.

Practical Synthesis of 6-Amino-1-hydroxy-2,1-benzoxaborolane: A Key Intermediate of DNDI-6148.

Visceral leishmaniasis (VL), a parasitic, poverty-linked, neglected disease, is endemic across multiple regions of the world and fatal if untreated. There is an urgent need for a better and more affordable treatment for VL. DNDI-6148 is a promising drug candidate being evaluated for the treatment of VL; however, the current process for producing the key intermediate of DNDI-6148, 6-amino-1-hydroxy-2,1-benzoxaborolane, is expensive and difficult to scale up.

Highly Regioselective Protecting-Group-Free Synthesis of the Antimalarial Drug MMV693183.

MMV693183 is a promising antimalarial drug candidate that works for uncomplicated malaria treatment and resistance management. Herein, we report an efficient and highly regioselective synthesis of MMV693183. This novel synthetic method highlights a three-step route with an overall yield of 46% from readily available starting materials.

Association between salt sensitivity of blood pressure and the risk of hypertension in a Chinese Tibetan population.

Epidemiological studies have confirmed salt sensitivity as a crucial risk factor for the development of hypertension. However, few studies have investigated the association between salt sensitivity of blood pressure (SSBP) and hypertension in Chinese Tibetan population. Therefore, we conducted a cross-sectional study based on a Tibetan population to evaluate the association between SSBP and the risk of hypertension.

Associations of nickel exposure and kidney function in U.S. adults, NHANES 2017-2018.

Backgrounds: Nickel (Ni) is a ubiquitous heavy metal, but epidemiological studies on the association between Ni and kidney function are limited and controversial.

Aim: We aimed to explore the relationship between urinary Ni concentrations and kidney function in U.S.

Association of air pollutants and hospital admissions for respiratory diseases in Lanzhou, China, 2014-2019.

The aim of this study was to assess the effects of air pollutants on hospital admissions for respiratory disease (RD) by using distributed lag nonlinear model (DLNM) in Lanzhou during 2014-2019. In this study, the dataset of air pollutants, meteorological, and daily hospital admissions for RD in Lanzhou, from January 1st, 2014 to December 31st, 2019, were collected from three national environmental monitoring stations, China meteorological data service center, and three large general hospitals, respectively. A time-series analysis with DLNM was used to estimate the associations between air pollutants and hospital admissions for RD including the stratified analysis of age, gender, and season.

Metalloradical activation of carbonyl azides for enantioselective radical aziridination.

Organic azides have been increasingly employed as nitrogen sources for catalytic olefine aziridination due to their ease of preparation and generation of benign N as the only byproduct. Among common organic azides, carbonyl azides have not been previously demonstrated as effective nitrogen sources for intermolecular olefin aziridination despite the synthetic utilities of N-carbonyl aziridines. As a new application of metalloradical catalysis, we have developed a catalytic system that can effectively employ the carbonyl azide TrocN for highly asymmetric aziridination of alkenes at room temperature.

Enantioselective Intermolecular Radical C-H Amination.

Radical reactions hold a number of inherent advantages in organic synthesis that may potentially impact the planning and practice for construction of organic molecules. However, the control of enantioselectivity in radical processes remains one of the longstanding challenges. While significant advances have recently been achieved in intramolecular radical reactions, the governing of asymmetric induction in intermolecular radical reactions still poses challenging issues.

Critical flux investigation in treating o/w emulsion by TiO/AlO-PVDF UF membrane.

A standard transmembrane pressure (TMP) step method has been used in membrane fouling assessment in tube ultrafiltration (UF) membrane system treating oil water (o/w) emulsion operated at constant TMP. Three flux reduction curve with different o/w concentration based on TMP variation were concluded by experiment, then, to describe fouling behavior and identify the occurrence of fouling in the so-called critical flux. Furthermore, sub-critical and super-critical flux experiment with a long time was determined, and zero rate of flux reduction (dF/dt) was never found during the whole trial period, indicating that critical flux in o/w UF process with its strict definition could not be defined in this paper.

Removal of toxic and alkali/alkaline earth metals during co-thermal treatment of two types of MSWI fly ashes in China.

This study aims to vaporize heavy metals and alkali/alkaline earth metals from two different types of fly ashes by thermal treatment method. Fly ash from a fluidized bed incinerator (HK fly ash) was mixed with one from a grate incinerator (HS fly ash) in various proportions and thermally treated under different temperatures. The melting of HS fly ash was avoided when treated with HK fly ash.

Room Temperature Activation of Aryloxysulfonyl Azides by [Co(II)(TPP)] for Selective Radical Aziridination of Alkenes via Metalloradical Catalysis.

Aryloxysulfonyl azides can be effectively activated by commercially available cobalt(II) complex of -tetraphenylporphyrin ([Co(TPP)]) at room temperature under neutral and nonoxidative conditions for selective radical aziridination of alkenes via metalloradical catalysis. The [Co(TPP)]-catalyzed radical aziridination system is suitable for different combinations of olefin substrates and aryloxysulfonyl azides, producing various -aryloxysulfonyl aziridine derivatives in good to excellent yields. In addition to generating the environmentally benign N as the only byproduct, this Co(II)-based metalloradical aziridination process features mild reaction conditions and operational simplicity.

Detoxification of ashes from a fluidized bed waste incinerator.

This paper was to test and control the toxicity of bottom and fly ashes from a circulated fluidized bed (CFB) incinerator. Bottom and fly ashes were firstly subject to TCLP test. Even though leachates of most particle size of bottom ash were below regulatory limit, the leachates of finer bottom ash may exceed the regulatory limit.

Stereoselective Radical C-H Alkylation with Acceptor/Acceptor-Substituted Diazo Reagents via Co(II)-Based Metalloradical Catalysis.

Co(II)-based metalloradical catalysis has been, for the first time, successfully applied for asymmetric intramolecular C-H alkylation of acceptor/acceptor-substituted diazo reagents. Through the design and synthesis of a new -symmetric chiral amidoporphyrin as the supporting ligand, the Co(II)-based metalloradical system, which operates at room temperature, is capable of 1,5-C-H alkylation of α-methoxycarbonyl-α-diazosulfones with a broad range of electronic properties, providing the 5-membered sulfolane derivatives in high yields with excellent diastereoselectivity and enantioselectivity. In addition to complete chemoselectivity toward allylic and allenic C-H bonds, the Co(II)-based metalloradical catalysis for asymmetric C-H alkylation features a remarkable degree of functional group tolerance.

Selective Radical Amination of Aldehydic C(sp)-H Bonds with Fluoroaryl Azides via Co(II)-Based Metalloradical Catalysis: Synthesis of -Fluoroaryl Amides from Aldehydes under Neutral and Nonoxidative Conditions.

The Co(II) complex of the -symmetric amidoporphyrin 3,5-Di Bu-IbuPhyrin, [Co()], has proven to be an effective metalloradical catalyst for intermolecular amination of C(sp)-H bonds of aldehydes with fluoroaryl azides. The [Co()]-catalyzed process can employ aldehydes as the limiting reagents and operate under neutral and non-oxidative conditions, generating nitrogen gas as the only byproduct. The metalloradical aldehydic C-H amination is suitable for different combinations of aldehydes and fluoroaryl azides, producing the corresponding -fluoroaryl amides in good to excellent yields.

Synthesis of chiral N-phosphoryl aziridines through enantioselective aziridination of alkenes with phosphoryl azide via Co(II)-based metalloradical catalysis.

The Co(II) complex of a new D 2-symmetric chiral porphyrin 3,5-DiMes-QingPhyrin, [Co(P6)], can catalyze asymmetric aziridination of alkenes with bis(2,2,2-trichloroethyl)phosphoryl azide (TcepN3) as a nitrene source. This new Co(II)-based metalloradical aziridination is suitable for different aromatic olefins, producing the corresponding N-phosphorylaziridines in good to excellent yields (up to 99%) with moderate to high enantioselectivities (up to 85% ee). In addition to mild reaction conditions and generation of N2 as the only byproduct, this new metalloradical catalytic system is highlighted with a practical protocol that operates under neutral and non-oxidative conditions.

Effects of oriented surface dipole on photoconversion efficiency in an alkane/lipid-hybrid-bilayer-based photovoltaic model system.

When a phospholipid monolayer containing a zinc-coordinated porphyrin species formed atop a self-assembled monolayer of heptadecafluoro-1-decanethiol (CF3(CF2)7(CH2)2SH) is subjected to photoelectrochemical current generation, a significant modulation effect is observed. Compared with devices that contain similar photoactive lipid monolayers but formed on 1-dodecanethiol SAMs, these fluorinated hybrid bilayers produce a >60% increase in cathodic currents and a similar decrease in anodic currents. Photovoltages recorded from these hybrid bilayers are found to vary in the same fashion.

Physical and chemical characterization of ashes from a municipal solid waste incinerator in China.

In this study we analyzed the characteristics of bottom and fly ashes from a municipal solid waste incinerator in China. The physical properties of particle size distribution and morphology were evaluated. At the chemical level, the chemical composition, heavy metal leaching behavior and BCR sequential extraction procedure (the Community Bureau of Reference, now the European Union 'Measurement and Testing Programme') were determined.

Thermal processing as a means to prepare durable, submicron thickness ionomer films for study by transmission infrared spectroscopy.

A high temperature solution processing method was adapted to prepare durable, freestanding, submicrometer thickness films for transmission infrared spectroscopy studies of ionomer membrane. The materials retain structural integrity following cleaning and ion-exchange steps in boiling solutions, similar to a commercial fuel cell membrane. Unlike commercial membrane, which typically has thicknesses of >25 μm, the structural properties of the submicrometer thickness materials can be probed in mid-infrared spectral measurements with the use of transmission sampling.

Novel O-glycosidic gossypol isomers and their bioactivities.

Novel glycosidic gossypol analogs, 7,7'-gossypol diglucoside tetraacetate GS1, 6,7'-gossypol diglucoside tetraacetate GS2, 7,7'-gossypol diglycoside GS1', 6,7'-gossypol diglycoside GS2' were obtained by the ultrasound-assisted reaction of the potassium salt of gossypol with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide under PTC conditions and were fully characterized by 1D NMR ((1)H NMR, (13)C NMR, DEPT, 1D NOE), 2D NMR (HMBC, HMQC), FTIR, HRMS and HPLC. The anticancer activities, cytotoxic effects as well as anti-trypanosomal activities of these novel glycosidic gossypols were explored and suggest that gossypol glycosides could be used to develop new candidates for anticancer drugs and anti-trypanosomal agents.

Synthesis of novel thermally reversible photochromic axially chiral spirooxazines.

The Suzuki reactions of diboronic acid 1 and bromo-spirooxazine 2, under N(2) atmosphere and aerobic conditions, gave the dispirooxazine-substituted binaphthyl product 3 and the monospirooxazine-substituted binaphthyl derivative 4, respectively. The thermally reversible photochromic behavior of the target axially chiral spirooxazines 3 was investigated, and both the ring-opening process upon irradiation with 365 nm light and the thermally reverse ring-closing process were fast. These chiral spirooxazines were found to impart their chirality to an achiral liquid crystal host, at low doping levels, to form a self-organized photoresponsive helical superstructure.

Phylogenetic analysis of the sequences of rDNA internal transcribed spacer (ITS) of Phytophthora sojae.

The internal transcribed spacer (ITS) region (ITS1, ITS2 and 5.8S rDNA) of the nuclear ribosomal DNA (nrDNA) was amplified via the PCR method in seventeen different isolates of Phytophthora sojae using the common primers of the ITS of fungi. Around 800 bp-1,000 bp fragments were obtained based on the DL2000 marker and the sequences of the PCR products were tested.