Calix[4]arene Bridge Mononitration with tert-Butyl Nitrite: Synthesis of Bridging Chiral p-tert-Butylcalix[4]arene with a Mononitro Bridge Substituent.

To explore the reaction universality of bridge nitration, the mononitration of different p-tert-butylcalix[4]arene derivatives was executed with tert-butyl nitrite as a nitration reagent. The effects of calix[4]arene conformations, substituents on the lower rim, and reaction conditions on bridge mononitration are systematically studied. The bridge nitration of p-tert-butylcalix[4]arene derivatives in 1,3-alternate, 1,2-alternate, and partial cone conformations can be smoothly executed while that of p-tert-butylcalix[4]arene derivatives strictly regulated in a cone conformation cannot. The nitration product complexity shows a positive correlation with the bridge-hydrogen types, and the optimal bridge-mononitrated substrate is calix[4]arene with only one bridge-hydrogen type. The electron-withdrawing substituent on the lower rim is apparently beneficial for the bridge mononitration. As a result, a variety of bridging chiral p-tert-butylcalix[4]arenes with a mononitro bridge substituent have been successfully synthesized. The highest bridge-mononitrated yield can reach 27% from 1,3-alternate p-tert-butylcalix[4]arene biscrown-5 under optimal reaction conditions.

Retrospective Analysis of Clinicopathological Characteristics of Lacrimal Gland Pleomorphic Adenoma and Mechanism of Tumorigenesis by the Imbalance Between Apoptosis and Proliferation.

BACKGROUND Lacrimal gland pleomorphic adenoma (LGPA) is the most common clinically benign epithelial tumor of the lacrimal gland and is predominantly comprised of epithelial cells and interstitial components. At present, the exact pathogenesis of LGPA remains unclear. Previous research has indicated that the occurrence of LGPA may be related to excessive cell proliferation. MATERIAL AND METHODS This study observed the clinicopathological characteristics of LGPA and investigated the tumorigenesis mechanism of cell over-proliferation caused by the imbalance between apoptosis and proliferation. A total of 27 cases were collected from the Department of Ophthalmology of the Affiliated Hospital of Chengde Medical University and the Third Medical Center of Chinese PLA General Hospital from April 2017 to November 2019. Hematoxylin-eosin (HE) staining and immunohistochemical staining were used to observe the pathological characteristics and analyze the expression of bcl-2 and bax in the lacrimal gland. RESULTS Compared with normal lacrimal gland tissues, LGPA tumor tissues had obvious changes in pathological morphology. The expression of bcl-2 in LGPA lesion tissues was dramatically higher (P<0.001), the expression of bax was not significantly different between groups (P=0.25), but the ratio of bcl-2/bax was significantly higher in tumor tissues (P=0.01). CONCLUSIONS We found that the lacrimal gland tumor tissues had obvious excessive proliferation in pathomorphology, which revealed the necessity of complete surgical removal of the capsule from the perspective of pathological morphology and provided a theoretical basis for the hypothesis that the imbalance between apoptosis and proliferation could lead to cell hyperproliferation.

Mononitration of a Calix[4]arene Methylene Bridge: Synthesis and Preliminary Catalysis Performances of Bridging Chiral p-tert-Butylcalix[4]arenes with a Monoamino Bridge Substituent in a 1,3-Alternate Conformation.

In order to prepare bridging chiral p-tert-butylcalix[4]crown-5 with a mononitro bridge substituent in a 1,3-alternate conformation, a mononitration method of calix[4]arene bridging methylene has been first developed with tert-butyl nitrite as a nitration reagent. The effects of solvent, reaction temperature, reaction time, and nitration reagent dosage on bridge mononitration have been deeply explored to obtain an optimal nitration condition. The facile nitration presents a new key for calix[4]arene bridge derivatization. After further modification and diastereoisomeric resolution, a pair of bridging chiral p-tert-butylcalix[4]arenes with a monoamino bridge substituent were produced from the bridge-mono-nitrated calix[4]arene. Their preliminary catalysis results in the Henry reaction show good catalytic activities (up to 95% yield) and still low but obviously enhanced enantioselectivities (up to 22.3% ee from 7a, 6% ee from 1), which confirms that the structural transformation indeed improves asymmetric catalysis performances of bridging chiral calix[4]crown-5 amines in a 1,3-alternate conformation.

Diagnosis of lacrimal punctum lesions using optical coherence tomography: a preliminary study.

AIM: To study the imaging characteristics of lacrimal punctum lesion with optical coherence tomography (OCT), and provide imaging basis for the diagnosis and treatment of lacrimal punctum diseases. METHODS: A total of 25 patients (28 eyes) with epiphora and lacrimal puncta lesions were enrolled. Lacrimal puncta lesions included: punctum membrane obstruction in 7 cases (9 eyes), punctum agenesis in 1 case (1 eye), a mass protruded from the punctum in 1 case (1 eye), slit puncta in 1 case (1 eye), peri-puncta mass in 2 cases (2 eyes), chronic dacryocystitis in 4 cases (4 eyes), and primary puncta stenosis in 9 cases (10 eyes; 3 eyes mild, 4 eyes moderate and 3 eyes severe). All patients were examined by slit lamp microscopy and OCT to observe the morphological characteristics of abnormal punctum. RESULTS: Two types of complete membrane obstruction and incomplete membrane obstruction of puncta were observed in OCT images of 7 patients. No lacrimal punctum and lacrimal canalicular cavity were found in 1 case with punctum agenesis. OCT images showed that a narrow lumen remained in the lacrimal puncta in 1 patient with a mass protruded from the punctum. OCT of punctum in a patient with slit punctum after stent placement showed stent and abnormal lacrimal structure. No abnormal intraluminal structure was found in 2 cases of peri-puncta mass after OCT scan, and the lacunar space was narrower than that of the contralateral eye. OCT of puncta in 4 patients with chronic dacryocystitis showed that pus floated in tear with lump-like medium-low reflex. In 9 patients with primary lacrimal puncta stenosis, OCT image could clearly show the changes of puncta lumen in different degrees and shapes. CONCLUSION: OCT is feasible for the examination of pathological punctum, and can provide imaging basis for the diagnosis and treatment of punctum disease.

Design, synthesis and antifungal activity of threoninamide carbamate derivatives via pharmacophore model.

Thirty-six novel threoninamide carbamate derivatives were designed and synthesised using active fragment-based pharmacophore model. Antifungal activities of these compounds were tested against Oomycete fungi Phytophthora capsici in vitro and in vivo. Interestingly, compound I-1, I-2, I-3, I-6 and I-7 exhibited moderate control effect (>50%) against Pseudoperonospora cubensis in greenhouse at 6.25 µg/mL, which is better than that of control. Meanwhile most of these compounds exhibited significant inhibitory against P. capsici. The other nine fungi were also tested. More importantly, some compounds exhibited remarkably high activities against Sclerotinia sclerotiorum, P. piricola and R. solan in vitro with EC50 values of 3.74-9.76 µg/mL. It is possible that the model is reliabile and this method can be used to discover lead compounds for the development of fungicides.

Design, synthesis, biological evaluation and molecular dynamics studies of 4-thiazolinone derivatives as protein tyrosine phosphatase 1B (PTP1B) inhibitors.

Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of insulin signaling pathway, and more and more studies have shown that it is a potential target for the treatment of type 2 diabetes mellitus (T2DM). In this study, 17 new 4-thiazolinone derivatives were designed and synthesized as novel PTP1B inhibitors, and ADMET prediction confirmed that these compounds were to be drug-like. In vitro enzyme activity experiments were performed on these compounds, and it was found that a plurality of compounds had good inhibitory activity and high selectivity against PTP1B protein. Among them, compound 7p exhibited the best inhibitory activity with an IC50 of 0.92 µM. The binding mode of compound 7p and PTP1B protein was explored, revealing the reason for its high efficiency. In addition, molecular dynamics simulations for the PTP1BWT and PTP1Bcomp#7p systems revealed the effects of compound 7p on PTP1B protein at the molecular level. In summary, the study reported for the first time that 4-thiazolinone derivatives as a novel PTP1B inhibitor had good inhibitory activity and selectivity for the treatment of T2DM, providing more options for the development of PTP1B inhibitors. AbbreviationsBBBblood-brain barrierCDC25Bcell division cycle 25 homolog BCYP2D6Cytochrome P450 2D6 bindingDCCMdynamic cross-correlation mapDSDiscovery StudioH bondhydrogen bondHIAhuman intestinal absorptionLARleukocyte antigen-related phosphataseMDmolecular dynamicsMEG-2maternal-effect germ-cell defective 2MM-PBSAmolecular mechanics Poisson Boltzmann surface area)PCAprincipal component analysisPDBProtein Data BankpNPPp-nitrophenyl phosphatePPBplasma protein bindingPTP1Bprotein tyrosine phosphotase 1BRMSDroot mean square deviationRMSFroot mean square fluctuationSHP-1src homologous phosphatase-1SHP-2src homologous phosphatase-2SPCsingle-point chargeTCPTPT cell protein tyrosine phosphataseT2DMType 2 diabetes mellitusVDWvan der WaalsCommunicated by Ramaswamy H. Sarma.

The design of novel inhibitors for treating cancer by targeting CDC25B through disruption of CDC25B-CDK2/Cyclin A interaction using computational approaches.

Cell division cycle 25B is a key cell cycle regulator and widely considered as potent clinical drug target for cancers. This research focused on identifying potential compounds in theory which are able to disrupt transient interactions between CDC25B and its CDK2/Cyclin A substrate.By using the method of ZDOCK and RDOCK, the most optimized 3D structure of CDK2/Cyclin A in complex with CDC25B was constructed and validated using two methods: 1) the superimposition of proteins; 2) analysis of the hydrogen bond distances of Arg 488(N1)-Asp 206(OD1), Arg 492(NE)-Asp 206(OD1), Arg 492(N1)-Asp 206(OD2) and Tyr 497(NE)-Asp 210(OD1). A series of new compounds was gained through searching the fragment database derived from ZINC based on the known inhibitor-compound 7 by the means of "replace fragment" technique. The compounds acquired via meeting the requirements of the absorption, distribution, metabolism, and excretion (ADME) predictions. Finally, 12 compounds with better binding affinity were identified. The comp#1, as a representative, was selected to be synthesized and assayed for their CDC25B inhibitory activities. The comp#1 exhibited mild inhibitory activities against human CDC25B with IC50 values at about 39.02 µM. Molecular Dynamic (MD) simulation revealed that the new inhibitor-comp#1 had favorable conformations for binding to CDC25B and disturbing the interactions between CDC25B and CDK2/Cyclin A.

Content comparison of four constituents in aqueous extract of three Psoraleae Fructus processed products / 中成药

AIM To compare the effects of sealed moistening with brine,simple stir-frying and stir-frying with brine on the contents of psoralen,psoralen,psoralen and psoralen in Psoraleae Fructus aqueous extract.METHODS The HPLC analysis of aqueous extract was performed on a 30 ℃ thermostatic Hibar C1s column (250 mm × 4.6 mm,5 μm),with the mobile phase comprising of 0.1％ formic acid-methanol flowing at 1.0 mL/min in a gradient elution manner,and the detection wavelength was set at 246 nm.RESULTS Compared with the raw product,the contents of glycosides and total components in the product processed with sealed moistening with brine were significantly decreased.Stir-frying with brine could significantly promote the dissolution of glycosides (psoralen and psoralen),but had no significant effect on that of aglycones (psoralen and isopsoralen).Simple stirfrying markedly increased the contents of various constituents.CONCLUSION Both simple stir-frying and stir-frying with brine can significantly increase the total content of four constituents in Psoraleae Fructus aqueous extract.

Content comparison of four constituents in aqueous extract of three Psoraleae Fructus processed products / 中成药

AIM To compare the effects of sealed moistening with brine,simple stir-frying and stir-frying with brine on the contents of psoralen,psoralen,psoralen and psoralen in Psoraleae Fructus aqueous extract.METHODS The HPLC analysis of aqueous extract was performed on a 30 ℃ thermostatic Hibar C1s column (250 mm × 4.6 mm,5 μm),with the mobile phase comprising of 0.1％ formic acid-methanol flowing at 1.0 mL/min in a gradient elution manner,and the detection wavelength was set at 246 nm.RESULTS Compared with the raw product,the contents of glycosides and total components in the product processed with sealed moistening with brine were significantly decreased.Stir-frying with brine could significantly promote the dissolution of glycosides (psoralen and psoralen),but had no significant effect on that of aglycones (psoralen and isopsoralen).Simple stirfrying markedly increased the contents of various constituents.CONCLUSION Both simple stir-frying and stir-frying with brine can significantly increase the total content of four constituents in Psoraleae Fructus aqueous extract.

Epidemiological characteristics of imported malaria and influencing factors of severe cases in Anhui Province / 中国血吸虫病防治杂志

Objective To analyze the epidemiological characteristics of imported malaria cases and investigate the influenc-ing factors of severe cases in Anhui Province,so as to provide the evidence for improving the control strategy. Methods The ep-idemiological data of imported malaria cases in Anhui Province from January 1st,2012 to April 18th,2017 were collected and analyzed. Results The imported malaria cases in Anhui Province were mainly young men of migrant workers. There were im-ported malaria cases in 79％(83/105)of counties(districts)in Anhui Province. . Totally 686 imported malaria cases were re-corded,in which there were 62 severe cases(9.04％),and four death cases with the mortality rate of 0.58％. The age,educa-tion,initial diagnosed departments,initial diagnosed results,time from onset to seeing a doctor,and time from seeing a doctor to diagnosis were the influencing factors for the severe cases. Conclusion The proportion of severe imported malaria cases is high in Anhui Province. The monitoring sensitivity,clinician's awareness of malaria diagnosis,and health education for migrant workers should be improved.

Synthesis, biological evaluation and 3D-QSAR studies of imidazolidine-2,4-dione derivatives as novel protein tyrosine phosphatase 1B inhibitors.

Protein tyrosine phosphatase 1B (PTP1B) plays a vital role in the regulation of insulin sensitivity and dephosphorylation of the insulin receptor, so PTP1B inhibitors may be potential agents to treat type 2 diabetes. In this work, a series of novel imidazolidine-2,4-dione derivatives were designed, synthesized and assayed for their PTP1B inhibitory activities. These compounds exhibited potent activities with IC50 values at 0.57-172 µM. A 3D-QSAR study using CoMFA and CoMSIA techniques was carried out to explore structure activity relationship of these molecules. The CoMSIA model was more predictive with q(2) = 0.777, r(2) = 0.999, SEE = 0.013 and r(2)pred = 0.836, while the CoMFA model gave q(2) = 0.543, r(2) = 0.998, SEE = 0.029 and r(2)pred = 0.754. The contour maps derived from the best CoMFA and CoMSIA models combined with docking analysis provided good insights into the structural features relevant to the bioactivity, and could be used in the molecular design of novel imidazolidine-2,4-dione derivatives.

Related research on corneal higher-order aberrations after different ways refractive surgery / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the changes of corneal high - order aberration (including Coma, Spab, RMSh) after laser in situ keratomileusis (LASIK) with femtosecond laser, sub- Bowman keratomileusis ( SBK ) and laser epithelial keratomileusis (LASEK). METHODS: Of 82 myopic patients ( 164 eyes ), 31 patients (62 eyes) were treated by FS-LASIK, 31 patients (62 eyes) were treated by SBK, 20 patients (40 eyes) were treated by LASEK. Sirius system was used for measuring the coma aberration, spherical aberration, and high order aberration at 1, 15d,1, 3mo after surgery. RESULTS: 1) Vision: The uncorrected visual acuity of the three groups had no differences (P>0. 05). 2) Corneal aberrations: Three kinds of surgical procedure for patients with corneal aberration had significant impact. The C7, C8, C12 and RMSh of three groups were increased significantly (P<0. 05). The C7, C8, C12 and RMSh were not recovered to preoperative levels after 3mo. But the increase of patients after FS- LASIK was smaller than the other two groups, with statistical significance (P<0. 05). CONCLUSION: Compared with SBK and LASEK, FS - LASIK has better visual acuity in the early postoperative and corneal higher-order aberrations increase is relatively small.

Design novel inhibitors for treating cancer by targeting Cdc25B catalytic domain with de novo design.

The cell division cycle 25 (Cdc25) family of proteins is a group of highly conserved dual specificity phosphatases that regulate cyclin-dependent kinases and represent a group of attractive drug targets for anticancer therapies. To develop novel Cdc25B inhibitors, the ZINC database was screened for finding optimal fragments with de novo design approaches. As a result, top 11 compounds with higher binding affinities in flexible docking were obtained, which were derived from five novel scaffolds (scaffold C) consisting of the linker-part and two isolated scaffolds (scaffold A and B)located in the two binding domains (catalytic pocket and swimming pool), respectively. The subsequent molecular docking and molecular dynamics studies showed that these compounds not only adopt more favorable conformations but also have stronger binding interaction with receptor than the inhibitors identified previously. The additional absorption, distribution, metabolism, excretion and toxicity (ADMET) predictions also indicted that the 11 compounds (especially Comp#1) hold a high potential to be novel lead compounds for anticarcinogen. Consequently, the findings reported here may at least provide a new strategy or useful insights for designing effective Cdc25B inhibitors.

Design potential selective inhibitors for treating cancer by targeting the Src homology 2 (SH2) domain-containing phosphatase 2 (Shp2) with core hopping approach.

Due to the vital role in many cell regulatory processes, such as cell cycle control, survival and apoptosis, as well as growth and neurotransmitter signaling, Src homology 2 (SH2) domain-containing phosphatase 2(Shp2) has attracted considerable attention for developing drugs to treat cancers. In this study, by means of the powerful "core hopping" technique, a novel class of inhibitors was discovered based on the compound II-B08. It was observed by molecular dynamics simulations that these novel inhibitors not only possessed the same function as II-B08 did in inhibiting Shp2, but also had stronger binding to the receptor. It was further validated by the outcomes of their ADME (absorption, distribution, metabolism, and excretion) predictions that the new inhibitors hold high potential to become promising drug candidates for developing novel and powerful drugs for anticancer. Subsequently, in vitro evaluation of promising hits revealed a novel and selective inhibitor of Shp2.

Design and synthesis of imidazolidine-2,4-dione derivatives as selective inhibitors by targeting protein tyrosine phosphatase-1B over T-cell protein tyrosine phosphatase.

Owing to its special role as a negative regulator in both insulin and leptin signaling, protein tyrosine phosphatase-1B (PTP1B) has drawn considerable attention as a target for treating type 2 diabetes and obesity. It, however, is a great challenge to discover inhibitors specific to each PTP due to the highly homologous. In this study, a series of compounds were discovered to inhibit PTP1B based on imidazolidine-2,4-dione by means of 'core hopping'. A selective PTP1B inhibitor (comp#h) was identified, and molecular dynamics simulation and binding free energy calculation were carried out to propose the most likely binding mode of comp#h with PTP1B. The findings reported here may provide a new strategy in discovering selective and effective inhibitors for treating diabetes.

A series of propofol analogs design by targeting pentameric ligand-gated ion channel in silico method.

The crystal complex propofol/GLIC (the bacterial homologue from Gloeobacter violaceus) recently determined also showed sensitivity to general anesthetics, belonging to the pLGIC (pentameric ligand-gated ion channels) family as a homopentameric member, which are potentiated and inhibited by general anesthetics and mimic changes elicited by anesthetics in physiologic targets as ion channels, providing the useful information for general anesthetics and allosteric modulators design. Thirteen active compounds selected from the previous data sets are used as reference and seed structures for developing novel general anesthetics via the scoring function of lead optimization using pharmacophoric & shape similarity integrated in Muse™ molecular design workflow. Autodock4.0 is validated its accuracy by two computational procedures and used for docking calculations in this study. Finally, the top ten invented propofol analogs reported here exhibit more favorable binding energies geometric matching than propofol. Especially, the comp#1 fits the binding site well in geometric shape with the lowest binding energy than any other compounds, and makes the hydrophobic interaction with the binding site formed by M4 helixes and lipids of receptor as well. More importantly, the interactions between ligand and lipids caused by general-anesthetic binding would be specially considered in novel general anesthetic design. accordingly, the findings reported here may provide useful insights for discovering more effective general anesthetics.

Synthesis, structure and insecticidal activities of some novel amides containing N-pyridylpyrazole moeities.

In our search for environmentally benign insecticides with high activity, low toxicity and low residue, a novel series of amides containing N- pyridylpyrazole moieties were designed and synthesized. The structures of the title compounds were characterized and confirmed by 1H-NMR and elemental analysis. Furthermore, the structure of compound 7l was determined by single crystal X-ray diffraction. The preliminary bioassay tests showed that some of them exhibited good insecticidal activities against Mythimna separata Walker, Plutella xylostella (Linnaeus, 1758) and Laphygma exigua Hübner.

Ethyl 4-[(4-chloro-phen-oxy)meth-yl]-2-(4-nitro-phen-yl)-1,3-thia-zole-5-carboxyl-ate.

The title compound, C(19)H(15)ClN(2)O(5)S, contains two mol-ecules (A and B) in the asymmetric unit. In mol-ecule A, the dihedral angles between the thia-zole ring and the pendant chloro-benzene and nitro-benzene rings are 72.14 (15) and 3.03 (15)°, respectively. The corresponding angles for mol-ecule B are 45.56 (16) and 1.51 (14)°, respectively. In the crystal, both mol-ecules form inversion dimers linked by pairs of weak C-H⋯O inter-actions.

Synthesis and biological evaluation of isosteric analogs of mandipropamid for the control of oomycete pathogens.

A series of isosteric analogs of mandipropamid were designed and synthesized via 'click chemistry'. The amide bond of mandipropamid was substituted by a 1,2,3-triazole functional group. The bioassay results have indicated that some of the title compounds exhibited moderate fungicidal activity against Pseudoperonospora cubensis, and the activity has been systematically studied as a function of molecular structure. The low activity of the mandipropamid analog that contains a lipid chain is likely due to the presence of a weak hydrogen bond donor in the 1,2,3-triazole. Furthermore, we have performed the molecular modeling and found that N-methylamide could be more effective than amide as the surrogates to 1,2,3-triazole, which ultimately leads to a longer distance (1.1 Å longer) between the two substitutes in the 1,4-disubstituted 1,2,3-triazole compound.

Three new powerful oseltamivir derivatives for inhibiting the neuraminidase of influenza virus.

Owing to its unique function in assisting the release of newly formed virus particles from the surface of an infected cell, neuraminidase, an antigenic glycoprotein enzyme, is a main target for drug design against influenza viruses. The group-1 neuraminidase of influenza virus possesses a 150-cavity, which is adjacent to the active pocket, and which renders conformational change from the 'open' form to the 'closed' form when the enzyme is binding with a ligand. Using AutoGrow evolutionary algorithm, one very unique fragment is screened out from the fragment databases by exploiting additional interactions with the 150-cavity. Subsequently, three derivatives were constructed by linking the unique fragment to oseltamivir at its three different sites. The three derivatives thus formed show much stronger inhibition power than oseltamivir, and hence may become excellent candidates for developing new and more powerful drugs for treating influenza. Or at the very least, the findings may stimulate new strategy or provide useful insights for working on the target vitally important to the health of human beings.