Discovery of Novel Coumarin-quinolinium Derivatives as Pan-KRAS Translation Inhibitors by Targeting 5'-UTR RNA G-Quadruplexes.

Hyperactivated KRAS mutations fuel tumorigenesis and represent attractive targets for cancer treatment. While covalent inhibitors have shown clinical benefits against the KRASG12C mutant, advancements for non-G12C mutants remain limited, highlighting the urgent demand for pan-KRAS inhibitors. RNA G-quadruplexes (rG4s) in the 5'-untranslated region of KRAS mRNA can regulate KRAS translation, making them promising targets for pan-KRAS inhibitor development. Herein, we designed and synthesized 50 novel coumarin-quinolinium derivatives, leveraging our previously developed rG4-specific ligand, QUMA-1. Notably, several compounds exhibited potent antiproliferative activity against cancer cells as pan-KRAS translation inhibitors. Among them, 15a displayed exceptional capability in stabilizing KRAS rG4s, suppressing KRAS translation, and consequently modulating MAPK and PI3K-AKT pathways. 15a induced cell cycle arrest, prompted apoptosis in KRAS-driven cancer cells, and effectively inhibited tumor growth in a KRAS mutant xenograft model. These findings underscore the potential of 15a as a pan-KRAS translation inhibitor, offering a novel and promising approach to target various KRAS-driven cancers.

Analysis of the Ability of a Distal Tibial Anatomical Locking Plate to Capture the Distal Tibial Fragments in Patients with Pilon Fractures.

OBJECTIVE: Although pilon fractures are rare in clinical practice, they are difficult to treat because of their complexity. Effective fixation of the fracture fragment is the key to the treatment of pilon fractures. Plate osteosynthesis is common clinically, but there are many types of plates and the evaluation of the effect of fixation plates is not comprehensive. This study attempted to compare the capture effect of different fixation plates on the fracture fragments based on 3D modeling and fine distinctions of fracture fragments. METHODS: The computed tomography (CT) images before treatment of 127 patients with pilon fractures from January 2019 to December 2021 were retrospectively collected. The fracture lines were mapped and digitally displayed as 3D images using MIMICS 21 software. APLUS distal tibia anatomical locking plate (Plate A) and ZIMMER distal tibia anatomical plate (Plate B) were placed on a pseudo-bone model and CT scans were used to determine the number of screws in the major and minor fragments of pilon fractures. The frequency of the two plates capturing the fracture fragments was recorded. RESULTS: Under Assumption 1 or 2, Plate A performed significantly better than Plate B in capturing the major, Chaput, Volkmann, medial malleolus, and die-punch fracture fragments. Plate A captured markedly more minor fragments than Plate B under Assumption 2 but was not significantly different from Plate B under Assumption 1. Plate A or Plate B showed no obvious difference between major and minor capture rates under the same assumption, and A1 or B1 showed a markedly higher capture rate compared with A2 or B2. In addition, there was a significant positive correlation between the major capture rate and the major fragments in B1, and a significant negative correlation between the minor capture rate and the minor fragments in Plates A and B. However, there was no correlation between the major capture rate of Plate A and the major fragments. CONCLUSION: The APLUS distal tibial anatomical locking plate is superior to the ZIMMER distal tibia anatomical plate in the ability to capture distal tibial fragments in pilon fracture cases.

Enantioselective Synthesis of Chiral Amides by a Phosphoric Acid Catalyzed Asymmetric Wolff Rearrangement.

The enantioselective addition of potent nucleophiles to ketenes poses challenges due to competing background reactions and poor stereocontrol. Herein, we present a method for enantioselective phosphoric acid catalyzed amination of ketenes generated from α-aryl-α-diazoketones. Upon exposure to visible light, the diazoketones undergo Wolff rearrangement to generate ketenes. The phosphoric acid not only accelerates ketene capture by amines to form a single configuration of aminoenol intermediates but also promotes an enantioselective proton-transfer reaction of the intermediates to yield the products. Mechanistic studies elucidated the reaction pathway and explained how the catalyst expedited the transformation and controlled the enantioselectivity.

A retrospective comparison of double-hooked locking plates versus non-locking plates in minimally invasive percutaneous plate osteosynthesis for the treatment of comminuted distal fibular fractures accompanied by tibial Pilon fractures.

BACKGROUND: Surgical approach and fixation material are crucial in the treatment of comminuted distal fibular fractures accompanied by tibial Pilon fractures. This study compared the efficacy of double-hooked locking plates and anatomic plates in minimally invasive percutaneous plate osteosynthesis (MIPPO) for the treatment of comminuted distal fibular fractures accompanied by tibial Pilon fractures. METHODS: Clinical data were collected from 96 patients diagnosed with comminuted distal fibular fractures accompanied by tibial Pilon fractures who had undergone MIPPO. Patients in the study group (n = 48) received double-hooked locking plate fixations and the control group (n = 48) received anatomical plate fixations. The operating time, intraoperative bleeding, length of hospital stays, full weight-bearing time, fracture healing time and complication rates in the two groups were compared. The quality of fracture reduction was evaluated using the Burwell-Chamley imaging scoring system; the ankle function was assessed based on the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Score. RESULTS: Patients in the study group had shorter operating time, less bleeding, significantly shorter hospital stays, and shorter time to full weight-bearing as well as fracture healing compared to the control group (P < 0.05). Additionally, the post-operative complication rates were significantly lower in the study group (6.16% vs. 22.92%) (P < 0.05), but there was no significant difference in the fracture reduction rate between the two groups (P > 0.05). Patients in the study group experienced better ankle recovery than those in the control group (93.75% vs. 75.00%) (P < 0.05). CONCLUSION: Double-hooked locking plates have advantages in the treatment of comminuted distal fibular fractures accompanied by tibial Pilon fractures during MIPPO due to their shorter operating time and less intraoperative bleeding, as well as shorter hospital stays, full weight-bearing time and fracture healing time, fewer complications and better ankle recovery. Therefore, double-hooked locking plates are worthy of clinical application.

A Spiro Phosphamide Catalyzed Enantioselective Proton Transfer of Ylides in a Free Carbene Insertion into N-H Bonds.

Free carbene readily causes multiple side reactions due to its high energy, thus its asymmetric transformation is very difficult. We present here our findings of high-pKa Brønsted acid catalysts that enable free carbene insertion into N-H bonds of amines to prepare chiral α-amino acid derivatives with high enantioselectivity. Under irradiation with visible light, diazo compounds produce high-energy free carbenes that are captured by amines to form free ylide intermediates, and then the newly designed high-pKa Brønsted acids, chiral spiro phosphamides, promote the proton transfer of ylides to afford the products. Computational and kinetic studies uncover the principle for the rational design of proton-transfer catalysts and explain how the catalysts accelerate this transformation and provide stereocontrol.

Design, Synthesis, and Evaluation of New Sugar-Substituted Imidazole Derivatives as Selective c-MYC Transcription Repressors Targeting the Promoter G-Quadruplex.

c-MYC is a key driver of tumorigenesis. Repressing the transcription of c-MYC by stabilizing the G-quadruplex (G4) structure with small molecules is a potential strategy for cancer therapy. Herein, we designed and synthesized 49 new derivatives by introducing carbohydrates to our previously developed c-MYC G4 ligand 1. Among these compounds, 19a coupled with a d-glucose 1,2-orthoester displayed better c-MYC G4 binding, stabilization, and protein binding disruption abilities than 1. Our further evaluation indicated that 19a blocked c-MYC transcription by targeting the promoter G4, leading to c-MYC-dependent cancer cell death in triple-negative breast cancer cell MDA-MB-231. Also, 19a significantly inhibited tumor growth in the MDA-MB-231 mouse xenograft model accompanied by c-MYC downregulation. Notably, the safety of 19a was dramatically improved compared to 1. Our findings indicated that 19a could become a promising anticancer candidate, which suggested that introducing carbohydrates to improve the G4-targeting and antitumor activity is a feasible option.

Optimized XGBoost Model with Small Dataset for Predicting Relative Density of Ti-6Al-4V Parts Manufactured by Selective Laser Melting.

Determining the quality of Ti-6Al-4V parts fabricated by selective laser melting (SLM) remains a challenge due to the high cost of SLM and the need for expertise in processes and materials. In order to understand the correspondence of the relative density of SLMed Ti-6Al-4V parts with process parameters, an optimized extreme gradient boosting (XGBoost) decision tree model was developed in the present paper using hyperparameter optimization with the GridsearchCV method. In particular, the effect of the size of the dataset for model training and testing on model prediction accuracy was examined. The results show that with the reduction in dataset size, the prediction accuracy of the proposed model decreases, but the overall accuracy can be maintained within a relatively high accuracy range, showing good agreement with the experimental results. Based on a small dataset, the prediction accuracy of the optimized XGBoost model was also compared with that of artificial neural network (ANN) and support vector regression (SVR) models, and it was found that the optimized XGBoost model has better evaluation indicators such as mean absolute error, root mean square error, and the coefficient of determination. In addition, the optimized XGBoost model can be easily extended to the prediction of mechanical properties of more metal materials manufactured by SLM processes.

[on oligozoospermia and asthenospermia].

OBJECTIVE: To observe the clinical effect of Yihechun Capsules (YHC) on oligozoospermia and asthenospermia. METHODS: A total of 181 male patients with infertility were randomly divided into a YHC+Levocarnitine (LC) group (n = 93, including 42 cases of oligozoospermia, 20 cases of asthenospermia and 31 cases of oligoasthenospermia) and an LC control group (n = 88, including 39 cases of oligozoospermia, 22 cases of asthenospermia and 27 cases of oligoasthenospermia), the former treated with YHC (ï¼»0.3 g per capsuleï¼½, once 4 capsules, bid, 30 minutes after meal) combined with LC oral liquid (2－3 g/d, tid, at mealtime) and the latter with LC oral liquid only (2－3 g/d, tid, at mealtime). After 3 months of treatment, comparisons were made between the two groups of patients in sperm concentration, the percentages of grade a and grade a+b sperm, and the rate of pregnancy. RESULTS: Of the 181 patients, 5 in the YHC+LC group and 2 in the LC control group failed to complete the course of treatment. There were no statistically significant differences between the two groups of patients in the baseline sperm concentration and the percentages of grade a and grade a+b sperm (P > 0.05), wich were all markedly increased in both the YHC+LC and the LC control groups (P < 0.05) after 3 months of treatment. And the patients of the YHC+LC group, compared with the controls, showed even more significant increases, as the oligozoospermia patients in sperm concentration (ï¼»21.07 ± 6.98ï¼½ vs ï¼»16.56 ± 1.82ï¼½ ×106/ml, P < 0.05) and the percentages of grade a sperm (ï¼»27.53 ± 3.34ï¼½% vs ï¼»26.88 ± 1.35ï¼½%, P < 0.05) and grade a+b sperm (ï¼»53.32 ± 3.16ï¼½% vs ï¼»52.63 ± 2.48ï¼½%, P < 0.05), the asthenospermia patients in sperm concentration (ï¼»26.36 ± 3.37ï¼½ vs ï¼»24.42 ± 2.21ï¼½ ×106/ml, P < 0.05) and the percentages of grade a sperm (ï¼»25.28 ± 4.64ï¼½% vs ï¼»21.32 ± 3.28ï¼½%, P < 0.05) and grade a+b sperm (ï¼»49.19 ± 2.87ï¼½% vs ï¼»45.64 ± 1.78ï¼½%, P < 0.05), and the oligoasthenospermia patients in sperm concentration (ï¼»19.38 ± 3.39ï¼½ vs ï¼»18.75 ± 1.35ï¼½ ×106/ml, P < 0.05) and the percentages of grade a sperm (ï¼»22.65 ± 4.81ï¼½% vs ï¼»21.31 ± 2.42ï¼½%, P < 0.05) and grade a+b sperm (ï¼»48.74 ± 5.61ï¼½% vs ï¼»44.36 ± 1.32ï¼½%, P < 0.05). The pregnancy rate was dramatically higher in the YHC+LC than in the LC control group (36.4% ï¼»32/88ï¼½ vs 15.1% ï¼»13/86ï¼½, P < 0.01). CONCLUSIONS: Yihechun Capsules combined with Levocarnitine oral liquid is evidently effective for the treatment of oligozoospermia and asthenospermia.

Insertion of Alkylidene Carbenes into B-H Bonds.

We have developed a protocol for insertion of alkylidene carbenes into the B-H bonds of amine-borane adducts, enabling, for the first time, the construction of C(sp2)-B bonds by means of carbene-insertion reactions. Various acyclic and cyclic alkenyl borane-amine adducts were prepared from readily accessible starting materials in good to high yields and were subsequently subjected to a diverse array of functional group transformations. The unprecedented spiro B-N heterocycles prepared in this study have potential utility as building blocks for the synthesis of pharmaceuticals. Preliminary mechanistic studies suggest that insertion of the alkylidene carbenes into the B-H bonds of the amine-borane adducts proceeds via a concerted process involving a three-membered-ring transition state.

Enantioselective Diarylcarbene Insertion into Si-H Bonds Induced by Electronic Properties of the Carbenes.

Catalytic enantioselection usually depends on differences in steric interactions between prochiral substrates and a chiral catalyst. We have discovered a carbene Si-H insertion in which the enantioselectivity depends primarily on the electronic characteristics of the carbene substrate, and the log(er) values are linearly related to Hammett parameters. A new class of chiral tetraphosphate dirhodium catalysts was developed; it shows excellent activity and enantioselectivity for the insertion of diarylcarbenes into the Si-H bond of silanes. Computational and mechanistic studies show how the electronic differences between the two aryls of the carbene lead to differences in energies of the diastereomeric transition states. This study provides a new strategy for asymmetric catalysis exploiting the electronic properties of the substrates.

Highly enantioselective carbene insertion into N-H bonds of aliphatic amines.

Aliphatic amines strongly coordinate, and therefore easily inhibit, the activity of transition-metal catalysts, posing a marked challenge to nitrogen-hydrogen (N-H) insertion reactions. Here, we report highly enantioselective carbene insertion into N-H bonds of aliphatic amines using two catalysts in tandem: an achiral copper complex and chiral amino-thiourea. Coordination by a homoscorpionate ligand protects the copper center that activates the carbene precursor. The chiral amino-thiourea catalyst then promotes enantioselective proton transfer to generate the stereocenter of the insertion product. This reaction couples a wide variety of diazo esters and amines to produce chiral α-alkyl α-amino acid derivatives.

Highly Enantioselective Nickel-Catalyzed Intramolecular Hydroalkenylation of N- and O-Tethered 1,6-Dienes To Form Six-Membered Heterocycles.

A highly enantioselective nickel-catalyzed intramolecular hydroalkenylation of N- or O-tethered 1,6-dienes was developed by using monodentate chiral spiro phosphoramidite ligands. The reaction provides an efficient and straightforward method for preparing very useful six-membered N- and O-heterocycles with high regioselectivity as well as excellent stereoselectivity from easily accessible starting materials under mild reaction conditions. The chiral spiro nickel catalyst developed in this study represents one of the few catalysts for highly enantioselective cyclization of unconjugated dienes.

Nickel(0)-Catalyzed Hydroarylation of Styrenes and 1,3-Dienes with Organoboron Compounds.

A Ni-catalyzed hydroarylation of styrenes and 1,3-dienes with organoboron compounds has been developed. The reaction offers a highly selective approach to diarylalkanes and allylarenes under redox-neutral conditions. In this hydroarylation reaction, a new strategy that uses the proton of methanol to generate the active catalyst species Ni-H was developed. The Ni-catalyzed hydroarylation, combined with a Ir-catalyzed C-H borylation, affords a very efficient and straightforward access to a retinoic acid receptor agonist.

Catalytic B-H Bond Insertion Reactions Using Alkynes as Carbene Precursors.

Herein, we report transition-metal-catalyzed B-H bond insertion reactions between borane adducts and alkynes to afford organoboron compounds in excellent yields under mild reaction conditions. This successful use of alkynes as carbene precursors in these reactions constitutes a new route to organoboron compounds. The starting materials are safe and readily available, and the reaction exhibits 100% atom-economy. Moreover, an asymmetric version catalyzed by chiral dirhodium complexes produced chiral boranes with excellent enantioselectivity (up to 96% ee). This is the first report of highly enantioselective heteroatom-hydrogen bond insertion reactions of metal carbenes generated in situ from alkynes. The chiral products of the reaction could be easily transformed to widely used borates and diaryl methanol compounds without loss of optical purity, which demonstrates its potential utility in organic synthesis. A kinetics study indicated that the Cu-catalyzed B-H bond insertion reaction is first order with respect to the catalyst and the alkyne and zero order with respect to the borane adduct, and no kinetic isotopic effect was observed in the reaction of the adduct. These results, along with density functional theory calculations, suggest that the formation of the Cu carbene is the rate-limiting step and that the B-H bond insertion is a fast, concerted process.

Mechanism Studies of Ir-Catalyzed Asymmetric Hydrogenation of Unsaturated Carboxylic Acids.

The Ir-catalyzed asymmetric hydrogenation of olefins is widely used for production of value-added bulk and fine chemicals. The iridium catalysts with chiral spiro phosphine-oxazoline ligands developed in our group show high activity and high enantioselectivity in the hydrogenation of olefins bearing a coordinative carboxyl group, such as α,ß-unsaturated carboxylic acids, ß,γ-unsaturated carboxylic acids, and γ,δ-unsaturated carboxylic acids. Here we conducted detailed mechanistic studies on these Ir-catalyzed asymmetric hydrogenation reactions by using (E)-2-methyl-3-phenylacrylic acid as a model substrate. We isolated and characterized several key intermediates having Ir-H bonds under the real hydrogenation conditions. Particularly, an Ir(III) migratory insertion intermediate was first isolated in an asymmetric hydrogenation reaction promoted by chiral Ir catalysts. That this intermediate cannot undergo reductive elimination in the absence of hydrogen strongly supports the involvement of an Ir(III)/Ir(V) cycle in the hydrogenation. On the basis of the structure of the Ir(III) intermediate, variable-temperature NMR spectroscopy, and density functional theory calculations, we elucidated the mechanistic details of the Ir-catalyzed hydrogenation of unsaturated carboxylic acids and explained the enantioselectivity of the reactions. These findings experimentally and computationally elucidate the mechanism of Ir-catalyzed asymmetric hydrogenation of olefins with a strong coordinative carboxyl group and will likely inspire further catalyst design.

Catalytic Asymmetric Arylation of α-Aryl-α-diazoacetates with Aniline Derivatives.

The asymmetric arylation of diazo compounds with aniline derivatives cooperatively catalyzed by an achiral dirhodium complex and a chiral spiro phosphoric acid is reported. The reaction provides a new method for the facile synthesis of α-diarylacetates, versatile building blocks with a diaryl tertiary chiral center, in good yields (up to 95%) with high enantioselectivities (up to 97% ee). Preliminary mechanistic studies suggest that the arylation reaction proceeds via a stepwise process, in which the enantioselectivity is controlled by a chiral spiro phosphoric acid-promoted proton shift in a zwitterionic intermediate. This work represents the first asymmetric intermolecular C(sp(2))-H bond insertion reaction with arenes.