bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transition Metal‐Free Activation of Carbon Monoxide: Ketenyl Anions by PPh3/CO Exchange
Authors: Hansmann Max M. 
Published: February 2023

AbstractKetenes (R2C=C=O) are important reactive intermediates in organic chemistry which are often challenging to access in stable form due to their polarized cumulenic structure and inherent high reactivity. Ketenyl anions (R(M)C=C=O) or metal ynolates (R−C≡C−OM) represent alternative, highly attractive synthetic targets, but are typically prepared in situ and their structure and synthetic access are little investigated. Now, a fundamentally new strategy utilizing an exchange reaction of a phosphine with carbon monoxide at a metalated ylide gives rise to a series of novel ketenyl anions. These compounds are flexible reagents and can easily be transferred with electrophiles into more complex building blocks for synthetic applications. Since carbon monoxide is an inexpensive C1 building block, the new exchange strategy is an elegant concept and a valuable new entry in the synthetic toolbox of organic synthesis.
Reduktive Eliminierung in geschlossener Schale und radikalische Kopplung in offener Schale für regioselektive Ruthenium‐katalysierte C−H‐Aktivierungen anhand von Berechnungen und Experimenten
Authors: Chen Xinran , Gülen Hasret Can , Wu Jun , Zhang Zi‐Jing , Hong Xin , Ackermann Lutz 
Published: February 2023

AbstractDie meta C–H‐Funktionalisierung durch Ruthenium‐katalysierte σ‐Bindungsaktivierung hat sich als nützliches Werkzeug zum Knüpfen distaler C–C‐Bindungen erwiesen. Aufgrund der begrenzten Anzahl von mechanistischen Studien ist jedoch kein klares Verständnis des Hintergrunds der Regioselektivität und des vollständigen Reaktionsmusters vorhanden. Hier präsentieren wir systematische computerchemische Studien zur Ruthenium‐katalysierten C–H‐Funktionalisierung mit primären, sekundären und tertiären Alkyl‐ sowie Arylbromiden. Die C–H‐Aktivierung und die C–C‐Bindungsbildung wurden sorgfältig untersucht. Monocyclometallierte Ruthenium(II)‐Komplexe wurden als aktive Spezies identifiziert, welche anschließend über einen Innersphären‐Elektronentransfer (ISET) Organobromide aktivieren. Die Regioselektivität ergibt sich aus der Konkurrenz zwischen der geschlossen schaligen reduktiven Eliminierung und der offen schaligen radikalischen Kopplung. Auf Grundlage dieses mechanistischen Verständnisses wurde ein multilineares Regressionsmodell zur Vorhersage der Regioselektivität erstellt, das durch Experimente bestätigt wurde.
Manganese‐Catalyzed Chemoselective Coupling of Secondary Alcohols, Primary Alcohols and Methanol
Authors: Tang Jun , He Jingxi , Zhao Sheng‐Yin , Liu Weiping 
Published: February 2023

AbstractHerein, we report a manganese‐catalyzed three‐component coupling of secondary alcohols, primary alcohols and methanol for the synthesis of β,β‐methylated/alkylated secondary alcohols. Using our method, a series of 1‐arylethanol, benzyl alcohol derivatives, and methanol undergo sequential coupling efficiently to construct assembled alcohols with high chemoselectivity in moderate to good yields. Mechanistic studies suggest that the reaction proceeds via methylation of a benzylated secondary alcohol intermediate to generate the final product.
Determining the Physico‐Chemical Composition of Biomolecular Condensates from Spatially‐Resolved NMR
Authors: Pantoja Christian F. , Ibáñez de Opakua Alain , Cima‐Omori Maria‐Sol , Zweckstetter Markus 
Published: February 2023

AbstractLiquid‐Liquid phase separation has emerged as fundamental process underlying the formation of biomolecular condensates. Insights into the composition and structure of biomolecular condensates is, however, complicated by their molecular complexity and dynamics. Here, we introduce an improved spatially‐resolved NMR experiment that enables quantitative analysis of the physico‐chemical composition of multi‐component biomolecular condensates in equilibrium and label‐free. Application of spatially‐resolved NMR to condensates formed by the Alzheimer's disease‐associated protein Tau demonstrates decreased water content, exclusion of the molecular crowding agent dextran, presence of a specific chemical environment of the small molecule DSS, and ≈150‐fold increased concentration of Tau inside the condensate. The results suggest that spatially‐resolved NMR can have a major impact in understanding the composition and physical chemistry of biomolecular condensates.
Organocatalytic Synthesis of Triflones Bearing Two Non‐Adjacent Stereogenic Centers
Authors: Budinská Alena , Wennemers Helma 
Published: February 2023

AbstractTrifluoromethylsulfones (triflones) are useful compounds for synthesis and beyond. Yet, methods to access chiral triflones are scarce. Here, we present a mild and efficient organocatalytic method for the stereoselective synthesis of chiral triflones using α‐aryl vinyl triflones, building blocks previously unexplored in asymmetric synthesis. The peptide‐catalyzed reaction gives rise to a broad range of γ‐triflylaldehydes with two non‐adjacent stereogenic centers in high yields and stereoselectivities. A catalyst‐controlled stereoselective protonation following a C−C bond formation is key to control over the absolute and relative configuration. Straightforward derivatization of the products into, e.g., disubstituted δ‐sultones, γ‐lactones, and pyrrolidine heterocycles highlights the synthetic versatility of the products.
Cobalt‐Catalyzed Enantioselective Hydrogenation of Trisubstituted Carbocyclic Olefins: An Access to Chiral Cyclic Amides
Authors: Chakrabortty Soumyadeep , Konieczny Katharina , de Zwart Felix J. , Bobylev Eduard. O. , Baráth Eszter , Tin Sergey , Müller Bernd H. , Reek Joost N. H. , de Bruin Bas , de Vries Johannes G. 
Published: February 2023

AbstractThe enantioselective hydrogenation of cyclic enamides has been achieved using an earth‐abundant cobalt‐bisphosphine catalyst. Using CoCl2/(S,S)‐Ph‐BPE, several trisubstituted carbocyclic enamides were reduced with high activity and excellent enantioselectivity (up to 99 %) to the corresponding saturated amides. The methodology can be extended to the synthesis of chiral amines by base hydrolysis of the hydrogenation products. Preliminary mechanistic investigations reveal the presence of a high spin cobalt (II) species in the catalytic cycle. We propose that the hydrogenation of the carbon‐carbon double bond proceeds via a sigma‐bond‐metathesis pathway.
The First UV Nonlinear Optical Selenite Material: Fluorination Control in CaYF(SeO3)2 and Y3F(SeO3)4
Authors: Li Peng‐Fei , Hu Chun‐Li , Kong Fang , Mao Jiang‐Gao 
Published: February 2023

AbstractIt is a great challenge to develop UV nonlinear optical (NLO) material due to the demanding conditions of strong second harmonic generation (SHG) intensity and wide band gap. The first ultraviolet NLO selenite material, Y3F(SeO3)4, has been obtained by control of the fluorine content in a centrosymmetric CaYF(SeO3)2. The two new compounds represent similar 3D structures composed of 3D yttrium open frameworks strengthened by selenite groups. CaYF(SeO3)2 has a large birefringence (0.138@532 nm and 0.127@1064 nm) and a wide optical band gap (5.06 eV). The non‐centrosymmetric Y3F(SeO3)4 can exhibit strong SHG intensity (5.5×KDP@1064 nm), wide band gap (5.03 eV), short UV cut‐off edge (204 nm) and high thermal stability (690 °C). So, Y3F(SeO3)4 is a new UV NLO material with excellent comprehensive properties. Our work shows that it is an effective method to develop new UV NLO selenite material by fluorination control of the centrosymmetric compounds.
Close‐Shell Reductive Elimination versus Open‐Shell Radical Coupling for Site‐Selective Ruthenium‐Catalyzed C−H Activations by Computation and Experiments
Authors: Chen Xinran , Gülen Hasret Can , Wu Jun , Zhang Zi‐Jing , Hong Xin , Ackermann Lutz 
Published: February 2023

AbstractRuthenium‐catalyzed σ‐bond activation‐assisted meta‐C−H functionalization has emerged as a useful tool to forge distal C−C bonds. However, given the limited number of mechanistic studies, a clear understanding of the origin of the site‐selectivity and the complete reaction pattern is not available. Here, we present systematic computational studies on ruthenium‐catalyzed C−H functionalization with primary, secondary, tertiary alkyl bromides and aryl bromides. The C−H scission and the C−C formation were carefully examined. Monocyclometalated ruthenium(II) complexes were identified as the active species, which then underwent inner‐sphere single electron transfer (ISET) to activate the organic bromides. The site‐selectivity results from the competition between the close‐shell reductive elimination and the open‐shell radical coupling. Based on this mechanistic understanding, a multilinear regression model was built to predict the site‐selectivity, which was further validated by experiments.
The femora ofDrepanosauromorpha(Reptilia:Diapsida): Implications for the functional evolution of the thigh ofSauropsida
Authors: Pritchard Adam C. , Irmis Randall B. , Olori Jennifer C. , Nesbitt Sterling J. , Smith Nathan D. , Stocker Michelle R. , Turner Alan H. 
Published: February 2023

AbstractThe femora of diapsids have undergone morphological changes related to shifts in postural and locomotor modes, such as the transition from plesiomorphic amniote and diapsid taxa to the apomorphic conditions related to a more erect posture within Archosauriformes. One remarkable clade of Triassic diapsids is the chameleon‐like Drepanosauromorpha. This group is known from numerous articulated but heavily compressed skeletons that have the potential to further inform early reptile femoral evolution. For the first time, we describe the three‐dimensional osteology of the femora of Drepanosauromorpha, based on undistorted fossils from the Upper Triassic Chinle Formation and Dockum Group of North America. We identify apomorphies and a combination of character states that link these femora to those in crushed specimens of drepanosauromorphs and compare our sample with a range of amniote taxa. Several characteristics of drepanosauromorph femora, including a hemispherical proximal articular surface, prominent asymmetry in the proximodistal length of the tibial condyles, and a deep intercondylar sulcus, are plesiomorphies shared with early diapsids. The femora contrast with those of most diapsids in lacking a crest‐like, distally tapering internal trochanter. They bear a ventrolaterally positioned tuberosity on the femoral shaft, resembling the fourth trochanter in Archosauriformes. The reduction of an internal trochanter parallels independent reductions in therapsids and archosauriforms. The presence of a ventrolaterally positioned trochanter is also similar to that of chameleonid squamates. Collectively, these features demonstrate a unique femoral morphology for drepanosauromorphs, and suggest an increased capacity for femoral adduction and protraction relative to most other Permo‐Triassic diapsids.
Base‐catalyzed Effective C2‐Amidation of Azolium Salts Using Isocyanates under Mild Conditions
Authors: Bauri Somnath , Ramachandran Arya , Rit Arnab 
Published: February 2023

AbstractAn unprecedented base‐catalyzed hydroarylation of isocyanates with azolium salts was developed, which follows a simple reaction pathway and provided facile access to diverse C2‐amidated azolium salts under mild conditions. Importantly, this methodology can also be applied for the successive C2‐amidation of a bisimidazolium salt with two different isocyanates to provide the corresponding unsymmetrically substituted bisamide derivatives. Notably, the obtained amidated salts can also serve as a prominent carbene surrogate for the synthesis of metal‐NHC complexes.
Die Orthoverbundplatte – Aktuelles aus Praxis und Forschung
Authors: Mansperger Tobias 
Published: February 2023

AbstractBei Großbrücken spielt das Eigengewicht der Fahrbahnplatte eine sehr wichtige Rolle. Orthotrope Stahlfahrbahnplatten sind leicht, jedoch sehr ermüdungsanfällig. Deswegen werden orthotrope Platten heute nur noch in Ausnahmefällen geplant. Stahlbetonfahrbahnplatten von Verbundbrücken sind robust, jedoch für große Spannweiten zu schwer. Die Orthoverbundplatte kombiniert die Vorteile der orthotropen Fahrbahnplatte mit der Stahlbetonfahrbahnplatte von Verbundbrücken auf ideale Weise. Das Grundprinzip von leichten Verbundfahrbahnplatten existiert schon seit den 1930er‐Jahren und wurde bei einigen Großbrücken erfolgreich eingesetzt. Die Orthoverbundplatte ist eine Kombination aus einer orthotropen Stahlplatte und einer im Verbund stehenden, bewehrten Aufbetonschicht. Sie vereint die positiven Eigenschaften beider Bauweisen. Sie ist leicht, aber dennoch robust, dauerhaft und widerstandsfähig gegenüber Materialermüdung. Sie kann mit einem sehr hohen Vorfertigungsgrad schnell, präzise und wirtschaftlich hergestellt werden. Die Orthoverbundplatte ist unanfällig bei extremen thermischen Ereignissen wie Blitzeisbildung und Zwangsbeanspruchungen infolge Heißeinbau von Gussasphalt.
Decreased plasma exposure of clopidogrel active metabolite in rats after long‐term treatment with clopidogrel
Authors: Wang Yani , Liu Yingrui , Yao Hongwei , Chen Xue , Sun Yantong , Guo Yingjie 
Published: February 2023

AbstractClopidogrel (Clop) is oxidized by cytochrome P450s (CYPs) to an active thiol metabolite, Clop‐AM, to inhibit platelet activation and aggregation. As an irreversible inhibitor of CYP2B6 and CYP2C19, clopidogrel may inhibit its own metabolism after long‐term administration. The study compared the pharmacokinetic profiles of clopidogrel and its metabolites in rats receiving a single or a 2 week administration of Clop. The mRNA and protein levels of hepatic clopidogrel‐metabolizing enzymes and their enzymatic activities were analyzed to explore their contribution to any altered plasma exposure of Clop and its metabolites. The results showed that long‐term treatment with clopidogrel significantly decreased the AUC(0‐t) and Cmax values of Clop‐AM in rats, accompanied with markedly impaired catalytic activities of Clop‐metabolizing CYPs including CYP1A2, CYP2B6, CYP2C9, CYP2C19, and CYP3A4. It suggests that consecutive administration of Clop to rats decreases hepatic CYPs activities, which may, in turn, inhibit clopidogrel metabolism and then reduce Clop‐AM plasma exposure. Therefore, long‐term treatment with clopidogrel has the potential to reduce its anti‐platelet activity and to increase the risk of drug–drug interaction.
Comparison of cohort and nested case‐control designs for estimating the effect of time‐varying drug exposure on the risk of adverse event in the presence of ties
Authors: Manitchoko Liliane , Abrahamowicz Michal , Tubert‐Bitter Pascale , Benichou Jacques , Thiébaut Anne C. M. 
Published: February 2023

AbstractCohort and nested case‐control (NCC) designs are frequently used in pharmacoepidemiology to assess the associations of drug exposure that can vary over time with the risk of an adverse event. Although it is typically expected that estimates from NCC analyses are similar to those from the full cohort analysis, with moderate loss of precision, only few studies have actually compared their respective performance for estimating the effects of time‐varying exposures (TVE). We used simulations to compare the properties of the resulting estimators of these designs for both time‐invariant exposure and TVE. We varied exposure prevalence, proportion of subjects experiencing the event, hazard ratio, and control‐to‐case ratio and considered matching on confounders. Using both designs, we also estimated the real‐world associations of time‐invariant ever use of menopausal hormone therapy (MHT) at baseline and updated, time‐varying MHT use with breast cancer incidence. In all simulated scenarios, the cohort‐based estimates had small relative bias and greater precision than the NCC design. NCC estimates displayed bias to the null that decreased with a greater number of controls per case. This bias markedly increased with higher proportion of events. Bias was seen with Breslow's and Efron's approximations for handling tied event times but was greatly reduced with the exact method or when NCC analyses were matched on confounders. When analyzing the MHT‐breast cancer association, differences between the two designs were consistent with simulated data. Once ties were taken correctly into account, NCC estimates were very similar to those of the full cohort analysis.
Neuropsychiatric manifestations of monkeypox: A clinically oriented comprehensive review
Authors: Sethi Yashendra , Agarwal Pratik , Murli Hamsa , Waheed Summaiya , Matar Sajeda Ghassan , Baklola Mohamed , Chopra Hitesh , Emran Talha Bin , Hasabo Elfatih A. 
Published: February 2023

AbstractMonkeypox (MPX) has emerged as a threatening outbreak in recent months. The understanding of disease pathogenesis and its systemic involvement has evolved with time. Both the virus and its vaccine, like other members of the Orthopoxvirus family, were always expected to have neuropsychiatric consequences. Several neurological complications have been reported with MPX and its vaccines that include but not limited to headaches, myalgia, encephalitis, and coma. Psychiatric complications like anxiety and depression have also been reported; however, we lack evidence to present a direct causality. We conducted a literature review to compile recent evidence on neuropsychiatric manifestations and underline the importance of evolving aspects and complications of MPX. We advocate for better reporting of cases and adverse events, to enhance our understanding of the disease, aiding physicians to make more informed decisions, thus facilitating timely diagnosis and treatment.
Green innovation in emerging economies: The role of managerial ties and market learning
Authors: Ushie Adadu Michael , Jiang Xu , Ali Adnan , Nwoba Arinze Christian , Hossain Syed Far Abid 
Published: February 2023

AbstractThis study adopts the social capital and organizational learning perspectives to examine (i) how managerial business and political ties drive green product and process innovation, respectively, and (ii) the roles that explorative and exploitative market learning play in moderating the effects of managerial business and political ties on green product and process innovation. Findings from a survey of 283 Chinese firms show that managerial business and political ties distinctively drive green product and process innovation. Explorative and exploitative market learning strengthens the positive effects of managerial business and political ties on green product and process innovation for sustainable development. These findings advance the green innovation literature by clarifying how firms convert top‐level managers' network ties and market‐learning capabilities to strengthen corporate green innovation practices.
Five‐year survival post hepatectomy for colorectal liver metastases in a real‐world Chinese cohort: Recurrence patterns and prediction for potential cure
Authors: Su Yu‐Ming , Liu Wei , Yan Xiao‐Luan , Wang Li‐Jun , Liu Ming , Wang Hong‐Wei , Jin Ke‐Min , Bao Quan , Wang Kun , Li Juan , Xu Da , Xing Bao‐Cai 
Published: February 2023

AbstractBackgroundPatients with a 5‐year recurrence‐free survival post liver resection for colorectal cancer liver metastases (CRLM) are considered to be potentially cured. However, there is a deficit of data on long‐term follow‐up and the recurrence status among these patients in the Chinese population. We analyzed real‐world follow‐up data of patients with CRLM who underwent hepatectomy, explored the recurrence patterns, and established a prediction model for a potential cure scenario.MethodsPatients who underwent radical hepatic resection for CRLM during 2000–2016, with actual follow‐up data for at least 5 years, were enrolled. The observed survival rate was calculated and compared among the groups with different recurrence patterns. The predictive factors for 5‐year non‐recurrence were determined using logistic regression analysis; a recurrence‐free survival model was developed to predict long‐term survival.ResultsA total of 433 patients were included, of whom 113 patients were found non‐recurrence after 5 years follow‐up, with a potential cure rate of 26.1%. Patients with late recurrence (>5 months) and lung relapse showed significantly superior survival. Repeated localized treatment significantly improved the long‐term survival of patients with intrahepatic or extrahepatic recurrences. Multivariate analysis showed that RAS wild‐type CRC, preoperative CEA <10 ng/ml, and liver metastases ≤3 were independent factors for a 5‐year disease‐free recurrence. A cure model was developed based on the above factors, achieving good performance in predicting long‐term survival.ConclusionsAbout one quarter patients with CRLM could achieve potential cure with non‐recurrence at 5‐year after surgery. The recurrence‐free cure model could well distinguish the long‐term survival, which would aid clinicians in determining the treatment strategy.
Potential Anti‐Inflammatory Components of Rhododendron molle G. Don Leaf Extracts in LPS‐Induced RAW 264.7
Authors: Luo Yuqiang , Wu Decai , Zong Luye , Shen Yu , Dai Liangfang , Luo Xiangdong 
Published: February 2023

AbstractAs a traditional Chinese medicine, Rhododendron molle G. Don has a long history of treating rheumatoid arthritis. In this study, RAW 264.7 cells induced by lipopolysaccharide (LPS) were established as cell inflammatory model to evaluate the anti‐inflammatory activity of chloroform extract from R. molle leaves (CERL), ethyl acetate extract from R. molle leaves (EERL) and butanol extract from R. molle leaves (BERL) and analyze the potential anti‐inflammatory components of R. molle. Potential anti‐inflammatory components analysis of CERL were performed by HPLC and UHPLC‐Q‐TOF‐MS. Prediction of potential anti‐inflammatory components by molecular docking experiments. Compared with negative control group, 25 μg/mL CERL could reduce the release level of NO by 62 %, and the mRNA expression levels of COX‐2, IL‐6, IL‐1β and TNF‐α were reduced by 69.74 %, 86.25 %, 77.94 % and 56.80 %, respectively. Western‐Blot showed similar results. CERL, EERL and BERL exerted their inhibitory activity in dose‐dependent manner. All results showed that the higher the concentration, the better the anti‐inflammatory activity. CERL showed the best inhibitory activity, the second was EERL, and then was BERL. 21 terpenoids and 4 flavonoids were identified in CERL by UHPLC‐Q‐TOF‐MS. Molecular docking results showed that triterpenoids in CERL had better interaction with target proteins (TNF‐α, IL‐1β). It indicated that triterpenoids may be potential anti‐inflammatory components of R. molle leaves. This study explored the anti‐inflammatory activities of CERL, EERL, BERL, which laid a foundation for further promoting the clinical application of R. molle.