π-Lewis-Base-Catalyzed Asymmetric Vinylogous Umpolung Reactions of Cyclopentadienones and Tropone.

We disclose that the carbonates of 4-hydroxy-2-cyclopentenones can form π-allylpalladium-based 1,2-carbodipoles, which isomerize to interesting η2 -Pd0 -cyclopentadienone complexes. Compared with the labile parent cyclopentadienone, the HOMO energy of the related η2 -complex was significantly raised via the back-bonding of Pd0 as a π-Lewis base, rendering the uncoordinated C=C bond an electron-richer dienophile in inverse-electron-demand aza-Diels-Alder-type reactions with diverse 1-azadienes. The vinylogous (aza)Morita-Baylis-Hillman or cross Rauhut-Currier addition to (imine)carbonyls or activated alkenes, respectively, was also realized to afford chiral [4+2] or [2+2] cycloadducts, respectively, after trapping the re-generated π-allylpalladium species. New C1 -symmetric ligands from simple chiral sources were developed, exhibiting high stereoselectivity even with racemic substrates via an unusual dynamic kinetic resolution process. Besides, tropone could be similarly activated by a Pd0 complex.

Production of a specific monoclonal antibody for 1-naphthol based on novel hapten strategy and development of an easy-to-use ELISA in urine samples.

1-naphthol (1-NAP) is the main metabolite of pesticide carbaryl and naphthalene, and is also a genotoxic and carcinogenic intermediate in the synthesis of organic compound, dyes, pigment and pharmaceutical industry. In this work, two novel haptens were designed and synthesized for developing a competitive indirect enzyme-linked immunosorbent assay (ciELISA) method for 1-NAP in urine samples. The assay showed a limit of detection of 2.21 ng/mL and working range from 4.02 ng/mL to 31.25 ng/mL for 1-NAP in optimized working buffer. The matrix effect of samples was eliminated via 15-fold dilution of optimized working buffer. Good average recoveries (102.4%-123.4%) with a coefficient of variation from 11.7% to 14.7% was obtained for spiked urine samples. Subsequent instrument verification test showed good correlation between the results of ciELISA and high-performance liquid chromatography. The developed ciELISA is a high-throughput tool to monitor 1-NAP in urine, which can provide technical support for the establishment of biological exposure level for the exposure to carbaryl, naphthalene and other related pollutants.

Asymmetric Allylic Alkylation with Deconjugated Carbonyl Compounds: Direct Vinylogous Umpolung Strategy.

An atom-economic and highly efficient vinylogous umpolung strategy is developed for deconjugated carbonyl compounds, which generate electron-deficient π-allylpalladium complexes with Pd(OAc)2 under ligand-free conditions. In cooperation with a chiral-phosphonium-based phase-transfer catalyst, the asymmetric direct oxidative allylic alkylations of 3-substituted oxindoles are furnished under O2 atmosphere. The γ- or even remote ϵ-regioselective alkylation products, with substantial substituents, are delivered with excellent enantioselectivity, and can be further used to access diverse chiral spirocyclic architectures effectively. The Mukaiyama dienol silyl ether can be utilized similarly, indicating that the current active π-allylpalladium species results from tautomerization of the PdII -dienolate intermediate.

Quality of Life and Glucose Regulation in Pediatric Patients with Type 1 Diabetes: A Study in the Ningxia Hui Autonomous Region.

Objective: In this study, we aimed to evaluate the current status of the quality of life (QOL) of pediatric patients and plasma glucose concentration regulation in children with type 1 diabetes (T1DM) in the Ningxia Hui autonomous region. Methods: The study involved children with T1DM admitted to the General Hospital of Ningxia Medical University between October 2011 and October 2021. The children and their parents completed general information and quality of life (QOL) questionnaires. The regulation of plasma glucose concentration was assessed based on HbA1c levels, and plasma glucose and QOL-influencing components were investigated. Results: Among the 136 pediatric patients diagnosed with T1DM, the mean glycated hemoglobin (HbA1c) level was recorded at 8.7% (7.2%, 10.5%). A breakdown of the patient cohort revealed that 44 patients (32.4%) demonstrated good regulation of plasma glucose, 33 patients (24.3%) exhibited acceptable glycemic control, and 59 patients (43.3%) displayed poor regulation of plasma glucose. The control of plasma glucose in pediatric patients diagnosed with T1DM was affected by the duration of the disease, the patient's age, the frequency of daily plasma glucose measurements, the use of CGM, diabetic ketoacidosis (DKA), and the education level of the mother. The control of plasma glucose, dietary management, DKA, the ability to learn, and health education are interfering factors of quality of life in children diagnosed with T1DM. Effective control of plasma glucose may ensure the QOL in children with T1DM, and DKA was the risk factor for QOL. Conclusion: In Ningxia, the regulation of plasma glucose in pediatric and adolescent patients with T1DM remains suboptimal, leading to poor QOL. There is a pressing need to enhance glucose regulation and QOL through comprehensive strategies, which include reinforced dietary management, rigorous monitoring of plasma glucose levels, and heightened health education levels.

De novo synthesis of a novel hapten and development of a monoclonal antibody-based immunoassay for the detection of dichlorvos and trichlorfon.

The absence of high-affinity antibodies has hindered the development of satisfactory immunoassays for dichlorvos (DDVP) and trichlorfon (TCP), two highly toxic organophosphorus pesticides. Herein, the de novo synthesis of a novel anti-DDVP hapten was introduced. Subsequently, a specific anti-DDVP monoclonal antibody (Mab) was produced with satisfying affinity to DDVP (IC50: 12.4 ng mL-1). This Mab was highly specific to DDVP, and TCP could readily convert into DDVP under mild alkaline conditions. Leveraging this insight, an indirect competitive ELISA was successfully developed for simultaneous detection of DDVP and TCP. The limit of detection in rice, cabbage and apple for DDVP /TCP was found to be 12.1/14.6 µg kg-1, 7.3/8.8 µg kg-1 and 6.9/8.3 µg kg-1, respectively. This study not only provides an effective strategy for producing a high-quality anti-DDVP Mab but also affords a reliable and cost-effective tool suitable for high-throughput detection of DDVP and TCP in food samples.

Conversion of Acids to S-Alkyl Dithiocarbamates by Decarboxylative Sulfuration Using Visible-Light Photocatalysis.

S-Alkyl dithiocarbamates, as an important class of sulfur-containing compounds, play pivotal roles in diverse fields, yet methods for the synthesis that start from simple, readily available feedstocks and exhibit mild conditions and structurally diverse products are scarce. In this work, we developed an efficient approach for the synthesis of various S-alkyl dithiocarbamates via visible-light photocatalysis with readily available and structurally diverse alkyl carboxylic acids (primary, secondary, and tertiary acids, amino acids, etc.) and disulfide tetraalkylthiuram as the starting materials. This protocol features high efficiency, mild reaction conditions, a broad substrate scope, and good functional group tolerance. Potential applications are further demonstrated by a sunlight experiment, H2O as a solvent, gram-scale synthesis, and facile synthesis of bioactive molecules.

A bio-inspired nano-material recapitulating the composition, ultra-structure, and function of the glycosaminoglycan-rich extracellular matrix of nucleus pulposus.

The nucleus pulposus (NP) of intervertebral disc represents a soft gel consisting of glycosaminoglycans (GAGs)-rich extracellular matrix (ECM). Significant loss of GAGs and normal functions are the most prevalent changes in degenerated disc. Attempts targeted to incorporate GAGs into collagen fibrous matrices have been made but the efficiency is very low, and the resulting structures showed no similarity with native NP. Inspired by the characteristic composition and structures of the ECM of native NP, here, we hypothesize that by chemically modifying the collagen (Col) and hyaluronic acid (HA) and co-precipitating with GAGs, a bio-inspired nano-material recapitulating the composition, ultra-structure and function of the GAG-rich ECM will be fabricated. Compositionally, the bio-inspired nano-material namely Aminated Collagen-Aminated Hyaluronic Acid-GAG (aCol-aHA-GAG) shows a record high GAG/hydroxyproline ratio up to 39.1:1 in a controllable manner, out-performing that of the native NP. Ultra-structurally, the nano-material recapitulates the characteristic 'nano-beads' (25 nm) and 'bottle-brushes' (133 nm) features as those found in native NP. Functionally, the nano-material supports the viability and maintains the morphological and phenotypic markers of bovine NP cells, and shows comparable mechanical properties of native NP. This work contributes to the development of a compositionally, structurally, and functionally biomimetic nano-material for NP tissue engineering.

Asymmetric inverse-electron-demand 1,3-dipolar cycloadditions of cyclopentadienones and thiophene-1,1-dioxide with C,N-cyclic azomethine imines.

The normal 1,3-dipolar cycloaddition between the carbonates of 4-hydroxy-2-cyclopentenones and C,N-cyclic azomethine imines can be switched to an inverse-electron-demand version under Pd(0) catalysis, by in situ generation of HOMO-raised η2-Pd(0)-cyclopentadienone complexes. An array of fused heterocyclic architectures are constructed with high levels of diastereo and enantioselectivity, and diastereodivergent synthesis is well realised by tuning the bifunctional phosphine ligands. In addition, similar reaction with in situ formed thiophene-1,1-dioxide is compatible by using a chiral bisphosphine ligand, and the fused cyclic sulfone frameworks are afforded with high stereoselectivity.

Highly selective monoclonal antibody-based lateral flow immunoassay for visual and sensitive determination of conazole fungicides propiconazole in vegetables.

The conazole fungicide propiconazole is frequently found in vegetables although usage is not allowed. To overcome the high-cost and time-consuming labour requirements of instrumental methods, we developed a simple and visual lateral flow immunoassay for the sensitive determination of propiconazole. A hapten was carefully designed to raise a monoclonal antibody against propiconazole. Bal b/c mice were immunised with the hapten-carrier protein conjugate and a specific monoclonal antibody (mAb) was produced. Based on this mAb, a sensitive immunochromatographic strip assay (ICA) was established for rapid screening of propiconazole in vegetable samples. After optimisation of analytical parameters, the ICA strip showed a detection limit of 0.13 ng g-1 and a linear range from 0.5 to 80 ng g-1 using a strip reader. The assay also can be read by the naked eye with a visual limit of detection of 80 ng g-1. The recoveries for spiked vegetable samples by ICA ranged from 85.2% to 114.9%, with a coefficient of variation less than 11.7%. The assay time is within 45 min for a single sample including the sample pre-treatment. For spiked and blind samples, the detection capability of ICA was equivalent to liquid chromatography-mass spectrometry.

Ligand-Controlled Regiodivergent Asymmetric [5 + 2] and [3 + 2] Annulations of Vinyl Indoloxazolidones Catalyzed by Palladium.

Here, we present palladium-catalyzed regiodivergent asymmetric annulations of vinyl indoloxazolidones, which can act as 1,5-carbodipoles or 1,3-carbodipoles by tuning the chiral ligands and conditions, in the assemblies with sulfamate-derived cyclic imines and even activated alkenes. A diversity of polycyclic products are generally constructed with high regio- and enantioselectivity.

Cu(I)-Catalyzed Asymmetric α-Allenylation of Activated Ketimines with 3-Butynoates.

An asymmetric α-regioselective allenylation reaction of activated ketimines with 3-butynoates is disclosed under Cu(I) catalysis, probably via the generation of nucleophilic γ-allenylcopper species in the presence of diisopropylethylamine. A broad range of imines, derived from diverse ketones such as isatins, pyrazolediones, isoquinoline-1,3,4-triones, and even trifluoromethyl alkynyl ketones, can be utilized, generally affording the corresponding α-allenyl amine derivatives in high yields (≤97%) with excellent enantioselectivities (≤99% ee).

3-Anilino-N-p-tolyl-benzamide.

The title compound, C(20)H(18)N(2)O, which crystallizes with two independent mol-ecules (A and B) in the asymmetric unit, is composed of three aromatic rings (I, II and III). The conformation of the two independent mol-ecules is slightly different. The dihedral angles between the central aromatic ring II and rings I and III are 47.13 (9) and 89.36 (9)°, respectively, for mol-ecule A, and 29.60 (9) and 70.72 (9)°, respectively, for mol-ecule B. Rings I and III are inclined to one another by 86.57 (9)° in mol-ecule A, and 64.59 (10)° in mol-ecule B. The mol-ecular structures are stabilized by intra-molecular N-H⋯O hydrogen bonds. In the crystal structure, mol-ecules are linked through inter-molecular N-H⋯O hydrogen bonds, forming chains propagating in the [010] direction. In addition, a number of C-H⋯π inter-actions are observed.

2-Anilino-N-methyl-N-phenyl-benzamide.

The title compound, C(20)H(18)N(2)O, is composed of three aromatic rings, the dihedral angles between the phenyl and benzamide rings, and between the benzamide and aniline rings being 59.86 (9) and 46.57 (10)°, respectively. The mol-ecular structure is stabilized by an intra-molecular N-H⋯O hydrogen bond involving the amino H atom and the benzamide carbonyl O atom. In the crystal structure, C-H⋯O and C-H⋯π inter-actions are present.

Asymmetric Cascade Assembly of 1,2-Diaza-1,3-dienes and α,ß-Unsaturated Aldehydes via Dienamine Activation.

A cascade vinylogous 1,6-Michael addition/1,4-proton shift/aza-Michael addition/hemiaminal formation sequence of 1,2-diaza-1,3-dienes and ß-substituted 2-butenals has been developed under the influence of dienamine activation of a chiral secondary amine. This method exhibits high regio- and chemoselectivity and provides an efficient and straightforward approach to bicyclic l,8-diazabicyclo[3.3.0]octane skeletons with a tetrasubstituted stereogenic center with fair to excellent enantioselectivity.