Synthesis of difluorinated 3-oxo-N,3-diarylpropanamides from 4-arylamino coumarins mediated by Selectfluor

An expeditious approach to synthesize difluorinated 3-oxo-N,3-diarylpropanamides from 4-arylamino coumarins has been accomplished in the presence of Selectfluor, which plays the dual role of a mild oxidant and a source of fluorine.

Adlay seed hull polysaccharide as a green corrosion inhibitor for mild steel in acid solution: surface analyses and theoretical calculations

Adlay seed hull polysaccharide was developed here as a green corrosion inhibitor for mild steel in 1 M HCl solution, and its inhibition effect was studied with electrochemical experiments, theoretical calculations, etc.

[Analysis on risk factors of the degree of radical resection and prognosis of patients with locally recurrent rectal cancer]

Objective: To evaluate the factors affecting the degree of radical resection and the prognosis of patients with locally recurrent rectal cancer (LRRC). Methods: A retrospective case-control study was performed. Clinical data of 111 patients with LRRC undergoing operation at the General Surgery Department of Peking University First Hospital from January 2009 to August 2019 were analyzed retrospectively. The "Peking University First Hospital F typing" was performed according to the preoperative images of the pelvic involvement. The pelvis was assigned into four directions: the front wall, lateral sides of the pelvic wall and the sacrum. According to the degree of pelvic wall involvement, F typing included F0 type (no involvement of the pelvic wall, the cancer only involved the adjacent organs or invaded conteriorly the urinary tract, genital organs or small intestine), F1 type (cancer involved the pelvic wall in one direction, such as the sacrum, or one side of the pelvic wall), F2 type (cancer involved the pelvic wall in two directions) and F3 type (cancer involved the pelvic wall in three directions). Case inclusion criteria: (1) LRRC was confirmed by imaging and pathological examination of samples (puncture or endoscopic biopsy); (2) complete clinical and follow-up data; (3) informed consent of patient. Those with dysfunction of heart, lung, etc., intolerance of operation, F3 type indicated by image, and distant metastasis were excluded. The degree of radical resection was evaluated according to the postoperative pathological results. Patients were followed up every 12 months and related examinations were arranged. The univariate analysis of radical resection was performed by χ(2) test, and the multivariate analysis was performed by logistic methods. The survival rate was calculated by Kaplan-Meier method and the survival curve was drawn. The survival rate was compared by log-rank test. Cox proportional hazards model was used to analyze the factors affecting the prognosis of patients with LRRC. Results: A total of 111 patients were included in this study. Of 111 patients, 59 were male and 52 were female; recurrent age of 36 cases was ≥ 65 years old; CEA level of 48 cases was ≥15 μg/L. According to the "Peking University First Hospital F typing", 70 cases were F0 type, 38 F1 type and 3 F2 type. Surgical procedures were abdominoperineal resection (n=28), posterior pelvic exenteration (n=32), and total pelvic exenteration (n=51, including 1 case of TPE combined with sacrectomy). According to the postoperative pathological results, R0, R1 and R2 resections were 83, 20 and 8 cases, respectively. Univariate analysis showed that the degree of radical resection was associated with the secondary surgical procedure, F typing and lymph node metastasis (all P<0.05). Multivariate analysis showed that F typing (F1-F2) was an independent risk factor for non- R0 resection (OR=37.256, 95%CI:8.572 to 161.912, P<0.001). The morbidity of operative complications was 22.5% (25/111); the perioperative mortality was 1.8% (2/111); the local recurrence rate after the second operation was 37.8% (42/111). The 3- and 5-year overall survival rates were 41.2% and 21.9% respectively. The 3-year survival rates of patients with and without postoperative chemotherapy were 52.7% and 32.4% respectively (P=0.005). The 3-year survival rates of patients with lower (<15 μg/L) and higher CEA level (≥15 μg/L) were 52.9% and 24.3% respectively (P<0.001). The 3-year survival rates of patients with R0, R1 and R2 resection were 49.8%, 21.3% and 8.5% respectively (P=0.002). The 3-year survival rates of patients with F0, F1 and F2 type were 52.7%, 22.0% and 0 respectively (P<0.001). Cox analysis confirmed that the degree of radical resection (HR=2.088, 95%CI:1.095 to 3.979, P=0.025), the CEA level before the secondary operation (HR=1.857, 95%CI:1.157 to 2.980, P=0.010) and postoperative chemotherapy (HR=1.826, 95%CI:1.137 to 2.934, P=0.013) were independent factors affecting the prognosis. Conclusions: The indication of LRRC surgical treatments must be strictly limited. Evaluation of the fixation site to the pelvic wall is helpful for improving the rate of R0 resection. Lower preoperative CEA level, radical resection and postoperative chemotherapy are protective factors of prolonged overall survival time of patients with LRRC.

Fructan from Polygonatum cyrtonema Hua as an eco-friendly corrosion inhibitor for mild steel in HCl media

An effective and biodegradable polygonatum fructan (PF) from Polygonatum cyrtonema Hua was studied as an eco-friendly corrosion inhibitor for mild steel protection in 1 M HCl, whose inhibition performance was studied by weight loss tests, electrochemical techniques, and surface analysis techniques (SECM, FTIR). The experimental results showed that PF has outstanding inhibition performance for mild steel in hydrochloric acid, and the inhibition efficiency increased with the increase of its concentration and temperature. Polarization studies indicated that PF is a mixed-type corrosion inhibitor, and its adsorption mode conforms to Langmuir isotherm, mainly chemisorption. An adsorption-related protective inhibitor film formed on the surface of mild steel was verified and investigated based on its surface analysis and characterization. Quantum chemical analysis showed that the adsorption of PF on the surface of mild steel has obvious chemical properties.

Direct oxidative coupling of N-acyl pyrroles with alkenes by ruthenium(ii)-catalyzed regioselective C2-alkenylation

Ruthenium(ii)-catalyzed oxidative coupling by C2-alkenylation of N-acyl pyrroles with alkenes has been described. The acyl unit was found to be an effective chelating group for the activation of aryl C-H bonds ortho to the directing group. The alkenylation reaction of benzoyl pyrroles occurred regioselectively at the C2-position of the pyrrole ring, without touching the benzene ring. The reaction provides exclusively monosubstituted pyrroles under the optimized conditions. Disubstituted pyrroles could be obtained using higher loadings of the ruthenium(ii)-catalyst and the additives.

TMSOTf-Promoted Sulfinylation of Electron-Rich Aromatics with Sodium Arylsulfinates

A new transition-metal-free route for the direct sulfinylation of electron-rich aromatics with sodium arylsulfinates in the presence of TMSOTf is reported. Various electron-rich aromatics, including pyrroles, thiophenes, indoles, and electron-rich arenes, with sodium arylsulfinates are converted into the corresponding sulfoxides in moderate to excellent yields. This protocol possesses many advantages such as readily available and stable starting materials, broad substrate scopes, and transition-metal-free reaction conditions.

9-Substituted acridines as effective corrosion inhibitors for mild steel: electrochemical, surface morphology, and computational studies

The inhibition performance and mechanism of mild steel in hydrochloric acid for 9-substituted acridines were studied for the first time.

Chlorination of Arylaldehyde-Derived Arylsulfonylhydrazones with N-Chlorosuccinimide Leading to 1,2,4,5-Tetrazine Derivatives

It has been reported previously that treatment of aryl­ketone-derived arylsulfonylhydrazones with NXS/(nBu)4NX affords exclusively vinyl halides. In contrast, we have found that treatment of aryl­aldehyde-derived arylsulfonylhydrazones with N-chlorosuccinimide in the presence of potassium hydroxide affords 1,2,4,5-tetrazine derivatives in good to excellent yields. The present reactions are carried out under metal-free and mild reaction conditions.

Tin(ii)-catalyzed dehydrative cross-coupling of 2H-chromene hemiacetals with ketones

Without the derivatization of 2H-chromene hemiacetals to 2H-chromene acetals, the direct C–OH/C–H coupling reaction has been accomplished with water as the only by-product.

Search for Light Weakly-Interacting-Massive-Particle Dark Matter by Annual Modulation Analysis with a Point-Contact Germanium Detector at the China Jinping Underground Laboratory

We present results on light weakly interacting massive particle (WIMP) searches with annual modulation (AM) analysis on data from a 1-kg mass p-type point-contact germanium detector of the CDEX-1B experiment at the China Jinping Underground Laboratory. Datasets with a total live time of 3.2 yr within a 4.2-yr span are analyzed with analysis threshold of 250 eVee. Limits on WIMP-nucleus (χ-N) spin-independent cross sections as function of WIMP mass (m_{χ}) at 90% confidence level (C.L.) are derived using the dark matter halo model. Within the context of the standard halo model, the 90% C.L. allowed regions implied by the DAMA/LIBRA and CoGeNT AM-based analysis are excluded at >99.99% and 98% C.L., respectively. These results correspond to the best sensitivity at m_{χ}<6  GeV/c^{2} among WIMP AM measurements to date.

Base-Promoted Direct Synthesis of Sulfinates from N-Sulfonyl­hydrazones under Metal-Free Conditions

A base-promoted direct synthesis of sulfinates from N-sulfonylhydrazones is described. Various N-sulfonylhydrazones, derived from aldehydes and ketones, are converted into the corresponding sulfinates in moderate to good yields. This protocol possesses many advantages such as readily available and stable starting materials, broad substrate scope, and metal-free reaction conditions.

Constraints on Spin-Independent Nucleus Scattering with sub-GeV Weakly Interacting Massive Particle Dark Matter from the CDEX-1B Experiment at the China Jinping Underground Laboratory

We report results on the searches of weakly interacting massive particles (WIMPs) with sub-GeV masses (m_{χ}) via WIMP-nucleus spin-independent scattering with Migdal effect incorporated. Analysis on time-integrated (TI) and annual modulation (AM) effects on CDEX-1B data are performed, with 737.1 kg day exposure and 160 eVee threshold for TI analysis, and 1107.5 kg day exposure and 250 eVee threshold for AM analysis. The sensitive windows in m_{χ} are expanded by an order of magnitude to lower DM masses with Migdal effect incorporated. New limits on σ_{χN}^{SI} at 90% confidence level are derived as 2×10^{-32}∼7×10^{-35}  cm^{2} for TI analysis at m_{χ}∼50-180  MeV/c^{2}, and 3×10^{-32}∼9×10^{-38}  cm^{2} for AM analysis at m_{χ}∼75  MeV/c^{2}-3.0  GeV/c^{2}.

Synthesis of N-Sulfonyl- and N-Acylpyrroles via a Ring-Closing Metathesis/Dehydrogenation Tandem Reaction

N-Sulfonyl- and N-acylpyrroles were synthesized via olefin ring-closing metathesis of diallylamines and in situ oxidative aromatization in the presence of the ruthenium Grubbs catalyst and a suitable copper catalyst. In the presence of Cu(OTf)2 and CuBr2, the reaction afforded N-sulfonyl- and N-acylpyrroles, respectively, in one pot. Under an oxygen atmosphere, the reaction went smoothly without the need of hydroperoxide oxidants. This protocol possesses many advantages, such as using a nonhazardous oxidant and readily available starting materials, operating in one pot, and showing a broad substrate scope.

Prevention of Postdental Procedure Bacteremia: A Network Meta-analysis

Postdental procedure bacteremia is common and troublesome. The comparative efficacy of multiple prophylactic interventions is unclear. We compared the efficacy of interventions for the prevention of postdental procedure bacteremia. We conducted a review of ClinicalKey, Cochrane CENTRAL, Embase, ProQuest, PubMed, ScienceDirect, Web of Science, and ClinicalTrials.gov from inception to December 4, 2018. Randomized controlled trials that evaluated prophylactic interventions for the prevention of postdental procedure bacteremia were eligible. The primary outcome was the incidence of postdental procedure bacteremia. A total of 24 trials were included with 2,147 participants. Our network meta-analysis demonstrated that intravenous administration of 1,000/200 mg of amoxicillin/clavulanate provided the least incidence of postdental procedure bacteremia among all the prophylactic interventions (odds ratio = 0.03, 95% CI = 0.00 to 0.63) as compared with the placebo/controls. Oral 3 g of amoxicillin had the least incidence of postdental procedure bacteremia among all oral or topical forms of prophylactic interventions (odds ratio = 0.10, 95% CI = 0.02 to 0.44) as compared with the placebo/controls. No serious adverse events, such as anaphylactic shock, mortality, and the development of antibiotic-resistant bacteria, were reported. None of the included subjects were of high risk of infectious endocarditis. Our network meta-analysis demonstrates that intravenous amoxicillin/clavulanate and oral amoxicillin might be the best prophylactic interventions in preventing postdental procedure bacteremia among all the oral/topical forms of interventions for the overall populations.

Synthesis of Bisflavanol-Type Natural Products and Their Analogues­ via Self-Coupling of C8-Methylol Catechin Derivatives

A highly efficient and regioselective self-coupling of C8-methylol catechin derivatives is developed for the synthesis of dimeric flavanol analogues under metal-free and mild conditions. Its applicability is showcased by the efficient synthesis of bisflavanol-type natural products bis-8,8′-catechinylmethane, bis-8,8′-epicatechinylmethane, talienbisflavan A, and oolonghomobisflavan A. The novel self-coupling mechanism sheds new light on the classical Friedel–Crafts alkylation mechanism in acid-catalyzed catechin–formaldehyde condensation.

Regioselective and oxidant-free sulfinylation of indoles and pyrroles with sulfinamides

An unexpected time-controlled highly selective C3- or C2-sulfinylation of pyrroles with sulfinamides is reported for the first time. The sulfinylation of indoles with sulfinamides using this protocol is oxidant-free and can be performed under obviously more feasible conditions (1.2 equiv. of indoles, 10 min) in comparison with the precedent procedure (3-20 equiv. of indoles, 16-18 h, ammonium persulfate as oxidant, hv). A variety of functional groups were tolerated, and various C2-thioindoles and C2/3-thiopyrroles were obtained in moderate to excellent yields.

[Predictive value of single nucleotide polymorphisms of HLA-C and UBE2L3 in evaluating the effect of telbivudine antiviral therapy during pregnancy]

Objective: To investigate the association between single nucleotide polymorphisms (SNPs) of rs3130542 and rs4821116 in the HLA-C and UBE2L3 genes and the effect of telbivudine antiviral therapy during pregnancy in HBeAg-positive mothers through a large-sample control study, and to provide a basis for the development of individualized blocking strategies for pregnant women with a high viral load. Methods: The genotypes of rs3130542 and rs4821116 were determined for 312 pregnant women with a high viral load who received telbivudine antiviral therapy during the second or third trimester of pregnancy, and the dominant model, recessive model, and additive model were used to analyze the association between the genotypes of these two loci and the reduction in HBV DNA load. The Shapiro-Wilk test and the Levene test were used to evaluate data normality and homogeneity of variances, and the t-test or the non-parametric Mann-Whitney U test was selected based on data type and was used for the comparison of means between groups. The Hardy-Weinberg equilibrium was used to determine the genotype of SNPs, and the dominant model, recessive model, and additive model were used for analysis. Results: Mothers with an AA/AG genotype of rs3130542 in the HLA-C gene had a significantly higher probability of HBV DNA load ≥10(3) IU/ml at the time of delivery (P < 0.05) and a significantly higher risk of failure in the prevention of mother-to-child transmission, no matter whether they started to take telbivudine at week 24 or 28 of pregnancy. The association between the genotype of rs4821116 in the UBE2L3 gene and the reduction in viral load in pregnant women needed to be confirmed by studies with a larger sample size. Conclusion: Pregnant women with a high viral load and an AA/AG genotype of rs3130542 in the HLA-C gene tend to have poor response to antiviral therapy during pregnancy, and early antiviral intervention is recommended for such patients.

Highly effective inhibition of mild steel corrosion in HCl solution by using pyrido[1,2-a]benzimidazoles

Pyrido[1,2-a]benzimidazoles are reported herein for the first time as effective inhibitors of mild steel corrosion in hydrochloric acid.

Switchable regioselection of C–H thiolation of indoles using different TMS counterions

Simply swapping the counteranions of TMS leads to a switchable regioselectivity in C2– and C3–H thiolation of indoles.