Pd(II)-Catalyzed Synthesis of Alicyclic[b]-Fused Pyridines via C(sp2)-H Activation of α,ß-Unsaturated N-Acetyl Hydrazones with Vinyl Azides.

A new synthetic protocol for alicyclic[b]-fused pyridines with complete regioselectivity from α,ß-unsaturated N-acetyl hydrazones and vinyl azides via Pd(II)-catalyzed C-H activation/cyclization/aromatization strategy has been described. A series of five- to eight-membered alicyclic[b]-fused pyridines were prepared in a one-step manner with wide substrate scope and good functional group tolerance.

Synthesis of 2,1-Benzoisoxazole-Containing 1,2,3-Triazoles through Copper-Catalyzed Three-Component Domino Reactions of o-Bromoacetophenones, Aldehydes, and Sodium Azide.

We herein describe an efficient copper-catalyzed three-component domino protocol used to prepare 2,1-benzoisoxazole-containing 1,2,3-triazoles from commercially available o-bromoacetophenones, aldehydes, and sodium azide. This domino process involves Aldol condensation, copper-catalyzed azide-chalcone oxidative cyclization, 1,2,3-triazole-assisted azidation, and denitrogenative cyclization sequences. The formed compounds could be considered as benzo[c]isoxazole-functionalized combretastatin A-4 triazole analogues, which might be potential applications in the discovery of a new anticarcinogen.

Development of DHQ-based chemical biology probe to profile cellular targets for HBV.

Chronic hepatitis B virus (HBV) infection has been a serious public health burden worldwide. Current anti-HBV therapies could not eliminate HBV ultimately. Considering the characteristics of HBV, it is impossible to be entirely cured based on current therapies. Therefore, it is urgently needed to develop novel therapeutic agents with new mechanism of action. The dihydroquinolizinone (DHQ) derivatives exhibited potent anti-HBV activity by decreasing HBV DNA and HBsAg level in an obscure mechanism of action. In this study, we have optimized the DHQ scaffold, developed the photoaffinity probe, with which to identify potential binding proteins.

A First-in-Human Trial of GLS4, a Novel Inhibitor of Hepatitis B Virus Capsid Assembly, following Single- and Multiple-Ascending-Oral-Dose Studies with or without Ritonavir in Healthy Adult Volunteers.

GLS4 is a novel inhibitor of the hepatitis B virus (HBV) capsid assembly with inhibitory activities against nucleot(s)ide-resistant HBV strains. This study investigated the pharmacokinetics, safety, and tolerability of GLS4 and the effects of food and ritonavir in healthy adults. GLS4 was administered in a single-ascending-dose study over 1 to 240 mg and multiple-ascending-dose study that ranged from 30 mg once daily to 180 mg three times daily. The drug interaction study included sequential design (day 1 for 120 mg GLS4 alone, day 5 for 100 mg ritonavir alone, followed by 9 days of both drugs) and a placebo control (9 days of both 240 mg GLS4 and 100 mg ritonavir). The results showed that the steady-state trough concentration of multiple dosing of GLS4 alone was significantly lower than the 90% effective concentration of 55.7 ng/ml, even with increasing dosing frequency and dosage. An initial dose of 100 mg ritonavir significantly boosted plasma concentration at 24 h of 120 mg GLS4 from 2.40 to 49.8 ng/ml (geometric mean ratio, 20.7; 90% confidence interval, 17.0 to 25.3), while a milder effect was observed on the area under the curve from 0 to 24 h, with a 7.42-fold increase, and on the maximum concentration, with a 4.82-fold increase. The pharmacokinetics change in GLS4 persisted after 9 days of chronic dosing, with a trough concentration of 182 ng/ml. Both single and multiple doses of GLS4 up to 240 mg with or without ritonavir were well tolerated. These results support the investigation of a novel HBV treatment regimen containing GLS4 with 100 mg ritonavir added solely to enhance GLS4 concentrations in plasma. (This study was registered at the China Platform for Registry and Publicity of Drug Clinical Trials [http://www.chinadrugtrials.org.cn] under numbers CTR20132137 and CTR20150230.).

Influences on viral replication and sensitivity to GLS4, a HAP compound, of naturally occurring T109/V124 mutations in hepatitis B virus core protein.

Heteroaryldihydropyrimidine (HAP) compounds inhibit HBV replication by binding to a hydrophobic pocket at the interface between hepatitis B virus core protein (HBcAg) dimer, which interrupts capsid assembly by changing the kinetics and thermodynamics during this process. Structure biological studies have identified several amino acids in HBcAg crucial for compound binding. Here, we investigated the polymorphisms of T109 and V124 amino acids in HBV sequences submitted to GenBank database. Naturally occurring T109 and V124 and/or possible compensatory mutations in neighbored amino acids were introduced into HBV-expressing plasmids. Viral replication competence and sensitivity to GLS4, a HAP compound, were evaluated using transient transfection and in vitro infection cell models. All tested mutations in these amino acids led to decreasing viral DNA replication at different levels. Specially, T109N and all V124 mutants caused severe deficiencies in viral plus-strand DNA synthesis. T109I single mutation and all T109S/M/C/N mutations impaired HBeAg secretion. T109I showed modestly decreased sensitivities with IC50 3.3- to 6.8-folds higher than wild-type virus. In vitro infection assay showed T109N and all V124 mutants failed to synthesize cccDNA and following viral proteins. The other mutants, however, produced functional cccDNA pools as wild-type virus did. Taken together, we profiled the competences of viral replication and sensitivities to capsid inhibitor of naturally existing mutations in T109 and V124. This will help to understand the possible antiviral resistance issues in future clinical applications of capsid inhibitors.

Discovery of hepatitis B virus capsid assembly inhibitors leading to a heteroaryldihydropyrimidine based clinical candidate (GLS4).

Inhibition of hepatitis B virus (HBV) capsid assembly is a novel strategy for the development of chronic hepatitis B (CHB) therapeutics. Herein we described our lead optimization studies including the synthesis, molecular docking studies and structure-activity relationship (SAR) studies of a series of novel heteroaryldihydropyrimidine (HAP) inhibitors of HBV capsid assembly inhibitors, and the discovery of a potent inhibitor of HBV capsid assembly of GLS4 (ethyl 4-[2-bromo-4-fluorophenyl]-6-[morpholino-methyl]-2-[2-thiazolyl]-1,4-dihydro-pyrimidine-5-carboxylate) which is now in clinical phase 2. GLS4 demonstrated potent inhibitory activities in HBV HepG2.2.15 cell assay with an EC50 value of 1nM, and it also exhibited high potency against various drug-resistant HBV viral strains with EC50 values in the range of 10-20nM, more potent than the typical HBV polymerase inhibitors such as lamivudine, telbivudine, and entecavir. Pharmacokinetic profiles of GLS4 were favorable and safety evaluation including acute toxicity and repeated toxicity study indicated that GLS4 was safe enough to support clinical experiments in human.

Preclinical characterization of GLS4, an inhibitor of hepatitis B virus core particle assembly.

Hepatitis B virus (HBV)-associated chronic liver diseases are treated with nucleoside analogs that target the virus polymerase. While these analogs are potent, drugs are needed to target other virus-encoded gene products to better block the virus replication cycle and chronic liver disease. This work further characterized GLS4 and compared it to the related BAY 41-4109, both of which trigger aberrant HBV core particle assembly, where the virus replication cycle occurs. This was done in HepAD38 cells, which replicate HBV to high levels. In vitro, GLS4 was significantly less toxic for primary human hepatocytes (P < 0.01 up to 100 µM), inhibited virus accumulation in the supernantant of HepAD38 cells (P < 0.02 up to 100 nM), inhibited HBV replicative forms in the liver with a significantly lower 50% effective concentration (EC50) (P < 0.02), and more strongly inhibited core gene expression (P < 0.001 at 100 to 200 nM) compared to BAY 41-4109. In vivo characterization was performed in nude mice inoculated with HepAD38 cells, which grew out as tumors, resulting in viremia. Treatment of mice with GLS4 and BAY 41-4109 showed strong and sustained suppression of virus DNA to about the same extents both during and after treatment. Both drugs reduced the levels of intracellular core antigen in the tumors. Alanine aminotransferase levels were normal. Tumor and total body weights were not affected by treatment. Thus, GLS4 was as potent as the prototype, BAY 41-4109, and was superior to lamivudine, in that there was little virus relapse after the end of treatment and no indication of toxicity.

Measurement of Hounsfield units on proximal femur computed tomography for predicting regional osteoporosis.

OBJECTIVE: This study was designed to investigate the use of proximal femoral Hounsfield units (HU) in conventional abdominal and pelvic computed tomography (CT) to predict hip osteoporosis by coupling with data from quantitative CT (QCT). METHODS: In this study, 315 patients who underwent routine abdominal and pelvic CT with the proximal femur included in the scanning range were also subjected to QCT of the proximal femur. Pearson correlation test was performed to analyze the correlations of the femoral head, femoral neck, proximal femur, and femoral trochanter CT HU with the femoral neck, femoral trochanter, and intertrochanteric femur bone mineral density (BMD) values from QCT. The diagnostic performance of CT HU measurement of the proximal femur for osteoporosis was analyzed using receiver operating characteristic (ROC) curves. RESULTS: The CT HU of the proximal femur showed the highest correlation with the BMD value of the hip (r = 0.826; p < 0.01). The mean CT HU of the proximal femur differed significantly (all p < 0.01) for the three QCT-defined BMD categories of osteoporosis (192.23 HU vs. 188.71), of osteopenia (247.86 HU vs. 248.36 HU), and of normal individuals (308.13 HU vs. 310.41 HU) in left and right sides, respectively. In the ROC curve analysis, the area under the ROC curve values to predict osteoporosis in the left and right proximal femurs were 0.942 and 0.941, respectively. CONCLUSION: The CT HU of the proximal femur was significantly associated with the BMD value of the hip measured by QCT. The CT HU of the proximal femur is highly effective in diagnosing osteoporosis and could be used for hip osteoporosis screening.

(1) H and (13) C NMR assignments of four series bioactive pyrido[4,3-d]pyrimidine derivatives.

The complete (1) H and (13) C NMR assignments of four series pyrido[4,3-d]pyrimidine derivatives were achieved by combination of one and two-dimensional NMR experiments, and the NMR signals of these compounds were analyzed and compared.

Detection of COVID-19 With CT Images Using Hybrid Complex Shearlet Scattering Networks.

With the ongoing worldwide coronavirus disease 2019 (COVID-19) pandemic, it is desirable to develop effective algorithms to automatically detect COVID-19 with chest computed tomography (CT) images. Recently, a considerable number of methods based on deep learning have indeed been proposed. However, training an accurate deep learning model requires a large-scale chest CT dataset, which is hard to collect due to the high contagiousness of COVID-19. To achieve improved detection performance, this paper proposes a hybrid framework that fuses the complex shearlet scattering transform (CSST) and a suitable convolutional neural network into a single model. The introduced CSST cascades complex shearlet transforms with modulus nonlinearities and low-pass filter convolutions to compute a sparse and locally invariant image representation. The features computed from the input chest CT images are discriminative for COVID-19 detection. Furthermore, a wide residual network with a redesigned residual block (WR2N) is developed to learn more granular multiscale representations by applying it to scattering features. The combination of model-based CSST and data-driven WR2N leads to a more convenient neural network for image representation, where the idea is to learn only the image parts that the CSST cannot handle instead of all parts. Experiments on two public datasets demonstrate the superiority of our method. We can obtain more accurate results than several state-of-the-art COVID-19 classification methods in terms of measures such as accuracy, the F1-score, and the area under the receiver operating characteristic curve.

Radiomics Based on Lumbar Spine Magnetic Resonance Imaging to Detect Osteoporosis.

RATIONALE AND OBJECTIVES: Signal intensity of the lumbar spine in magnetic resonance imaging (MRI) correlates to bone mineral density (BMD). This study aims to explore a lumbar spine magnetic resonance imaging based on the radiomics model for detecting osteoporosis. MATERIALS AND METHODS: A total of 109 patients, who underwent both dual-energy X-ray absorptiometry (DEXA) and MRI of the lumbar spine, were recruited. Among these patients, 38 patients were normal, 32 patients had osteopenia, and 39 patients had osteoporosis, according to the DEXA results. A total of 396 × 2 radiomic features were extracted from the T1WI and T2WI images of the segmentation images in the lumbar magnetic resonance imaging. The correlated radiomic features were selected to establish the radiomic classification model. Then, the classification models (based on T1WI, T2WI, and T1WI+T2WI) of normal vs. osteopenia, normal vs. osteoporosis, and osteopenia vs. osteoporosis were established. The performance of the classification models was evaluated through the estimated area under the receiver operating characteristic curve. RESULTS: The area under the receiver operating characteristic curves based on T1WI, T2WI, and T1WI+T2WI were 0.772, 0.772, and 0.810, respectively, for the models of normal vs. osteopenia, 0.724, 0.682, and 0.797, respectively, for the models of normal vs. osteoporosis, and 0.730, 0.734, and 0.769, respectively, for the models of osteopenia vs. osteoporosis. CONCLUSION: Radiomic models established based on lumbar spine MRI can be used to detect osteoporosis.

A novel Apigenin derivative suppresses renal cell carcinoma via directly inhibiting wild-type and mutant MET.

MET, the receptor of hepatocyte growth factor (HGF), is a driving factor in renal cell carcinoma (RCC) and also a proven drug target for cancer treatment. To improve the activity and to investigate the mechanisms of action of Apigenin (APG), novel derivatives of APG with improved properties were synthesized and their activities against Caki-1 human renal cancer cell line were evaluated. It was found that compound 15e exhibited excellent potency against the growth of multiple RCC cell lines including Caki-1, Caki-2 and ACHN and is superior to APG and Crizotinib. Subsequent investigations demonstrated that compound 15e can inhibit Caki-1 cell proliferation, migration and invasion. Mechanistically, 15e directly targeted the MET kinase domain, decreased its auto-phosphorylation at Y1234/Y1235 and inhibited its kinase activity and downstream signaling. Importantly, 15e had inhibitory activity against mutant MET V1238I and Y1248H which were resistant to approved MET inhibitors Cabozantinib, Crizotinib or Capmatinib. In vivo tumor graft study confirmed that 15e repressed RCC growth through inhibition of MET activation. These results indicate that compound 15e has the potential to be developed as a treatment for RCC, and especially against drug-resistant MET mutations.

Access to Cycloalkeno[c]-Fused Pyridines via Pd-Catalyzed C(sp2)-H Activation and Cyclization of N-Acetyl Hydrazones of Acylcycloalkenes with Vinyl Azides.

A novel Pd(II)-catalyzed vinylic C-H activation and cyclization has been developed, reacting a series of small, medium, and large N-acetyl hydrazones of acylcycloalkenes with vinyl azides to access diverse cycloalkeno[c]-fused pyridine scaffolds. This protocol provides progress in C(sp2)-H bond activation of medium to large cycloalkenes, and the target products can be obtained in a specific regioselectivity with good functional group tolerance and a broad substrate scope.

Efficacy and Safety of All-oral Emitasvir and Sofosbuvir in Patients with Genotype 1b HCV Infections without Cirrhosis.

Background and Aims: Emitasvir is a new type of hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor, and the data of phase 2 trial has shown emitasvir-sofosbuvir to have good safety and tolerance. We conducted this phase 3 trial to further verify the efficacy and safety. Methods: We evaluated the antiviral activity and safety of a 12-week regimen of emitasvir phosphate (100 mg) combined with sofosbuvir (400 mg) once daily in non-cirrhotic patients with genotype 1 HCV infection. The primary endpoint was a sustained virological response at 12 weeks (SVR12) after the end of treatment. Results: Of the 362 patients enrolled in the trial, 39.8% were male, 99.2% had HCV genotype 1b, 0.8% had genotype 1a and 79.8% were treatment-naïve. The average age was 47.2 years. All patients completed the treatment and follow-up. All 3 patients with genotype 1a achieved SVR. Two genotype 1b treatment-naïve patients experienced virologic relapse. The rate of SVR12 was 99.7% (358/359), and SVR24 was 99.4% (357/359) in genotype 1b. Overall, 36.2% had resistance-associated substitutions (RASs) in NS5A and 98.3% had RASs in NS5B at baseline. The RASs at baseline had no effect on the rates of response. Serious adverse events were reported in 16 patients and were not related to emitasvir-sofosbuvir. Most adverse events did not require therapy. Conclusions: The 12 weeks of treatment with emitasvir-sofosbuvir was a highly efficient and safe treatment for a wide range of patients with HCV genotype 1b infection without cirrhosis, who had not been treated or who had been treated with interferon-based regimen previously.

A facile synthesis and biological activity of novel tetrahydrobenzo[4',5']thieno[3',2':5,6]pyrido[4,3-d]pyrimidin-4(3H)-ones.

The synthesis and biological activity of 2-substituted-8,9,10,11-tetrahydrobenzo[4',5']thieno[3',2':5,6] pyrido[4,3-d]pyrimidin-4(3H)-ones are described. Bioassay results indicated that these compounds have antifungal activity against Botrytis cinerea at a concentration of 50mg/L. In addition, compounds 5m and 5n were effective to both KB cells and their parent multidrug resistant KBv200 cells with the overexpression of ABCB1. For example, compound 5m showed the best inhibition against KB and KBv200 cells with IC(50) values of 17.4 and 25.4 microM, respectively.

Safety, Tolerability and Pharmacokinetics of Yimitasvir Phosphate Capsule, a Novel Oral Hepatitis C Virus NS5A Inhibitor, in Healthy Chinese Volunteers.

BACKGROUND AND OBJECTIVES: Yimitasvir is a novel oral hepatitis C virus non-structural protein 5A (NS5A) inhibitor. The aims of this first-in-human study were to evaluate the safety, tolerability and pharmacokinetics of single and multiple doses of yimitasvir in healthy adult Chinese volunteers and to assess the effect of food on yimitasvir pharmacokinetics. METHODS: Randomized, double-blind, placebo-controlled, single-ascending-dose (30, 100, 200 and 400 mg) and multiple-ascending-dose (100 and 200 mg once daily for 7 days) studies were performed in 32 and 24 subjects, respectively, in male and female adults. Additionally, the effect of food on yimitasvir pharmacokinetics was assessed with a crossover study in 15 male subjects. RESULTS: Yimitasvir was absorbed slowly after oral administration with a median time to maximum plasma concentration (Tmax) of 3.5-4.0 h. Increases in the maximum plasma concentration (Cmax) and area under the concentration-time curve from 0 to the last measurable time point (AUC0-t) were proportional to the dose of yimitasvir over a dose range of 30-100 mg, while increases were less than dose proportional over a dose range of 200-400 mg in part 1, indicating that absorption at the 200-mg dose was nearly saturated. The geometric mean terminal half-life of yimitasvir was 13.4-19.7 h in each cohort, supporting once-daily dosing. Faecal excretion of parent yimitasvir was the major route of elimination. Steady state was achieved following 5 days of dosing with minimal accumulation. A standardized high-fat meal decreased the rate and extent of absorption. All doses of yimitasvir were well tolerated. CONCLUSIONS: Yimitasvir, at single doses of 30-400 mg and multiple doses of 100-200 mg for 7 days, was well tolerated in healthy Chinese subjects. The results of this study formed the basis for the dosing schemes evaluated in a phase Ib study and subsequent phase II and phase III clinical studies. CLINICAL TRIAL REGISTRATION: This study was registered at the China Food and Drug Administration (Registration numbers: 2014L02064 and 2014L02065) and at http://www.chictr.org.cn (Nos. CTR20140854, CTR20150048 and CTR20150123).

3-((R)-4-(((R)-6-(2-Bromo-4-fluorophenyl)-5-(ethoxycarbonyl)-2-(thiazol-2-yl)-3,6-dihydropyrimidin-4-yl)methyl)morpholin-2-yl)propanoic Acid (HEC72702), a Novel Hepatitis B Virus Capsid Inhibitor Based on Clinical Candidate GLS4.

The inhibition of hepatitis B virus (HBV) capsid assembly is a novel strategy for the development of chronic hepatitis B (CHB) therapeutics. On the basis of the preclinical properties and clinical results of GLS4, we carried out further investigation to seek a better candidate compound with appropriate anti-HBV potency, reduced hERG activity, decreased CYP enzyme induction, and improved pharmacokinetic (PK) properties. To this end, we have successfully found that morpholine carboxyl analogues with comparable anti-HBV activities to that of GLS4 showed decreased hERG activities, but they displayed strong CYP3A4 induction in a concentration-dependent manner, except for morpholine propionic acid analogues. After several rounds of modification, compound 58 (HEC72702), which had an (R)-morpholine-2-propionic acid at the C6 position of its dihydropyrimidine core ring, was found to display no induction of the CYP1A2, CYP3A4, or CYP2B6 enzyme at the high concentration of 10 µM. In particular, it demonstrated a good systemic exposure and high oral bioavailability and achieved a viral-load reduction greater than 2 log in a hydrodynamic-injected (HDI) HBV mouse model and has now been selected for further development.

[The effect of the metallic dental materials on magnetic resonance imaging].

OBJECTIVE: To explore the influence of conventional metal materials in oral cavity on brain magnetic resonance imaging (MRI). METHODS: Four kinds of metal materials (metal ligature wire, forging hard and slotless denture, casting nichrome denture, casting copper alloy denture) in oral cavity were scanned through MRI. FSE sequence T1 weighted imaging (FSE T1), EPI diffusion-weighted imaging (DWI) sequence of ordinary, Propeller DWI imaging were used. RESULTS: In FSE T1 sequence, metal ligature wire and forging hard and slotless denture produced serious false image, casting nichrome denture produced moderate false image, casting copper alloy denture produced only little false image. In EPI DWI sequence, obvious magnetic-sensitive false image were produced in the dissection tissue of the brain by metal ligature wire. While in Propeller DWI sequence, magnetic-sensitive false image were greatly reduced and satisfactory images were formed. CONCLUSION: Different metal materials in oral cavity have different influence on the MRI. The false images produced by different metal materials are closely related to the type of the material. Magnetic-sensitive false images can be eliminated by Propeller DWI technique.

[The evaluation of virtual endoscopy and fiberoptic endoscopy in the diagnosis of obstructive sleep apnea syndrome].

OBJECTIVE: The utility of virtual endoscopy is compared to fiberoptic endoscopy and was also investigated with respect to accuracy of diagnosis and reproduction of images in patients with obstructive sleep apnea hypopnea syndrome (OSAHS). METHOD: Twenty-one patients with OSAHS were examined by helical spiral CT axial images and fiberoptic endoscopy. The helical spiral CT axial data was reconstructed using a VE software program. The results were compared to the fiberoptic endoscopic findings done by the otolaryngologists. All the patients were examined both in the sleeping and nonsleeping status. The dimensions of soft palate, uvula, lingua and epiglottis region were evaluated. RESULT: The results both in the virtual endoscopy evaluation and fiberoptic endoscopy was statistically significant difference in all of region. In the palate region, there was statistically significant difference in the left-and-right dimension, but no difference in the fore-and-aft dimension both in the sleeping and nonsleeping status. CONCLUSION: The dimensions of upper airway were more difference between in the sleeping and nonsleeping status. The change of dimension was more in the left-and-right; the fiberoptic endoscopy has more diagnostic significance in evaluation of dynamic movement of the upper airway; virtual endoscopy evaluation of the upper airway was accurate in assessing stenosis width and length; virtual endoscopy added more information about anatomic structure and pathological change of the upper airway.