Ring Expansion of Cyclic Boronates via Oxyboration of Arynes.

The oxyboration of arynes was achieved for the first time. A series of 2-aryl-1,3,2-dioxaborolane derivatives were reacted with aryne precursors in the presence of CsF to give the corresponding ring-expanded seven-membered borinic acid esters via selective boron-oxygen bond activation. Preliminary experimental mechanistic studies and density functional theory (DFT) calculations suggest that this unprecedented aryne oxyboration proceeds through the formation of boron ate complexes of arylboronates with CsF, followed by aryne insertion into the boron-oxygen bond.

Using Mechanochemistry to Activate Commodity Plastics as Initiators for Radical Chain Reactions of Small Organic Molecules.

Radical initiators such as azo compounds and organic peroxides have been widely used to facilitate numerous transformations of free radicals, which enable the efficient synthesis of structurally complex molecules, natural products, polymers, and functional materials. However, these high-energy reagents are potentially explosive and thus often require special precautions or delicate operating conditions. We postulated that a more convenient and safer alternative for radical chain initiation could be developed by mechanical activation of thermodynamically stable covalent bonds. Here, we show that commodity plastics such as polyethylene and poly(vinyl acetate) are capable of acting as efficient initiators for radical chain reactions under solvent-free mechanochemical conditions. In this approach, polymeric mechanoradicals, which are generated by homolytic cleavage of the polymer chains in response to the applied mechanical energy provided by ball milling, react with tris(trimethylsilyl)silane to initiate radical chain dehalogenation of organic halides. Preliminary calculations support our proposed force-induced radical chain mechanism.

Mechanochemical Synthesis of Non-Solvated Dialkylalumanyl Anion and XPS Characterization of Al(I) and Al(II) Species.

A non-solvated alkyl-substituted Al(I) anion dimer was synthesized by a reduction of haloalumane precursor using a mechanochemical method. The crystallographic and theoretical analysis revealed its structure and electronic properties. Experimental XPS analysis of the Al(I) anions with reference compounds revealed the lower Al 2p binding energy corresponds to the lower oxidation state of Al species. It should be emphasized that the experimentally obtained XPS binding energies were reproduced by delta SCF calculations and were linearly correlated with NPA charges and 2p orbital energies.

The platelet-to-lymphocyte ratio is a complementary prognostic factor to tumor markers in predicting early recurrence of hepatocellular carcinoma after hepatectomy.

BACKGROUND: The usefulness of inflammation-based prognostic scores for early recurrence (ER) after hepatectomy for hepatocellular carcinoma has rarely been reported. This study aimed to evaluate the potential of inflammation-based prognostic scores as predictors of ER and their relationship with tumor markers. METHODS: We enrolled 338 patients who underwent hepatectomy for hepatocellular carcinoma between January 2007 and December 2021. Clinicopathological factors were compared between patients who developed ER (ER group) and those who did not develop ER (non-ER group). The association between inflammation-based prognostic scores and ER status was evaluated. These scores were compared with those of well-established tumor markers. RESULTS: The platelet-to-lymphocyte ratio (PLR) correlated with ER of hepatocellular carcinoma, with an area under the curve (AUC) value of 0.70, sensitivity of 68.1%, and specificity of 67.7%. In patients with low tumor marker levels, the PLR showed a strong correlation with ER of hepatocellular carcinoma, with an AUC value of 0.851, sensitivity of 100%, and specificity of 76.2%. Multivariate analysis revealed that the PLR was an independent prognostic factor for ER. CONCLUSIONS: The PLR is useful and complementary to tumor markers for predicting ER after hepatectomy for hepatocellular carcinoma.

Usefulness of intratumoral perfusion analysis for assessing biological features of non-functional pancreatic neuroendocrine neoplasm.

PURPOSE: Here, we evaluated the usefulness of intratumoral perfusion analysis using preoperative contrast-enhanced CT (E-CT) to assess biological features of non-functional pancreatic neuroendocrine neoplasms (NF-PanNENs). METHODS: We retrospectively studied 44 patients who underwent curative surgery for NF-PanNENs. We used preoperative E-CT with compartment model analysis to calculate the tumor perfusion parameters K1 (inflow rate constant), 1/k2 (mean transit time), and K1/k2 (distribution volume). We assessed the association between perfusion parameters and biological features of NF-PanNENs, including the WHO classification tumor histopathological grade and prognosis after surgery. RESULTS: Patients in this study had a neuroendocrine tumor (NET) G1 (n = 32) or NET G2 (n = 12). Neither NET G3 or NEC tumors were observed. Among perfusion parameters, K1 was the most accurate predictor of the high-grade tumor (AUC: 0.726). K1-low (< 0.028 s-1) was significantly associated with large tumors (≥ 20 mm) (p = 0.022), high mitotic index (p = 0.017), high Ki-67 index (p = 0.004), and lymphatic invasion (p = 0.025). Synchronous extra-pancreatic metastasis, including lymph node metastasis or liver metastasis, more frequently developed in K1-low patients than in K1-high patients (29% vs 4%, p = 0.025). Disease-free survival of patients with a K1-low tumor was poorer than that of patients with a K1-high tumor (p = 0.005). Furthermore, no patient with a K1-high tumor developed recurrence after initial surgery. CONCLUSION: The perfusion parameters obtained using E-CT were significantly associated with biological features and prognosis of NF-PanNENs.

Mechanochemistry-Directed Ligand Design: Development of a High-Performance Phosphine Ligand for Palladium-Catalyzed Mechanochemical Organoboron Cross-Coupling.

Mechanochemical synthesis that uses transition-metal catalysts has attracted significant attention due to its numerous advantages, including low solvent waste, short reaction times, and the avoidance of problems associated with the low solubility of starting materials. However, even though the mechanochemical reaction environment is largely different from that of homogeneous solution systems, transition-metal catalysts, which were originally developed for use in solution, have been used directly in mechanochemical reactions without any molecular-level modifications to ensure their suitability for mechanochemistry. Alas, this has limited the development of more efficient mechanochemical cross-coupling processes. Here, we report a conceptually distinct approach, whereby a mechanochemistry-directed design is used to develop ligands for mechanochemical Suzuki-Miyaura cross-coupling reactions. The ligand development was guided by the experimental observation of catalyst deactivation via the aggregation of palladium species, a problem that is particularly prominent in solid-state reactions. By embedding the ligand into a poly(ethylene glycol) (PEG) polymer, we found that phosphine-ligated palladium(0) species could be immobilized in the fluid phase created by the PEG chains, preventing the physical mixing of the catalyst into the crystalline solid phase and thus undesired catalyst deactivation. This catalytic system showed high catalytic activity in reactions of polyaromatic substrates close to room temperature. These substrates usually require elevated temperatures to be reactive in the presence of catalyst systems with conventional ligands such as SPhos. The present study hence provides important insights for the design of high-performance catalysts for solid-state reactions and has the potential to inspire the development of industrially attractive, almost solvent-free mechanochemical cross-coupling technologies.

In Situ and Real-Time Visualization of Mechanochemical Damage in Double-Network Hydrogels by Prefluorescent Probe via Oxygen-Relayed Radical Trapping.

Visualization of mechanochemical damages, especially for those in the molecular-scale (e.g., bond scission in polymeric materials), is of great industrial and academic significance. Herein, we report a novel strategy for in situ and real-time visualization of mechanochemical damages in hydrogels by utilizing prefluorescent probes via oxygen-relayed free-radical trapping. Double-network (DN) hydrogels that generate numerous mechanoradicals by homolytic bond scission of the brittle first network at large deformation are used as model materials. Theoretical calculation suggests that mechanoradicals generated by the damage of the first network undergo an oxygen-relayed radical-transfer process which can be detected by the prefluorescent probe through the radical-radical coupling reaction. Such an oxygen-relayed radical-trapping process of the prefluorescent probe exhibits a dramatically enhanced emission, which enables the real-time sensing and visualization of mechanochemical damages in DN hydrogels made from brittle networks of varied chemical structures. To the best of authors' knowledge, this work is the first report utilizing oxygen as a radical-relaying molecule for visualizing mechanoradical damages in polymer materials. Moreover, this new method based on the probe post-loading is simple and does not introduce any chemical structural changes in the materials, outperforming most previous methods that require chemical incorporation of mechanophores into polymer networks.

Increased mitochondria are responsible for the acquisition of gemcitabine resistance in pancreatic cancer cell lines.

Pancreatic ductal adenocarcinoma has a particularly poor prognosis as it is often detected at an advanced stage and acquires resistance to chemotherapy early during its course. Stress adaptations by mitochondria, such as metabolic plasticity and regulation of apoptosis, promote cancer cell survival; however, the relationship between mitochondrial dynamics and chemoresistance in pancreatic ductal adenocarcinoma remains unclear. We here established human pancreatic cancer cell lines resistant to gemcitabine from MIA PaCa-2 and Panc1 cells. We compared the cells before and after the acquisition of gemcitabine resistance to investigate the mitochondrial dynamics and protein expression that contribute to this resistance. The mitochondrial number increased in gemcitabine-resistant cells after resistance acquisition, accompanied by a decrease in mitochondrial fission 1 protein, which induces peripheral mitosis, leading to mitophagy. An increase in the number of mitochondria promoted oxidative phosphorylation and increased anti-apoptotic protein expression. Additionally, enhanced oxidative phosphorylation decreased the AMP/ATP ratio and suppressed AMPK activity, resulting in the activation of the HSF1-heat shock protein pathway, which is required for environmental stress tolerance. Synergistic effects observed with BCL2 family or HSF1 inhibition in combination with gemcitabine suggested that the upregulated expression of apoptosis-related proteins caused by the mitochondrial increase may contribute to gemcitabine resistance. The combination of gemcitabine with BCL2 or HSF1 inhibitors may represent a new therapeutic strategy for the treatment of acquired gemcitabine resistance in pancreatic ductal adenocarcinoma.

Solid-state cross-coupling reactions of insoluble aryl halides under polymer-assisted grinding conditions.

In this study, polymer-assisted grinding (POLAG), a ball-milling technique based on the use of polymer additives, was applied to mechanochemical solid-state Suzuki-Miyaura cross-coupling reactions of insoluble aryl halides. We found that the efficiency of this challenging solid-state cross-coupling was improved by the addition of polytetrafluoroethylene (PTFE) as a POLAG additive under high-temperature ball-milling conditions. Our results suggest that POLAG is a promising approach for controlling the reactivity of insoluble substrates that are barely reactive under conventional solution-based conditions.

Clinical characteristics, prognosis, and surgical outcomes of patients with non-HBV and non-HCV related hepatocellular carcinoma: three-decade observational study.

BACKGROUND: The incidence of non-hepatitis B virus, non-hepatitis C virus hepatocellular carcinoma (non-B non-C-HCC) is increasing worldwide. We assessed the clinical characteristics and surgical outcomes of non-B non-C-HCC, versus hepatitis B (HBV-HCC) and hepatitis C (HCV-HCC). METHODS: Etiologies, fibrosis stages, and survival outcomes were analyzed of 789 consecutive patients who underwent surgery from 1990 to 2020 (HBV-HCC, n = 149; HCV-HCC, n = 424; non-B non-C-HCC, n = 216). RESULTS: The incidence of hypertension and diabetes mellitus was significantly higher in patients with NON-B NON-C-HCC than in those with HBV-HCC and HCV-HCC. Significantly more advanced tumor stages were observed in patients with non-B non-C-HCC; however, better liver function and lower fibrosis stages were observed. Patients with non-B non-C-HCC had significantly worse 5-year overall survival than patients with HBV-HCC; overall survival was comparable between patients with non-B non-C-HCC and HCV-HCC. Patients with HCV-HCC had significantly worse 5-year recurrence-free survival than patients with HBV-HCC and non-B non-C-HCC. In patients with non-B non-C-HCC, overall survival was comparable among three periods (1990-2000, 2001-2010, and 2011-2020) despite significant improvement in patients with HBV-HCC and HCV-HCC. CONCLUSION: The prognosis of non-B non-C-HCC was similar to that of HBV-HCC and HCV-HCC regardless of tumor progression at surgery. Patients with hypertension, diabetes mellitus, and dyslipidemia require careful systematic follow-up and treatment.

Impact of Early Enteral Nutrition on Delayed Gastric Emptying and Nutritional Status After Pancreaticoduodenectomy.

BACKGROUND: Although early enteral nutrition (EEN) is an accepted practice after pancreaticoduodenectomy (PD), the impact of EEN on postoperative complications or nutritional status remains unclear. We aimed to investigate the impact of EEN on delayed gastric emptying (DGE) and nutritional status after PD. METHODS: A total of 143 patients underwent PD between January 2012 and September 2020. We excluded patients who underwent a two-stage pancreatojejunostomy, in whom the enteral tube was accidentally pulled out, or with insufficient information in their medical records. The incidence of postoperative complications was compared between patients who received EEN (EEN group, n = 21) and those who did not (control group, n = 21) after propensity score matching. Univariate and multivariate analyses were performed to identify the risk factors affecting the incidence of these complications. Nutritional status was assessed at postoperative months 1, 3, and 6. RESULTS: The incidence of grade B/C DGE in the EEN group was significantly lower than that in the control group (4.8% vs. 28.6%, p = 0.03). There was no significant difference in overall morbidity, incidence of any other postoperative complications, or all-grade DGE. In multivariate analysis, EEN was associated with a reduction in the incidence of grade B/C DGE (p < 0.01). In the analysis of nutritional status, EEN was significantly associated with better nutritional status at postoperative month 1. CONCLUSION: EEN can lead to a lower clinically relevant DGE rate and better nutritional status in the early postoperative period in patients undergoing PD.

Dual Nickel(II)/Mechanoredox Catalysis: Mechanical-Force-Driven Aryl-Amination Reactions Using Ball Milling and Piezoelectric Materials.

The combination of a nickel(II) catalyst and a mechanoredox catalyst under ball-milling conditions promotes mechanical-force-driven C-N cross-coupling reactions. In this nickel(II)/mechanoredox cocatalyst system, the modulation of the oxidation state of the nickel center, induced by piezoelectricity, is used to facilitate a highly efficient aryl-amination reaction, which is characterized by a broad substrate scope, an inexpensive combination of catalysts (NiBr2 and BaTiO3 ), short reaction times, and an almost negligible quantity of solvents. Moreover, this reaction can be readily up-scaled to the multi-gram scale, and all synthetic operations can be carried out under atmospheric conditions without the need for complicated reaction setups. Furthermore, this force-induced system is suitable for excitation-energy-accepting molecules and poorly soluble polyaromatic substrates that are incompatible with solution-based nickel(II)/photoredox cocatalysts.

Mechanochemical Approach for Air-Tolerant and Extremely Fast Lithium-Based Birch Reductions in Minutes.

Birch reduction has been widely used in organic synthesis for over half a century as a powerful method to dearomatize arenes into 1,4-cyclohexadiene derivatives. However, the conventional Birch reduction reaction using liquid ammonia requires laborious procedures to ensure inert conditions and low temperatures. Although several ammonia-free modifications have been reported, the development of an operationally simple, efficient, and scalable protocol remains a challenge. Herein, we report an ammonia-free lithium-based Birch reduction in air without special operating conditions using a ball-milling technique. This method is characterized by its operational simplicity and an extremely short reaction time (within 1 min), probably owing to the in situ mechanical activation of lithium metal, broad substrate scope, and no requirement for dry bulk solvents. The potential of our flash Birch reaction is also demonstrated by the efficient reduction of bioactive target molecules and gram-scale synthesis.

Preoperative Peripheral Blood Lymphocyte-to-Monocyte Ratio Predicts Long-Term Outcome for Patients with Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Although various biomarkers are useful in predicting cancer prognosis, the most effective preoperative systemic biomarkers for pancreatic ductal adenocarcinoma (PDAC) have not been established. This study aimed to evaluate whether the lymphocyte-to-monocyte ratio (LMR) can predict the long-term outcomes for patients who were to undergo surgical resection of PDAC. METHODS: The study involved 170 patients with PDAC who underwent resection. Multivariate analysis was performed to identify the independent prognostic factors for overall survival (OS) and disease-free survival (DFS) among clinicopathologic, surgical, and seven systemic biomarker-related factors including LMR. Subgroup analysis of PDAC located in the body and tail of the pancreas (B/T PDAC) was performed (n = 60) to eliminate the influence of preoperative cholangitis and surgical procedure. Furthermore, OS according to the postoperative course of the LMR value group was investigated. RESULTS: A low LMR (<3.3) was the only independent predictive factor for OS (hazard ratio [HR], 3.52; p < 0.001) and DFS (HR, 3.31; p < 0.001) among the systemic biomarkers. Subgroup analysis of the B/T PDAC also showed that low the LMR was the independent predictive factor for OS (HR, 3.24; p = 0.002) and DFS (HR, 4.42; p = 0.003). The PDAC that maintained a high LMR from before surgery to 1 year after surgery showed good long-term outcomes (median OS, 8.5 years; 5-year survival rate, 61.8 %). CONCLUSIONS: Preoperative LMR was an independent predictor of OS and DFS after surgery for PDAC. Maintaining a high LMR through the pre- and postoperative courses might improve the prognosis for patients with PDAC.

Mechanochemically Generated Calcium-Based Heavy Grignard Reagents and Their Application to Carbon-Carbon Bond-Forming Reactions.

In sharp contrast to the use of conventional magnesium-based Grignard reagents (R-MgX), the application of calcium-based heavy Grignard reagents (R-CaX) in organic synthesis remains poorly explored. This is mainly due to the lack of experimentally simple ways to access such organocalcium nucleophiles from readily available starting materials under mild conditions. Here, we show that a mechanochemical technique using ball milling allows the generation of calcium-based heavy Grignard reagents from aryl halides and commercially available calcium metal without complicated pre-activation processes. Notably, all experimental operations can be carried out in air. Our operationally simple protocol enables the rapid development of novel cross-electrophile-coupling reactions mediated by arylcalcium nucleophiles, which are rather difficult using conventional Grignard reagents. This method will allow synthetic chemists to readily access the novel and unique reactivity of organocalcium nucleophiles.

Palladium-catalyzed solid-state borylation of aryl halides using mechanochemistry.

This study describes the solid-state palladium-catalyzed cross-coupling between aryl halides and bis(pinacolato)diboron using ball milling. The reactions were completed within 10 min for most aryl halides to afford a variety of synthetically useful arylboronates in high yields. Notably, all experimental operations could be performed in air, and did not require the use of large amounts of dry and degassed organic solvents. The utility of this method was further demonstrated by gram-scale synthesis under solvent-free, mechanochemical conditions.

Tackling Solubility Issues in Organic Synthesis: Solid-State Cross-Coupling of Insoluble Aryl Halides.

Conventional organic synthesis generally relies on the use of liquid organic solvents to dissolve the reactants. Therefore, reactions of sparingly soluble or insoluble substrates are challenging and often ineffective. The development of a solvent-independent solid-state approach that overcomes this longstanding solubility issue would provide innovative synthetic solutions and access to new areas of chemical space. Here, we report extremely fast and highly efficient solid-state palladium-catalyzed Suzuki-Miyaura cross-coupling reactions via a high-temperature ball-milling technique. This solid-state protocol enables the highly efficient cross-couplings of insoluble aryl halides with large polyaromatic structures that are barely reactive under conventional solution-based conditions. Notably, we discovered a new luminescent organic material with a strong red emission. This material was prepared via the solid-state coupling of Pigment violet 23, a compound that has so far not been involved in molecular transformations due to its extremely low solubility. This study thus provides a practical method for accessing unexplored areas of chemical space through molecular transformations of insoluble organic compounds that cannot be carried out by any other approach.

A Copper(I)-Catalyzed Radical-Relay Reaction Enabling the Intermolecular 1,2-Alkylborylation of Unactivated Olefins.

The first catalytic intermolecular 1,2-alkylborylation reaction via a radical-relay mechanism between unactivated olefins, bis(pinacolato)diboron, and an alkyl electrophile is reported. Successful implementation of this method requires that the competing boryl substitution of the alkyl electrophile is retarded to facilitate the radical relay. This challenge was overcome using electronically or sterically demanding alkyl electrophiles, which results in the simultaneous and highly regioselective introduction of a gem-difluoro, monofluoro, tertiary, or secondary alkyl group and a boryl group across the C═C double bond.

Safety and Oncological Benefit of Hepatopancreatoduodenectomy for Advanced Extrahepatic Cholangiocarcinoma with Horizontal Tumor Spread: Shinshu University Experience.

BACKGROUND: Although hepatopancreatoduodenectomy (HPD) is the only means of achieving R0 resection of widespread extrahepatic cholangiocarcinoma, its safety and oncological benefit remain controversial because of its inherent high risk of mortality and morbidity. OBJECTIVE: The aim of this study was to retrospectively analyze short- and long-term outcomes and evaluate the safety and oncological benefit of this advanced procedure. METHODS: The study cohort comprised 37 consecutive patients who had undergone major HPD. Portal vein embolization was performed before surgery in 20 (54%) patients with future remnant liver volume < 35%. RESULTS: The median operative time and blood loss were 866 min and 1000 mL, respectively. Concomitant vascular resection was performed in five patients (14%). The overall morbidity and mortality rates were 100% and 5.4% (n = 2), respectively. Nineteen patients (51%) had major (Clavien-Dindo grade III or higher) complications, the most common being intra-abdominal infection (49%) and post-hepatectomy liver failure (46%, grade B/C: 32%/5%), followed by postoperative pancreatic fistula (30%, grade B/C). R0 resection was achieved in 31 patients (84%). The 1-, 3-, and 5-year overall survival (OS) rates were 83%, 48%, and 37%, respectively. In patients with R0 resection, 5-year OS was comparable between patients who had undergone major HPD and major hepatectomy alone (41% vs. 40%, p = non-significant). CONCLUSIONS: HPD is a valid treatment option for extensive cholangiocarcinoma, offering long-term survival benefit at the cost of relatively high but acceptable morbidity and mortality rates. HPD is advocated in selected patients provided that it is considered possible to achieve R0 resection.

Survival Outcomes of Gemcitabine Plus S-1 Adjuvant Chemotherapy after Surgical Resection for Advanced Biliary Tract Cancer.

INTRODUCTION: The usefulness of adjuvant chemotherapy in biliary tract cancer (BTC) is poorly reported. This study aimed to evaluate the effectiveness and safety of adjuvant gemcitabine plus S-1 (GS) chemotherapy after curative surgical resection for BTC. METHODS: 225 BTC patients who underwent surgical resection between January 2006 and May 2019 were enrolled in this study. Twenty-seven patients received adjuvant chemotherapy with GS (GS group), whereas 67 patients underwent surgery alone (S group). Twenty-three matching pairs were derived through propensity score (PS) matching analysis. Patients received 12 cycles of adjuvant chemotherapy (70 mg/m2 oral S-1 for 7 consecutive days plus intravenous gemcitabine 1,000 mg/m2 on day 7). The primary end point was recurrence-free survival (RFS). The secondary end points were the 1-, 2-, and 3-year RFS and overall survival (OS) rates, tolerability, and frequency of grade 3/4 toxicity. RESULTS: The completion rate was 81.5%; no treatment-related deaths were observed. Grade 3/4 adverse events were seen in 40.7% of the patients. RFS (3-year RFS rate: 59.3% vs. 39.1%, p = 0.049) and OS (3-year OS rate: 71.7% vs. 53.4%, p = 0.008) were significantly better in the GS group than in the S group among PS-matched pairs. DISCUSSION/CONCLUSION: GS chemotherapy after curative surgery was well tolerated, showed better clinical benefit in the adjuvant setting, and can effectively reduce BTC recurrence.